Ballroom                              07:30 – 8:20                                                                                        Chair: Vivian S. Lee, ISMRM President

7:30                    Welcome and Awards Presentations

2009 MANSFIELD LECTURE

Ballroom                              08:20 – 9:00                                                                                       Chair:  Vivian S. Lee, ISMRM President

8:20                    Brain Energy & Brain Work

Robert G. Shulman, Ph.D.

Yale University School of Medicine, New Haven, CT, USA

PLENARY LECTURES
Stroke: A Forward Looking Retrospective on the Role of MR

Ballroom                              09:00-09:50                                                                Moderators: Jeffry R. Alger and Fernando Calamante

09:00         1.           Multiparametric MR Guidance of Acute Stroke Treatment

A. Gregory Sorensen 1

1Massachusetts General Hospital, Charlestown, MA, USA

MRI has become a standard method for diagnosing acute ischemic stroke. The development of diffusion MRI, perfusion MRI, MRA, and other techniques have provided tremendous insight into the pathophysiology of stroke and offered substantial improvements in patient management. Advances in hardware, pulse sequences, and post-processing methods are still needed to fully exploit the opportunities that MR provides to improve patient outcomes. This lecture will review the successes as well as the unmet needs in stroke, with an eye to both validation of existing methods and development of newer approaches.

09:25         2.           The Role of MR in Promoting Long Term Recovery from Stroke

Rudiger J. Seitz 1

1Heinrich-Heine-University, Dusseldorf, Germany

Stroke recovery is a dynamic process which can be monitored with MR imaging. Recovery starts in the acute state of the disease with rapid arterial recanalization of the occluded cerebral artery. In the manifest infarct lesion, functional reorganization represents the physiological basis for training-related recovery. Reorganization has a perilesional and a bihemispheric aspect. The participation of the non-affected, contralesional hemisphere is critically modulated by an abnormal interhemispheric balance. Successful recovery shares similarities with learning and results in a normalization of the cerebral activation patterns.

CLINICAL INTENSIVE COURSE
(Admission limited to Clinical Intensive Course registrants only)
Advances in Musculoskeletal MRI

Room 310                             08:20-10:15                                    Moderators:  Garry E. Gold, Elmar M. Merkle, and Lynne S. Steinbach

08:20       MSK MRI: Technical Considerations 
                Garry E. Gold

 

09:15       MRI of the Shoulder Instability
                Christine Chung

 

09:45       Routine 3D Imaging of the Joints

Richard Kijowski

 

11:15       Break and poster viewing

Garry E. Gold, Guide

CLINICAL INTENSIVE COURSE
Breast MRI

Room 310                             11:00 - 13:00                                                                                                           Moderator:  Clare Tempany

Educational Objectives:
Upon completion of this course, participants should be able to:

•  Interpret MRI findings with a detailed understanding of the pathological correlates in breast disease;
•  Compare the pros and cons of use of 1.5T and 3T devices and design protocols that will apply to their patient population; and
•  Predict treatment response with MR findings for women after surgery, chemotherapy or before, during and after focused ultrasound surgery.

 

11:00       MR and Pathological Characterization of Breast Cancer 
                Eva C. Gombos

 

11:30       Breast MRI Update on New Techniques 3T vs. 1.5T
                Mark A. Rosen

 

12:00       Assessment of Treatment Response

Constance D. Lehman

 

12:30       MR Guided Breast FUS

Kiyoshi Namba

 

Lung Imaging

Room 316A                         11:00-13:00                                                      Moderators: Bastiaan Driehuys and Tessa Sundarem Cook

11:00         3.           Young Investigator Award Finalist: Three Dimensional Imaging of Ventilation Dynamics in Obstructive Lung Disease

James H. Holmes1, Rafael L. O'Halloran1, Ethan K. Brodsky1,2, Thorsten A. Bley2, Christopher J. Francois2, Julia V. Velikina1, Ronald L. Sorkness3, William W. Busse3, Sean B. Fain1,2

1Department of Medical Physics, University of Wisconsin-Madison, Madison, WI, USA; 2Department of Radiology, University of Wisconsin-Madison, Madison, WI, USA; 3Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA

Whole-lung 3D imaging of respiration dynamics and gas trapping in asthma is demonstrated using hyperpolarized He-3 gas in combination with an accelerated data acquisition and constrained reconstruction. This technique enables the acquisition of a wealth of information on inflow and exhalation kinetics as well as breathhold ventilation defects, while readily accommodating individual patients’ breathhold capabilities, all within a single comprehensive maneuver. Volunteer studies show agreement with plethysmography and MDCT. However, an advantage of this technique is that it enables regional depiction of dynamic gas trapping in a setting more comparable to a spirometry maneuver, unlike MDCT.

11:20         4.           Single Acquisition Time-Resolved T2* Mapping in Lungs Using HYPR 3He MRI

Katarzyna Cieslar1, Achraf Al Faraj1, Sophie Gaillard1, Yannick Crémillieux1

1Université de Lyon, CREATIS-LRMN, UMR CNRS 5220 INSERM U630, Lyon, France

Local T2* measurement of HP 3He in the lung can serve as a potential diagnostic biomarker of tissue microstucture changes. Standard T2* mapping protocol at different lung inflation state involves multiple gas inhalations. In this study, T2* mapping protocol combining HYPR reconstruction and spontaneous breathing ventilation was implemented. The protocol, validated on rats, was designed for single acquisition of multiple echo time ventilation images obtained at different inflation states of the lung. The variations of T2* measured at different breathing phases at tidal volume demonstrate the sensitivity of the technique for detecting changes in the 3He physical environment.

11:32         5.           Single Breath-Hold 3D Q-Space Imaging of Lung Structures Using He-3 MRI

Rafael Luis O'Halloran1, James H. Holmes1,2, Yu-Chien Wu3,4, Andrew L. Alexander1, Sean B. Fain1,4

1Medical Physics, University of Wisconsin, Madison, WI, USA; 2Applied Science Laboratory, GE Healthcare, Waukesha, WI, USA; 3Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin, Madison, WI, USA; 4Radiology, University of Wisconsin, Madison, WI, USA

A 3D undersampled stack-of-stars q-space MRI acquisition using hyperpolarized helium-3 was performed in asthmatic adults (n=10), healthy adults (n=4), and healthy children (n=3). Q-space data were fit to a Gaussian function providing maps of the mean structure size. The mean structure size in the adult subjects was 333 ± 23 µm, while the structure size in the children was 312 ± 9 µm agreeing with the known age dependence of lung structure size. The acquisition was also performed in a healthy volunteer at three inhalation volumes. Structure size was observed to increase with lung volume.

11:44         6.           In Vivo Lung Elastography with Hyperpolarized Helium-3 MRI

Xavier Maître1, Ralph Sinkus2, Roberta Santarelli1, Mathieu Sarracanie1, Rose-Marie Dubuisson1, Emeline Boriasse1, Emmanuel Durand1, Luc Darrasse1, Jacques Bittoun1

1Unité de Recherche en Résonance Magnétique Médicale (UMR8081), Univ Paris-Sud, CNRS, Orsay, France; 2Laboratoire Ondes et Acoustique (UMR 7587), ESPCI, Univ Denis Diderot, CNRS, Paris, France

The viscoelastic properties of human tissue depend on its structures, biological conditions, and related pathologies. In the lung parenchyma, these properties participate in the basic function of the organ. They are dramatically altered by diseases like cancer, emphysema, asthma, or interstitial fibrosis. Besides tactual exploration, there is no other non-invasive technique to assess such changes. This work aims to produce a novel measurement tool based on magnetic resonance imaging of hyperpolarised helium-3 to monitor the mechanical properties of the lung, which allow mapping of its compliance and relating it to pathology. We demonstrate its feasibility in vivo.

11:56         7.           Compressed Sensing for Hyperpolarized 3He 3D ADC Measurements

Lise Vejby Søgaard1, Torsten Dorniok1, Frederik Hengstenberg1,2, Sergei Karpuk3, Jørgen Vestbo2, Per Åkeson1, Peter Magnusson1

1Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital, Hvidovre, Denmark; 2Department of Cardiology and Respiratory Medicine, Copenhagen University Hospital, Hvidovre, Denmark; 3Institute of Physics, University of Mainz, Germany

The feasibility of applying compressed sensing methods to hyperpolarized 3He apparent diffusion coefficient measurements was investigated. Fully sampled 3D k-space data from one healthy subject and three COPD patients were undersampled and reconstructed by compressed sensing methods. We expect that the method can be used to either decrease scan time (breath-hold) or increase spatial resolution which will be especially important in longitudinal studies of lung disease progression.

12:08         8.           Parallel Acquisition as a Key for Rapid High Resolution 3He-ADC Imaging

Maxim V. Terekhov1, Julien Rivoire1, Florian M. Meise1, Davide Santoro1, Wolfgang G. Schreiber1

1Department of Diagnostic and Interventional Radiology, Section of Medical Physics, Mainz University Medical School, Mainz, Germany

Apparent Diffusion Coefficient (ADC) of hyperpolarized 3He-gas in lungs is a proven method of non-invasive probing the integrity of the lung’s microstructure. The essential problem of efficiency of 3He-ADC-imaging as the diagnostic tool is the poor localisation of integrity defects due to low spatial resolution of ADC-maps. The purpose of current work is to demonstrate the possibilities, provided by the phased-array parallel acquisition (32ch) for improving the efficiency of 3He ADC-measurements including creating full-3D ADC-maps. The second important task is making comparison of different methods of reconstruction the undersampled imaging datasets (e.g. mSENSE and GRAPPA) to get optimal quality ADC-image.

12:20         9.           Compartment-Selective XTC MRI at 1.5T and 3T

Kai Ruppert1, Yulin Chang1, Talissa A. Altes1, Isabel M. Dregely2, Stephen Ketel3, Iulian C. Ruset2,3, Jaime F. Mata1, F William Hersman2,3, John P. Mugler III1

1Radiology, University of Virginia, Charlottesville, VA, USA; 2Physics, University of New Hampshire, Durham, NH, USA; 3Xemed LLC, Durham, NH, USA

Hyperpolarized xenon-129 spectroscopy has revealed at least two dissolved-phase compartments in the lung: xenon bound to hemoglobin and xenon dissolved in lung tissue and blood plasma. In this work we demonstrate the feasibility of obtaining gas-phase depolarization maps in humans using Xenon polarization Transfer Contrast (XTC) MRI by selectively inverting the magnetization in one of the two compartments. Preliminary results at 1.5T and 3T are presented. These findings will considerably increase the specificity of XTC MRI for the detection of pathological lung function changes.

12:32         10.         Non-Constrast Enhanced MRI of Lung Perfusion and Ventilation by Fourier Decomposition

Grzegorz Bauman1, Michael Puderbach2, Michael Deimling3, Vladimir Jellus3, Christophe Chefd'hotel4, Hans-Ulrich Kauczor5, Lothar Schad6

1Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany; 2Department of Radiology, German Cancer Research Center, Heidelberg, Germany; 3Siemens Healthcare, Erlangen, Germany; 4Siemens Corporate Research, Princeton, NJ, USA; 5Department of Diagnostic Radiology, University Hospital Heidelberg, Heidelberg, Germany; 6Computer Clinical Assisted Medicine, University of Heidelberg, Mannheim, Germany

We showed the feasibility and reproducibility of a novel approach for non-contrast enhanced perfusion and ventilation assessment in proton MRI. The Fourier Decomposition method was implemented on a 1.5T clinical MR scanner and applied in a healthy volunteer study. A fast steady-state free precession (SSFP) pulse sequence was used to produce 2D time-resolved data stacks. Non-rigid image registration and spectral analysis of the data allowed separating the signal from the lung parenchyma and pulsative blood to generate ventilation and perfusion maps. The presented method requires only minimal patient compliance and is not dependent on triggering techniques.

12:44         11.         Ultra-Short Echo Time (UTE) MR Imaging of the Lung: Comparison  Between Normal and Emphysematous Mice

Masaya Takahashi1, Osamu Togao1, Makoto Obara2, Marc van Cauteren2, Yoshiharu Ohno3, Craig Malloy1, Makoto Kuro-o4, Ivan Dimitrov1,5

1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; 2Philips Electronics Japan, Tokyo, Japan; 3Radiology, Kobe University Graduate School of Medicine, Hyogo, Japan; 4Pathology, University of Texas Southwestern Medical Center, Dallas, TX, USA; 5Philips Medical Systems, Cleveland, OH, USA

The recent development of techniques has made possible detailed, non-invasive imaging of pulmonary parenchyma. The utility of ultra-short TE (UTE) imaging in conjunction with projection acquisition of the free inducting decay helps to acquire the MR signal from the lung parenchyma. It allows us to reduce TE up to less than 100 µsec to minimize signal decay caused by short T2 relaxation time, and brings high SNR rather than a conventional FFT short echo image sequence. Here we report our measure of short T2 relaxation time of the lung in the wild-type and emphysematous mice using three-dimensional UTE imaging.

fMRI:  Acquisition Methods

Room 323ABC                    11:00-13:00                                                          Moderators: Luis Hernandez-Garcia and Hanzhang Lu

11:00         12.         Functional MRI Using Arteriolar Cerebral Blood Volume Changes

Jun Hua1, Qin Qin1, Manus J. Donahue2, Jinyuan Zhou1, James J. Pekar1, Peter CM van Zijl1

1Dept. of Radiology, The Johns Hopkins University, Baltimore, MD, USA; 2Dept. of Clinical Neurology, University of Oxford, Oxford, UK

Vascular changes during functional brain activity occur predominantly in the arterioles, and an MRI method sensitive to such changes is expected to improve spatial and temporal specificity for fMRI. Vascular-space-occupancy (VASO) fMRI is a blood-nulling approach assessing total CBV changes. We introduce an approach called “inflow VASO” or “iVASO”, which nulls only blood flowing into the slice. By using a blood-nulling time comparable to arterial transit times (~700ms), iVASO signal was sensitized to predominantly arteriolar blood volume effects. This arteriolar character was subsequently reflected in an effectively immediate hemodynamic response for iVASO when studying visual activation.

11:12         13.         Neuronal Activity-Induced Cerebral Blood Volume Changes in Humans: Measurements with VASO and VERVE

Claire Cohalan1, Jean J. Chen1, G. Bruce Pike1

1McConnell Brain Imaging Center, Montréal Neurological Institute, McGill University, Montréal, Québec, Canada

The vascular-space-occupancy (VASO) technique targets changes in total cerebral blood volume (CBV), whereas the venous-refocusing for volume-estimation (VERVE) technique measures changes in venous CBV, which is more relevant for BOLD. In this work, ΔCBV measurements acquired in healthy humans using both techniques were compared. VASO produced a higher contrast-to-noise ratio and larger ΔCBV values than VERVE, as expected since VERVE measures only venous CBV changes. VERVE-based activation was more correlated with BOLD activation, since BOLD is sensitive to the venous compartment. Though the VASO technique is easier to implement, its signal potentially has many contributions other than CBV, and eliminating these contaminants is difficult, but necessary.

11:24         14.         Whole-Brain Non-Invasive Hemodynamic Imaging, Enabled by a Novel CBV-Weighted Single-Shot 3D VASO-FLAIR GRASE Sequence Combined with CBF-Weighted ASL and BOLD FMRI, Identifies Regional Hemodynamic and Metabolic Discrepancies

Manus J. Donahue1, Jakob U. Blicher2, Bradley J. MacIntosh1, Karla L. Miller1, Leif Ostergaard2, David A. Feinberg3,4, Matthias Guenther3, Peter Jezzard1

1Clinical Neurology, The University of Oxford, Oxford, UK; 2Center for Functionally Integrative Neuroscience, Arhus University Hospital, Arhus, Denmark; 3Advanced MRI Technologies, Sebastopol, CA, USA; 4University of California at Berkeley, Berkeley, CA, USA

VASO-FLAIR magnetization preparation, previously limited to single-slice imaging, is appended to a single-shot 3D-GRASE readout to generate whole-brain CBV-weighted maps. CBV-weighted courses are compared to BOLD and CBF-weighted ASL during and following motor and visual stimulation. The 3D-GRASE VASO-FLAIR approach gives similar CBV traces to those found from single-slice techniques and corresponds well with BOLD and ASL. Following stimulation, the BOLD post-stimulus undershoot is larger and endures longer in visual cortex compared to motor cortex, whereas CBV and CBF returns to baseline at the same time.

11:36         15.         3D Single-Shot VASO FMRI Using a Maxwell-Gradient Compensated GRASE Sequence

Benedikt Andreas Poser1,2, David G. Norris1,2

1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany; 2Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands

The VASO sequence was recently proposed as first fMRI method capable of detecting activation related CBV changes without the need for a contrast agent. We here present a new whole-brain VASO technique based on a parallel-accelerated single-shot 3D GRASE sequence. A flow-compensated correction scheme for concomitant Maxwell gradients is introduced, and shown to be an essential feature for 3D GRASE sequences at 3T if smearing artifacts due to violation of the CPMG condition in off-resonance excitation are to be avoided. The effectiveness of the new method demonstrated in fMRI studies with visuo-motor stimulation, and a cognitive Stroop task paradigm.

11:48         16.         Studies of BOLD Signal Characteristics Using a Modified HASTE Sequence with GRAPPA

Yongquan Ye1, Yan Zhuo1, Rong Xue1, Dehe Weng1,2, Xiaohong Joe Zhou3

1State Key Laboratory of Brain and Cognitive Science, Institute of Biophysics, CAS, Beijing, China; 2Siemens Mindit Magnetic Resonance Ltd., Shenzhen, China; 3University of Illinois Medical Center, Chicago, IL, USA

Turbo spin echo (TSE) has been proposed as an alternative to echo planar imaging (EPI) for fMRI. We have used a modified HASTE (mHASTE) sequence with GRAPPA to investigate TSE signal characteristics in fMRI and compared the results with gradient-echo and spin-echo EPI. mHASTE exhibited reliable and consistent activation with higher SNR than EPI and minimal artifacts. More interestingly, we have observed evidence suggesting that BOLD signals in mHASTE can be dominated by extravascular contributions around microvascular networks, which offers more accurate localization of neurofunctional activities.

12:00         17.         A Parallel Transmission Method for Improved BOLD FMRI

Weiran Deng1, Cungeng Yang1, Vijayanand Alagappan2, Lawrence L. Wald2, V A. Stenger1

1University of Hawaii JABSOM, Honolulu, HI, USA; 2Harvard University Martinos Center for Biomedical Imaging, Charlestown, MA

Susceptibility-induced gradients at the air/tissue interface above the sinus regions create signal voids in axial slices of the orbitofrontal cortex (OFC) in BOLD fMRI. We present a parallel transmission technique to recover signal in the OFC with a customized four-channel TR array. A slice-selection pulse with a unique time shift is applied into each channel. Signal recovery and increased BOLD activation in the OFC is demonstrated during a breath-holding task at 3T.

12:12         18.         Comparison of Template and Individual-Based Gradient Compensated EPI in Regions Affected by Local Susceptibility-Induced Signal Loss

Jochen Rick1, Oliver Speck2, Olaf Dössel3, Jürgen Hennig1, Maxim Zaitsev1

1Dept. of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany; 2Biomedical Magnetic Resonance, Otto-von-Guericke University, Magdeburg, Germany; 3Institute of Biomedical Engineering, University Karlsruhe (TH), Karlsruhe, Germany

Anatomy-related susceptibility gradients in the human head lead to artefacts in echo planar imaging (EPI). The use of a slice-dependent common gradient compensation template improves fMRI sensitivity in areas affected by strong susceptibility gradients. This study evaluates the concept through a comparison between four groups (no compensation, common template (member), common template (not member), individual). In general the signal improvement of the three compensated cases is about 35%. No significant variations are present between these cases. Thus, it seems possible to use this method for functional experiments without repeating the calibration individually, thus saving adjustment and calculation time.

12:24         19.         Robust Detection of Functional Activation in the Superior Colliculus Without ECG-Triggering

Ute Goerke1, Kamil Ugurbil1

1Radiology, CMRR/University of Minnesota Medical School, Minneapolis, MN, USA

In fMRI, high spatial resolution is usually achieved by segmenting the echo-planar imaging (EPI) acquisition scheme. However, such images are susceptible to ghosting due to pulsatile flow of blood and cerebrospinal fluid (CSF), especially in regions near the brain stem. We propose a novel post processing technique, the spectral side band analysis (SSBA), to detect activation in deep brain structures without the need of ECG-triggering. This is demonstrated in a high resolution fMRI study of the superior colliculus stimulated with a visual paradigm.

12:36         20.         Simultaneous Monitoring of Tongue Tip Movements in Functional MRI Motor Tasks for Speech and Swallowing Studies

Bradley P. Sutton1,2, Charles A. Conway1, David P. Kuehn3

1Bioengineering Department, University of Illinois at Urbana-Champaign, Urbana, IL, USA; 2Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, IL, USA; 3Speech and Hearing Science, University of Illinois at Urbana-Champaign, Champaign, IL, USA

A pulse sequence is developed that acquires images of dynamic movement of the tongue during speech or swallowing simultaneously with the acquisition of functional MRI data. A single midsagittal dynamic slice is acquired at 16 frames per second while several oblique axial functional slices are acquired with lower temporal resolution and functional MRI contrast. The acquisition allows for real-time monitoring of task performance without the need for, or interference from, additional monitoring hardware. The sequence is shown to detect similar activations of the primary motor cortex in a self-paced compared to a cued tongue-tapping task.

12:48         21.         Investigating the Whole Brain with 1.5mm Isotropic Resolution and 1.5s TRs Using Highly Accelerated High-Field FMRI

Cheryl A. Olman1,2, Steen Moeller2, Jennifer F. Schumacher3, Serena K. Thompson3, Edward J. Auerbach2, Kamil Ugurbil2, Essa Yacoub2

1Psychology, University of Minnesota, Minneapolis, MN, USA; 2Radiology, University of Minnesota, Minneapolis, MN, USA; 3Neuroscience, University of Minnesota, Minneapolis, MN, USA

Neuroscientists who want to take advantage of the higher spatial resolutions afforded by the increased SNR and CNR at 7 Tesla do not want to sacrifice temporal resolution in exchange for whole-brain coverage with high spatial resolution. A multi-band acquisition at 7T (simultaneous excitation of 4 coronal slices) permits whole-brain coverage with higher spatial and temporal resolutions than previously feasible. In this study we measure whole-brain activation patterns during a visual object recognition task with 1.5 mm spatial resolution and 1.5 s temporal resolution. Whole-brain, high-resolution fMRI is therefore possible with temporal resolutions sufficient for event-related designs.

Coronaries & Aorta:  Lumen & All

Room 313A                         11:00-13:00                                                                                   Moderators: Matthias Stuber and Qi Yang

11:00         22.         3T Contrast-Enhanced Whole Heart Coronary MRA Using 32-Channel Cardiac Coils for the Detection of Coronary Artery Disease

Qi Yang1, Kuncheng Li1, Xiaoming Bi2, Jing An3, Feng Huang4, Renate Jerecic2, Debiao Li5

1Radiology, Xuanwu Hospital, Beijing, China; 2Siemens Medical Solutions; 3Siemens Mindit Magnetic Resonance Ltd; 4Invivo Corporation; 5Northwestern University

Higher study success rate achieved by 32-channel coils substantially improved overall accuracy of 3T coronary MRA in detecting coronary artery disease when using the intention to diagnose method.

11:12         23.         In Vivo Human Coronary Magnetic Resonance Angiography at 7 Tesla

Saskia Gerdina Cornelia van Elderen1, Andrew G. Webb1, Maarten J. Versluis1, Jos J.M. Westenberg1, Joost Doornbos1, Nadine B. Smith1, Albert de Roos1, Matthias Stuber2

1Radiology, Leiden University Medical Centre, Leiden, Netherlands; 2Radiology, Johns Hopkins University Medical School, Baltimore, USA

Coronary MRA has been implemented on a 7 tesla human system and tested on eleven volunteers. Adaptations from protocols at lower field strengths include the optimization of navigators, fat suppression and vector ECG placement, as well as volume selective power optimization using a transmit/receive surface coil due to the absence of available body coils at 7 tesla. MRA’s were successfully obtained from all subjects, allowing quantitative measurements of RCA diameter and length, as well as vessel sharpness.

11:24         24.         3.0T Whole Heart Coronary MR Angiography Performed as a Part of Comprehensive Contrast Enhanced CMR Study.

Motonori Nagata1, Hajime Sakuma1, Nanaka Ishida1, Shingo Kato1, Hiroshi Nakajima2, Masaki Ishida1, Katsuya Onishi2, Masaaki Ito2, Kan Takeda1

1Radiology, Mie University hospital, Tsu, Mie, Japan; 2Cardiology, Mie University hospital, Tsu, Mie, Japan

Whole heart coronary MRA at 3T was acquired in 52 patients with suspected CAD as apart of comprehensive CMR study. After acquiring perfusion MRI and late gadolinium enhanced MRI, navigator-echo gated, 3D-TFE images were obtained with a patient-specific narrow acquisition window (57.9ms}26.8). Acquisition of MRA was successfully completed in all 52 patients, with averaged imaging time of 11.4 } 4.5 minutes. On a vessel based analysis, the sensitivity, specificity and NPV were 88%, 97% and 97%, respectively. 3.0 T coronary MRA performed as a part of comprehensive cardiac MR study is useful for ruling out significant CAD.

11:36         25.         Contrast-Enhanced Whole-Heart Coronary MRA at 1.5T in Less Than 5 Minutes Using Gradient Echo Interleaved EPI and Double Dose of Gd-DTPA

Himanshu Bhat1, Sven Zuehlsdorff2, Xiaoming Bi2, Xin Liu1, Renate Jerecic2, Debiao Li1

1Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, USA; 2Siemens Medical Solutions, Chicago, IL, USA

A gradient echo interleaved EPI (GRE-EPI) sequence was optimized for contrast-enhanced whole-heart coronary MRA at 1.5T in a scan time less than 5 minutes. This is approximately a factor of 2 reduction in scan time compared to current whole-heart TrueFISP protocols. The reduced scan time made it feasible to acquire images with a more commonly used contrast agent Gd-DTPA instead of high relaxivity contrast agent Gd-BOPTA.

11:48         26.         Are We Reconstructing the Best Images Using Navigator-Gated 3D Coronary MRA?  Multiple-Image Reconstruction Using CLAWS

Permi Jhooti1, Jennifer Keegan2, Klaus Scheffler1, David Firmin2

1Radiological Physics, University Hospital Basel, Basel, Switzerland; 2CMR Unit, Royal Brompton Hospital, London, UK

A technique is presented which acquires a 3D-whole heart scan in the quickest time possible for any respiratory trace (p=ns) and enables 3 images to be reconstructed: the most-frequent 5mm navigator window, an end-expiratory image and an end-inspiratory image. Previous techniques require manual window selections which may not be optimal for scan efficiency or image quality. This modified CLAWS approach enables multiple-image reconstruction in the same acquisition time as for a single image. It is not possible to predict which image will be best. A multi-image technique is therefore optimal, particularly as there is no scan time loss.

12:00         27.         Association of Coronary Calcification and Carotid Artery Morphology: A High Resolution Magnetic Resonance Imaging Study

qian zhao1, Xihai Zhao2, Feiyu Li2, Qingjun Wang1, Zulong Cai1, Chun Yuan2, Jianming Cai1

1Department of radiology, PLA General Hospital, Beijing, China; 2Department of radiology, University of Washington, Seattle, WA, USA

Atherosclerosis has been shown a systematic disease which often involves multiple arterial vascular beds. Recently, a number of studies demonstrated a significant correlation between coronary and carotid atherosclerosis. This study sought to evaluate the association between coronary calcification and carotid artery morphology. The results showed moderate to strong correlation between coronary calcium score detected by CT and carotid morphological measurements by MRI. It indicates that patients with high coronary calcium score may have big plaque burden in carotid arteries. Coronary calcium score as a marker of coronary disease is potentially capable of predicting carotid atherosclerosis.

12:12         28.         Multi-Slice Breathhold Phase-Sensitive Coronary Vessel Wall Imaging at 3T

Khaled Z. Abd-Elmoniem1, Matthias Stuber1

1Department of Radiology, Johns Hopkins University, Baltimore, MD, USA

Black-blood coronary vessel wall imaging is a powerful non-invasive tool for the quantitative assessment of atherosclerotic positive arterial remodeling. Although dual-inversion-recovery (DIR) is the current standard for black-blood coronary vessel wall imaging, optimization of lumen-vessel wall contrast is associated with competing requirements related to TI* (blood signal nulling time), TD (period of minimal myocardial motion), and heart rate. Because of these constraints, the collection of multi slice data during the same cardiac cycle is not easily possible. For these reasons, we have exploited phase-sensitive dual-inversion recovery (PS-DIR) and combined it with a multi-slice spiral signal readout for black-blood coronary vessel wall imaging. Phantom and in vivo data are discussed.

12:24         29.         Diagnostic Impact of Aortic MRI at 3Tesla in Acute Stroke Patients

Andreas Harloff1, Stefanie Brendecke1, Jan Simon1, Wolf Wallis1, Dawit Assefa2, Thomas Helbing2, Alex Frydrychowicz3, Johannes Weber4, Cornelius Weiller1, Jürgen Hennig3, Michael Markl3

1Neurology, University Hospital Freiburg, Freiburg, Germany; 2Cardiology and Angiology, University Hospital Freiburg, Freiburg, Germany; 3Diagnostic Radiology, MR Physics, University Hospital Freiburg, Freiburg, Germany; 4Neuroradiology, University Hospital Freiburg, Freiburg, Germany

The purpose of this study was to evaluate a dedicated multi-contrast 3D MRI protocol for the reliable detection of aortic high-risk plaques in the entire thoracic aorta of acute stroke patients. Findings were compared with transesophageal echocardiography (TEE).

12:36         30.         In Vivo Volumetric MRI in Drug Discovery: A Preclinical Study of the Ezetimibe Therapeutic Efficacy on Atherosclerotic Plaque Burden in the Thoracic Ascending Arterial Tree in ApoE-/- Mice

Haiying Tang1, Ching H. Chang2, Donna Suresch1, Lesley A. Mcnamara2, Christopher Tong3, Bernd Misselwitz4, Dan Zhou1, Brett M. Connolly1, Jing Xu5, Xun Chen2, Xiaolan Shen6, Chunlian Zhang1, Eric L. Rickes2, Michelle Mariano6, Karim Azer5, Jun Wang2, Cyrille Sur1, Donald S. Williams1, Michael Klimas1, Andrew S. Plump1, Richard Hargreaves1, Haiying Liu1

1Imaging, Merck Research Laboratories, Rahway, NJ, USA; 2Cadiovascular Disease, Merck Research Laboratories, Rahway, NJ, USA; 3Biometrics, Merck Research Laboratories, Rahway, NJ, USA; 4TRG Diagnostic Imaging, Bayer Schering Pharma AG., Berlin, Germany; 5Applied Computer Science & Math, Merck Research Laboratories, Rahway, NJ, USA; 6LAR, Merck Research Laboratories, Rahway, NJ, USA

Volumetric MRI of atherosclerotic plaque in the thoracic ascending arterial tree may provide valuable insight into disease progression and therapeutic responses. In this study, in vivo MRI was validated to demonstrate the effectiveness of a potent cholesterol absorption inhibitor, ezetimibe, on the inhibition of the progression of atherosclerosis. Atherosclerotic plaque burden changes in apoE-/- mouse were monitored by longitudinal MRI using a plaque targeting contrast agent Gadofluorine-M. MRI plaque burden quantitation and therapeutic responses were validated by biological approaches. The volumetric data were evaluated to determine the most sensitive biomarker through univariate analysis of plaque volume, area, and thickness measurements.

12:48         31.         Complex Plaques in the Descending Aorta as a Potential Source of Stroke – Visualization of Potential Retrograde Flow Into the Supra-Aortic Arteries Using Multi-Directional 4D Velocity Mapping at 3 Tesla

Andreas Harloff1, Jan Simon1, stefanie Brendecke1, Wolf Wallis1, Dawit Assefa2, Alex Frydrychowicz3, Johannes Weber4, Jürgen Hennig3, Cornelius Weiller1, Michael Markl3

1Neurology, University Hospital Freiburg, Freiburg, Germany; 2Cardiology and Angiology, University Hospital Freiburg, Freiburg, Germany; 3Diagnostic Radiology, MR Physics, University Hospital Freiburg, Freiburg, Germany; 4Neuroradiology, University Hospital Freiburg, Freiburg, Germany

Detection of the precise localization of plaques in the descending aorta using 3D MRI in combination with multi-directional 4D velocity mapping was used to systematically analyze retrograde embolic pathways within the aorta of acute stroke patients. Similar distribution of descending aortic plaque distance and extent of retrograde flow indicate the potential for retrograde embolization in these patients. Particularly, we assessed how frequently the brachiocephalic trunk, the left common carotid and/or subclavian artery were reached by individual flow channels originating directly at the atheroma in the descending aorta.

Multiparametric Approaches to Clinical Stroke Imaging

Room 311                             11:00-13:00                                                                       Moderators: Jeffry R. Alger and Lawrence Latour

11:00         32.         Comparison of ASL and PWI Perfusion in Stroke Patients

Esben Thade Petersen1,2, Tchoyoson C.C. Lim2, N Venketasubramanian2, Xavier Golay2,3

1Center of Functionally Integrative Neuroscience, University of Aarhus, Aarhus, Denmark; 2National Neuroscience Institute, Singapore; 3Institute of Neurology, University College London, UK

One obvious problem of ASL in stroke imaging is the limited duration of the label, which makes it arguable whether ASL will have a chance as compared to PWI when it comes to penumbra estimation and subsequent risk-benefit weighting of possible intervention. In this work we show that ASL acquired at multiple time-points provides similar information to PWI in the affected areas. In addition, ASL can probe the existence of collateral perfusion and combined they could potentially be valuable in this risk assessment. However it still remains to future studies of hyperacute stroke to tell whether ASL can prove sufficient.

11:12         33.         3 T Pulsed Arterial Spin Labeling MRI Reveals Perfusion Deficits in Patients with Minor Stroke or Transient Ischaemic Attack

Bradley J. MacIntosh1, Alistair C. Lindsay2, Ilias Kylintireas2, Justin M. Lee2, Matthew D. Robson2, James Kennedy3, Robin P. Choudhury2, Peter Jezzard1

1Clinical Neurology, FMRIB Centre, Oxford, Oxfordshire, UK; 2Department of Cardiovascular Medicine, John Radcliffe; 3Acute Stroke Programme, Nuffield Department of Clinical Medicine, John Radcliffe

Dynamic susceptibility contrast (DSC) is the clinical-standard perfusion MRI technique for acute ischaemic stroke. Arterial spin labeling (ASL) is a complementary non-invasive perfusion MRI technique and has demonstrated promise in a limited number of clinical ASL studies. The purpose of the current study is test the feasibility of acute multiple-inflow pulsed ASL in a group of minor stroke patients. An automated clustering technique is used to visualise voxels where the arterial transit times are delayed and produce low CBF levels. We argue that ASL has the sensitivity to detect perfusion deficits even in patients that have low impairment.

11:24         34.         Comparison of CBF Measurement by ASL and SPECT in Patients with Internal Carotid Artery Stenosis.

Yoshito Uchihashi1, Kohkichi Hosoda1, Ivan Zimine2, Atsushi Fujita1, Satoshi Inoue1, Hideo Aihara1, Hideaki Kawamitsu3, Nobukazu Aoyama3, Hajime Aoki3, Masahiko Fujii3, Eiji Kohmura1

1Dept. of OrganTherapeutics, Neurosurgery, Kobe University graduate school of Medicine, Kobe, Hyogo, Japan; 2Philips Healthcare Japan; 3Dept. of Radiology, Kobe University graduate school of Medicine, Kobe, Hyogo, Japan

ASL tecknique provide quantative CBF measurement of brain perfusion in good agreement with SPECT which is already established method for making decision for Neurosurgical interventions.

11:36         35.         Predictive Value of Structural Integrity of Affected Corticospinal Tracts in Motor Function Outcome of Affected Upper Extremities in Patients with Subcortical Ischemic Stroke: A Diffusion Spectrum Imaging Tractography Study

Miao-Chi Lo1, Yi-Hsin Ko2, Pei-Fang Tang2,3, Wen-Yih Isaac Tseng1,4

1Center for Optoetectronic Biomedicine, National Taiwan University College of Medicine, Taipei, Taiwan; 2School and Graduate Institute of Physical Therapy, National Taiwan University College of Medicine, Taipei, Taiwan; 3Physical Therapy Center, National Taiwan University Hospital, Taipei, Taiwan; 4Department of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan

We used diffusion spectrum imaging (DSI) tractography to investigate whether the structural integrity of the corticospinal tract (CST) of the affected upper extremity can predict the motor outcome in patients with subcortical ischemic stroke. The entire CST of each subject was reconstructed and the mean generalized fractional anisotropy (GFA) values of the tract were analyzed. The tract-specific quantitative analysis of the relative GFA (rGFA) values of different segments of bilateral CSTs was derived to indicate the structural integrity of CST in various segments. The rGFA values in the IC segment of CST at D30 were highly correlated with the FMA-UE scores at D180 (N = 7, r = -.802, p = .030). In conclusion, the structural integrity of the affected CST early after stroke appears to have predictive value for late motor recovery.

11:48         36.         Predicting Tissue Outcome in Acute Ischemic Stroke Using Projection Pursuit Regression

Kartheeban Nagenthiraja1, Kristjana Yr Jonsdottir1, Leif Østergaard1, Kim Mouridsen1

1Dept. of Neuroradiology, Århus University Hospital, CFIN, Århus C, Denmark

We have presented a flexible procedure for predicting final tissue outcome combining a dimension reduction method with efficient regression modeling of the resulting low-dimensional projections using smooth non-linear ridge functions. Increase in performance was observed for PPR notably in single-subject models, while performance in data pooled across patients was similar to LR, possibly owing to increased heterogeneity (reperfusion status, time of scan). We speculate that PPR in combination with techniques for identifying homogenous patient subgroups could further improve quantification of regional risk of infarct progression.

12:00         37.         ADC Values in the Corticospinal Tract at the Acute Stage Can Help Predict Stroke Outcome

Charlotte Rosso1,2, Olivier Colliot2, Christine Delmaire3, Romain Valabregue3, Sylvain Baillet2, Sophie Crozier1, Didier Dormont2,4, Yves Samson1, Stéphane Lehéricy3,4

1Stroke Center, Pitie Salpetriere Hospital, University Pierre and Marie Curie, Paris, France; 2Cognitive neuroscience and Brain Imaging Laboratory, CNRS-UPR 640 LENA, Pitie Salpetriere Hospital, University Pierre and Marie Curie, Paris, France; 3Center for NeuroImaging Research, Pitie Salpetriere Hospital, University Pierre and Marie Curie, Paris, France; 4Department of Neuroradiology, Pitie Salpetriere Hospital, University Pierre and Marie Curie, Paris, France

We used DWI and ADC maps acquired in the first six hours of stroke onset-H6 and the day after-D1 to predict ischemic stroke outcome at three months in 76 patients. Normalized ADC maps were analyzed for differences between patients with good and poor outcome. ADC values in the corticospinal tract were measured in both groups and used to classify patients according to outcome. ADC values were lower in the CST of patients with poor than patients with good outcomes at both examinations (p<0.05). ADC values in the “damaged” CST predicted outcome with 65% accuracy at H6 and 71% at D1.

12:12         38.         Identifying Stroke Patients Most Likely to Benefit from Reperfusion Therapy Using Acute MRI

Ona Wu1,2, Søren Christensen2, Niels Hjort2, Anders Neumann2, A Gregory Sorensen1, Gotz Thomalla3, Jens Fiehler4, Thomas Kucinski4, Joachim Rother3, Leif Østergaard2

1Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA; 2Center for Functionally Integrative Neuroscience, Aarhus University Hospital, Aarhus, Denmark; 3Neurology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; 4Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Identification of patients most likely to benefit from reperfusion therapy is a key question in the management of acute stroke patients. Algorithms combining DWI/PWI for predicting infarction in stroke patients (< 6h) were trained on patients receiving standard non-thrombolytic treatment and then applied to patients who received thrombolysis. Predicted lesion volumes were significantly higher in patients without early reperfusion compared to patients who did reperfuse. Our results show that for patients given thrombolytic therapy, the likelihood of reperfusion depends on the degree and extent of the ischemic injury at the time of treatment, which we measured using multiparametric predictive algorithms.

12:24         39.         Oxygen Metabolic Index as a Predictor of Tissue Viability in Acute Ischemic Stroke Patients

Hongyu An1, Andria L. Ford2, Katie Vo3, William J. Powers4, Jin-Moo Lee2, Weili Lin1

1Radiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; 2Neurology, Washington University in St. Louis, St. Louis, MO, USA; 3Radiology, Washington University in St. Louis, St. Louis, MO, USA; 4Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA

We have utilized MR_OMI to assess the cerebral oxygen metabolic activity sequentially (<3.5 hours and at 6 hours) in hyper-acute stroke patients. By using the reperfusion and final infarct status, tissue with different outcomes (dead or alive) were examined in regions either with or without reperfusion. We found that dead tissue had much lower MR_OMI values than alive tissue independent of reperfusion status, suggesting that MR_OMI is capable of predicting tissue outcome in hyper-acute ischemic stroke.

12:36         40.         Diffusion Time Dependent Kurtosis Maps Visualize Ischemic Lesions in Stroke Patients

Jimmy Lätt1, Danielle van Westen1, Markus Nilsson2, Ronnie Wirestam2, Freddy Ståhlberg2,3, Stig Holtås1,3, Sara Brockstedt1,2

1MR Department, Center for Medical Imaging and Physiology, Lund University Hospital, Lund, Sweden; 2Department of Medical Radiation Physics, Lund University, Lund, Sweden; 3Department of Diagnostic Radiology, Lund University, Lund, Sweden

Diffusion time dependence of the diffusion weighted signal for high b-values in ischemic stroke lesions was recently reported, allowing for the extraction of more information on the tissue microstructure. Here, we express the diffusion time dependence as a change kurtosis, where kurtosis reflects the degree of deviation from free diffusion. The changes in kurtosis for different diffusion times were calculated for nine ischemic stroke patients, examined at a 3T clinical scanner. The change in kurtosis successfully visualized the lesions. Changes in kurtosis are suggested to reflect changes in cell sizes as well as in cell physiology (cellular membrane functionality).

12:48         41.         Functional MRI Exploration of Visuospatial Attention in Acute Neglect and Non-Neglect Stroke Patients

Roza M. Umarova1, Dorothee Saur2, Christoph Kaller1, Magnus-Sebastian Vry1, Volkmar Glauche2, Irina Mader3, Cornelius Weiller1

1Department of Neurology, University Medical Center , Freiburg, Germany; 2Department of Neurology, University Medical Center, Freiburg, Germany; 3Department of  Neuroradilogy, University Medical Center , Freiburg, Germany

We aimed to explore what distinguishes patients with and without neglect after acute stroke in the right hemisphere using fMRI with visuospatial attention task. Patients without neglect showed spared function of key attentional centers in the left hemisphere and post-Rolandic structures in the right hemisphere. Neglect patients presented a down-regulation in most of attentional centers, while the infrequent left targets detection correlated with involvement of the left hemisphere structures. Thus, the spared function of the attention relevant regions in non-neglect patients enabled the modulation of the right primary and association visual areas with a subsequent left targets detection.

Ultrahigh Field & High Resolution Neuroimaging

Room 316BC                       11:00-13:00                                                              Moderators: Joseph J. H. Ackerman and Kamil Ugurbil

11:00         42.         Investigating the Sources of Phase Contrast: Iron Oxide Nanoparticle Study to Exclude Deoxyhemoglobin as a Major Source for the Gray/white Matter Phase Contrast

Jongho Lee1, Yoshiyuki Hirano, Masaki Fukunaga1, Afonso Silva, Jeff H. Duyn1

1Advanced MRI/LFMI/NINDS, National Institute of Health, Bethesda, MD, USA

An intravascular contrast agent (iron oxide nanoparticle) was used to investigate the sources of phase contrast. The result indicates that deoxy-hemoglobin is not a major source for the white and gray matter contrast.

11:12         43.         Susceptibility Weighted Imaging of the Human Brain at 9.4T

Juliane Sabine Budde1, Rolf Pohmann1, Gunamony Shajan1, Kâmil Ugurbil2

1Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tuebingen, Germany; 2Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA

Susceptibility weighted imaging benefits from ultra-high field in terms of increased contrast-to-noise ratio and SNR. High resolution phase images with up to 0.175mm x 0.175mm in-plane resolution were acquired at a 9.4T scanner using a 3D velocity compensated gradient echo sequence. The images, covering almost the whole brain area, show excellent susceptibility weighted contrast and SNR. Compared to 3T images with an in-plane resolution of 0.45mm x 0.50mm acquired in about the same scan time, a qualitative improvement can be observed and a greatly increased number of small veins can be visualized at 9.4T.

11:24         44.         Presurgical Visualization of Cerebral Surface Veins with Susceptibility Weighted Imaging

Zeinab Al-Rekabi1,2, Kelly McPhee3, Kevin Fitzpatrick3,4, Bruce Bjornson3,5, Alexander Rauscher3,6

1University of British Columbia , Vancouver, BC, Canada; 2University of Ottawa, Ottawa, Ontario, Canada; 3University of British Columbia, Vancouver, BC, Canada; 4Children's Brain Mapping Centre, BC Children's Hospital; 5Children's Brain Mapping Centre, BC Children's Hospital and Child & Family Research Institute; 6UBC MRI Research Centre

Susceptibility Weighted Imaging combines magnitude and phase of a high resolution fully flow-compensated 3D gradient echo scan, from which detailed images of the cerebral venous vasculature can be obtained without using a contrast agent. Due to the required high pass filtering of the phase, visualization of veins at the brain's surface has been poor. We used bilateral filtering to preserve vein related phase information at the brain's surface, by minimizing blurring across boundaries between brain and noise. A combination of resulting surface venograms with a structural scan provides images of the brains

surface with venous vessels as landmarks for surgery.

11:36         45.         Susceptibility and T2/T1 Weighted Contrast Enhancements in Rat Brain Using BSSFP at 9.4T

Joseph S. Gati1, L Martyn Klassen1, Robert Bartha1, Ravi S. Menon1

1CFMM, Robarts Research Institute, London, Ontario, Canada

Balanced steady-state free precession (bSSFP) pulse sequences have found widespread use at clinical field strengths, particularly for cardiac applications, because of short acquisition times, high contrast and increased signal to noise characteristics compared to similarly acquired gradient echo (GRE) methods. We have previously demonstrated there to be a greater than 3 times signal to noise advantage, per unit time, using a fully optimized bSSFP sequence over a similarly matched gradient echo acquisitions. The current study demonstrates unique image contrast at high magnetic field strength observed in both high resolution ex vivo and in vivo rat brain images.

11:48         46.         Cortical Layers Imaging with Inversion Recovery MRI

Daniel Barazany1, Ory Levy1, Yaniv Assaf1

1Department of Neurobiology, Tel Aviv University, Tel Aviv, Israel

Cyto-architecture is a histological features that delineate the neuronal morphology of the tissue in general and layers in cortex in particular. Currently there is no in-vivo imaging modality that enables accurate and robust visualization of neuronal cell structures. In this work we use a multi-parametric MRI and clustering approach to segment the cortex into a laminar pattern based on multi-spectral inversion recovery dataset. This approach was implemented on the rat brain and compared with cyto-architectonic analysis; there is a good agreement between the MRI layers and histological identification of the layers. Similar results were also obtained on the human brain.

12:00         47.         Within Gray and White Mater R2* Variations Correlate Histochemical Iron Stain of the Human Brain

Masaki Fukunaga1, Jongho Lee1, Tie-Qiang Li, Kant K. Matsuda2, Hellmut Merkle, Peter van Gelderen1, Jacco A. de Zwart1, Jeff H. Duyn1

1Advanced MRI/LFMI/NINDS, National Institutes of Health, Bethesda, MD, USA; 2Laboratory of Pathology/NCI, National Institutes of Health, Bethesda, MD, USA

High resolution T2* weighted MRI at high field strength shows substantial contrast variation across laminae in cortical gray matter. This contrast variation also exist within cortical gray matter and subcortical white matter. In this work, to assess the contribution of non-heme iron and myelin in the R2* variations, we investigated the similarity of R2* map and histochemical stained image of the human brain. The contrast variation of R2* map highly corresponded to iron stain than myelin stain, it demonstrates that possible main contributor of R2* variation is non-heme iron.

12:12         48.         Detection and Delineation of Focal Cortical Lesions in Patients with Focal Epilepsy: Preliminary Results at 7T and 3T with 32 Channel Phased Arrays

Neel Madan1, Thomas Benner2, Elizabeth Anne Thiele3, Emad N. Eskandar4, Lawrence L. Wald2,5, Patricia Ellen Grant1,2

1Department of Pediatric Radiology, Massachusetts General Hospital, Boston, MA, USA; 2A.A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Boston, MA, USA; 3Pediatric Epilepsy Service, Department of Neurology, Massachusetts General Hospital, Boston, MA, USA; 4MGH-HMS Center for Nervous System Repair, Department of Neurosurgery, Massachusetts General Hospital, Boston, MA, USA; 5Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, USA

Identification of focal cortical dysplasias (FCD) on MRI is critical in the management of patients with medically refractory epilepsy. In this study, four patients with known or suspected FCD were imaged at 7T and 3T with 32 channel phased array coils. High resolution imaging allowed characterization and delineation of tissue involvement in three of the patients. These two technologies complemented each other in defining lesion boundary and characterizing the involved tissue. Both 7T and 3T with 32 channel coil hold great promise as a problem solving tool for lesion identification in those patients with “MR negative” medically refractory epilepsy.

12:24         49.         Three-Dimensional Segmentation of the Internal Structures of the Human Hippocampus  at 7 Tesla

Marie Chupin1, Stephane Lehericy2,3, Olivier Colliot1, Malgorzata Marjanska4, Ute Goerke4, Kamil Ugurbil4, Pierre-Francois Van de Moortele4

1CNRS UPR 640 - LENA, University Pierre and Marie Curie - Paris 6, Paris, France; 2Center for NeuroImaging Research, University Pierre and Marie Curie - Paris 6, Paris, France; 3Neuroradiology, Inserm U610, Pitie-Salpetriere Hospital, Paris, France; 4Center for Magnetic Resonance Research and Department of radiology, University of Minnesota, Minneapolis, MN, USA

In this work, we used 7T whole body to image and segment in three dimension the internal structure of the human hippocampus. Three human volunteers were included. Six subparts of the hippocampus were clearly differentiated including the stratum pyramidale of the cornu ammonis (CA), more precisely the first 3 segments of CA (CA1-3), the hilum of the dentate (corresponding to the dentate proper and CA4), the subiculum, the alveus and the fimbria. Segmentation of the internal structure of the hippocampus at 7T provides new biomarkers that can be used in brain pathologies.

12:36         50.         Separation and Reproducibility of Touch Activations in Areas 3b and 1 Within the Primary Somatosensory Cortex by High Resolution FMRI at 7T

Elizabeth Ann Stringer1, Robert M. Friedman2, J Chris Gatenby1, Li Min Chen1, John C. Gore1

1Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; 2Department of Psychology, Vanderbilt University, Nashville, TN, USA

Ultra-high field fMRI provides greater sensitivity and increases spatial resolution, resulting in finer scale activity maps than at lower fields. Here, we test the feasibility of 7T fMRI to visualize millimeter resolution somatotopic maps in neighboring regions, Brodmann Areas 3b and 1, within the primary somatosensory cortex. Images were acquired using a 7T Philips Achieva scanner while innocuous air puffs were delivered to alternating digits. Repeated trials within single subjects showed reproducible topological activations within areas 3b and 1 of the primary somatosensory cortex. The data support findings from nonhuman primate studies.

SPECIAL INTEREST SESSION
In Vivo
MR with DNP Polarized Compounds

Room 315                             11:00-13:00                                                         Moderators: Charles Cunningham and John Kurhanewicz               

11:00         51.         Preclinical Studies in Cancer Models using Hyperpolarized Carbon-13 MR

Daniel B. Vigneron1

1University of California San Francisco

11:20         52.         Investigating the Effects of Hyperthyroidism on Cardiac Metabolism Using Hyperpolarized Magnetic Resonance

Helen J. Atherton1, Marie A. Shroeder1, Lisa C. Heather1, Julian L. Griffin2, Kieran Clarke1, George K. Radda1, Damian J. Tyler1

1Physiology, Anatomy and Genetics, University of Oxford, Oxford, Oxfordshire, UK; 2Biochemistry, University of Cambridge, Cambridge, Cambridgeshire, UK

In this study Dynamic Nuclear Polarization enhanced 13C-MRS was used to investigate the effects of elevated thyroid hormone (T3) levels on cardiac metabolism in vivo. Our study uniquely revealed that pyruvate dehydrogenase (PDH) flux was reduced by 76 % in rats administered T3 for 7 days, indicative of an increased reliance on fatty acid oxidation (FAO) for ATP production. Metabolically profiling cardiac tissue ex vivo using 1H-NMR revealed a concomitant increase in glycolysis, evidenced by increased lactate and alanine, and decreased glucose. Together these results suggest that the hyperthyroid heart can be characterized by increased FAO and glycolysis, and decreased PDH flux.

11:32         53.         Hyperpolarized 13C MR Spectroscopic Imaging: Application to Brain Tumors

Ilwoo Park1,2, Peder E. Larson2, Simon Hu1,2, Robert Bok2, Tomoko Ozawa3, John Kurhanewicz1,2, Daniel B. Vigneron1,2, Scott R. VandenBerg3, C David James3, Sarah J. Nelson1,2

1Bioengineering, University of California, San Francisco/Berkeley, San Francisco, CA, USA; 2Surbeck Laboratory of Advanced Imaging, Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; 3Brain Tumor Research Center, Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, USA

The purpose of this study was to explore the feasibility of using 13C MRSI with hyperpolarized 13C1-pyruvate as a substrate for evaluation of in vivo brain tumor by comparing hyperpolarized 13C MRSI data from rats with and without intracranial human xenograft tumors. Significant differences in 13C metabolic characteristics were found between tumor and normal brain tissue. The SNR of lactate, pyruvate and total carbon were observed to be different between U-251 MG and U-87 MG model, in a manner that was consistent with the findings of immunochemical analysis, and the SNR of lactate showed strong correlation with proliferation marker (MIB-1).

11:48         54.         Real-Time Cardiac Metabolism in a Pig Model of Cardiac Disease Using Hyperpolarized 13C MR

Angus Zoen Lau1,2, Nilesh Ghugre2, Albert P. Chen3, Wilfred W. Lam2, Venkat Ramanan2, Yuesong Yang2, Graham A. Wright1,2, Charles H. Cunningham1,2

1Dept. of Medical Biophysics, University of Toronto, Toronto, ON, Canada; 2Imaging Research, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; 3GE Healthcare, Toronto, ON, Canada

Hyperpolarization of spins via DNP has been explored as a method to non-invasively study real-time metabolic processes in vivo. In this abstract, we investigate the use of hyperpolarized 13C MR to study real-time cardiac metabolism in a pig model of cardiac disease. A 13C-tuned transmit/receive surface coil was used to acquire cardiac-gated non-localized dynamic spectra following injection of a hyperpolarized [1-13C]-pyruvate solution. Pyruvate, lactate, and bicarbonate resonances were observed. Spatially encoded breath-held cardiac-gated CSIs were also obtained displaying the presence of pyruvate in the blood in the chambers of the heart.

12:00         55.         13C-Labeled Malate as a Treatment Response Marker in a Murine Lymphoma Model in Vivo

Rene in 't Zandt1, Mikko Kettunen2, Magnus Karlsson1, Pernille Rose Jensen1, Anna Gisselsson1, Ferdia Gallagher2,3, De Hu2, Georg Hansson1, Kevin Brindle2, Mathilde Lerche1

1Imagnia AB, Malmö, Sweden; 2Cancer Research UK Cambridge Research Institute and Dept. of Biochemistry, University of Cambridge, Cambridge, UK; 3Dept. of Radiology, Addenbrooke’s Hospital, University of Cambridge, Cambridge, UK

Early measurements of tumor responses to therapy have been shown to help predict the subsequent treatment outcome in many tumor cell lines. Previously it has been shown that the flux of hyperpolarized 13C label between pyruvate and lactate in a murine lymphoma model can be used as an early marker of cell death following chemotherapy both in vitro and in vivo. This study show that a promising new tumor biomarker - hyperpolarized [1,4-13C2]fumarate - can be used in the same model to image the effects of chemotherapy.

12:12         56.         Hyperpolarized 1-[13C]-Ethyl-Pyruvate Metabolic Imaging in Anesthetized Rat Brain

Ralph E. Hurd1, Yi-Fen Yen1, Dirk Mayer2,3, Albert Chen4, David Wilson5, Susan Kohler6, James Tropp1, Robert Bok5, Daniel Vigneron5, John Kurhanewicz5, Daniel Spielman2, Adolf Pfefferbaum3,7

1Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA; 2Department of Radiology, Stanford, Stanford, CA, USA; 3SRI International, Menlo Park, CA, USA; 4Applied Science Laboratory, GE Healthcare, Toronto, Ontario, Canada; 5Department of Radiology, UCSF, San Francisco, CA, USA; 6Union College, Schenectady, NY, USA; 7Psychiatry, Stanford, Stanford, CA, USA

Formulation, polarization and dissolution conditions were developed to obtain a stable hyperpolarized solution of 1-[13C]-ethyl-pyruvate. A maximum tolerated dose and injection rate were determined, and 13C spectroscopic imaging was used to compare the uptake of hyperpolarized 1-[13C]-ethyl pyruvate relative to hyperpolarized 1-[13C]- pyruvate into anesthetized rat brain. Hyperpolarized 1-[13C]-ethyl pyruvate metabolic imaging in normal brain is demonstrated in this feasibility study.

12:24         57.         Extending the Utility of Hyperpolarized Compounds by Storing Polarization in the Singlet State

Elizabeth R. Jenista1, Rosa T. Branca1, Debadeep Bhattacharyya2, Xin Chen1, Warren S. Warren1

1Department of Chemistry, Duke University, Durham, NC, USA; 2Oxford Instruments, Concord, MA, USA

Magnetic resonance is limited as a molecular imaging modality by its poor sensitivity, due to the small fractional magnetization achieved in even large magnets. Hyperpolarization methods have been demonstrated to increase this sensitivity by orders of magnitude, but the enhanced signal relaxes away in tens of seconds in favorable cases, making many imaging applications problematic. We show theoretically and experimentally that symmetry protected, true singlet states can be used to store and retrieve population in very long lived states, extending the utility of hyperpolarization techniques.

12:36         58.         Measuring Michaelis-Menten Kinetics of Hyperpolarized 13C1-Pyruvate Metabolism in a Single Bolus Injection

Tao Xu1, Dirk Mayer2, Meng Gu1, Yi-Fen Yen3, Edvin Johansson4, Jim Tropp5, Ralph Hurd3, Daniel Spielman2

1Department of Electrical Engineering, Stanford University, Stanford, CA, USA; 2Department of Radiology, Stanford University, Stanford, CA, USA; 3Global Applied Sciences Laboratory, GE Healthcare, Menlo Park, CA, USA; 4Medical Diagnostics R&D, GE Healthcare, Oslo, Norway; 5Global Applied Sciences Laboratory, GE Healthcare, Fremont, CA, USA

Hyperpolarized MRS of metabolically active substrates allows the study of both the injected substrate and downstream metabolic products in vivo. Nowadays, most dynamic studies have employed slice-select excitation pulses with small flip angles to measure the metabolic time curves following bolus injection of the hyperpolarized substrate. Constant metabolic exchange rates are typically assumed throughout the observation window. We developed a new technique for measuring Michaelis-Menten kinetics of hyperpolarized 13C1-pyruvate metabolism in a single bolus injection. The results clearly demonstrate the nonlinear relationship between metabolic exchange rates and pyruvate concentration.

12:48         59.         Imaging Brain PH Using Hyperpolarized 13C-Labeled Bicarbonate

Ferdia Aidan Gallagher1,2, Mikko I. Kettunen2,3, De-en Hu2,3, Lorna B. Jarvis4, Rebekah L. McLaughlin2,3, Tim H. Witney2,3, Sam E. Day2,3, Jan H. Ardenkjaer-Larsen5, Ken G. Smith4, Kevin M. Brindle2,3

1Radiology, University of Cambridge, Cambridge, UK; 2CRUK Cambridge Research Institute, Cambridge, UK; 3Biochemistry, University of Cambridge, Cambridge, UK; 4Cambridge Institute for Medical Research, University of Cambridge, Cambridge, UK; 5GE Healthcare, Amersham, UK

Few imaging biomarkers can cross an intact blood-brain barrier. We show here that hyperpolarized 13C-labeled carbon dioxide can be detected within normal mouse brain following the injection of hyperpolarized 13C-labeled bicarbonate. The spatial distribution of the two molecules can also be imaged and the calculated brain pH was shown to be lower than the surrounding tissues, in keeping with previous invasive studies. This method therefore offers the possibility of a new cerebral imaging technique which could be applied to imaging brain function and pathology.

MR Guided Interventions: Devices, Sequences, & Applications

Room 313BC                       11:00-13:00                                                                      Moderators: Sherif G. Nour and Cengizhan Ozturk

11:00         60.         Three Dimensional Acute Radiofrequency Ablation Lesion Visualisation and Correlation with Electro-Anatomical Mapping System Ablation Points.

Benjamin R. Knowles1, Dennis Caulfield1, Aldo Rivaldi2, Michael Cooklin2, Jaswinder S. Gill2, Julian Bostock2, Reza Razavi1, Tobias Schaeffter1, Kawal S. Rhode1

1Division of Imaging Sciences, King's College London, London, UK; 2Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, UK

Radiofrequency ablation has become an increasingly common treatment for cardiac arrhythmias such as atrial flutter and atrial fibrillation. Delayed enhancement MRI has been previously been used to visualise the ablation lesions in the left atrium, however, determination of the ablation patterns is difficult from visualisation of the 2D slices. We present an automated method for the 3D visualisation of ablation lesions that allows for an intuitive assessment of lesion patterns. In this investigation, we demonstrate how our novel technique can be used to verify lesion locations as determined from electro-anatomical mapping systems.

11:12         61.         Four-Dimensional Transcatheter Intraarterial Perfusion MRI Monitoring of Chemoembolization for Hepatocellular Carcinoma

Dingxin Wang1, Ron Gaba2, Robert Lewandowski2, Robert Ryu2, Kent Sato2, Mary Mulcahy3,4, Riad Salem2,4, Reed Omary1,4, Andrew Larson1,4

1Departments of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, USA; 2Department of Radiology, Northwestern University, Chicago, IL, USA; 3Department of Medicine, Northwestern University, Chicago, IL, USA; 4Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL, USA

Transcatheter Intra-arterial Perfusion TRIP-MRI, using catheter-directed intraarterial (IA) contrast delivery, offers an objective method to intra-procedurally quantify tumor perfusion changes during TACE. The TRIP-MRI technique has previously been performed with 2D acquisitions in a combined clinical magnetic resonance/DSA unit (termed MR-IR unit) to monitor TACE. In this study, using a clinical MR-IR unit, we tested the hypothesis that 4D TRIP-MRI can be used to measure intra-procedural perfusion changes in liver tumors during TACE.

11:24         62.         Initial Clinical Experience with a Robotic Assistance System for Liver Biopsies in a Diagnostic 1.5T MR Scanner

Michael Moche1, Dirk Zajonz1, Thomas Kahn1, Harald Busse1

1Dept. of Diagnostic and Interventional Radiology, Leipzig University Hospital, Leipzig, Germany

We report on our initial experience from 12 liver biopsies guided by a commercial stereotactic robotic system with six degrees of freedom in a closed-bore MRI scanner. Because the liver is subject to respiratory motion, (i) a preinterventional breathhold training with the patient was considered essential, and (ii) immediately after needle placement, the guiding sleeve had to be disconnected from the system to avoid liver injury. The device appears to provide a substantial benefit for biopsies with double oblique access paths. Most of the interventions could be performed without contrast media and the learning curve suggests a mean intervention time of less than one hour.

11:36         63.         MRI-Compatible Haptics: Strain Sensing for Real-Time Estimation of Three Dimensional Needle Deflection in MRI Environments

Yong-Lae Park1, Santhi Elayaperumal1, Seok Chang Ryu1, Bruce Daniel2, Richard J. Black3, Behzad Moslehi3, Mark R. Cutkosky1

1Mechanical Engineering, Stanford University, Stanford, CA, USA; 2Radiology, Stanford University, Stanford, CA, USA; 3Intelligent Fiber Optic Systems Corporation, Santa Clara, CA, USA

There is a need for methods to accurately manipulate instruments within closed MRI systems. During such procedures, it is useful to track deviations from the planned trajectory to minimize positioning error. This research focuses on using MRI-compatible sensors to measure strain on a standard biopsy needle. The sensors used are based on fiber Bragg grating (FBG) technology. FBG sensors produce wavelength shifts under various loads. Our results show that the FBG sensors do not produce image artifacts, and the sensor signals are not affected by the magnetic field.

11:48         64.         Passive Navigation Concept for MR-Assisted Orthopedic Interventions - Evaluation in Retrograde Drilling of Osteochondrosis Dissecans (OD) of the Talus

Christian Jürgen Seebauer1, Ulf Teichgräber2, Florian Wichlas1, Tobias Jung1, Jens Rump2, René Schilling2, Thula Walther2, Hermann Josef Bail1

1Center for Musculoskeletal Surgery, Charité Universitätsmedizin Berlin, Berlin, Germany; 2Department of Radiology, Charité Universitätsmedizin Berlin, Berlin, Germany

Drilling under conventional X]ray guidance often leads to damage of the bone and cartilage, due to poor visualization and the complex anatomy of the ankle. We propose a passive, simple and inexpensive navigation concept, based on the cross-sectional nature of MRI for retrograde drilling of osteochondral lesions of the talus under MRI-guidance. For navigation, we used a custom]made MR]compatible drilling device. The passive navigation concept was fast and safe in practice. Saw cut specimens showed that the artificial lesion was hit in all cases. We conclude that our method is a viable alternative to conventional navigation concepts.

12:00         65.         Real-Time Intravascular MRI Endoscopy at 3T

Shashank Sathyanarayana1, Michael Schär2,3, Meiyappan Solaiyappan2, Paul Arthur Bottomley1,2

1Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA; 2Radiology, Johns Hopkins University, Baltimore, MD, USA; 3Philips Healthcare, Cleveland, OH, USA

RF transmission and reception by modified miniature internal probes can intrinsically localize MRI signals to a sensitive “plane” locked to the probe-head, analogous to an endoscope. Here, intra-vascular “MRI endoscopy” is implemented in real-time at 3T in diseased human vessels in-vitro, and in a rabbit model of atherosclerosis in-vivo. Imaging at up to 4 frames-per-second can identify suspect lesions, with high-resolution (≥80µm) follow-up. Cine images from the rabbit aorta are rendered in 3D to visualize the advancing probe from its own perspective. MRI endoscopy offers the potential for fast high-resolution intravascular imaging of vascular pathology and morphology.

12:12         66.         An Active Two Channel Guidewire for Interventional Cardiovascular MRI

Ozgur Kocaturk1, Christina E. Saikus2, Anthony Z. Faranesh2, Michael A. Guttman2, Kanishka Ratnayaka2, Robert J. Lederman2

1Translational Medicine Branch, Division of Intramural Research, National Heart Lung Blood Institute, National Institutes of Health , Bethesda, MD, USA; 2Translational Medicine Branch, Division of Intramural Research, National Heart Lung Blood Institute, National Institutes of Health, Bethesda, MD, USA

The success and safety of interventional magnetic resonance imaging (iMRI) procedures require conspicuous intravascular instruments that can be distinguished from surrounding tissues. We have developed an active two channel guidewire that incorporates individual channels to provide superior distal tip and whole shaft visibility simultaneously under real time iMRI. The guidewire visibility and handling were evaluated during in vitro phantom imaging and in vivo real-time MRI-guided vascular access experiments in swine. Also mechanical properties (torquability, tip flexibility, pushability) of the guidewire prototype were compared in several bench-top evaluations with representative 0.035” commercially-available guidewires.

12:24         67.         Active Catheter Tracking in Air Cavities Using a Semisolid Signal Source

Stefan Alt1, Reiner Umathum1, Wolfhard Semmler1, Michael Bock1

1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany

An active tracking catheter using a semisolid rubber as signal source was constructed to be used for MRI-guided interventions in air-filled cavities of the body. Exploiting the short relaxation time of the material and providing suppression of interfering signals, a special tracking sequence and algorithm is shown. Results from phantom and animal experiments with a tracking catheter prototype are presented.

12:36         68.         A View-Sharing Compressed Sensing Technique for 3D Catheter Visualization from Bi-Planar Views

Carsten Oliver Schirra1, Steffen Weiss2, Sascha Krueger2, Reza Razavi1, Sebastian Kozerke1,3, Tobias Schaeffter1

1Division of Imaging Sciences, King's College London, London, UK; 2Philips Research Europe, Hamburg, Germany; 3Institute for Biomedical Engineering, Univeristy and ETH Zurich, Zurich, Switzerland

Fast visualization of catheters is indispensable for MR-guided interventions. We propose a new method based on bi-planar imaging using two perpendicular 2D projection views. The two projection views are acquired rapidly by using a randomized view-sharing 1D phase encoding scheme allowing for accelerated recovery of the catheter shape using Compressed Sensing as well as measurement of organ motion. Furthermore, a new catheter design is proposed that allows for better shape recovery and robust tip tracking. The method was assessed on a simulation and its feasibility tested in an in-vivo.

12:48         69.         Outer Volume Suppression for Three Different Steady State Sequences Used in Percutaneous Interventions

Jaane Rauschenberg1, Patrik Zamecnik2, Wolfhard Semmler1, Michael Bock1

1Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany; 2Division of Radiology, German Cancer Research Center, Heidelberg, Germany

Outer volume suppression (OVS) is performed in steady state sequences to restrict the field of view and thus, to accelerate the image acquisition. Without destroying the steady state, OVS is integrated in three different pulse sequences (FLASH, PSIF, trueFISP) which provide T1, T2-like and T2/T1 image contrast. With a 12.5% FOV restriction an update rate of 5 images/s could be achieved.

Quantitative MR Analysis of Articular Cartilage:  MSK Applications

Room 312                             11:00-13:00                                                                               Moderators: Xiaojuan Li and Hollis G. Potter

11:00         70.         Morphological and Biochemical (T2) MR Evaluation and Comparison of Cartilage Repair Tissue of the Patella and the Medial Femoral Condyle

Goetz Hannes Welsch1, Tallal Charles Mamisch2, Lukas Zak3, Sebastian Quirbach1, Stefan Marlovits3, Siegfried Trattnig1

1MR Center, Department of Radiology, Medical University of Vienna, Vienna, Austria; 2Department of Orthopedic Surgery, University of Berne, Berne, Switzerland; 3Center for Joints and Cartilage, Department of Trauma Surgery, Medical University of Vienna, Vienna, Austria

The objective of this study was to use advanced MR techniques to evaluate and compare cartilage repair tissue after matrix-associated autologous chondrocyte transplantation in the patella and in the medial femoral condyle (MFC). For morphological evaluation, the MR observation of cartilage repair tissue (MOCART) score was used, with a 3D-True-FISP sequence. For biochemical assessment, T2-mapping was prepared by a multi-echo spin-echo approach with particular attention to the zonal structure of cartilage. The assessment of cartilage repair tissue of the patella and the MFC demonstrated comparable morphological results, whereas biochemical T2 values showed differences, possibly due to dissimilar biomechanical loading conditions.

11:12         71.         Effect of Knee Alignment on T2 Relaxation Time of Articular Cartilage

Risto Ojala1, Riikka Partanen1, Ilkka Hannila1, Eveliina Lammentausta1, Marianne Haapea1, Osmo Tervonen1,2, Miika T. Nieminen1,2

1Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland; 2Department of Radiology, University of Oulu, Oulu, Finland

Varus and valgus malalignment of the knee is known to increase the risk of medial and lateral osteoarthritis, respectively. To assess whether knee alignment influences T2 relaxation time of tibio-femoral cartilage, T2 was measured at the weight-bearing cartilages of 30 patients with knee symptoms and 20 asymptomatic volunteers at 1.5T. Varus alignment resulted in a significant increase in T2 in the whole medial tibial cartilage and the deep parts of the femoral cartilage. Valgus alignment caused an increase only in tibial cartilage, predominantly in the medial compartment. T2 mapping may provide a sensitive tool to detect early degenerative cartilage changes.

11:24         72.         Multiexponential T2 Analysis in Cartilage Degraded Using Different Enzymatic Protocols

David A. Reiter1, Ligaya Roque1, Richard G. Spencer1

1National Institute on Aging, National Institutes of Health, Baltimore, MD, USA

We sought to improve the specificity for cartilage matrix degradation through multiexponential analysis of T2 relaxation, which can delineate macromolecular compartments with varying water fraction and mobility. Multiexponential T2 analysis of control cartilage and of cartilage subjected to three enzymatic degradation protocols showed distinct patterns, consistent with the known actions of the degradative enzymes used. In contrast, while monoexponential T2 values increased with degradation, there was no enzyme-specificity in this increase. Therefore, multiexponential T2 analysis demonstrates greatly improved specificity over standard monoexponential T2 analysis to changes in cartilage matrix, indicating the diagnostic potential of such analysis for detecting cartilage disease.

11:36         73.         Evaluation of Cartilage T2 Using Loading in Situ MRI in Early Osteoarthritis with Hip Dysplasia

Takashi Nishii1, Toshiyuki Shiomi2, Hisashi Tanaka3, Youichi Yamazaki4, Kenya Murase4, Takashi Sakai2, Masaki Takao2, Hideki Yoshikawa2, Nobuhiko Sugano1

1Department of Orthopaedic Medical Engineering, Osaka University Medical School, Osaka, Japan; 2Department of Orthopaedic Surgery, Osaka University Medical School, Osaka, Japan; 3Department of Radiology, Osaka University Medical School, Osaka, Japan; 4Department of Medical Physics & Engineering, Osaka University Medical School, Osaka, Japan

Cartilage T2 with use of loading in situ MR imaging (50% of body weight) was evaluated in 9 patients with hip dysplasia and 9 normal volunteers, for evaluation of cartilage pressure distribution in vivo. There was significant decrease of T2 by loading at the outer zone of the acetabular cartilage and inner zone of the femoral cartilage in dysplastic hips (p<0.05). Loading in situ MR imaging with T2 assessment may allow biomechanical assessment of pathological conditions related to localized stress concentration and have prognostic significance for osteoarthritic changes in hip dysplasia.

11:48         74.         Localised Cartilage Assessment with Three-Dimensional DGEMRIC in Subjects with Normal and Cam-Type Abnormal Hip Joint  Morphology. an Assay of Early Disease.

Tom C B Pollard1, Eugene G. McNally1, Derek C. Wilson2, Burkhard Maedler3, David R. Wilson2, Marion Watson1, Andrew J. Carr1

1Nuffield Department of Orthopaedic Surgery, University of Oxford, Oxford, UK; 2Department of Orthopaedics, University of British Columbia, Vancouver, BC, Canada; 3Philips Healthcare, Vancouver, BC, Canada

The majority of cases of hip osteoarthritis are caused by morphological abnormalities, such as the cam deformity. Treating such deformity may prevent disease progression. A sensitive, responsive assay of chondral damage is needed to assess treatment efficacy.

dGEMRIC was performed on subjects without radiographic osteoarthritis, with and without cam deformities. The ratio of the T1-index in the anterosuperior acetabular cartilage, divided by the T1-index for the whole joint cartilage, was significantly different between the two groups.

Using dGEMRIC to map chondral damage may have advantages over a single measure of whole joint cartilage in OA. dGEMRIC offers promise as an assay of early hip osteoarthritis.

 

12:00         75.         Factors Affecting Accuracy of T1 Estimates in Vivo by Variable Flip Angle Approach for DGEMRIC

Angela Manuel1, Wei Li1, Vladimir Jellus2, Timothy Hughes2, Pottumarthi V. Prasad1

1NorthShore University HealthSystem, Evanston, IL, USA; 2Healthcare Sector, Siemens AG, Erlangen, Germany

Previous experience with phantoms has shown good agreement in T1s obtained by standard 2D IR-TSE and 3D VFA techniques. However, the level of agreement in vivo was less. In order to determine the reason behind this inaccuracy, we investigated a number of potential factors, such as number of flip angles used, fitting routines, and effects of B1 inhomogeneity. Our results suggest that increasing the number of flip angles had minimal or no effect on improving the agreement between the techniques and that B1 inhomogeneity may be most responsible for the apparent poor agreement between 3D VFA and 2D IR-TSE estimates.

12:12         76.         Longitudinal Evaluation of Cartilage Degeneration in ACL-Injured Knees Using MR T1ρ Quantification and Laminar Analysis

Daniel Kuo1, Alekos A. Theologis1,2, Radu I. Bolbos1, Julio Carballido-Gamio1, ChunBong Benjamin Ma3, Xiaojuan Li1

1Musculoskeletal Quantitative Imaging Research (MQIR), Department of Radiology, University of California, San Francisco, San Francisco, CA, USA; 2School of Medicine, University of California, San Francisco, San Francisco, CA, USA; 3Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA, USA

Patients with ACL injuries have a high risk of developing osteoarthritis (OA) despite ACL reconstruction. However, the mechanism of OA development in ACL-injured knees remains elusive. Nine ACL-injured patients were studied over 2 years to evaluate changes in bone marrow edema-like lesions (BMEL) and cartilage degeneration. Degenerative changes were evaluated using MR T1ρ relaxation time quantification and laminar analysis. Although BMEL resolved significantly over time, T1ρ values in BMEL-overlying cartilage were elevated at both baseline and follow-ups, suggesting irreversible damage in those regions. T1ρ values were also elevated in superficial layers of the weight-bearing cartilage sub-compartments of the medial knee.

12:24         77.         Demonstration of the Pre-Clinical Efficacy of Aggrecanase Selective Inhibitor by T1p MRI

Reddy Beesam Shashank1, Ashwini Anumandla2, Eric Albert Mellon2, Jennifer H. Lee3, Jingsong Wang3, Ravinder Reddy2

1MMRRCC,Radiology, University of pennsylvania, philadelphia, PA, USA; 2MMRRCC,Radiology, University of pennsylvania, USA; 3Wyeth Research, Collegeville, USA

To demonstrate the effectiveness of T1p MRI as a pre-clinical tool in drug development.

12:36         78.         Ultrashort TE MRI of the Osteochondral Junction of the Knee at 3T:Identification of Anatomic Structures Contributing to Signal Intensity

Won C. Bae1, Jerry R. Dwek2, Richard Znamirowski1, Sheronda Statum1, Juan C. Hermida3, Darryl D. D’Lima4, Robert L. Sah5, Jiang Du1, Christine B. Chung1

1Radiology, UC San Diego, San Diego, CA, USA; 2Children’s Hospital and Health Center, UC San Diego, San Diego, CA, USA; 3Scripps Clinic; 4Scripps Clinic, La Jolla, CA, USA; 5Bioengineering, UC San Diego, La Jolla, CA

Joint diseases may involve abnormalities in the junction between cartilage and bone. Using Ultrashort Time-to-Echo (UTE) MRI techniques, tissues with short T2 properties at this junction become visible, unlike when conventional sequences are used. UTE MR signature of human osteochondral tissues near the junction (uncalcified cartilage, calcified cartilage and subchondral bone) was determined, using experimental treatments to isolate specific components. Both calcified cartilage and the deepest layer of uncalcified cartilage were identified as tissues contributing to the UTE signal. This study has implications for clinical evaluation of the osteochondral junction and introduces new opportunities for assessing joint disease using MRI.

12:48         79.         Evaluation of Articular Cartilage of Lumbar Facet Joints with UTE MR Imaging and Multi-Echo SE T2 Mapping Techniques

Hatice Tuba Sanal1, Tobias Mett2, Sheronda Statum1, Jiang Du1, Richard Znamirowski1, Graeme Bydder1, Christine Chung1

1Radiology, UCSD, San Diego, CA, USA; 2THE VIENNA SCHOOLS OF MEDICINE, Vienna, Austria

Evaluation of articular cartilage (AC) of lumbar facet joints (LFJS) with UTE/Multi-Echo SE T2 Mapping.  Objective: Qualitatively/quantitatively evaluate morphology and biochemical integrity of AC of LFJs.  Materials and methods: A cadaveric lumbar spine was evaluated with standard clinical, UTE sequences, multi-echo SE T2 mapping and T1/T2* measurement.  Results: Mean T2 value of superficial layer of cartilage was 53 ms on abnormal side and 40ms on normal side. T2* value of calcified layer of cartilage on abnormal side and normal side were calculated 6.8 ms and 2.1 respectively.

Conclusion/Discussion: Quantitative evaluation of FJ’s cartilage might be useful for lower back pain.

EDUCATIONAL COURSE
The Rise & Fall of the Brain Part 1: The Developing Brain

Room 314                             11:00 - 13:00                                                                              Moderators:  P. Ellen Grant and John D. Port

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Describe the basic phases of brain development in the fetal and infant age ranges;

·   List the imaging findings seen with various developmental brain abnormalities;

·   Describe the basic MRI techniques necessary to obtain good quality fetal and infant brain imaging;

·   Recognize the challenges, limitations, and pitfalls of current imaging techniques with respect to this challenging patient population; and

·   Discuss future potential MR imaging techniques for the diagnosis of these entities. 

 

11:00       MRI of Normal Fetal Brain Development
Richard L. Robertson


11:30      
MRI of Fetal Developmental Anomalies

Nadine J. Girard

12:00       Cortical Folding and Connectivity in the Developing Brain

Petra S. Hüppi

12:30       Abnormalities Affecting Post Natal White Matter Development: Leukodystrophies

Florian Eichler


GOLD CORPORATE MEMBER LUNCHTIME SYMPOSIUM
Philips

Ballroom                              13:00 - 14:00                                                                                                                                                                                                                          

CLINICAL INTENSIVE COURSE
Case-Based Teaching 1: Soft Tissue Imaging

Room 310                             14:00 - 16:00                                                                    Moderators:  Christine Chung and Hollis G. Potter               

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Plan optimal imaging protocols for all relevant soft tissue abnormalities;

·   Describe the indications for MRI of specific soft tissue abnormalities; and

·   Identify four soft tissue abnormalities which radiologists should not miss.

 

14:00          Neoplasm and Their Mimickers

                   David M. Panicek

15:00          Trauma
Mario Maas                                                                                                                                              

Pelvis & Fetal

Room 316A                         14:00-16:00                                                                         Moderators: Nandita de Souza and Patricia Noël

14:00         80.         Better Understanding Maturation Arrested Men Through HR-MAS Spectroscopy of Human Testicular Biospy Tissue

Rahwa Berhanu Iman1, Mark Swanson1, Thomas Walsh2, David Aaronson2, Shoujun Zhao, Ying Lu, John Kurhanewicz1

1Radiology, University of California, San Francisco, San Francisco, CA, USA; 2Urology, University of California, San Francisco

1H high resolution magic angle spinning (HR-MAS) spectroscopy was used to determine metabolic profiles of normal, maturation arrested, and azoospermatic human testicular biopsy tissues. Twenty seven 1H HR-MAS spectra were acquired and quantified using the electronic standard ERETIC and the algorithm HR-QUEST. Phosphocholine (PC), phosphoethanolamine (PE), and glutamine were found to significantly differentiate between normal and azoospermatic tissue. This study further suggests that PC could serve as a specific in vivo marker for fertility in 1H MRSI studies of human testes and a model can be used to predict fertility of maturation arrested men.

14:12         81.         31P Chemical Shift Imaging of Testicular Infertility at 3.0 Tesla

Jonathan P. Dyke1,2, Darius A. Paduch3, Joseph Kiper3, Eric Aronowitz1, Peter N. Schlegel3, Douglas Ballon1,2

1Citigroup Biomedical Imaging Center, Weill Cornell Medical College, New York, NY, USA; 2Radiology, Weill Cornell Medical College, New York, NY, USA; 3Urology, Weill Cornell Medical College, New York, NY, USA

31P chemical shift imaging (CSI) at 3.0 Tesla provided localized metabolic information in the testes of subjects presenting with male infertility. Spectroscopic results were compared with testicular sperm extraction (TSE) which confirmed the presence of viable sperm. The PM/β-ATP ratio was decreased in subjects that lacked viable sperm compared to those containing viable sperm. This technique may provide information aiding clinicians in finding regions of viability in the testes during TSE. Future utility of 31P spectroscopic imaging may allow non-invasive serial assessment of testicular function that would allow for patient specific timing and tailoring of therapy.

14:24         82.         Diffusion Weighted Imaging of Uterine Fibroids: Predicting Volumetric Response Following Uterine Artery Embolization

Kinh Gian Do1, Stella Kang1, Timothy Clark1, Elizabeth Hecht1

1Radiology, NYU Medical Center, New York, NY, USA

In 8 patients with 21 uterine fibroids, higher apparent diffusion coefficient of uterine fibroids on pre-procedural MRI correlate with greater volumetric reduction following uterine artery embolization. Fibroid volume reduction did not correlate with fibroid size or relative enhancement.


14:36         83.         Diffusion-Weighted MR Hysterography: Initial Evaluation and Determination of Optimal Imaging Timing During the Menstruation Cycle

Wenche M. Klerkx1, Taro Takahara2, Qvinny Leemans2, Thomas C. Kwee2, Peter Luijten2, Willem P. Mali2

1Gynecology, University Medical Center Utrecht, Utrecht, Netherlands; 2Radiology, University Medical Center Utrecht, Utrecht, Netherlands

Hysteroscopy, saline infusion sonohysterography, and hysterosalpingography are commonly used for the evaluation of uterine pathologies, but are invasive and operator-dependant procedures. MRI does not have these disadvantages, but evaluation of the shape of the uterine cavity is often difficult using conventional MRI. MR hysterography, using a diffusion-weighted sequence based on the concept of Diffusion weighted Whole body Imaging with Background body signal Suppression (DWIBS) may be an excellent alternative. In this study, we introduce the MR hysterography technique and show that the best visualization of the uterine cavity can be obtained in the follicular phase of the menstruation cycle.

14:48         84.         Staging of Ovarian Cancer with Continuously Moving Table MR Acquisitions: A Comparison to Computed Tomography

Ute Ariane Ludwig1, Gregor Pache2, Tobias Baumann2, Jürgen Hennig1, Oliver Schäfer2

1Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany; 2Department of Diagnostic Radiology, University Hospital Freiburg, Freiburg, Germany

Ovarian cancer is one of the most frequently occurring cancer diseases amongst women. Currently, whole body staging of ovarian cancer is performed with Computed Tomography (CT), but small peritoneal nodules are hardly detectable using this imaging modality. In this study a MRI protocol including high resolution pelvic and Sliding Multi Slice (SMS) imaging with continuously moving table was investigated for whole body staging of ovarian cancer and images were compared to CT. It could be demonstrated that MRI was superior to CT for staging of local tumor extent and showed excellent detection of peritoneal or metastatic spread from ovarian cancer.

15:00         85.         The Role of 3 Tesla DWI in Evaluation of Primary and Metastatic Ovarian Cancer Before and After Neo-Adjuvant Chemotherapy

Masako Yano Kataoka1, Andrew Nicholas Priest1, Martin J. Graves1, Ilse Joubert1, Robin Crawford2, Helena Earl3, James Brenton3,4, Mary A. McLean4, John R. Griffiths4, David          J. Lomas1, Evis Sala1

1Radiology, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK; 2Obstetrics & Gynaecology, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK; 3Oncology, Addenbrooke's Hospital, University of Cambridge, Cambridge, UK; 4Cancer Research UK, Cambridge Research Institute, Cambridge, UK

We evaluated the ADC values of primary ovarian, omental and peritoneal lesions in 16 patients with advanced ovarian cancer before and after neo-adjuvant chemotherapy. Baseline ADC values of peritoneal implants were considerably lower than that of primary ovarian lesions and significantly lower than those of omental cake. The primary ovarian tumours tended to have the highest ADC values which increased significantly after treatment. Our findings may reflect mixed treatment response that frequently occurs clinically at different sites of disease. This may be explained by variable blood supply and hypoxia which limits delivery and efficacy of chemotherapy at certain anatomical sites.

15:12         86.         Tumour Necrosis Assessed by Magnetic Resonance Dynamic Contrast-Enhanced Subtraction Imaging Is a Predictor of Chemoradiotherapy Response in Advanced Cervical Cancer

Lorenzo Mannelli1, Andrew N. Priest1, Martin J. Graves1, Ilse Joubert1, Li Tee Tan2, Robin Crawford3, James Brenton2,4, David J. Lomas1, Evis Sala1

1Radiology, Addenbrooke's Hospital and University of Cambridge, Cambridge, UK; 2Oncology, Addenbrooke's Hospital and University of Cambridge, Cambridge, UK; 3Obstetrics & Gynaecology, Addenbrooke's Hospital and University of Cambridge, Cambridge, UK; 4Cambridge Research Institute, Cancer Research UK, Cambridge, UK

Radiotherapy is usually effective in cervix cancer treatment. Imaging techniques that can predict treatment outcome would allow further treatment individualisation. There is a current lack of standardised and independently validated analysis of quantitative DCE-MRI parameters. Subtraction imaging is easy, widely available and it overcomes protocols variability. The pre-treatment percentage of non enhancing tumour was visually assessed in 13 patients using subtracted images. The tumour volume regression from pre-treatment to post-treatment was calculated. A strong correlation (r = -0.821; p < 0.001) was found between the pre-treatment percentage of non-enhancing tumour and the percentage of tumour volume regression.

15:24         87.         Differentiation Between Malignant and Benign Cervical Tissue on the Basis of the Apparent Diffusion Coefficient Is Sensitive and Independent of the B-Value Combination Used for ADC Calculation.

Jaap Hoogendam1, Wenche Margrethe Klerkx2, Gerard de Kort1, Ronald Zweemer1, Willem Mali1, Wouter Veldhuis1

1University Medical Center Utrecht; 2Radiology, University Medical Center Utrecht, Utrecht, Netherlands

In diffusion weighted imaging a variety of b-value combinations is used to calculate apparent diffusion coefficients (ADC) for malignancy discrimination. We scanned 35 patients with cervical cancer at 3T and investigated three b-value combinations used in the literature (b=0,1000 vs 0,150,500,1000 vs 150,500,1000 s/mm2) for their influence on ADC and the ability to identify cervical malignancies. Results show a significantly lower ADC in cervical malignancies compared to benign cervical tissue. A high sensitivity and specificity (all over 90%) was found at all optimal ADC cut-off values, independent of the b-value combination used to calculate ADC.

15:36         88.         High Resolution MR Imaging of the Fetal Heart with Cardiac Triggering: A Feasibility Study in the Sheep Fetus

Jin Yamamura1, Bernhard Schnackenburg2, Hendrik Kooijman2, Michael Frisch1, Gerhard Adam1, Ulrike Wedegaertner1

1Diagnostic and Interventional Radiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany; 2Philips Medical Systems

Although the fetal MRI has already been applied to almost all fetal organs, the evaluation of the fetal heart has been omitted so far due to technical problems. Usually, cardiac imaging requires electro-cardiogram (ECG) triggering and breath holds of the patient during measurements. Since the fetal heart lies within the uterus, there is no possibility for a direct triggering of the fetal heart frequency. The visualization of anomalies both of the heart and the great vessels is actually of great importance for prenatal diagnostics, though not yet feasible.  In this here present study the attempt was to develop a fetal cardiac MRI by using a fetal sheep model and thus to improve the image quality of fetal cardiac imaging. This feasibility study is based on performing fetal cardiac MR imaging by triggering the fetal heart beat in utero in a sheep model.

15:48         89.         In-Vivo MRI Measurement of Fetal Blood Oxygen Saturation in Cardiac Ventricles of Fetal Sheep: A Feasibility Study

Ulrike Wedegärtner1, Hendrik Kooijman2, Jin Yamamura1, Michael Frisch1, Kurt Hecher1, Gerhard Adam1

1University Hospital Hamburg Eppendorf, Hamburg, Germany; 2Philips Medical Systems, Germany

T2-based MR oximetry might allow the assessment of fetal oxygen saturation non-invasively which is important for high risk pregnancies. However, for practical application of this method to detect fetuses at risk, measurements have to be more accurate. Therefore technical difficulties due to the fetal model have to be improved.

MRA & Flow of Neurovascular Disease

Room 311                             14:00-16:00                                                                                       Moderators: John Detre and J. Paul Finn

14:00         90.         SWI-Based Intracranial MR Venography Using Image-Domain High-Pass Filtering with Second-Order Phase Difference

Yiping P. Du1, Zhaoyang Jin2,3

1Psychiatry, Radiology, University of Colorado Denver, Aurora, CO, USA; 2Institute of Information and Control, Hangzhou Dianzi University, Hangzhou, Zhejiang, China; 3Biomedical Engineering, Zhejiang University, Hangzhou, Zhejiang, China

An image-domain high-pass filtering with second-order phase difference is proposed to enhance the visibility of venous vasculature and suppress the off-resonance artifact in regions with severe field inhomogeneity in susceptibility weighted imaging (SWI). Using this filtering technique, 3D venography with positive venous contrast is generated. A Fermi weighting function is used to suppress the noise in air. The proposed filtering approach circumvents the signal loss commonly observed in the minimum-intensity projection of 3D SWI data processed with a conventional procedure.

14:12         91.         3D Fast Inversion Recovery Magnetic Resonance Angiography (FIR-MRA)

Ek Tsoon Tan1, John III Huston1, Stephen J. Riederer1

1Radiology, Mayo Clinic, Rochester, MN, USA

A non-contrast-enhanced MRA technique for imaging the intracranial arteries is described. The complex difference between selective and non-selective cycles of inversion-prepared gradient echo subtracts out static tissue, leaving only the vascular signal from proximal blood flow during the inversion interval. Each cycle also produces T1-weighted tissue contrast, which may be fused with the angiogram-only image for anatomical reference. A two-slab FIR-MRA acquisition is compared against a three-slab standard 3D time-of-flight sequence. FIR-MRA has significantly improved vessel conspicuity, background and artifact suppression but has a longer scan time (11 min vs. 6.5 min).

14:24         92.         High Resolution, Non-Contrast Imaging of Both Cerebral Veins and Arteries by Use of Gradient Echo T2 Star Weighted Angiography (SWAN)

Jennifer Linn1, Jürgen Lutz1, Michael Burke2, Tim Wesemann1, Hartmut Brückmann1

1Dept. of Neuroradiology, University Hospital Munich, Munich, Germany; 2GE Healthcare, Solingen, Germany

Problem: To assess the potential of T2 Star Weighted Angiography (SWAN) for the depiction of cerebral veins and arteries.

Methods: A SWAN sequence, and an arterial (MRA) and a venous (MRV) TOF-MRA were performed on 12 volunteers using a 3T MRI. MinIP and MIP images were analysed by two readers regarding the depiction of cerebral veins and arteries, respectively.

Results: The SWAN sequence was superior compared to tMRV with regard to the veins, and comparable to MRA with respect to the arteries.

Conclusions: SWAN allows for high-resolution, non-contrast visualization of both cerebral veins and arteries without application of contrast agent.

 

14:36         93.         Non Contrast MRA of the Extracranial Carotid Arteries Utilizing a 3D ECG-Triggered Balanced Steady State Free Precession Technique with Spatial Saturation

Calvin Lo1, Bidyut K. Pramanik1, Daniel Kim1, Xiaoming Bi2, Peter Weale2, Anna Nazarenko1, Thomas P. Mulholland1, Edmond A. Knopp1, Vivian S. Lee1, Ruth P. Lim1

1Radiology, NYU Langone Medical Center, New York, USA; 2Siemens Medical Solutions USA, Inc., Chicago, IL, USA

An ECG-gated 3D balanced steady state free precession (b-SSFP) MRA sequence, utilizing an inversion pulse to null out background tissue and a spatial saturation pulse to null out slowly flowing venous blood, has been described to visualize "fresh" arterial blood flowing into the image. We assessed the feasibility, diagnostic quality and accuracy of 3D b-SSFP MRA, compared with conventional TOF MRA for evaluation of the extracranial carotid arteries with reference to CE MRA. We found significantly superior SNR, CNR, image quality and diagnostic confidence for b-SSFP MRA compared with TOF MRA, and high concordance for stenosis with the reference standard.

14:48         94.         High Resolution 3D MR Angiography Using Arterial Spin Labeling

Yi Wang1, Seong-Eun Kim2, Dennis L. Parker1

1Utah Center for Advanced Imaging Research , University of Utah, Salt Lake City, UT, USA; 2Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT, USA

In this work, we used arterial spin labeling to acquire 3D high resolution angiography with increased signal to noise ratio. A 3D turbo-FLASH sequence was modified by incorporating the in-plane slice-selective double inversion magnetization preparation. Arterial blood inflow time was determined experimentally and high resolution 3D MR angiography was obtained at three inversion times.

15:00         95.         4D Contrast Enhanced MRA with Flow Measurements (HYPR FLOW) in Arteriovenous Malformations

Yijing Wu1, Kevin M. Johnson1, Elizabeth J. Nett1, Patrick Turski2, Charles A. Mistretta3

1Medical Physics, University of Wisconsin, Madison, MADISON, WI, USA; 2Radiology, University of Wisconsin, Madison, MADISON, WI, USA; 3Medical Physics and Radiology, University of Wisconsin, Madison, MADISON, WI, USA

Phase Contrast (PC) HYPR FLOW, which employs post contrast PC VIPR images as the composite and reconstructs the first pass time resolved contrast enhanced VIPR acquisition using HYPR LR technique, is able to achieve 4D Contrast Enhanced (CE) MRA with both high temporal resolution and isotropic spatial resolution and quantitative flow dynamics from the PC images. PC HYPR FLOW was performed on normal subjects and patients with brain AVMs. 4D CE MRA images with sub-second temporal resolution and sub-millimeter isotropic spatial resolution were generated as well as the flow dynamic maps including the wall shear stress and pressure. Quantitative measurements of velocity, WSS and pressure gradients were conducted and compared between control and patient groups.

15:12         96.         4D-MRA in Combination with Selective Arterial Spin Labelling for Functional Characterization of Arteriovenous Malformations at 3 T

Guido Matthias Kukuk1, Dariusch Reza Hadizadeh1, Jürgen Gieseke1,2, Julia Bergener1, Gabriele Beck2, Lisbeth Geerts2, Petra Mürtz1, Azize Boström3, Horst Urbach1, Johannes Schramm3, Hans Heinz Schild1, Winfried Albert Willinek1

1Department of Radiology, University of Bonn, Bonn, NRW, Germany; 2Philips Healthcare, Best, Netherlands; 3Department of Neurosurgery, University of Bonn, Bonn, NRW, Germany

4D-MRA is a promising diagnostic tool for characterization of cerebral arteriovenous malformations (cAVMs), however it lacks the selectivity that is inherent to DSA. Therefore we combined selective arterial spin labelling (sASL) with 4D-MRA for anatomic and functional characterization of cAVMs at 3.0 Tesla. 4D-MRA enabled the correct Spetzler-Martin classification in 10/10 symptomatic patients. In addition the sensitivity of identification of arterial feeders and anatomic variants could be markedly improved due to the combination with sASL. Our data suggest, that 4D-MRA in combination with sASL can provide functional information that so far has been gained only with selective DSA.

15:24         97.         The Influence of K-T BLAST on Intracranial Aneurismal PC Velocity Mapping Data

Pim van Ooij1, Joppe J. Schneiders1, Marieke E.S. Sprengers1, Ed van Bavel2, Charles B.L.M. Majoie1, Aart J. Nederveen1

1Radiology, AMC, Amsterdam, Noord - Holland, Netherlands; 2Biomedical Engineering & Physics, AMC, Amsterdam, Noord - Holland, Netherlands

k-t BLAST is a measurement acceleration technique by undersampling k-t space. This indicates that some data will be lost during acquisition. It has been shown that phase contrast angiography measurements in the aorta can be accelerated without significant loss of data. In this study it is tested if k-t BLAST can also be used in PCA measurements of intracranial aneurysms without significant loss of accuracy. It is shown that if an aneurysm is large, results are more accurate than in a small aneurysm. A possible explanation is that small aneurysms contain a relatively large amount of pixels where velocity is low and thus where difference between full measurement and k-t BLAST velocities is large. If aneurysms are large enough (>5 mm), k-t BLAST can be used without much loss of accuracy.

15:36         98.         Cerebral Collateral Imaging in Patients with Carotid Stenosis Using MR Perfusion Territory Arterial Spin Labeling, Compared with DSA

Bing Wu1, Xiaoying Wang1, Jia Guo2, Eric C. Wong3, Jue Zhang2, Xuexiang Jiang1

1Radiology of Dept., Peking Uni. 1st hospital, Beijing, China; 2Interdisciplinary academy, Peking University; 3Center for Functional Magnetic Resonance Imaging and Departments of Radiology and Psychiatry, University of California, San Diego

This study was to investigate the presence of collaterals in patients with carotid stenosis and the change of perfusion territory after internal carotid artery stent therapy using the MR perfusion territory imaging.

15:48         99.         TOF MR Angiography at 3.0 Tesla During Acetazolamide Provocation Demonstrates Decreased Vasomotor Reactivity Ipsilateral to a Carotid Artery Stenosis

Reinoud Pieter Harmen Bokkers1, Frank J. Wessels2, H B. van der Worp3, Jaco Zwanenburg4, Jeroen Hendrikse1

1Department of Radiology, UMC Utrecht, Utrecht, Netherlands; 2Faculty of Medical Sciences, University of Groningen, Groningen, Netherlands; 3Department of Neurology, UMC Utrecht, Utrecht, Netherlands; 4Image Sciences Institute, UMC Utrecht, Utrecht, Netherlands

The vasomotor reactivity of the proximal and distal cerebral vasculature was investigated in healthy subjects and patients with a symptomatic stenosis of the ICA. High-resolution MRA was performed at 3T before and 20 minutes after an intravenous administration of acetazolamide. In healthy subjects, vessel diameter increased significantly in 10 of 11 measured arteries. Arteries in hemispheres ipsilateral to the symptomatic ICA showed no significant increase in diameter, whereas in hemispheres contralateral to the stenosis diameters increased significantly in the proximal vasculature. Findings show that high-field MRA combined with a vasodilatory challenge may contribute to a better understanding of vasomotor reactivity.

SPECIAL SYMPOSIUM
SMRT & ISMRM Joint Forum

Room 315                             14:00 - 16:00          Moderators: Gary H. Glover, Bryon A. Mueller, Caron Murray and Douglas C. Noll               

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Recognize the challenges associated with performing a multi-site MRI experiment;

·   Explain how existing multi-center MRI experiments were designed and implemented;

·   Describe the unique challenges associated with executing multi-center structural, diffusion tensor, functional, and perfusion imaging experiments; and

·   Implement a multi-center study using best practices.


14:00       Foundations for Performing any Multi-Center Neuro-Imaging Study

Gary H. Glover

14:18       How to do a Structural Multi-Center Neuro-Imaging Study

                Matthew A. Bernstein

 

14:36       How to do a DTI Multi-Center Neuro-Imaging Study

                Carlo Pierpaoli

 

14:54       How to do a Functional Multi-Center Neuro-Imaging Study

                Bryon A. Mueller

 

15:12       How to do an ASL Multi-Center Neuro-Imaging Study

                Xavier G. Golay

 

15:30       How to do a Multi-Center Neuro-Imaging Study: A Technologist’s Perspective

                Maureen Ainslie

 

15:48       Panel Discussion

                Douglas C. Noll

EDUCATIONAL COURSE
Tools & Tips for Mouse Imaging & Spectroscopy

Room 314                             14:00 - 16:00                                                                              Moderators:  Carles Arús and Klaas Nicolay               

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Explain the main acquisition protocols that are used for in vivo high-resolution MR imaging and spectroscopy of alive mice;

·   Recognize the specific requirements of physiological monitoring of anesthetized mice;

·   Indicate the opportunities and the limitations of the use of clinical MR scanners for research on mice;

·   Recognize the strength and the limitations of the use of genetically modified animal models of human disease for translational research; and

·   Describe the main design concepts of RF coils for MR studies on mouse models.


14:00       Introduction

Klaas Nicolay

14:05       The Strength and Limitations of the Use of Transgenic and Knock-Out Animal Models

                Frederick H. Epstein

 

14:25       High-Field Imaging of Small Animal Brain

                Stephen J. Blackband

 

14:45       Ultra Small Voxel Spectroscopy

                Rolf Gruetter

 

15:05       Diffusion Imaging of Mouse Skeletal and Cardiac Muscle

                Gustav Strijkers

 

 

15:25       The Use of Whole Body Scanners for Mouse MRI Studies

                Brian K. Rutt

 

15:45       The Design of Dedicated RF Coils for Mouse MR

                Dennis W. J. Klomp

CLINICAL INTENSIVE COURSE
MR Physics & Techniques for Clinicians

Room 313A                         16:30 – 18:30                                                                   Moderators:  Marcus Alley and Frank R. Korosec               

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Define and describe the fundamental principles of MR imaging, including the definition of spin magnetization, the Larmor relationship, relaxation phenomena, and the process of using the spin magnetization to produce an image;

·   Explain imaging pulse sequences based upon spin and gradient echoes, including fast spin-echo and echo planar techniques;

·   Design MR imaging protocols for diagnostic applications considering image contrast, spatial resolution, acquisition time, signal-to-noise ratio, and artifacts; and

·   Describe the principles of parallel imaging, high-field imaging, perfusion imaging, diffusion imaging, and functional MR imaging.


16:30       Spin Gymnastics I and II

Walter Kucharczyk and Donald B. Plewes

17:50       k-Space

                Anja C. Brau

Receive Array Technology

Room 312                             16:30-18:30                                                                Moderators: James A. Bankson and Graham Wiggins

16:30         100.       Cutting the Cord - Wireless Coils for MRI

Oliver Heid1, Markus Vester2, Peter Cork3, Peter Hulbert3, David William Huish3

1H Technology and Concepts, Siemens, 91052 Erlangen, Germany; 2H IM MR PLM SC, Siemens, 91052 Erlangen, Germany; 3Technology and Innovation, Roke Manor Research, Romsey, Hampshire, UK

MRI scanner workflow improvement will result from replacing the existing cable connection from patient coils to image processing system with a cordless link. A multiple input multiple output microwave link system is proposed. Parametric upconverters in the patient coils will convert Larmor signals from the coils to microwave frequency. A transceiver array integrated into the bore will provide the local oscillator and receive functions. Parametric amplifiers implement upconversion with gain in simple and cheap circuits. Since only patient coils in the field of view are active the system is ideally suited to whole body scan.

16:42         101.       A Generalized Analog Mode-Mixing Matrix for Channel Compression in Receive Arrays

Jonathan Rizzo Polimeni1, Vijayanand Alagappan1, Thomas Witzel2, Azma Mareyam1, Lawrence Leroy Wald1,2

1A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA; 2Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, USA

Highly parallel arrays of small receiver coils enable dramatic gains in both SNR and accelerated imaging performance, but at a considerable cost in system complexity. Here we present a general analog mode-mixing matrix that can compress a large array coil into a small subset of channels, while retaining most of the SNR of the array. The matrix is calculated via SVD of the whitened signal correlation matrix, and implemented with phase shifters and programmable attenuators. By combining data from a 32-element array into 8 modes the mode-mixing matrix was able to retain 70% of the full-array image SNR.

16:54         102.       element Design for Increased Sensitivity in 64-Channel Wide-Field-Of-View Microscopy

Chieh-Wei Chang1, Steve M. Wright2, Mary Preston McDougall1,2

1Biomedical Engineering, Texas A&M University, College Station, TX, USA; 2Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA

Single Echo Acquisition (SEA) has decreased imaging time dramatically through the implementation of 64 channel array elements to provide spatial localization in the phase encode direction. Previous versions of the array coil employed a planar pair design. This coil design does not afford the SNR values and imaging depth needed to pursue high-resolution applications such as wide-field-of-view microscopy. In this work, a raised-leg coil design was implemented as a variation of the planar pair coil, and improvements in SNR and imaging depth were attained. Future coil modifications will seek to maintain imaging speed while moving into high-resolution applications.

17:06         103.       Resonance Shift Decoupling: A Potential Alternative to Low Input Impedance Preamplifiers

Marc Stephen Ramirez1, James Andrew Bankson1

1The Department of Imaging Physics, The University of Texas M. D. Anderson Cancer Center, Houston, TX, USA

Current minimization schemes are critical to reduce inductive coupling between non-adjacent elements in MRI phased arrays. Traditionally, low input impedance preamplifiers have been used to accomplish this. In this work, we test an alternate method involving a transistor amplifier that is built into the coil to minimize loop current and maximize gain, while simultaneously achieving low-noise operation. Design methodologies involving low-noise, high-gain transistor impedance matching and a shift in the resonance frequency due to the parasitic capacitance of the transistor are described. Initial results indicate the potential to provide effective element decoupling for MRI phased arrays.

17:18         104.       Studies on MR Reception Efficiency and SNR of Non-Resonance RF Method (NORM)

Xiaoliang Zhang1,2, Chunsheng Wang1, Daniel Vigneron1,2, Sarah Nelson1,2

1Department of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA, USA; 2UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco/Berkeley, CA, USA

Non-resonance method (NORM) for MR signal excitation and reception has been advocated due to its unmatched advantages in multinuclear and parallel imaging applications. In this work, the reception efficiency and SNR of the NORM technology were validated. No statistical difference in reception efficiency was observed between NORM and the conventional resonance technology. The advantages of NORM technology is not a trade-off of MR sensitivity.

17:30         105.       The Shielding of RF MRI Coils Using Double-Sided EMI Shield

Ibrahim Abu El-Khair1, Jan G. Korvink1, Juergen Hennig2, Gerhard Moenich3

1Dept. of Microsystems Engineering–IMTEK, University of Freiburg, Freiburg, Germany; 2Dept. of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany; 3Dept. of Radio Frequency Technology, Technical University of Berlin, Berlin, Germany

Radiation losses associated with RF coils increase up to the fourth power of frequency; it becomes significant at high fields above 2 Teslas. Furthermore, loading an RF MRI Coil with a sample leads to a shift in the resonant frequency, f0 away from the one specified. This also leads to a very poor reception at f0. A double-sided EMI (ElecroMagnetic Interference) shield using the CTLM (Coaxial Transmission Line Modeling) technique of shielding restores f0, and eliminates the radiation loss. The mutual capacitive coupling among the neighboring coils within an array, and associated electronics, is also eliminated

17:42         106.       A 30 Channel Receive-Only 7T Array for Ex Vivo Brain Hemisphere Imaging

Azma Mareyam1, Jonathan Rizzo Polimeni1, Vijayanand Alagappan1, Bruce Fischl1,2, Lawrence L. Wald1,3

1A. A. Martinos Center for Biomedical Imaging, Dept. of Radiology,MGH, Charlestown, MA, USA; 2CSAIL, MIT, Cambridge, MA, USA; 3Harvard-MIT Division of Health Sciences and Technology , Harvard-MIT , Cambridge, MA, USA

High-field MRI of ex vivo samples provides 3D image encoding at resolutions capable of resolving laminar and myeloarchitectonic features, thus providing a potential replacement for the technically challenging task of whole-brain histological sectioning. Here we present a 30-channel receive-only coil array for high-resolution whole-cerebral-hemisphere imaging. With this array, whole-hemisphere acquisitions of 150 µm voxel size in which laminar details are clearly detectable are possible within six hours. Considerations for satisfying the many constraints imposed by ex vivo imaging on surface coil are discussed, and imaging performance is compared with other available 3T and 7T arrays.

17:54         107.       Multi-Purpose Flexible Transceiver Array at 7T

Bing Wu1, Chunsheng Wang1, Roland Krug1, Douglas Kelley2, Yong Pang1, Duan Xu1, Sharmila Majumder1,3, Sarah Nelson1,3, Daniel Vigneron1,3, Xiaoliang Zhang1,3

1Radiology&Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; 2GE Healthcare, San Francisco, CA, USA; 3UCSF/UC Berkeley Joint Group Program in Bioengineering, SanFrancisco&Berkeley, CA, USA

A multi-purpose flexible transceiver array was designed for ultra-high field MRI using a mixing technique of primary and 2nd harmonic microstrips. Besides the coil geometry, the number of coil elements in the proposed design is also selectable for different applications. The feasibility of this multi-purpose flexible array has been demonstrated by 7T MR imaging for human wrist, knee, head and liver.

18:06         108.       A 32-Channel Receive Array Coil for Pediatric Brain Imaging at 3T

Vijayanand Alagappan1,2, Graham Charles Wiggins3, Jonathan Rizzo Polimeni3, Lawrence Leroy Wald3,4

1Department  of Radiology, A.A Martinos Center for Biomedical Imaging, Charlestown, MA, USA; 2Department of Biomedical engineering, Tufts University, Medford, MA, USA; 3Department of Radiology, A.A Martinos Center for Biomedical Imaging, Charlestown, MA, USA; 4Health Science and Technology, MIT, Cambridge, MA, USA

We describe a 32 channel receive-only 3T phased array head coil for the pediatric population. The 32-channel coil was built on a close fitting fiberglass helmet with soccer-ball element geometry. SNR gains of 4 and 2 times in the cortex and 1.2 and 2 times in the center of the head were observed when compared to a commercial 32-channel adult head coil and a 12-channel adult head coil. The Maximum G factors were also reduced significantly with the 32-channel coil optimized for the pediatric head imaging.

18:18         109.       Hole-Slotted Phased Array at 7 Tesla

Marcos A. Lopez1,2, Philipp Ehses1, Felix Breuer2, Daniel Gareis1, Peter Michael Jakob1,2

1Experimental Physics 5, University of Wuerzburg, Wuerzburg, Bavaria, Germany; 2Research Center Magnetic Resonance Bavaria, Wuerzburg, Bavaria, Germany

The hole-slot magnetron is used as a HF oscillator in radar applications. A surface coil based on the hole-slot magnetron’s geometry was introduced showing deeper RF penetration than a conventional coil at 1.5 and 4 Tesla. Four different conventional coil geometries were compared with a hole-slotted coil at 7 Tesla. Furthermore a hole-slotted array was built and evaluated. The hole-slotted loop improves RF penetration depth compared to the different loops showing a improved SNR in the second half of the phantom. The images acquired with the hole-slotted array show high SNR as well as good homogeneity and RF penetration depth.

Advances in Hepatobiliary Imaging

Room 316A                         16:30-18:30                                                                  Moderators: Elizabeth M. Hecht and Claude B. Sirlin

16:30         110.       MR Elastography of Dynamic Postprandial Hepatic Stiffness Augmentation in Chronic Liver Disease

Meng Yin1, Jayant A. Talwalkar2, Sudhakar K. Venkatesh3, Richard L. Ehman1

1Department of Radiology, Mayo Clinic, Rochester, MN, USA; 2Division of Gastroenterology & Hepatology , Mayo Clinic, Rochester, MN, USA; 3Diagnostic Radiology, National University of Singapore, Singapore

This preliminary investigation provides evidence that MRE-assessed hepatic stiffness in patients with chronic liver disease has a dynamic component that can increase following a test meal. This may reflect the transient increase in portal pressure that is known to occur in some of these patients postprandially. If confirmed, these findings will provide motivation for further studies to determine the potential value of assessing postprandial hepatic stiffness augmentation for predicting progression of fibrotic disease and the development of portal varices. The technique may also provide new insights into the natural history and pathophysiology of chronic liver disease.

16:42         111.       Carbogen Gas-Challenge BOLD MRI in Rat Liver Fibrosis Model

Ning Jin1,2, Jie Deng1,3, Tamuna Chadashvili4, Yue Zhang4,5, Yang Guo4, Guangyu Yang6, Reed Omary2,4, Andrew C. Larson1,2

1Department of Radiology , Northwestern University, Chicago, IL, USA; 2Department of Biomedical Engineering, Northwestern University, Chicago, IL, USA; 3Department of Medical Imaging, Children's Memorial Hospital, Chicago, IL, USA; 4Department of Radiology, Northwestern University, Chicago, IL, USA; 5Department of Bioengineering, University of Illinois Chicago, Chicago, IL, USA; 6Department of Pathology, Northwestern University, Chicago, IL, USA

Hepatic fibrosis is a dynamic and reversible process leading to regional and global blood perfusion alteration. We hypothesis that in the setting of liver fibrosis BOLD signal changes between normal and hyperoxia conditions would be reduced. In this work, a negative correlation was found between the BOLD response to gas-challenge and the degree of liver fibrosis. Gas-challenge BOLD MRI is a potential non-invasive method for liver fibrosis diagnosis and staging.

16:54         112.       T1ρ-Based MR Imaging for the Non-Invasive Quantification of Extracellullar Matrix Protein Concentration in Hepatic Fibrosis

Dania Daye1, Chenyang Wang, Eric Mellon2, Santosh Gaddam3, Rebecca Wells4, Emma Furth5, Ravinder Reddy3

1Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; 2Department of Biophysics and Molecular Biochemistry, University of Pennsylvania; 3Department of Radiology, University of Pennsylvania; 4Department of Medicine, University of Pennsylvania; 5Department of Pathology and Laboratory Medicine, University of Pennsylvania

While hepatic cirrhosis is a major leading cause of adult death in the US, the gold standard to diagnose and monitor the progress of patients afflicted with this condition remains limited to liver biopsy. Biopsies, however, an often irreproducible and plagued with many complications. T1ρ-based MR imaging is a technique that has previously shown promise in quantifying macromolecular concentration. Given that liver fibrosis manifests as a progressive deposition of extracellular matrix proteins, we hypothesized that T1ρ imaging can be used to quantify protein deposition in fibrosis. Our preliminary results show that T1ρ imaging might have significant potential to provide for a quantitative and non-invasive assessment of hepatic fibrosis.

17:06         113.       In Vivo Assessment of Hepatic Ischemia/Reperfusion Injury in Rat Using Diffusion Tensor Imaging

Jerry S. Cheung1,2, Shu Juan Fan1,2, April M. Chow1,2, Edward S. Hui1,2, Ke Xia Cai1,2, Kwan Man3, Ed X. Wu1,2

1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China; 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China; 3Department of Surgery, The University of Hong Kong, Hong Kong SAR, China

Hepatic ischemia/reperfusion injury (IRI) occurs during liver transplantation, tumor resection, hemorrhagic shock and veno-occlusive disease, and is a major cause of acute liver failure. IRI in liver is also responsible for early organ failure and increased incidence of both acute and chronic rejection after liver transplantation. This study aims to examine the changes of diffusion measurements by diffusion tensor imaging (DTI). The experimental results demonstrated that DTI is useful in identifying hepatic IRI by characterizing the transient changes in mean diffusivity and fractional anisotropy.

17:18         114.       Combined T2-Weighted and MRCP 3D Imaging of the Abdomen Using a Dual-Contrast Single-Slab 3D-TSE Pulse Sequence

John P. Mugler, III1, Wilhelm Horger2, Berthold Kiefer2

1Radiology, University of Virginia, Charlottesville, VA, USA; 2Siemens Healthcare, Erlangen, Germany

This work explored the feasibility of acquiring both T2-weighted and MRCP images within the same 3D turbo-spin-echo (TSE) acquisition. By using a very long flip-angle train of up to 400 echoes that includes variable and constant flip-angle segments, T2-weighted and heavily T2-weighted (MRCP) high-resolution, 3D image sets of the abdomen were obtained with a single 3D-TSE acquisition in a clinically-acceptable acquisition time of 5-7 minutes. This approach has the potential to improve the quality and efficiency of diagnostic evaluation of the abdomen using MRI.

17:30         115.       MRCP After the Injection of Gd-EOB-DTPA: Are 3 Minutes Safe for T2 Weighted Navigated 3D MRCP?

Kristina Ringe1, R Gupta2, Angela Reichel1, Thomas Rodt1, Sabine Dettmer1, Nils Hellige3, Michael Galanski4, Elmar M. Merkle2, Joachim Lotz5

1Department of Radiology, Hannover Medical School, Hannover, Germany; 2Department of Radiology, Duke University School of Medicine, Durham, NC, USA; 3department of Radiology, Hannover Medical School, hannover, Germany; 4Department of Radiology, Hannover Medical School, hannover, Germany; 5Department of Radiology, Hannover Medical School, Hannover , Germany

T2-weighted respiration navigated MRCP was performed before and 3.3+/-0.4min after administration of GD-EOB-DTPA in 21 patients. SNR in bile ducts was assessed to quantify alterations in the quality of MRCP induced by biliary excretion of the contrast agent. SNR decreased by 26.5 +/- 33.5% in the MRCP after the injection of GD-EOB. Maximal decrease of SNR was 90% making the MRCP non-diagnostic. A non-significant tendency for larger decreases of SNR in younger patients and preserved SNR in patients with parenchymal disease was seen.  GD-EOB-DTPA should be injected after a T2w-MRCP to avoid negative effects on the quality of the MRCP.

17:42         116.       Combining Diffusion-Weighted MR Imaging with Gd-EOB-DTPA Enhanced MR Imaging Improves the Detection of Colorectal Liver Metastases

Dow-Mu Koh1, Toni Wallace1, Erica Scurr1, David J. Collins1,2, Angela Riddell1

1Department of Radiology, Royal Marsden Hospital, Sutton, Surrey, UK; 2CR UK Clinical Magnetic Resonance Research Group, Institute of Cancer Research, Sutton, Surrey, UK

The combination of diffusion-weighted MR imaging with Gd-EOB-DTPA enhanced T1-weighted MR imaging resulted in the highest diagnostic accuracy for the detection of colorectal liver metastases compared with either technique on its own. Combining both techniques appear to be optimum for defining the burden and distribution of liver metastases in patients with colorectal cancer to inform management strategies.

17:54         117.       Ultra High Spatio-Temporal Resolution Hepatic MRI Using a Novel 2-Point Dixon Time Resolved 3D SPGR Sequence at 3T

Manojkumar Saranathan1, Dan Rettmann1, Ersin Bayram2, Christine Lee3, James Glockner3

1Applied Science Laboratory, GE Healthcare, Rochester, MN, USA; 2MR Engineering, GE Healthcare, Waukesha, WI, USA; 3Dept. of Radiology, Mayo Clinic, Rochester, MN, USA

Dynamic contrast enhanced MRI (DCEMRI) is commonly used in abdominal-pelvic imaging for detection and characterization of primary and metastatic lesions. It affords adequate spatial resolution but the temporal resolution is often insufficient. Optimal timing of the contrast arrival is critical in capturing the arterial phases and in improving lesion conspicuity. Traditional fat suppression methods perform suboptimally at 3T due to Bo and B1 inhomogeneities, causing non-uniform fat suppression across the image and signal loss. We report clinical results of a novel DCEMRI technique called META (Multi-Echo Tricks Acquisition) that combines a multi-echo TRICKS scan with a two-point Dixon fat-water reconstruction algorithm to generate fat-only and water-only time resolved images at very high spatio-temporal resolution. META was scanned on 23 patients referred for hepatic MRI.

18:06         118.       Diffusion-Weighted MR Imaging (DWI) Using TRacking Only Navigator Echo (TRON): Initial Clinical Evaluation and Comparison to Respiratory Triggered and Free Breathing DWI

Thomas Kwee1, Taro Takahara1, Tetsuo Ogino2, Gwen Herigault3, Maarten van Leeuwen1, Willem Mali1, Peter Luijten1

1Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands; 2Philips Healthcare, Tokyo, Japan; 3Philips Healthcare, Best, Netherlands

Respiratory triggered (RT) and free breathing (FB) diffusion-weighted MR imaging (DWI) of the liver suffer from a prolonged examination time and image blurring, respectively. The TRacking Only Navigator echo (TRON) technique allows continuous real-time slice tracking and may be an excellent alternative. In this study, conspicuity of liver metastases (N=14) between TRON, RT, and FB DWI was equal, while actual scan time of RT DWI was two to three times longer and FB DWI inherently suffers from image blurring. Reproducibility of ADC measurements of liver metastases among TRON, RT and FB DWI was moderate to poor.

18:18         119.       Clinical Liver MRI at 3.0 Tesla Using Parallel RF Transmission with Patient-Adaptive B1 Shimming

Guido Matthias Kukuk1, Jürgen Gieseke1,2, Michael Nelles1, Roy König1, Magnus Andersson1, Eugen Muschler1, Petra Mürtz1, Jeroen Stout2, Marco Nijenhuis2, Frank Träber1, Nuschin Morakkabati-Spitz1, Daniel Thomas1, Christiane Katharina Kuhl1, Hans Heinz Schild1, Winfried Albert Willinek1

1Department of Radiology, University of Bonn, Bonn, NRW, Germany; 2Philips Healthcare, Best, Netherlands

The clinical implementation of high field MRI systems has introduced new challenges for body imaging with respect to B1 field non-uniformities, generation of standing waves and signal loss particularly in abdominal imaging. To achieve a more homogeneous excitation we evaluated patient-adaptive RF shimming using parallel RF transmission for liver imaging in 22 patients at 3.0 Tesla. Our data demonstrate a significant improvement of image quality and lesion conspicuity in T2-TSE sequences and DWI.

fMRI Fluctuations

Room 323ABC                    16:30-18:30                                                                          Moderators: Rasmus M. Birn and Mark J. Lowe

16:30         120.       Resting State FMRI of Retinotopically Defined Sub-Regions in Human Visual Cortex

Egbert J. W. Bleeker1,2, Hubert Fonteijn1,3, Elena Shumskaya1, Jens Schwarzbach1,4, David G. Norris1,5

1Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands; 2Leiden University Medical Centre, Leiden, Netherlands; 3University College , London, UK; 4Centre for Mind/Brain Science, Trento, Italy; 5Erwin L Hahn Institute for MRI, Essen, Germany

This study examines the uniqueness of resting state connections between sub-regions of the human visual cortex. The sub-regions are defined using retinotopic mapping: eccentricity for central and peripheral regions; polar mapping for the main visual regions, and also to subdivide these into octants. Connectivity between sub-regions is evaluated using the partial correlation coefficients. Central to central and peripheral to peripheral connections are strong, but central to peripheral connections weaker. Octants generally show significant connections to either the same octant in a hierarchically adjacent or homologous area, or to a different octant in the same retinotopic region.

16:42         121.       Sources of FMRI Signal Variance in the Human Brain at Rest: A 7T Study

Marta Bianciardi1, Masaki Fukunaga1, Peter van Gelderen1, Silvina G. Horovitz1, Jacco A. de Zwart1, Karin Shmueli1, Jeff H. Duyn1

1Advanced MRI Section, LFMI, NINDS, National Institutes of Health, Bethesda, MD, USA, Bethesda, MD, USA

To exploit the increased BOLD contrast available at 7T for fMRI studies, it is crucial to identify the various noise sources. We determined the contribution of noise to fMRI signal fluctuations in the visual cortex and in the gray matter at 7T during rest. The following noise sources were considered: scanner instability, motion and BOLD effects due to respiration and cardiac cycles, thermal noise, and other sources, tentatively attributed to spontaneous neuronal activity. Our findings demonstrate that at 7T with a resolution of 3mm3 spontaneous fMRI activity is still one of the major contributors to the total fMRI signal fluctuations.

16:54         122.       Physiological Noise in Gradient Echo and Spin Echo EPI at 3T and 7T

Christina Triantafyllou1,2, Jonathan R. Polimeni2, Mattijs Elschot2,3, Lawrence L. Wald2,4

1A.A. Martinos Imaging Center,  McGovern Institute for Brain Research, MIT, Cambridge, MA, USA; 2A.A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Charlestown, MA, USA; 3Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands; 4Harvard-MIT Division of Health Sciences and Technology, MIT, Cambridge, MA, USA

The physiological noise in both spin echo and gradient echo EPI sequences as a function of (thermal) image SNR (SNR0) is investigated by modulating the spatial resolution, receive coil, and field strength. Our findings demonstrate that physiological noise in both sequences exhibit similar properties and the relationship between time-course SNR (tSNR) and SNR0 is well described by the same model. The largest gains in tSNR as a function of voxel size occurred at the highest spatial resolution. At coarser spatial resolutions, both field strengths and sequences showed asymptotic behavior, with higher field strengths nearing the asymptote at smaller voxel volumes.

17:06         123.       Insights Into the Origin of Spontaneous Coherent BOLD Fluctuations in a Resting Rat Brain Under Varied Isoflurane Anesthesia Depth

Xiao Liu1,2, Xiao-Hong Zhu1, Yi Zhang1, Wei Chen1,2

1CMRR, Radiology, University of Minnesota, Minneapolis, MN, USA; 2Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA

This study observed the spontaneous coherent BOLD fluctuations in the somatosensory system of isoflurane-anesthetized rats. It was found that both the amplitude and coherence strength of the BOLD fluctuations could be modulated by changing the anesthesia level in the critical range of 1.8% ~ 2.2% isoflurane, and such anesthesia-level-dependent modulation of BOLD fluctuation is very similar to that of CBF fluctuation signal, which has been proven to be tightly coupled with simultaneous-recorded EEG signals. Therefore, the overall results suggest the neural origin of coherent BOLD fluctuations observed in the present study and thus provide an important MRI signal source for mapping resting-state connectivity.

17:18         124.       Spatiotemporal Correlation Between Alpha Modulation and BOLD Fluctuation in an Eyes-Open-Eyes-Closed Task

Lin Yang1, Zhongming Liu1, Cristina Rios1, Han Yuan1, Bin He1

1Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA

The purpose of this study is to investigate the spatial and temporal relationship between the electrophysiological alpha rhythmic modulation and the BOLD fluctuation using an eyes-open-eyes-closed task. We reconstructed the spatiotemporal cortical source activity underlying the task-modulated EEG alpha rhythm. The resulting source activity was compared, in both space and time, with the BOLD signal recorded with the same task. The cortical regions generating alpha modulation were co-localized with the fMRI activations/deactivations within the occipital and parietal lobes, where the alpha modulation was found temporally negatively correlated with the BOLD fluctuation. The results may suggest a common neural origin that accounts for both alpha modulation and BOLD fluctuation due to transitions between two common resting conditions.

17:30         125.       Functional MRI Study on Brain Plasticity Induced by Different Peripheral Nerve Injury Patterns: What Makes the Difference?

Rupeng Li1, Seth Jones2, Christopher Pawela1, Maida Parkins2, Daniel Shefchik1, Mark Bosbous2, Ji-Geng Yan2, Safwan S. Jaradeh3, Hani S. Matloub2, James S. Hyde1

1Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA; 2Plastic Surgery, Medical College of Wisconsin, Milwaukee, WI, USA; 3Neurology, Medical College of Wisconsin, Milwaukee, WI, USA

This study reveals, for the first time using (fMRI), brain plasticity patterns that are induced by various peripheral nerve injuries. The methodology provides a laboratory basis for selection of optimum surgical procedures.

17:42         126.       Development of the Brain Default Mode Network from Wakefulness Into Slow Wave Sleep

Philipp G. Sämann1, Renate Wehrle1, Victor I. Spoormaker1, David Höhn1, Henning Peters1, Florian Holsboer1, Michael Czisch1

1Max-Planck-Institute of Psychiatry, Munich, Germany

We report preserved DMN activity throughout all human NREM sleep stages, including so far unreported human slow wave sleep, from EEG validated group analysis. Vigilance was found a critical determinant of general DMN strength and of posterior and anterior DMN nodes as well as temporomesial contributions. We observed retreat of temporomesial contributions to the DMN, possibly related to reduced access to memory during sleep, reduction of PCC/retrosplenial and thalamic contribution, likely reflecting more the arousal systems, and increasing decoupling of medial prefrontal areas from the DMN, that may reflect reduced self-awareness.

17:54         127.       Decoupling of the Default Mode Network During Deep Sleep

Silvina G. Horovitz1,2, Allen R. Braun3, Walter S. Carr4, Dante Picchioni5, Thomas J. Balkin5, Masaki Fukunaga2, Jeff H. Duyn2

1Human Motor Control Section - MNB, NINDS-NIH, Bethesda, MD, USA; 2Advanced MRI - LFMI, NINDS-NIH, Bethesda, MD, USA; 3Language Section Voice, Speech and Language Branch , NIDCD - NIH, Bethesda, MD, USA; 4MSC USN, Naval Medical Research Center, Silver Srping, MD, USA; 5Department of Behavioral Biology, Walter Reed Army Institute of Research, Silver Srping, MD, USA

The default-mode-network (DMN) is a collection of brain regions highly active in absence of overt behavior. Its function has been attributed to self-reflective thoughts, though it has also been observed in light-sleep and in anesthetized monkeys. Here, we studied the human DMN connectivity during deep sleep, a condition devoid of self-reflective thoughts and low conscious awareness. We show a decoupling of anterior and posterior portions of the DMN, suggesting that reduction of consciousness is reflected in altered levels of network coherence. The activity in each area remains unchanged suggesting it is not activity per-se but rather the coherent activation of the parts that lead to a conscious experience.

18:06         128.       Influence of Spontaneous BOLD Fluctuation on Stimulus-Evoked BOLD in Human Visual Cortex Using Event-Related Paradigm

Xiao Liu1, Xiao-Hong Zhu1, Wei Chen1

1CMRR, Radiology, University of Minnesota, Minneapolis, MN, USA

This study found that the spontaneous BOLD fluctuations account for the trial-to-trial variation of stimulus-evoked BOLD responses in human visual cortex, and thus confirmed the linear superimposition of spontaneous BOLD fluctuation and stimulus-evoked BOLD signal in the event-related fMRI studies. Combined with the results from one previous study using continuous visual stimulation, it also suggested that the instantaneous stimuli used by the event-related studies could probably only perturb the spontaneous brain activity briefly and slightly, and thus result in the linear superimposition of BOLD signals approximately, which however could not hold when continuous stimuli are used to constantly stimulate the brain.

18:18         129.       Resting-State Connections in Prefrontal Cortex Indicate Cognitive Network Efficiency During Working Memoryτ

Jolyn Nicole Alexis D'Andrea1, Bradley G. Goodyear2

1Medical Science, University of Calgary, Calgary, Alberta, Canada; 2Radiology, University of Calgary, Calgary, Alberta, Canada

The dorsolateral prefrontal cortex (DLFPC) has been identified as critical for working memory, especially as task difficulty increases. The current study used fMRI to investigate resting-state connectivity between left and right DLPFC, and its relationship to recruitment of right DLFPC during a working memory task. Our results show that subjects exhibiting greater resting-state connectivity recruit DLPFC in the right hemisphere to a lesser degree during the performance of a working memory task, as the task becomes more complex. This suggests that subjects with greater resting-state connectivity may possess more efficient cognitive networks during working memory task performance.

MRS Methodology

Room 315                             16:30-18:30                                                          Moderators: Gabriele R. Ende and Malgorzate Marjanska

16:30         130.       BISEP-Based, Ultra-Short TE 1H–[13C] NMR Spectroscopy of the Rat Brain at 14.1 T

Lijing Xin1, Bernard Lanz1, Hanne Frenkel1, Rolf Gruetter1,2

1Laboratory of functional and metabolic imaging, Ecole Polytechnique Federale de Lausanne (EPFL), Lausanne, Switzerland; 2Department of Radiology, University of Lausanne , Lausanne, Switzerland

Indirect detection of 13C label through proton offers higher sensitivity but suffers from lower spectral resolution, such as the GluC3 and GlnC3 region. A novel 1H-[13C] sequence combining SPECIAL localization and BISEP pulse was proposed and applied in vivo during infusion of the glia-specific substrate - [2-13C] acetate at 14.1T. The results showed the separate measurement of GluC4, GlnC4, GlnC3 and GluC3 time courses with high temporal resolution at 14.1T, which greatly enhanced the ability to study neuron-glial metabolism using 1H-[13C] NMR spectroscopy.

16:42         131.       High Acceleration 3D Compressed Sensing Hyperpolarized 13C MRSI of a Transgenic Mouse Model of Liver Cancer

Simon Hu1,2, Asha Balakrishnan3, Michael Lustig4, Peder E Z Larson1, Robert Bok1, John Kurhanewicz1,2, Sarah J. Nelson1,2, John M. Pauly4, Andrei Goga3, Daniel B. Vigneron1,2

1Dept. of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; 2UCSF & UCB Joint Graduate Group in Bioengineering, San Francisco, CA, USA; 3Dept. of Medicine, Division of Hematology/Oncology, University of California, San Francisco, CA, USA; 4Dept. of Electrical Engineering, Stanford University, Stanford, CA, USA

Hyperpolarized technology has enabled rapid in vivo 13C spectroscopic imaging at high SNR. Acquisition time limitations due to rapid hyperpolarized signal loss make accelerated imaging methods, such as compressed sensing, extremely valuable. In this project, we developed a 3.4-fold accelerated compressed sensing 3D-MRSI sequence and acquired hyperpolarized spectra in a transgenic mouse model of liver cancer, observing elevated lactate and alanine in tumors at a 0.034 cm3 spatial resolution. We also developed a 7.5-fold accelerated sequence, which we validated in simulations and phantom experiments and applied to prostate cancer mice to achieve 4-fold resolution enhancement in approximately half the acquisition time.

16:54         132.       Cost Function Guided 3rdorder B0 Shimming for MR Spectroscopic Imaging at 7T

Jeroen Cornelis Willem Siero1,2, Vincent Oltman Boer2, Johannus Marinus Hoogduin1,2, Peter R. Luijten2, Dennis W. Klomp2

1Brain Division, University Medical Center Utrecht, Utrecht, Netherlands; 2Radiology, University Medical Center Utrecht, Utrecht, Netherlands

A novel shimming method was developed for finding optimal shim fields that minimize B0 inhomogeneities on a user-defined region of interest while confining the B0 inhomogeneities outside this ROI. Experiments show that employing this shimming approach, chemical shift imaging (CSI) can be obtained without baseline distortions while maintaining a narrow spectral line width.

17:06         133.       Higher Order B0 Shimming of the Human Brain at 7T

Hoby Patrick Hetherington1, Andrey M. Kuznetsov1, Nikolai I. Avdievich1, Jullie W. Pan1

1Neurosurgery, Yale University, New Haven, CT, USA

Ultrahigh field systems (7T), offer significant advantages for spectroscopic imaging studies of the human brain. Although excellent B0 homogeneity is a requisite for SI, the hardware requirements in terms of shim strength and shim order necessary for 7T is controversial, with the majority of systems delivered having only 2nd order shims. The goal of this work was to: 1) determine the role of 3rd order shims for SI studies at 7T in two representative regions (the frontal and temporal lobes); 2) characterize the remaining inhomogeneity and 3) demonstrate high resolution spectroscopic imaging in the frontal and temporal lobes.

17:18         134.       A Comparison of Two Phase Correction Strategies in Multi-Channel MRSI Reconstruction

Wei Bian1, Jason C. Crane1, Wonjoon Sohn2, Ilwoo Park1,3, Esin Ozturk-Isik1, Sarah J. Nelson1,3

1Radiology, University of California San Francisco, San Francisco, CA, USA; 2Computer Science, University of California Berkeley, Berkeley, CA, USA; 3Program in Bioengineering, University of California San Francisco, San Francisco, CA, USA

Two phase correction strategies for the reconstruction of multi-channel MRSI were compared in this study. The first is to find the optimal phase for voxels from each channel prior to coil combination. The second is to determine the optimal phase from the sum of the spectra from the central 8 voxels from each channel, and then applying this phase to all voxels in that channel prior to coil combination. Results from phantom and glioma patient experiments showed that the first strategy yielded a slightly improved phase correction for high SNR data but the second was more robust and accurate for the clinical relevant flyback echo-planar encoding data.

17:30         135.       High Resolution 31P Magnetic Resonance Spectroscopic Imaging with Polarization Transfer of Phosphomono and -Diesters in the Human Brain at 3T

Jannie Petra Wijnen1, Tom W.J. Scheenen1, Arend Heerschap1

1Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Gelderland, Netherlands

(Glycero)phosphocholine and (glycero)phosphoetanolamine are important substances in membrane metabolism, and can be detected in the brain by 31P MRS. We have developed a spectroscopic imaging sequence with efficient 1H to 31P polarisation transfer, optimized for the signals of PE, PC, GPE and GPC by using chemical shift selective refocusing pulses. Here we present the first results of the ratios of these compounds in the cerebellum, white matter and gray matter of the normal human brain at different ages.

17:42         136.       31P Exchange Sensitive Imaging in Human Brain at 7T

Jullie W. Pan1,2, Nikolai Avdievich1, Dennis Spencer1, Hoby P. Hetherington1,3

1Neurosurgery, Yale University School of Medicine, New Haven, CT, USA; 2BME, Yale University School of Medicine, New Haven, CT, USA; 3Radiology, Yale University School of Medicine, New Haven, CT, USA

As a functional measure of bioenergetic state in human brain, 31P MRS is sensitive to effects of relaxation, concentration and chemical exchange. While the sensitivity to creatine kinase has been well used in muscle spectroscopy with saturation transfer experiments it has been less developed for brain. Given that creatine kinase rates have demonstrated sensitivity to physiologic condition it may be informative for pathologic state. We implemented exchange sensitive weighting to the 31P spectroscopic imaging acquisition, parameters based on 3site exchange simulations to ascertain sensitivity to varying levels of exchange. We demonstrate this approach in controls and epilepsy patients at 7T.

17:54         137.       Improved 31P Saturation Transfer Approach for Imaging Cerebral ATP Metabolic Rates In Vivo

Xiao-Hong Zhu1, Qiang Xiong1,2, Yi Zhang1, Wei Chen1,2

1CMRR, Department of Radiology, University of Minnesota Medical School, Minneapolis, MN, USA; 2Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA

The cerebral ATP metabolism plays a central role in neuroenergetics for supporting brain energy and function. The approach of combining in vivo 31P MRS with magnetization saturation transfer (ST) is useful for noninvasively determining the cerebral metabolic rates of ATP involving ATPase reaction (CMRATP) and CK reaction (CMRCK). However, the conventional ST measurement requires a fully relaxed condition before the frequency-selected γ-ATP saturation for precise quantification of flux, resulting in a long repetition time (TR) and low efficiency. This poses a major hurdle for 3D CSI application in which many scans are needed. In this study, we implemented a newly developed ST strategy, which can achieve the same saturation transfer effect with a much short TR, with 3D 31P CSI for imaging CMRATP and CMRCK in animal at 9.4T with high efficacy.

18:06         138.       Dual Band Water and Lipid Suppression for Multi-Slice MRSI of Human Brain at 3T

He Zhu1,2, Ronald Ouwerkerk1, Richard A.E. Edden1,2, Michael Schär1,3, Peter B. Barker1,2

1Russell H Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Maryland, MD, USA; 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Maryland, MD, USA; 3Philips Healthcare, Cleveland, OH, USA

A dual band water and lipid suppression sequence was developed for in vivo multi-slice MRSI of the brain. This pre-pulse sequence consists of five frequency modulated pulses with variable delay times and flip angles. Both timing and flip angle parameters were optimized via simulations to suppress water and lipid signals simultaneously. Outer volume suppression pulses were integrated into the sequence to improve lipid suppression, particularly for lipid resonances outside of the dual-band suppression bandwidth. Experimental results at 3T show comparable water suppression performance to the longer VAPOR sequence, and excellent lipid suppression factors.

18:18         139.       In Vivo Cross-Relaxation in ATP in Skeletal Muscle Measured by 31P Saturation Transfer MRS

Christine Nabuurs1, Bertolt Huijbregts1, Andor Veltien1, Be Wieringa2, Cees Hilbers3, Arend Heerschap1

1Radiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands; 2Cellbiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands; 3Physical Chemistry, Radboud University, Nijmegen, Netherlands

ATP involvement in multiple enzymatic exchange reactions has been extensively studied by 31P saturation transfer (ST) MR spectroscopy. So far, however, little attention has been paid to in vivo 31P-31P cross-relaxation processes possibly interfering in the analysis of the exchange rates. Here we performed 31P ST experiments on hind-limb muscle of mice with deficiencies in adenylate and creatine kinase. In these conditions the enzyme contributions to exchange effects can be excluded and cross relaxation contributions to ST effects observed. However, in experiments on ATP, free in solution, cross relaxation effects did not become manifest. This was corroborated by theoretical calculations. These results indicate that in vivo ATP is involved in the formation of short lived complexes where cross relaxation is effective and saturation effects can be can be transferred to the free ATP.

Imaging in Brain Tumor - Diagnosis

Room 311                             16:30-18:30                                                                     Moderators: Micheal D. Phillips and Brian D. Ross

16:30         140.       Simultaneous MR and PET Imaging of Human Brain Tumors Using an Integrated MR-PET Scanner

Ciprian Catana1, Thomas Benner1, Andre van der Kouwe1, Dominique L. Jennings1, Michael Hamm2, Poe-Jou Chen1,3, Ovidiu C. Andronesi1, Elizabeth R. Gerstner4, Larry Byars5, Christian Michel5, Josef Pfeuffer2, Matthias Schmand5, Bruce R. Rosen1, A. Gregory Sorensen1

1MGH, Radiology, A.A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA; 2Siemens Medical Solutions USA Inc., Charlestown, MA, USA; 3Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA; 4Massachusetts General Hospital, Boston, MA, USA; 5Siemens Medical Solutions USA Inc., Knoxville, TN, USA

Magnetic resonance imaging (MRI) and positron emission tomography (PET) are widely used imaging technologies with both clinical and biomedical research applications. An MRI-compatible PET scanner prototype has been built for brain applications that allows data from both modalities to be acquired simultaneously. In this work, we demonstrate the feasibility of this combined system for performing simultaneous MR-PET data acquisition in brain tumor patients, including dynamic data acquisition.

16:42         141.       Molecular Imaging of High-Grade Brain Tumors Using Endogenous Protein and Peptide-Based Contrast

Zhibo Wen1, Shuguang Hu2, Fanheng Huang1, Peter C.M. van Zijl3,4, Jinyuan Zhou3,4

1Department of Radiology, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China; 2Philips Healthcare, Guangzhou, Guangdong, China; 3Department of Radiology, Johns Hopkins University, Baltimore, MD, USA; 4F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA

Amide proton transfer (APT)-MRI is a chemical exchange saturation transfer (CEST) based approach in which the amide protons of endogenous proteins and peptides are irradiated to accomplish detection using the water signal. In this abstract, the APT approach was added to standard brain MRI for tumor patients at 3T. The initial results (n = 4) show that APT imaging can enhance noninvasive identification of tissue heterogeneity in high grade brain tumors.

16:54         142.       Random Walk Model for Predicting Patterns of Microscopic Glioma Spread Using DTI: A Prospective Study

AnithaPriya Krishnan1, Delphine Davis2, Paul Okunieff3, Walter O'Dell4

1Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA; 2Departments of Imaging Sciences and Radiation Oncology, University of Rochester, Rochester, NY, USA; 3Department of Radiation Oncology, University of Rochester, Rochester, NY, USA; 4Departments of Radiation Oncology and Biomedical Engineering, University of Rochester, Rochester, NY, USA

Current methods for determining the treatment margins needed to encompass microscopic tumor spread for Stereotactic Radiotherapy (SRT) are inadequate as recurrences often occur at/near the boundary of the treatment margin. If our hypothesis that paths of elevated water diffusion along white matter tracts provide a preferred route for migration of tumor cells is correct, then future SRT plans would be modified accordingly to reduce the incidence of recurrence. Areas of high cell concentration as prospectively predicted by our random walk model based on MR DTI matched the subsequent appearance of secondary tumors in patients undergoing SRT for high-grade gliomas.

17:06         143.       Contrast-Enhanced Three-Dimensional Whole-Brain Black-Blood Imaging for Efficient Detection of Small Metastases

Jaeseok Park1, Eung Yeop Kim1,2

1Department of Radiology and Research Institute of Radiological Science, Yonsei University College of Medicine, Seoul, Korea; 2Brain Korea 21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea

Contrast-enhanced three-dimensional T1-weighted MR imaging based on magnetization-prepared-rapid-gradient-recalled-echo (MP-RAGE), has been shown to be sensitive for the detection of small brain metastases due to the T1-shortening effect of contrast agent. However, since contrast agent remains in blood and tumors, and thus increases signal intensity in both parts, it is challenging to accurately detect the brain tumors using the conventional method. The purpose of this work was to develop a novel contrast-enhanced 3D whole-brain black-blood imaging method which enhances the signal intensity of brain tumor while selectively suppressing that of blood, and thus enhance the accuracy of diagnosis for small brain metastases

17:18         144.       New Diffusion Restriction Precedes the Development of Enhancing Tumor in Glioblastomas

Ajay Gupta1,2, Sahil Sood1,2, Robert Young2, Sasan Karimi2, Zhigang Zhang2, Andrei Holodny2

1Weill Cornell Medical College, New York City, NY, USA; 2Memorial Sloan Kettering Cancer Center, New York City, NY, USA

Assessment of glioma progression vs. stability or response has traditionally relied on typical MR imaging characteristics, such as changes in tumor size and extent of contrast enhancement. Finding earlier imaging biomarkers of glioma progression can have an enormous impact on clinical treatment decision-making. In this study, we demonstrate that in a subset of patients with GBM, new nonenhancing regions of restricted diffusion can predict the future development of enhancing tumor and tumor progression. This information may therefore be useful in guiding clinical decision making and treatment changes prior to the development of abnormal tumoral enhancement.

17:30         145.       The Value of MRS Detectable Lipids as Prognostic Markers in Paediatric Brain Tumours

Martin Wilson1,2, Carole Cummins2, Leslie MacPherson2, Yu Sun2,3, Kal Natarajan2, Nigel P. Davies2, Theo N. Arvanitis2,3, Risto A. Kauppinen4, Andrew C. Peet1,2

1Cancer Sciences, University of Birmingham, Birmingham, West Midlands, UK; 2Oncology, Birmingham Children's Hospital Foundation Trust, Birmingham, West Midlands, UK; 3School of Electronic, Electrical & Computer Engineering, University of Birmingham, Birmingham, West Midlands, UK; 4Dartmouth Medial School, Dartmouth College, Hanover, NH, USA

Brain tumours are an important cause of childhood morbidity and mortality and new approaches to brain tumour assessment and therapy are a priority for cancer research. In this study, short-echo time single voxel in-vivo 1H MRS was used to investigate 121 pre-treatment peadiatric brain tumour cases. Patients were followed-up for period of up to 5 years and lipids were found to be predictive of long term survival.

17:42         146.       Possibilistic Classification of Brain Tumors by MRS Based on Functional Data Analysis and Subpattern Discovery

Juan M García-Gómez1, Irene Epifanio2, Margarida Julià-Sapé3,4, Daniel Monleón3,5, Javier Vicente1, Salvador Tortajada1, Elies Fuster1, Angel Moreno-Torres6, Andrew Peet7,8, Franklyn Howe9, Bernardo Celda3,10, Carles Arús3,4, Montserrat Robles1

1ITACA-IBIME, Universidad Politécnica de Valencia, Valencia, Spain; 2Departament de Matemàtiques, Universitat Jaume I, Valencia, Spain; 3CIBER de Bioingeniería, Biomateriales y Nanomedicina, Spain; 4Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain; 5Fundación de Investigación del Hospital Clínico Universitario de Valencia, Valencia, Spain; 6Research Department, Centre Diagnòstic Pedralbes, Barcelona, Spain; 7University of Birmingham, Birmingham, UK; 8Birmingham Children’s Hospital, Birmingham, UK; 9St George’s Hospital Medical School, London, UK; 10Departamento de Química-Física, Universitat de València, Valencia, Spain

When designing a Clinical Decision Support System for Brain Tumors based on MRS, it would be of interest to deal with any prospective case. Besides, due to the possible acquisition artifacts, baseline differences, or molecular artifacts in MRS-SV, the in-vivo MRS pattern may be heterogeneous within each diagnostic class. We present a possibilistic classifier evaluated on the largest multicenter database of MRS of brain tumors available to us based on FDA and subpattern analysis. It overperformed the classical approaches. The detected in-vivo MR spectral pattern subtypes could be useful for the interpretation of the natural heterogeneity of the diagnoses.

17:54         147.       Development of an MR Spectroscopic Index to Differentiate Tumor from Treatment Induced Gliosis

Radhika Srinivasan1, Jan Wooten1, Jason C. Crane1, Soonmee Cha1, Suzanne Chang1, Scott Vandenberg1, John Kurhanewicz1, Sarah J. Nelson1

1UCSF, San Francisco, CA, USA

The goal of this study was to identify MR spectroscopic (MRS) markers that are likely to be able to differentiate active tumor from treatment induced gliosis. This is an important problem because while tumor regions should be included in follow-up treatment plans, regions represented by gliosis should be left untouched since these areas represent areas of normal brain that are influenced by treatment. Typically high choline levels are used to indicate tumor presence. The challenge in differentiating tumor from gliosis using this metric is that both of them could result in elevated levels of choline. To evaluate strategies to resolve this ambiguity we first determine the characteristic MR Spectroscopic markers that differentiate tumors from gliosis using High Resolution Magic Angle Spectroscopy (HR-MAS) of samples that are confirmed to belong to either tumor or gliosis using histopathology. The specific markers derived from this study are evaluated by ex-vivo HR-MAS of biopsies from within tumor regions in patients with newly diagnosed GBM. Finally these markers are evaluated against known MR markers of tumor presence from in-vivo 3T MR data. Following these studies the development of a suitable MRS index that has the potential to differentiate tumor from gliosis will be presented.

18:06         148.       Targeted Use of 1H-MRS Is as Accurate as Histology in the Diagnosis of Glioblastoma Multiforme.

Greg Fellows1, Alan James Wright2, Naomi Sibtain3, Philip Rich4, Kirstie S. Opstad2, Dominick J.O McIntyre5, Brian Anthony Bell1, John Griffiths5, Franklyn Arron Howe6

1Academic Neurosurgery Unit, St. George's University of London, London, UK; 2Basic Medical Sciences, St. George's University of London, London, UK; 3Neuroradiology, King’s College Hospital NHS Trust, London, UK; 4Neuroradiology, St. George's Hospital NHS Trust, London, UK; 5CRUK Cambridge Research Institute, Cambridge, UK; 6Cardiac and Vascular Sciences, St. George's University of London, London, UK

Oncological practice requires histopathological confirmation of glioblastoma multiforme (GBM) prior to radiotherapy. If lesion location or patient health precludes surgical debulking prior to treatment, then 1H MRS could provide a clinically useful alternative diagnosis to biopsy. 89 patients’ with 1H-MRS, CT and MRI were evaluated neuroradiologically and spectroscopically. Of patients selected on clinical and neuroradiological grounds for diagnostic biopsy alone, there was 100% concordance between a spectroscopy and histopathological diagnosis of GBM. We propose a 1H MRS protocol for accurate diagnosis of a subset of GBM patients for which a surgical procedure and treatment delay could be avoided.

18:18         149.       Sodium MRI and 1H MRS in the Diagnosis and Monitoring of Primary Brain Tumors

Fernando Emilio Boada1, Yongxian Qian1, Denise Davis1, Frank Lieberman2, Ronald Hamilton3, Arlan Mintz4, Eric Schwartz1

1Radiology, University of Pittsburgh, Pittsburgh, PA, USA; 2Neuro-oncology, University of Pittsburgh, Pittsburgh, PA, USA; 3Neuropathology, University of Pittsburgh, Pittsburgh, PA, USA; 4Neurosurgery, University of Pittsburgh, Pittsburgh, PA, USA

In this abstract we perform concurrent proton MRS and sodium MRI of primary brain tumor at 3 Tesla and evaluate the use of the two techniques with regards to ease of use, reproducibility and the correlation between their findings across tumor types.

Manganese Enhanced MRI: Methods & Applications

Room 310                             16:30-18:30                                                                                Moderators: Tom C.C. Hu and Robia Pautler

16:30         150.       Voxel Based Morphometric Analysis of the Gbx2 Mutant Mouse Phenotype via MEMRI

Kamila Urszula Szulc1,2, Brian J. Nieman1,2, Roy V. Sillitoe3, Alex L. Joyner3, Daniel H. Turnbull1,2

1Kimmel Center for Biology and Medicine at the Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY, USA; 2Radiology, NYU School of Medicine, New York, NY, USA; 3Developmental Biology, Sloan-Kettering Institute, NY, New York, NY, USA

The cerebellum (Cb) is a highly patterned brain structure with a stereotypical foliation pattern playing an essential role in normal motor and cognitive function. Previously we demonstrated the feasibility of in vivo longitudinal MEMRI of Cb development in normal and Gbx2-CKO mice during critical neonatal stages of foliation, including volumetric analysis of the vermis deletion and abnormalities in the flocculus-paraflocculus complex and deep cerebellar nuclei that were not previously reported. In the current study, we extended our analysis to whole brain deformation-based morphometry in order to provide a comprehensive, unbiased characterization of the Gbx2-CKO phenotype.

16:42         151.       Myelin Mapping in Living Mice Using Magnetization Transfer and Manganese

Takashi Watanabe1, Jens Frahm1, Thomas Michaelis1

1Max-Planck-Institut für biophysikalische Chemie, Göttingen, Germany

This work demonstrates for the first time the use of manganese for mapping myelin-rich structures in the brain of living mice in magnetization-transfer weighted MRI (3D FLASH). The contrast between myelin-rich structures and background was improved after manganese injection. A reduced saturation of mobile protons was pronouncedly seen in the water-rich background, while the marked saturation in myelin-rich structures through magnetization transfer from the large pool of bound protons was less affected. Administration of hydrophilic T1-shortening agents to neural tissue fluid in vivo increases the signal intensity of the brain advantageously for a magnetization-transfer based mapping of myelin-rich structures.

16:54         152.       Changes in Callosal and Thalamic Connectivity Following Peripheral Nerve Damage to the Rodent Forepaw Detected with Manganese Enhanced MRI

Jason Tucciarone1, Galit Pelled1, Alan Koretsky1

1National Institutes of Health, Bethesda, MD , USA

The purpose of this work was to determine if MEMRI neural tracing could detect changes in the laminar functional architecture of cortical-cortical and thalamo-cortical somatosensory pathways following complete nerve deafferentation of the rat forepaw. Previously it has been demonstrated that cortical reorganization observed following complete peripheral nerve injury affects functional MRI responses both in healthy and deprived cortices. Reduced manganese transport was found in lamina 3 of the deprived cortex after injection of manganese to the healthy cortex predicting that input into this layer has decreased. Second, increases in T1 enhancement in the healthy cortex were found after injecting manganese into the healthy thalamus. There was increased tracing throughout the cortex which was highest at the lamina 3/4 interface. Thus, both cortical-cortical and thalamic-cortical neuronal pathways are affected by the injury, and contribute to the deprived somatosensory reorganization.

17:06         153.       A Novel Method for Dynamic Manganese-Enhanced MRI

Hanbing Lu1, Steven Demny1, William Rea1, Yantao Zuo1, Yihong Yang1, Elliot A. Stein1

1National Institute on Drug Abuse, NIH, Baltimore, MD, USA

ME-MRI has been successfully applied to map neuronal response to a variety of stimuli. However, manganese has very low permeability through the blood-brain barrier(BBB). For studies employing pharmacological or other manipulations, where multiple cortical and subcortical structures are expected to be activated, temporal disruption of BBB appears to be necessary for whole brain imaging. A novel method using an agent that normally targets endothelial barrier antigen to open BBB for dynamic ME-MRI experiments is presented. This agent is infused intravenously, avoiding surgical trauma associated with carotid artery catheterization when hyperosmolar mannitol is used to open BBB.

17:18         154.       In Vivo Tracing of Cortical Laminar Structure in the Rodent Olfactory System Using Manganese-Enhanced MRI (MEMRI)

Der-Yow Chen1, Kai-Hsiang Chuang2, Stephen Dodd1, Alan Koretsky1

1NINDS, National Institutes of Health, Bethesda, MD, USA; 2Singapore Bioimaging Consortium, Singapore

MEMRI can be used for neuronal tracing in the olfactory pathway. Here it is demonstrated that MEMRI visualizes the laminar structure of the olfactory system and traces layer-specific inputs to olfactory cortices. MnCl2 was infused into nostrils of rats which were imaged at several time points. Layers and boundaries of olfactory cortices were evident 48 h after infusion. Mn2+ enhancement in the superficial layer was observed earlier than the deep cell layer, consistent with known connections. Therefore, MEMRI neural tracing is specific at the level of cortical layers in the olfactory pathway, consistent with previous measurements of the somatosensory pathway.

17:30         155.       Manganese Tract Tracing in Zebrafish

Miriam Scadeng1, David Julian Dubowitz1, Nathan Gray1, Ellen Breen2

1Radiology, University of California San Diego, La Jolla, CA, USA; 2Medicine, University of California San Diego, San Diego, CA, USA

The use of MEMRI to study neural networks and cardiac function has rapidly expanded in recent years. Zebrafish are rapidly emerging as a major new animal model for animal research as they have many unique qualities such as the ability to regenerate neuronal and cardiac tissues. The ability to perform in vivo MEMRI studies in zebrafish introduces this animal model to new areas of research.

17:42         156.       Manganese-Enhanced MRI and 1H MR  Spectroscopy of the Hypothalamus in a Model of Dehydration Induced Anorexic Rats

Nathalie Just1,2, Rolf Gruetter1,2

1LIFMET, CIBM, EPFL, Lausanne, Switzerland; 2Department of Radiology, UNIL and HUG, Lausanne and Geneva, Switzerland

The hypothalamus is responsible for metabolic processes of the Autonomic Nervous System. The ventromedial nucleus of the hypothalamus is responsible for the control of food intake. The use of manganese-enhanced MRI (MEMRI) to assess the neuronal circuitry involved in both autonomic and somatosensory pathways showed promises. In the present study, hypothalamic activation was performed by dehydration induced anorexia(DIA) in female rats. Enhancement of paraventricular nuclei following manganese injection coupled to metabolite concentration changes measured by 1H MR spectroscopy at 14.1T in DIA rats suggest that neuronal and metabolic analysis of the hypothalamus during activation are possible using MR methods.

17:54         157.       MEMRI Study of Neonatal Hypoxic-Ischemic Injury in the Late Stage

Iris Yuwen Zhou1,2, Kevin C. Chan1,2, Abby Y. Ding1,2, Edward S. Hui1,2, Ke Xia Cai1,2, Ed X. Wu1,2

1Laboratory of Biomedical and Signal Processing, The University of Hong Kong, Hong Kong SAR, China; 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China

In this study, in vivo MEMRI was employed to investigate the hypoxic-ischemic injury in the late phase. Mn2+ induced signal changes were examined using SPM coregistration and ROI analysis. T1WIs SI increase was detected in the perilesional region 24 hours after Mn2+ administration and it colocalized with the increase in glial cell density in GFAP staining, demonstrating the existence of reactive gliosis in the late phase after H-I injury.

18:06         158.       Using Magnanese-Enhanced MRI to Monitor the Efficacy of Angiotensin Converting Enzyme Inhibitor Treatment in a Murine Myocardial Infarction

Collier Gladin1, Lynsa Nguyen1, Christopher Middleton1, Jimei Liu1, Nathan Yanasak1, Tom C.-C. Hu1

1Small Animal Imaging, Medical College of Georgia, Augusta, GA, USA

There is a critical, yet unexplored, niche for using a non-invasive in vivo imaging technique to compare pharmaceutical treatment and assess the diagnostic improvement of ischemic tissue following myocardial infarction. This study demonstrates the ability of MEMRI to quantify the efficacy of an ACEi following myocardial infarction by segmenting and analyzing areas in and surrounding the ischemic site. This information potentially can be used to determine best used methods of clinical treatment following a cardiac event.

18:18         159.       MRI Monitored Uptake of Manganese in the Mouse During Continuous Administration Using Osmotic Infusion Pumps

Maria Rosario Sepulveda1, Tom Dresselaers2, Uwe Himmelreich2, Frank Wuytack1

1Laboratory of Ca2+-transport ATPases, Department of Molecular Cell Biology, K.U.Leuven, Faculty of Medicine, Leuven, Belgium; 2Biomedical NMR-unit  / MoSAIC, K.U.Leuven, Faculty of Medicine, Leuven, Belgium

NeuroMRI studies using manganese as a paramagnetic contrast agent are often limited by the neurotoxicity of Mn2+. Fractionated injections can reduce the toxicity; however, we hypotisezed that a constant administration at very low doses will reduce toxicity even more without affecting the T1-weighted contrast. For this purpose we evaluated the T1 changes observed by implanting subcutaneously a mini-osmotic infusion pump loaded with MnCl2 in mice. This administration route simulates better the chronic exposure reported in some patients. Evaluation of temporal changes in contrast allow monitoring of uptake and clearance in the brain and several glands.

Diffusion Acquisition

Room 316BC                       16:30-18:30                                                                       Moderators: Roland Bammer and Gareth J. Barker

16:30         160.       Concurrent Field Monitoring Removes Distortions from In-Vivo DWI Data

Bertram Jakob Wilm1, Christoph Barmet2, Nicola DeZanche2, Peter Boesiger2, Klaas Paul Pruessmann2

1Institute for Biomedical Engineering , University and ETH Zurich , Zurich , Switzerland; 2Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland

In diffusion-weighted MRI, eddy current effects notoriously result in geometrical image distortions. This problem is usually approached by fine-calibration of the scanner gradient system. We present a generic way of addressing this problem by deliberately tolerating a certain degree of field deviations in terms of eddy currents, gradient delays and field drifts and rather monitor the actual magnetic field during each scan. The field evolution thereby obtained is used for distortion correction of in-vivo DWI data that was acquired in the absence of hardware eddy current compensation.

16:42         161.       Influence of Gradient Design on the Measurement of S/V Using DWI.

Frederik Bernd Laun1, Bram Stieltjes1

1Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Baden-Württemberg, Germany

We show, that in the slow diffusion limit, the classical Stejskal-Tanner gradient scheme is optimal to measure the surface-to-volume ratio using the time dependent diffusion constant approach. We further show data supporting the assumption that S/V can not be determined properly by just shaping the gradients, e.g. using a train of short gradients, if the slow diffusion condition is not fulfilled as has been proposed previously.

16:54         162.       Addressing a Systematic Vibration Artefact in Diffusion-Weighted MR Images

Daniel Gallichan1, Jan Scholz1, Andreas J. Bartsch2, Timothy E. Behrens1, Matthew D. Robson3, Karla L. Miller1

1FMRIB Centre, University of Oxford, Oxford, Oxon, UK; 2Neuroradiology, University of Würzburg; 3OCMR, University of Oxford

Diffusion-weighted imaging employs large gradient lobes which are known to cause vibration of the patient table. We identify and characterise an artefact arising from these vibrations. We suggest a method to correct affected data as well as how to choose protocol parameters to avoid the acquisition of affected data.

17:06         163.       b-Matrix Correction Applied to High Resolution DTI

Murat Aksoy1, Samantha Holdsworth1, Stefan Skare1, Roland Bammer1

1Department of Radiology, Stanford University, Stanford, CA, USA

Due to its prolonged acquisition time, the correction of motion artifacts in high resolution DTI is essential for acceptable image quality. Short-Axis PROPELLER-EPI (SAP-EPI) has been proven to be very effective in eliminating phase and motion artifacts as well as geometric distortions. However, gross patient motion has two effects on the acquired data: pixel misregistration and change in diffusion encoding direction. While the pixel misregistration can be addressed by coregistration of low-resolution images, the change in diffusion encoding direction makes it incorrect to combine different blades to get the diffusion weighted images. In this study, we addressed this issue by combining SAP-EPI with the novel non-linear tensor estimation scheme that estimates the diffusion tensors from the complex k-space data directly. The results show an increased accuracy of main eigenvector orientation compared to the conventional schemes for tensor estimation.

17:18         164.       Consistent Signal for Non-CPMG Echo Trains

James G.  Pipe1, Donglai Huo1, Zhiqiang Li2, Eric Aboussouan1

1Imaging Research, Barrow Neurological Institute, Phoenix, AZ, USA; 2MRI, GE Healthcare, Phoenix, AZ, USA

Diffusion Weighting precludes the use of CPMG echo trains in FSE without crushing significant signal. The MLEV and LeRoux phase cycling schemes help stabilize the signal magnitude, but some residual signal dependence on the starting phase remains. This work illustrates that appropriately placed gradient pulses can remove this residual signal instability.

17:30         165.       Echo-Planar Diffusion-Tensor Imaging of Inner Field-Of-Views in the Human Brain and Spinal Cord Using 2D-Selective RF Excitations

Jürgen Finsterbusch1,2

1Dept. of Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; 2Neuroimage Nord, Hamburg-Kiel-Lübeck, Germany

Echo-planar imaging suffers from geometric distortions caused by magnetic field inhomogeneities in particular at high static magnetic fields. Because these artifacts depend on the field-of-view in the phase-encoding direction, several techniques to acquire inner field-of-views without aliasing have been presented, one of them involves 2D-selective RF excitations. In this work, the feasibility of this approach for diffusion-tensor imaging of inner field-of-views in the human brain and cervical spinal cord at in-plane resolution of up to 0.5x0.5 mm2 is demonstrated. Major fibres in the cerebellum can be identified as well as the reduced anisotropy of gray matter in the spinal cord.

17:42         166.       High-Resolution DWI Outside the CNS Using Reduced-FOV Single-Shot EPI

Emine Ulku Saritas1, Ajit Shankaranarayanan2, Eric T. Han2, Joelle K. Barral1, Jin Hyung Lee1, Dwight George Nishimura1

1Department of Electrical Engineering, Stanford University, Stanford, CA, USA; 2Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA

DWI has recently been recognized as a potential clinical tool for the diagnosis, assessment and treatment monitoring of cancer outside the central nervous system (CNS). Even though single-shot EPI (ss-EPI) is the preferred method for these applications, its resolution is limited. Recently, a reduced FOV method using a 2D echo-planar RF (2D-EPRF) excitation pulse has been proposed for high-resolution ss-EPI DWI. In this work, we present the investigated improvements on this method, particularly optimization of the 2D-EPRF pulse to allow its use in various parts of the body. Specifically, we apply the improved method to in vivo prostate, breast and larynx DWI to demonstrate the high-resolution DWI capability of the reduced-FOV ss-EPI method, with improved coverage in the slice direction.

17:54         167.       Steady-State Diffusion-Weighted Imaging with Trajectory Using Radially Batched Internal Navigator Echoes (TURBINE)

Jennifer Andrea McNab1, Daniel Gallichan1, Matthew D. Robson2, Karla L. Miller1

1Clinical Neurology, Oxford University, Oxford, UK; 2Cardiology, Oxford University Centre for Clinical Magnetic Resonance Research, Oxford, UK

2D segmented DWI with motion correction can improve image quality and in-plane resolution, relative to conventional single-shot EPI. The problems associated with thin slice-selection, however, render a 3D segmented pulse sequence the only way to achieve very small isotropic voxels. One challenge with 3D segmented DWI is the time-prohibitive nature of acquiring a 3D navigator echo along with each k-space segment. Here we present a novel approach to this problem with a fully 3D pulse sequence called steady-state DWI with Trajectory Using Radially Batched Internal Navigator Echoes (TURBINE).

18:06         168.       Steady-State Free Precession (SSFP) Diffusion Imaging Using 3D Rotating Spirals (3DRS)

Jian Zhang1,2, Chunlei Liu2, Michael Moseley2

1Department of Electrical Engineering, Stanford University, Stanford, CA, USA; 2Department of Radiology, Stanford University, Stanford, CA, USA

A new 3D diffusion imaging technique has been presented by using Steady-State Free Precession (SSFP) DWI and 3D rotation spirals (3DRS). The novel acquisition scheme offers very high SNR efficiency and low sensitivity to motion artifacts. In addition, the 0th order phase errors can be extracted and corrected with 3DRS. Experimental results have shown that high quality DWI and DTI whole brain volumes can be rapidly acquired with high SNR.

18:18         169.       Optimized EPI-DTI and TSE-DTI at 3 T and 7 T in the Brain

Eric Edward Sigmund1, David Gutman2, Mariana Lazar1, Jens H. Jensen3, Joseph A. Helpern1

1Radiology, New York University, New York, NY, USA; 2School of Medicine, New York University, New York, NY, USA; 3Radiology, New York University, New  York, NY, USA

Diffusion tensor imaging (DTI) and its higher order variants are powerful tools for elucidating brain tissue microstructure, but their processing schemes demand high SNR. The benefits of high field MRI (7 T) can be harnessed to amplify DTI processing or resolution, with the right strategy. Two single-shot sequences, echo-planar (EPI) and turbo spin echo (TSE) are often used for diffusion, but their migration to 7 T is ongoing and nontrivial. We present a validation study successfully achieving high quality DTI brain data from both sequences at both 3 T and 7 T through a combination of parallel imaging and post-processing.

RF Pulse Design

Room 314                             16:30-18:30                                                                       Moderators: Peter Börnert and Kawin Setsompop

16:30         170.       Sequential Optimal Spoke Selection for Spoke Trajectory Based RF Pulses Design in Parallel Excitation

Chao Ma1, Dan Xu2, Kevin F. King2, Zhi-Pei Liang1

1Department of Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA; 2Applied Science Laboratory, GE Healthcare, Milwaukee, WI, USA

A new method to select optimal spoke locations for spoke trajectory based RF pulses design is presented. The problem is formulated as a combinatorial optimization problem, which is then efficiently solved using a greedy algorithm with recursive evaluation of the cost function. Simulation results and experimental results on a 3T GE Excite scanner with two-channel parallel excitation system demonstrate that the proposed method outperformed existing methods with improved computational efficiency.

16:42         171.       Sparse Parallel Transmit Pulse Design Using Orthogonal Matching Pursuit Method

Dong Chen1,2, Folkmar Bornemann1, Mika W. Vogel2, Laura I. Sacolick2, Guido Kudielka2, Yudong Zhu3

1Center for Mathematical Science, Technical University of Munich, Munich, Germany; 2Imaging Technologies, GE Global Research Europe, Munich, Germany; 3New York University Langone Medical Center, New York, NY, USA

Parallel RF transmit offers additional degrees of freedom in excitation pulse design. One application of that is accelerating multidimensional selective excitation by under-sampling the excitation k space. Where to ideally under-sample the k space with optimal sparsity is determined by the target profile, B1 maps and error tolerance, which is known a priori. We propose an adaptive k space sparsifying method, which exploits this prior-knowledge using a greedy-wise algorithm that simultaneously sparsify over all Tx coils and significantly reduces the pulse duration. The method was validated with Bloch simulations and parallel transmit phantom imaging experiments.

16:54         172.       Coping with Off-Resonance Effects and Gradient Imperfections in Parallel Transmission Experiments

Johannes Thomas Schneider1,2, Martin Haas2, Jürgen Hennig2, Sven Junge1, Wolfgang Ruhm1, Peter Ullmann1

1Bruker BioSpin MRI GmbH, Ettlingen, Germany; 2Dept. of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany

For parallel spatially-selective excitation / TransmitSENSE the exact matching of the RF pulses and the gradient waveforms to be played out simultaneously is crucial in order to achieve high spatial accuracy and selectivity. In particular, off-resonance effects and gradient-system imperfections may significantly disturb this interplay resulting in poor spatial definition and artifacts. Therefore, in this study we investigated different methods to determine and compensate for such effects. It is shown that using measured global k-space trajectories, off-resonance maps and local phase evolutions for trajectory pre-calibration and accordingly adapted pulse calculations allow very precise excitation despite of experimental imperfections.

17:06         173.       Parallel Transmission Method for Susceptibility Artifact and B1+ Inhomogeneity Reduction

Cungeng Yang1, Weiran Deng1, Vijay A. Alagappan2, Lawrence L. Wald2, V. Andrew Stenger1

1Department of Medicine, University of Hawaii, Honolulu, HI, USA; 2A.A. Martinos Center for Biomedical Imaging, Havard Medical School, Charlestown, MA, USA

Susceptibility artifacts and B1+ inhomogeneity are major limitations in high field MRI. Although 3D RF pulses have been shown to be useful for reducing B1+ inhomogeneity with parallel transmission, susceptibility artifacts remain a problem. Parallel z-shim is a promising technique for reducing the through-plane signal loss susceptibility artifact without sacrificing temporal resolution and implementation ease. We present a parallel transmission, z-shim 3D tailored RF pulse for simultaneously reducing susceptibility artifacts and B1+ field inhomogeneity. The method is demonstrated in vivo in T2*-weighted human brain imaging at 3T. Reduced susceptibility artifacts and improved B1+ homogeneity is observed.

17:18         174.       Joint Design of Excitation and Refocusing Pulses for Fast Spin Echo Sequences in Parallel Transmission

Dan Xu1, Kevin F. King1

1Applied Science Laboratory, GE Healthcare, Waukesha, WI, USA

Parallel transmission of RF pulses has been shown to be effective in correcting B1 inhomogeneity. However, there has been no fast spin echo application with parallel transmission yet due to the lack of ways of designing parallel transmit pulses that satisfy the CPMG condition. We pose the design of excitation and refocusing pulse pair as a joint design problem under the optimal control framework, where the optimal pulse pair is sought jointly to drive the magnetization vector to its desired state while maintaining the CPMG condition. Bloch simulation results are shown to demonstrate the superior performance of the proposed method.

17:30         175.       Robust Parallel Excitation Pulse Design

William Allyn Grissom1, Adam B. Kerr2, Pascal Stang2, Greig Scott2, John Pauly2

1Electrical Engineering and Radiology, Stanford University, Stanford, CA, USA; 2Electrical Engineering, Stanford University, Stanford, CA, USA

In contrast to parallel receive, parallel excitation requires separate power amplifiers for each channel, which can be cost-prohibitive. Several groups are currently investigating the use of low-cost amplifiers as a solution to this problem. However, these amplifiers can have difficulty tracking steep RF envelope changes. In this work, we demonstrate a regularization technique for parallel excitation pulse design that results in pulses that are robust to amplifier non-idealities, with minimal impact on excitation accuracy. We demonstrate experimentally that excitation accuracy is improved using the new technique compared to unregularized pulses.

17:42         176.       SAR Hotspot Reduction by Temporal Averaging in Parallel Transmission

Ingmar Graesslin1, Julia Weller1, Ferdinand Schweser2, Bjoern Annighoefer3, Sven Biederer4, Ulrich Katscher1, Tim Nielsen1, Paul Harvey5, Peter Börnert1

1Philips Research Europe, Hamburg, Germany; 2IDIR / University Clinics, Jena, Germany; 3TU Hamburg-Harburg, Hamburg, Germany; 4University of Lübeck, Lübeck, Germany; 5Philips Healthcare, Best, Netherlands

This paper presents a novel approach for local SAR reduction by exploitation of the temporal degree of freedom of multi-shot imaging sequences. It is based on successive application of RF pulses with the same target excitation pattern, but different spatial distributions of SAR, levelling out by time averaging.

The concept was validated by simulations. Both computation of RF pulses and spatial SAR distributions were significantly accelerated implementing it on a graphics-processing unit. The local SAR calculation was carried out in real-time for a whole body bio-mesh.

 

17:54         177.       Spectral-Spatial Pulse Design for Through-Plane Phase Precompensatory Slice Selection in T2*-Weighted Functional MRI

Chun-yu Yip1, Daehyun Yoon2, Valur Olafsson2, Sangwoo Lee3, William A. Grissom4, Jeffrey A. Fessler2, Douglas C. Noll5

1A.A. Martinos Center, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA; 2Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, USA; 3GE Healthcare, Waukesha, WI, USA; 4Stanford University, Palo Alto, CA, USA; 5Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA

T2*-weighted functional MR images suffer from signal loss artifacts caused by the magnetic susceptibility differences between air cavities and brain tissues.

We propose a novel spectral-spatial pulse design that is slice-selective and capable of mitigating the signal loss.

The two-dimensional spectral-spatial pulses create precompensatory phase variations that counteract through-plane dephasing, relying on the assumption that resonance frequency offset and through-plane field gradient are spatially correlated. The pulses can be precomputed prior to functional MRI experiments and used repeatedly for different slices in different subjects.

18:06         178.       Design of High-Bandwidth Adiabatic RF Pulses Using the Shinnar Le-Roux Algorithm

Priti Balchandani1, John Pauly2, Daniel Spielman1

1Radiology, Stanford University, Stanford, CA, USA; 2Electrical Engineering, Stanford University, Stanford, CA, USA

We present a new, systematic method for designing adiabatic RF pulses that utilizes the Shinnar Le-Roux (SLR) algorithm for pulse design. By overlaying a sufficient amount of quadratic phase across the spectral profile prior to the inverse SLR transform, we generate RF pulses that exhibit the required spectral characteristics as well as adiabatic behavior. The addition of quadratic phase distributes RF energy more uniformly, resulting in reduced SAR pulses. The method enables the pulse designer to specify spectral profile parameters and the degree of quadratic phase. Simulations and phantom experiments demonstrate that pulses generated using this new method behave adiabatically.

18:18         179.       A VERSE Algorithm with Additional Acoustic Noise Constraints

Sebastian Schmitter1, Marco Mueller1, Wolfhard Semmler1, Michael Bock1

1Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany

In this work a general VERSE algorithm is presented, that reduces both the B1 amplitude (and thus SAR) and the acoustic noise of the gradient for arbitrary RF pulses. The resonance frequencies of the gradient coils are additional constraints in this algorithm. The Fourier transform of the VERSE gradient shape is adapted to these resonance frequencies. The method is demonstrated for SINC rf pulses. A noise reduction of more than 13 dB compared to non-optimized VERSE pulses is measured, whereas the effects of the VERSE algorithm on the slice profile is negligible.

Water Exchange & Binding

Room 313BC                       16:30-18:30                                                                         Moderators: R. Mark Henkelman and Bruce Pike

16:30         180.       Young Investigator Award Finalist: MRI Contrast from Relaxation Along a Fictitious Field (RAFF)

Timo Liimatainen1, Dennis Sorce1, Michael Garwood1, Shalom Michaeli1

1Center for Magnetic Resonance Research, Dept. of Radiology, University of Minnesota, Minneapolis, MN, USA

A method is described to create MRI contrast using rapid amplitude and frequency modulated RF irradiation in a sub-adiabatic condition, referred to relaxation along a fictitious field (RAFF). Bloch simulation of RAFF shows that magnetization follows a fictitious field when magnetization is oriented initially along the fictitious field. Theoretical calculations show sensitivity of RAFF to slow molecular motions with similar sensitivity as the continuous wave spin-locking experiment. The data obtained from human brain shows images with significant contribution of steady state which can be accounted for in the analysis.

16:50         181.       Balanced SSFP Profile Asymmetries Detect Small Frequency Shifts in White Matter

Karla L. Miller1, Peter Jezzard1

1FMRIB Centre, Oxford University, Oxford, Oxon, UK

We study a novel contrast mechanism based on the frequency dependence of the balanced SSFP signal. The balanced SSFP profile is theoretically symmetric with respect to frequency if only T1, T2 and diffusion effects are considered. However, the convolution model for the SSFP signal predicts that the profile becomes asymmetric for asymmetric lineshapes. Asymmetries are observed in white matter. The model is fit to data using a simple lineshape parameterization, and data is shown to be consistent with lineshape effects at small frequency offsets. SSFP asymmetries may be a sensitive marker of tissue microstructure, as reflected by small frequency shifts.

17:02         182.       Characterizing White Matter Pathology with Quantitative Magnetization Transfer Imaging: Insight from a Four-Pool Model

Ives R. Levesque1, G. Bruce Pike1

1Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada

Magnetization transfer is usually modeled using two proton pools. A model with four compartments is required to capture all of the commonly observed relaxation and cross-relaxation properties of human white matter; however, it is impractical for in vivo imaging. Simulations of magnetization transfer experiments were performed using variations on a basic four-model model of white matter, to investigate how these changes are reflected in the two-pool model of MT. We show that compartmental water exchange is negligible on an MT time-scale, and that estimation of the semi-solid-to-liquid pool ratio is robust, despite the presence of two liquid and semi-solid pools.

17:14         183.       A New, Polynomial-Based (PARA)CEST Analysis Method with B0 Correction and Increased Sensitivity

Lan Lu1, Tejas Shah2, Mark A. Griswold1,2, Chris A. Flask1,2

1Radiology, Case Western Reserve University, Cleveland, OH, USA; 2Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA

Chemical Exchange Saturation Transfer (CEST) MRI is rapidly becoming a popular tool for many in vivo imaging applications. However, the analysis of CEST imaging data has been limited for many studies which have utilized simple 2-point subtraction techniques to quantify the CEST effect which is susceptible to significant errors from both B0 and B1 variation. We have developed a new polynomial fitting technique to quantify the chemical exchange from CEST spectra. This new polynomial fitting technique allows for accurate B0 correction and is inherently less sensitive to experimental factors, such as B1 variation, that can broaden the CEST peaks.

17:26         184.       1H-CEST and 19F MRI of Temperature-Responsive Liposomal Contrast Agents for Image Guided Drug Delivery

Jochen Keupp1, Sander Langereis2, Inge de Roos2, Dirk Burdinski2, Jeroen Pikkemaat2, Holger Gruell2,3

1Philips Research Europe, Hamburg, Germany; 2Philips Research Europe, Eindhoven, Netherlands; 3Eindhoven University of Technology, Eindhoven, Netherlands

Localized delivery of anti-cancer drugs by external stimulation of nanocarriers (temperature, pH) promises a larger therapeutic window with reduced side effects of the treatment. The present imaging study is based on a new type of temperature-responsive liposomes, which are dually labeled for 1H-CEST and 19F MR imaging and release an encapsulated payload near the melting temperature (Tm) of their lipid membrane (38 C). In their lumen, a chemical shift agent for 1H-lipoCEST imaging and NH4PF6 for 19F detection is contained. Inside the liposome, the 19F spectral lines are strongly broadened and not detectable. Upon reaching Tm, the lipoCEST contrast vanishes, due to the release of the chemical shift agent and, simultaneously, the 19F MR signal becomes visible. Hence, the 19F signal could be used to quantify the amount of released drug payload, while the CEST signal could measure the local nanocarrier concentration before the release. The study demonstrates the potential of the new liposomal nanocarriers for MRI-guided drug delivery in cancer therapy.

17:38         185.       ZAPI Analysis of Z-Spectral Components in Acute Cerebral Ischemia

Johanna Närväinen1, Kimmo T. Jokivarsi2, Penny Louise Hubbard3, Olli H. Grohn4, Risto A. Kauppinen5, Gareth A. Morris6

1Biomedical Imaging Unit, University of Kuopio, Kuopio, Finland; 2Dept. of Neurobiology, University of Kuopio, Kuopio, Finland; 3School of Medicine, University of Manchester, Manchester, UK; 4Dept. of Neurobiology, University of Kuopio, Kuopio, Finland; 5Dept. of Radiology, Dartmouth College, Hanover, NH, USA; 6School of Chemistry, University of Manchester, Manchester, UK

T2-selective Z-spectroscopy (ZAPI) was applied to acute cerebral ischemia. It was shown that the magnetization transfer (MT) component can be measured directly at and near water resonance using sinusoidally modulated low-power RF saturation. This information was used to improve the separation of MT from other components in a Z-spectrum. In this study, a small decrease in MT asymmetry in stroke was observed. In the ischemic striatum the amide signals at 3.5 ppm showed decreased amide-water exchange, while aliphatic signals at -3.5 ppm remained unchanged.

17:50         186.       PCEST: Positive Contrast Using Chemical Exchange Saturation Transfer

Elena Vinogradov1, Todd C. Soesbe2, James A. Balschi3, Dean A. Sherry2,4, Robert E. Lenkinski1

1Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; 2Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; 3NMR Laboratory for Physiological Chemistry, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA; 4Department of Chemistry, University of Texas at Dallas, Dallas, TX, USA

Chemical Exchange Saturation Contrast utilizes selective presaturation of a small pool of exchanging protons and is manifested in the decrease of the free water signal. Thus, CEST contrast is negative and requires the detection of small signal changes on top of a strong background signal. Here we introduce a Positive CEST (PCEST) scheme that results in the increased signal intensity in the presence of the agent and RF. Similar to the original CEST, the contrast can be switched “ON” and “OFF”. The sequence leads to better utilization of the dynamic range and results in the substantial background suppression.

18:02         187.       Z-Spectrum Asymmetry : From 3T to 7T

Olivier E. Mougin1, Ron Coxon1, Penny A. Gowland1

1Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, Nottinghamshire, UK

Magnetization Transfer and related effects such as CEST are important sources of contrast in MRI. Studying MT in vivo at 7T is challenging due to the increase in longitudinal relaxation time and SAR limits. We used pulsed saturation with EPI readout a range of offset frequencies and on the approach to steady-state, providing data that can be used to measure MT parameters at 7T in a reasonable imaging time and to compare the z-spectrum at 7 and 3T. We have found considerably increased sensitivity to CEST at 7T.

18:14         188.       GlycoCEST Using FISPCEST

Tejas Jatin Shah1,2, Lan Lu2, Paul R. Ernsberger3, Christopher Allan Flask1,2

1Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA; 2Department of Radiology, University Hospitals of Cleveland, Cleveland, OH, USA; 3Department of Nutrition, Case Western Reserve University, Cleveland, OH, USA

In vivo and non-invasive measures of hepatic and muscular glycogen are needed to effectively study diabetes and metabolism in humans and animals. More recently, glycogen’s inherent CEST effect has been proposed as an alternative to C13-MRS1. While this initial “GlycoCEST” work is promising, the in vivo utility of the GlycoCEST technique is limited because of the long acquisition times (1-3 hours) for quantitative CEST-MRI acquisitions. In this study, we have developed and optimized a rapid GlycoCEST acquisition using our recently developed FISP-CEST technique to obtain quantitative glycogen CEST spectra in phantoms and ex vivo livers in 15-45 minutes.

Study Group
Cardiac MR

Room 313BC                       18:30 - 20:30                                                                                                                                                            

Study Group
Diffusion & Perfusion MR

Room 316BC                       18:30 - 20:30                                                                                                                                                            

Study Group
Dynamic NMR Spectroscopy

Room 311                             18:30 - 20:30                                                                                                                                                            

Study Groups
Molecular & Cellular Imaging/MR of Cancer

Room 313A                         18:30 - 20:30                                                                                                                                                            

Study Group
MR in Drug Research

Room 312                             18:30 - 20:30                                                                                                                                                            

Study Group
High Field Systems & Applications

Room 315                             18:30 - 20:30                                                                                                                                                            


SUNRISE EDUCATIONAL COURSE
Image Reconstruction

Room 314                             07:00 – 08:00                                         Moderators:  Peter Börnert, Klaas Pruessmann, and Jeffrey Tsao

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Describe the main steps involved in efficient non-Cartesian image reconstruction;

·          Formulate a generalized signal model incorporating gradient encoding, coil sensitivity and B0 inhomogeneity;

·          List the pros and cons of Cartesian and non-Cartesian parallel MRI;

·          Compare compressed sensing, HYPR, and k-t BLAST with respect to their use of prior knowledge;

·          Describe the principles of separating water and fat signals; and

·          Name three differentn approaches for motion correction and appraise their potential to become routine methods.

 

Non-Cartesian Trajectories and Off-Resonance Correction

07:00        
Fast Image Reconstruction from Non-Cartesian Data

                  Philip J. Beatty

                                                     

07:30         Off-Resonance Effects and Correction

                  Bradley P. Sutton

SUNRISE EDUCATIONAL COURSE
Safety Update

Room 320                             07:00 – 08:00                                                          Moderators:  Penny A. Gowland and Roger Luechinger

Educational Objectives:
Upon completion of this session, participants should be able to:

·          Explain the issues involved in setting the SAR limit for a pulse sequence;

·          List the causes of PINS and how coils are designed to prevent it;

·          Describe standards related to medical implants in the MR environment;

·          Describe causes of accidents and preventative measures in the MR environment; and

·          Explain risks and minimization of acoustic noice in the MR environment.

 

07:00         Introduction SAR

                  Paul R. Harvey

 

07:20         SAR Measurements

                  Daniel J. Schaefer

 

07:40         More on SAR

                  Franz Hebrank

SUNRISE EDUCATIONAL COURSE
Quantitative Neuroanatomic & Functional Image Assessment

Room 316A                         07:00 – 08:00                                                               Moderators:  Peter A. Bandettini and Carlo Pierpaoli

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Assess the challenges and obstacles involved with quantitative assessment of anatomic and functional MRI data;

·          Describe the necessary steps to perform group comparisons of anatomic data;

·          List the neuronal, scanner-related, and physiological factors that influence the fluctuations in fMRI data;

·          Explain the neuronal, scanner-related, and physiological factors that influence the magnitude of the activation-induced fMRI signal change;

·          Describe the methods by which fMRI activation-related signal may be calibrated; and

·          List the methods by which fMRI resting state data can be filtered such that only neuronally related signal changes remain.

 

07:00         Quantitative Assessment of White Matter

                  Andrew L. Alexander

SUNRISE EDUCATIONAL COURSE
Mobile Lipids in Disease

Room 313A                         07:00 – 08:00                                                                  Moderators:  Carles Arús and Edward J. Delikatny

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Recognize the various ML resonances detectable in the 1H NMR spectral pattern of a tissue or organ;

·          Select optimal acquisition conditions to detect ML resonances and appreciate their possible variation in biological samples;

·          Describe the possible biochemical origins of ML;

·          List possible causes for qualitative and quantitative changes in ML pattern;

·          Interpret qualitative and quantitative changes in the ML pattern of cells and tissues; and

·          List possible clinical applications of in vivo ML detection for disease diagnosis, staging and response to therapy.


Mobile Lipids (ML) from the Cellular Point of View


07:00         MRS Resonances as Indicators of Altered Phospholipid and Neutral Lipid Metabolism in Living Cells

                  Franca Podo

 

07:20         Mobile Lipids and Apoptosis

                  Kevin M. Brindle

07:40         Dynamics of NMR Visible Mobile Lipids in Cultured Cells

                  Carles Arús

SUNRISE EDUCATIONAL COURSE
MRI Applications for Tissue Engineering

Room 311                             07:00 – 08:00                                                                                               Moderator:  Richard G. S. Spencer

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Define what is meant by tissue engineering;

·          Appreciate the current status of the field of tissue engineering, including several of the products currently on the market;

·          Recognize some of the current approaches to development of tissue-engineered constructs;

·          Describe the role of MR in certain current tissue engineering studies; and

·          Identify further opportunities for application of MR to problems in tissue engineering.

07:00         Introduction

                  Richard G. S. Spencer

 

07:10         Tissue Engineering: From Research to Products - No syllabus contribution at time of publication.

                  Anthony Ratcliffe

SUNRISE EDUCATIONAL COURSE
Clinical Science for Physicists & Engineers

Room 313BC                       07:00 – 08:00                                                      Moderators:  Vivian S. Lee, Tim Leiner, and Bachir Taouli

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Identify basic anatomy and physiology of the central nervous system, kidney, liver, cardiac, vascular and musculoskeletal systems;

·          Describe the process and diagnosis of stroke and white matter formation and damage;

·          Explain kidney and liver anatomy and function and how MRI can be used to evaluate these organs;

·          Describe basic cardiac physiology and the consequences of coronary artery disease and heart failure;

·          Describe the process of bone and cartilage formation and degeneration; and

·          Appraise unmet clinical needs that could potentially be solved by physicists and engineers.

 

07:00         Stroke:  “A Brain Attack”

                  Kei Yamada

 

07:30         Demyelination:  “An Age Attack”

                  Mara A. Rocca

SUNRISE EDUCATIONAL COURSE
Cardiovascular Disease or Problem-Based Teaching & Practical Protocols

Room 316BC                       07:00 – 08:00                                                                 Moderators:  Victor A. Ferrari and Stefan G. Ruehm

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Critique the strengths and limitations of current cardiovascular MRI techniques when applied to clinical diagnostic testing;

·          Compare coronary MR and CT angiography at 1.5 and 3T field strengths and how practical these approaches currently are;

·          Describe the etiologies of right heart failure, and the clinical applications of MR techniques to evaluate these disorders, especially the assessment of right heart function;

·          Compare the current clinical techniques for assessment of ischemic heart disease and the use of MR methods for assessment of ischemia, perfusion reserve, and viability;

·          Appraise the potential clinical applications of 7T cardiovascular MRI and the technical challenges that will need to be resolved for wider application of the technique; and

·          Evaluate how the attendee’s current approaches to these diseases may need to be modified based on expert advise.

Coronary MRA

07:00        
Applications and Needs (including CT)

                  Michael V. McConnell

 

07:20         1.5T Techniques

                  Matthias Stuber

 

07:40         3.0T Techniques

                  Debiao Li

SUNRISE EDUCATIONAL COURSE
MRI & MRS of the Mouse Brain: Techniques & Applications

Room 312                             07:00 – 08:00                                                                     Moderators:  Jeffry R. Alger and Afonso C. Silva

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Identify hardware/software configurations that are needed to perform anatomical imaging, diffusion tensor imaging, functional imaging, and magnetic resonance spectroscopy in the mouse brain;

·          Recognize the constraints associated with the small size of the mouse body and brain and how to achieve stable physiology of the animals during the MRI/MRS experiments;

·          Define how to perform anatomical imaging, diffusion tensor imaging, functional imaging, and magnetic resonance spectroscopy in the mouse brain;

·          Describe the anatomical or physiological properties that can be measured with MRI in mouse brain; and

·          Identify significant biomedical findings that have been obtained through mouse brain neuroimaging using anatomical imaging, diffusion tensor imaging, functional imaging, and magnetic resonance spectroscopy.

Anatomical MRI of the Mouse Brain

07:00         Techniques for Anatomic Brain Imaging of Mouse Brain

                  Robia C. Pautler

07:30         Evaluation of Mouse Brain Development with MRI
                   Daniel H. Turnbull







SUNRISE EDUCATIONAL COURSE
(Clinical Intensive Course Option)
Unsolved Problems in MSK MRI:  What Do We Know and What Don’t We Know?

Room 310                             07:00 – 08:00                                                                         Moderators:  Juerg Hodler and Hollis G. Potter

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Avoid over-diagnosis and over-treatment when performing MR imaging of the lumbar spine, rotator cuff, wrist, and knee;

·          Describe the current developments potentially leading to more precise diagnosis of abnormalities in the lubar spine, rotator cuff, wrist, and knee; and

·          List six (6) pitfalls which lead to over- or under-diagnosis in the lumbar spine, rotator cuff, wrist, and knee.

Low Back Pain

07:00         MR Findings without Clinical Significance

                  Miriam A. Bredella

                                                     

07:30         Clinical Abnormalities not Detectable on MR Images

                  Michael T. Modic

SUNRISE EDUCATIONAL COURSE
(Clinical Intensive Course Option)
Hot Topics in Body MRI

Room 315                             07:00 – 08:00                                                                                                              Moderator:  Talissa Altes

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Compare the potential utility of the various methods for pulmonary MRI including proton-based techniques and hyperpolarized gas MRI;

·          Protocol and interpret MRI examinations for the evaluation of rectal cancer and non-neuro fetal abnormalities;

·          Describe the techniques for MRI guided interventions including vascular and non-vascular interventions;

·          Identify patients and clinical situations in which whole body MRI for cancer evaluation and lymph node detection would be appropriate, and protocol and interpret the examinations.

 

07:00         Proton Based Lung MRI

                  Lothar R. Schad

                                                     

07:30         Hyperpolarized Gas MRI of the Lungs

                  Bastiaan Driehuys

PLENARY LECTURES
Molecular MRI: MR Probe Development from Bench to Patient Table

Ballroom                              08:15-09:30                                                                              Moderators: Markus Rudin and Brian K. Rutt

08:15         189.       Probe Development: Fundamentals/Chemistry

Silvio Aime 1

1University of Torino, Torino, Italy

MRI suffers from an intrinsic insensitivity with respect to the competing imaging modalities that has to be overcome by designining suitable amplification procedures based on the development of reporting units endowed with an enhanced sensitivity and on the identification of efficient routes of accumulation of the imaging probes at the sites of intererest. Along the years, the progressive understanding of the relationships between structure/dynamics and the relaxation processes has been fundamental for the development of high sensitive MRI agents. Furthermore chemists have exploited the outstanding achievements in the field of supramolecular assemblies to deliver high payload of imaging agents at the targeting sites.

08:40         190.       Probe Development: Biophysics and Validation

Klaas Nicolay 1

1Eindhoven University of Technology, Eindhoven, Netherlands

The first part of this presentation deals with the biophysical concepts underlying the detection of the different classes of MRI contrast agents that are being explored for molecular and cellular imaging. Most traditional MRI contrast materials are based on rare earth metal ions, notably Gd3+, and nanoparticles of iron oxides, which are detected with T1- and T2/T2*-weighted MRI, respectively. In recent years, the utility of Chemical Exchange Saturation Transfer agents and F-19 containing formulations are also explored. The second portion of the talk focuses on in vitro and in vivo approaches to validate MRI contrast materials for the detection of disease biomarkers.

09:05         191.       MR Molecular Probes in a Clinical Setting: Potential and Issues. Early Clinical Experience

Elmar Spüntrup 1

1University of Cologne, Cologne, Germany

Initial in-vivo imaging of a new molecular MR imaging probe is typically performed in small animal models and on dedicated MR scanners. For translation towards any clinical use, investigations in large animal models and examinations on routine clinical MR scanners are needed. The MR-sequences used

need to maintain sufficient contrast properties for detecting the MR molecular probe but they have also to be suitable for scanning severely diseased patients. During the presentation requirements for MR molecular probes and for molecular MR-imaging sequences in a clinical setting will be discussed and some early clinical experience will be presented.

CLINICAL INTENSIVE COURSE
(Admission limited to Clinical Intensive Course registrants only)
Advances in MRA

Room 310                             08:10 – 09:30                                 Moderators:  Garry E. Gold, Elmar M. Merkle, and Lynne S. Steinbach

08:10         Recent Developments in Contrast-Enhanced Body MR Angiography

                  Thorsten Bley

                                                     

08:50         Unenhanced Body MRA: Is it Good Enough?

                  Henrik J. Michaely

                                                     

09:30         Break and Poster Viewing

                  Elmar M. Merkle

 

SPECIAL SESSION
Sounds & Visions:  Return of Aloha

Ballroom                              09:30-10:00                                                                           Moderators: Mark E. Ladd and Harald H. Quick

CLINICAL INTENSIVE COURSE
Extracranial Diffusion-Weighted Imaging

Room 310                             10:30 - 12:30                                                                                                 Moderator:  Bernard E. Van Beers

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Describe the value and limitations of diffusion-weighted imaging MRI in the body;

·          Apply diffusion-weighted MRI in their extracranial practice; and

·          Optimize the techniques of body diffusion-weighted MRI.

 

10:30       Diffusion-Weighted Imaging in the Body: Techniques and Optimization 
                Dow-Mu Koh

 

11:00       Diffuse Liver and Kidney Disease:  Value of DWI
                Bachir Taouli

 

11:30       Focal Abdominal Lesions:  Added Value of DWI

Vincent Vandecaveye

 

12:00       Predicting and Monitoring Treatment Response with DWI

Harriet C. Thoeny

Preclinical Studies on Cancer

Room 313A                         10:30-12:30                                                               Moderators: Zaver M. Bhujwalla and John R. Griffiths

10:30         192.       Unraveling Mouse Glioma Heterogeneity with DCE-T1 MRI and 1H-CSI Metabolome Pattern Perturbation

Rui Vasco Simões1,2, Maria Luisa García-Martín3, Teresa Delgado-Goñi1,4, Silvia Lope-Piedrafita4,5, Carles Arús1,4

1Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain; 2Bioquímica, Universidade de Coimbra, Coimbra, Portugal; 3Resonancia Magnética, Clínica Nuestra Señora del Rosario, Madrid, Spain; 4CIBER-BBN, Cerdanyola del Vallès, Spain; 5Servei de Resonància Magnètica Nuclear, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain

In this work we have investigated the heterogeneity of GL261 mouse glioma (n=9) microenvironments in vivo by correlating the information obtained from dynamic contrast-enhanced T1 MRI (DCE-T1) with that from dynamic 1H-CSI during an acute hyperglycemic challenge. The distinct enhancement patterns given by DCE-T1 and 1H-CSI maps (MR-detectable glucose and lactate) suggest different vascularization/permeability and metabolism, respectively, in the different regions of each studied tumor. Other metabolome challenges should be tested to better understand GL261 in vivo sampled glioma regional heterogeneity.

10:42         193.       Metabolic Imaging of Cachectic Tumors

Marie-France Penet1, Samata Kakkad1, Dmitri Artemov1, Zaver M. Bhujwalla1

1Department of Radiology and Radiological Science, JHU ICMIC Program, The Johns Hopkins University School of Medicine, Baltimore, MD, USA

Cachexia occurs with a high frequency in several cancers. The significant weight loss resulting from this condition causes impairment of immune function, poor outcome of chemotherapy, fatigue, and markedly reduced quality of life. The ability to noninvasively identify cachexia-inducing tumors, and understand the metabolic characteristics of these tumors is important for determining new targets to arrest or reverse this condition. Here we report on the metabolic differences, identified by 1H magnetic resonance spectroscopy (MRS), between cachectic and non-cachectic tumors.

10:54         194.       Magnetic Resonance Imaging Reveals the Progression, Regression and Indolence of in Situ Carcinoma in Transgenic Mice.

Sanaz Arkani Jansen1, Suzanne Conzen2, Xiaobing Fan, Erica Markiewicz, Gillian Newstead, Gregory Karczmar1

1University of Chicago, Chicago, IL, USA; 2Medicine, University of Chicago

The processes that trigger progression of preinvasive ductal carcinoma in situ (DCIS) to invasive

breast cancer remain elusive. Given the necessity of surgical excision of newly-diagnosed DCIS,

studying natural history of disease in women is nearly impossible. Here, we use MRI to track in vivo  the transition of in situ  to invasive cancer in transgenic mice. Significantly, we found direct evidence that DCIS is a non-obligate precursor: some lesions do not progress to invasive tumors, and some even regress. This sets the stage for future studies evaluating the efficacy of preventive therapy for progression of DCIS.

 

11:06         195.       Novel Nitroimdazolyl Derivatives and Its Reduction Products Reveal Hypoxia in Cultures of C6 Cells Using 1H HR MAS

Jesus Pacheco-Torres1,2, Paloma Ballesteros2, Sebastian Cerdan3, Pilar Lopez-Larrubia3

1Instituto de Investigaciones Biomédicas "Alberto Sols" - CSIC , Madrid, Spain; 2Instituto Universitario de Investigación - UNED, Madrid, Spain; 3Instituto de Investigaciones Biomédicas "Alberto Sols" - CSIC, Madrid, Spain

We describe a novel nitroimidazolyl derivative as a probe for the measurement of hypoxia by 1H MRS methods. We show that our nitroimidazole has a redox potential similar to NADP and that is reduced by the cytochrome P-450 reductase system under anoxic conditions. In cultures of C6 cells under hypoxic conditions, the compound shows at least two reduction products that are originated in a hypoxia dependent manner. These results are validated with those obtained with pimonidazole, a commercial hypoxia probe. The kinetics of the reduction process may be observed by 1H HR MAS spectroscopy

11:18         196.       In Vivo Imaging of Tumor Hypoxia Using 19F MRS of Trifluoromisonidazole

Ellen Ackerstaff1, Mihai Coman1, Sean Carlin1, Sean A. Burke1, Kristen L. Zakian1, Khushali Kotedia1, Joseph O'Donoghue1, Clifton C. Ling1, Jason A. Koutcher1

1Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, USA

Tumor hypoxia has been related to treatment response. We used in vivo 19F-MRS/MRSI of Trifluoromisonidazole (TF-MISO) to evaluate tumor hypoxia in two animal tumor models. Intratumoral TF-MISO concentrations were only moderately influenced by tumor growth in both tumor models. The breathing of 21%O2, 95%O2/5%CO2, or 100%O2 did not significantly influence intratumoral TF-MISO levels in the MCa tumor, whereas in R3327-AT tumors, breathing of 100%O2 decreased significantly intratumoral TF-MISO levels in tumors below ~600mm3. Our results suggest that hypoxia imaging by 19F MR of TF-MISO may help to identify tumors that can be successfully reoxygenated and, thus, sensitized for radiation therapy.

11:30         197.       Molecular Characterization of the Relationship Between Hypoxia, Total Choline and Breast Cancer Stem Cell Markers

Balaji Krishnamachary1, Marie-France Penet1, Sridhar Nimmagadda1, Meiyappan Solaiyappan1, Dmitri Artemov1, Kristine Glunde1, Arvind P. Pathak1, Paul Winnard1, Venu Raman1, Martin Pomper1, Zaver M. Bhujwalla1

1JHU ICMIC Program, The Russell H. Morgan Department of Radiology and Radiological Science, The Jonhs Hopkins University School of Medicine, Baltimore, MD, USA

We previously observed an association between hypoxia, total choline, and increased expression of CD44, a marker associated with stem-like breast cancer cells. Here we have validated our observations that hypoxia is strongly associated with several stem-like breast cancer cell markers, and confirmed with imaging, that increased total choline and hypoxia are co-localized in MDA-MB-231 breast cancer xenografts. These data suggest that noninvasive imaging of hypoxia can identify regions most likely to contain stem-like breast cancer cells, and that hypoxic environments and choline metabolism may be targeted to reduce stem-like cell burden and minimize tumor recurrence.

11:42         198.       Glycine as a Biomarker in Brain Tumors

Valeria Righi1,2, Dionyssios Mintzopoulos1,2, Ovidiu C. Andronesi2, Peter M. Black3, A Aria Tzika1,2

1NMR Surgical Laboratory, MGH & Shriners Hospitals, Harvard Medical School, Boston, MA, USA; 2Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Boston, MA, USA; 3Neurosurgery, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA, USA

We employed high-resolution magic angle spinning proton MR spectroscopy (HRMAS H1 MRS) to evaluate glycine as a biomarker for brain tumors. Glycine in combination with myo-inositol was useful for differentiating glioblasoma multiforme from metastatic brain tumors.

11:54         199.       Initial Metabolomic Analysis of Glioblastoma Multiforme Subtypes by HRMAS

Daniel Valverde-Saubí1,2, Ana Paula Candiota1,2, Maria Antònia Molins3, Miguel Feliz3, Óscar Godino4, Juan Martino4, Juan José Acebes2,4, Carles Arús1,2

1Bioquímica i Biologia molecular, Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Barcelona, Spain; 2Centro de Investigación Biomédica en Red de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Cerdanyola del Vallès, Barcelona, Spain; 3Servei RMN Parc Científic de Barcelona, Universitat de Barcelona, Barcelona, Spain; 4Servei de Neurocirurgia, Hospital Universitari de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain

The aim of this study was to identify possible metabolomic glioblastoma multiforme subtypes using High Resolution Magic Angle Spinning Spectroscopy. According to our results, we detect three different glioblastoma multiforme which may bear some relationship to different proliferation rates.

12:06         200.       Comparison of MRS with Fluorescence for Molecular Imaging and Determination of Phospholipase Isoforms

Daniel-Joseph Leung1, Theresa Mawn1, Edward James Delikatny1

1Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA

We present the modulation of MR-visible metabolic response through the inhibition of the calcium-independent phospholipase A2 (iPLA2) and the cytosolic phospholipase A2 (cPLA2) isoforms and their differential roles in mediating lipid responses using the specific inhibitors BEL and AACOCF3, respectively. At the same time, a separate pathway of overall phospholipase A2 (sPLA2 isoform) activity is shown by kinetic fluorescence activation in vitro. This not only suggests the possibility of using MRS and optical methods to compare findings, but also the ability to characterize enzyme isoforms relevant to tumor drug response collaterally.

12:18         201.       Detection of Lung Metastases Using Hyperpolarized 3He MRI and Targeted Magnetic Nanoparticles – Histologic Validation and Detection Limits

Rosa Tamara Branca1, Zackary Cleveland2, Boma Fubara2, Challa Kumar3, Carola Leuschner4, Warren Sloan Warren5, Bastiaan Driehuys2

1Center for molecular and biomolecular imaging, Duke University , Durham, NC, USA; 2Center for in vivo microscopy, Duke University, Durham, NC, USA; 3Center for Advanced Microstructures and Devices, Louisiana State University, Baton Rouge, LA, USA; 4William Hansel Cancer Prevention, Pennington Biomedical Research Center, Baton Rouge, LA, USA; 5Center for molecular and biomolecular imaging, Duke University, Durham, NC, USA

Breast and prostate metastases are detected in lungs using hyperpolarized helium MRI and targeted contrast agent. The method allows the detection of metastatic nodules smaller than 100 micrometers with high specificity and sensitivity and, more generally, can be used to detect and track any type of labeled cell in lungs

Hepatic Storage Disease

Room 316A                         10:30-12:30                                                                         Moderators: Hero K. Hussain and Bachir Taouli

10:30         202.       Simultaneous Estimation of Water-T2 and Fat Fraction Using a Single Breath Hold Radial GRASE Method

Christian Graff1, Zhiqiang Li2, Eric W. Clarkson2, Chuan Huang3, Ali Bilgin4, Maria I. Altbach2

1Program in Applied Mathematics, University of Arizona, Tucson, AZ, USA; 2Department of Radiology, University of Arizona, Tucson, AZ, USA; 3Department of Mathematics, University of Arizona, Tucson, AZ, USA; 4Department of Electrical and Computer Engineering, University of Arizona, Tucson, AZ, USA

A new algorithm for processing radial GRASE data has been developed. With this algorithm one obtains both fat-water information and T2 of the water component within a breath hold. This novel method is fast and should provide valuable information for the characterization of pathologies in the clinic.

10:42         203.       Breath-Hold FSE for Accurate Imaging of Myocardial and Hepatic R2

Daniel Kim1, Jens H. Jensen1, Ed X. Wu2, Sujit S. Sheth3, Gary M. Brittenham3

1Center for Biomedical Imaging and Radiology, NYU Langone Medical Center, New York, NY, USA; 2Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong; 3Pediatrics and Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA

MRI provides a means to non-invasively assess tissue iron concentration by exploiting the paramagnetic effects of iron on T2 or T2*. The most widely used method is T2* imaging is sensitive to non-iron related magnetic field (B0) inhomogeneities, which can confound T2* measurements within the whole heart and liver. An alternative method is T2 imaging, but they are generally performed during free breathing with respiratory gating due to their low data acquisition efficiency. The purpose of this study was to develop a breath-hold fast spin echo (FSE) sequence for fast and accurate imaging of myocardial and hepatic T2.

10:54         204.       Hepatic Fat Quantification in Children Using Multi-Echo Gradient-Echo Imaging and Fat Spectral Modeling at 1.5 T

Masoud Shiehmorteza1, Takeshi Yokoo1, Gavin Hamilton1, Mark Bydder1, Manuel Rodriguez1, Joel E. Lavine2, Jeffrey B. Schwimmer2, Claude B. Sirlin1

1Radiology, University of California San Diego, San Diego, CA, USA; 2Pediatrics, University of California San Diego, San Diego, CA, USA

Fatty liver disease is currently the most common cause of liver disease in children (12-17% prevalence). Although MR imaging has been applied to children previously, the accuracy of fat quantification has not been verified. Confirming that MR imaging is accurate in children is necessary because they may not be able or willing to cooperate with MR examinations. Also, the histological features of pediatric FLD differ from those of adult FLD, and generalization of adult study’s data may not be valid. In this dedicated pediatric study, we assessed fat estimation accuracy of MR imaging, using single-voxel MR spectroscopy as the reference.

11:06         205.       Correlation of T1 and T2* Corrected Dual-Echo MRI Vs. MRS for Hepatic Fat Determination in a Multicenter Clinical Trial: Results of the Phase II Study of the MTP Inhibitor AEGR-733

Mark Rosen1, Sarah Englander1, Harish Poptani1, Evan Siegelman1, James Gimpel2, Dena Flamini2, Matthew Parris3, Bill Sasiela3, Bruce Hillman4

1Radiology, University of Pennsylvania, Philadelphia, PA, USA; 2American College of Radiology Imaging Network, Philadelphia, PA, USA; 3Aegerion, Inc., Bridgewater, NJ, USA; 4Radiology, University of Virginia, Charlottesville, VA, USA

A multisite trial of the MTP inhibitor AEGR-733 using hepatic MRI/MRS for liver fat determination was performed. Both single voxel (SV) MRS and multiple dual-echo gradient echo MRI data were used to quantify hepatic fat. A total of 1160 exams with evaluable MRI and MRS data sets were obtained. Correlation of hepatic fat by SV-MRS and several dual-echo MRI methods ranged from 0.870-0.890 for all data sets, 0.935-0.942 for protocol compliant MRI data, and 0.949-0.955 high-quality MRS data. Dual-echo MRI with correction for T1 and T2* effects outperformed other methods, with lower mean squared variation and fewer outlying data points.

11:18         206.       Quantification of Abdominal Fat Accumulation During Hyperalimentation Using MRI

Olof Dahlqvist Leinhard1,2, Andreas Johansson1, Joakim Rydell1, Johan Kihlberg2, Örjan Smedby1,2, Fredrik H. Nyström1, Peter Lundberg1,2, Magnus Borga1,2

1Linköping University, Linköping, Sweden; 2Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden

The abdominal fat content was quantified using in- and out-of-phase imaging after phase sensitive reconstruction and an initial intensity correction procedure. Classification of all tissue as subcutaneous, intraabdominal or retroperitoneal was performed using a novel completely automatic segmentation procedure. This technique was used to determine intraabdominal fat before and after a two-fold increase in daily caloric intake. A significantly lower increase of intraabdominal fat tissue was observed in women than in men. The study highlighted the suitability of MR for accurate and user independent investigation of the compartmentalization of fat deposits in the body.

 

11:30         207.       Validation of Chemical Shift Based Fat-Fraction Imaging with MR Spectroscopy

Sina Meisamy1, Catherine DG Hines1,2, Gavin Hamilton3, Karl Vigen1, Jean H. Brittain4, Charles A. McKenzie5, Huanzhou Yu6, Scott K. Nagle1, Yu Grace Zeng1, Claude B. Sirlin3, Scott B. Reeder1,2

1Radiology, University of Wisconsin, Madison, WI, USA; 2Biomedical Engineering, University of Wisconsin, Madison, WI, USA; 3Liver Imaging Group, Department of Radiology, University of California, San Diego, CA, USA; 4Applied Science Laboratory, GE Healthcare, Madison, WI, USA; 5Medical Biophysics, University of Western Ontario, London, Ontario, Canada; 6Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA

Nonalcoholic steatohepatitis is a form of liver disease, which affects nearly 30% of the US population and 75% of obese individuals. 1H-MRS is regarded by many as the non-invasive gold standard for quantification of hepatic steatosis. In this study we compare a chemical shift based fat-fraction imaging method (IDEAL) of the liver with 1H-MRS for quantification of hepatic steatosis. The results of our study show that overall, there is excellent correlation between IDEAL and MR spectroscopy with the highest correlation and excellent one-one agreement seen when both T2* correction and accurate spectral modeling of fat is applied.

11:42         208.       A Dynamic Study of Changes in  Hepatic and Skeletal Muscle Lipid and Glycogen Levels, Due to 24h Starvation and Re-Feeding: A 1H and 13C MRS Study

Mary Charlotte Stephenson1, Sherif Awad2, Elisa Placidi1, Luca Marciani2, Kenneth C. H. Fearon3, Ian A. Macdonald4, Robin C. Spiller2, Penny A. Gowland1, Peter Gordon Morris1, Dileep N. Lobo2

1SPMMRC, School of Physics and Astronomy, University of Nottingham, Nottingham, UK; 2Nottingham Digestive Diseases Centre Biomedical Research Unit, University of Nottingham, Nottingham, UK; 3Department of Surgery, University of Edinburgh, Ednburgh, UK; 4School of Biomedical Sciences,, University of Nottingham, Nottingham, Nottinghamshire, UK

Short-term starvation has been shown to induce insulin resistance in hepatic and skeletal muscle tissue although the metabolic processes involved are unknown. The aim of this study was to measure changes in hepatic and skeletal muscle glycogen and lipid content in order to understand substrate metabolism leading to an insulin resistant state following short-term starvation and re-feeding using a carbohydrate rich drink. Short-term starvation induced decreases in hepatic liver glycogen and lipid stores, with associated decreases in liver volume. Lipid levels in calf muscle increased due to starvation which may be the mechanism via which tissue becomes insulin resistant.

11:54         209.       Spectrally-Modeled Hepatic Fat Quantification by Multi-Echo Gradient-Recalled-Echo Magnetic Resonance Imaging at 3.0T

Takeshi Yokoo1, Masoud Shiehmorteza1, Mark Bydder1, Gavin Hamilton1, Yuko Kono2, Alexander Kuo2, Joel E. Lavine3, Claude B. Sirlin1

1Radiology, UCSD, San Diego, CA, USA; 2Medicine, UCSD, San Diego, CA, USA; 3Pediatrics, UCSD, San Diego, CA, USA

Several groups recently suggested that accurate fat quantification by MR requires correction of the relaxation effects as well as modeling of multi-component fat signal. Using non-T1-weighted multi-echo GRE imaging and 3-peak fat spectral modeling, high fat estimation accuracy was demonstrated at 1.5 T in fatty liver patients. In principle, this general approach would be independent of the field strength and therefore is also applicable at 3.0 T. In this first human study on spectrally-modeled hepatic fat quantification at 3.0 T, we assessed fat estimation accuracy of MR imaging using MR spectroscopy as the reference standard.

12:06         210.       Identification of Brown Adipose Tissue in Mice Using IDEAL Fat-Water MRI

Houchun Harry Hu1, Daniel L. Smith, Jr. 2, Tim R. Nagy2, Michael I. Goran3, Krishna S. Nayak1

1Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA, USA; 2Department of Nutritional Sciences, University of Alabama, Birmingham, AL, USA; 3Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA

The fat-signal fraction derived from IDEAL-MRI is used to discriminate white (WAT) and brown adipose tissue (BAT) depots in mice. We found in both excised tissue samples and in vivo that WAT has a fat-signal fraction range of 90-93%. In contrast, BAT exhibits a much wider and significantly lower range of 39-62%. Analysis from high-resolution (0.6 mm isotropic) 3T results in whole juvenile and adult mice clearly identified BAT in the interscapular region, as well as perirenal and intercostal sites. We thus conclude that BAT can be non-invasively identified based on MRI measurements of IDEAL fat-signal fraction.

12:18         211.       On the Definition of Fat-Fraction for in Vivo Fat Quantification with Magnetic Resonance Imaging

Scott B. Reeder1,2, Catherine DG Hines1,3, Huanzhou Yu4, Charles A. McKenzie5, Jean H. Brittain6

1Radiology, University of Wisconsin, Madison, WI, USA; 2Medical Physics, University of Wisconsin, Madison, WI, USA; 3Biomedical Engineering, University of Wisconsin, Madison, WI, USA; 4Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA; 5Medical Biophysics, University of Western Ontario, London, Ontario, Canada; 6Applied Science Laboratory, GE Healthcare, Madison, WI, USA

The most commonly used metric for fat quantification with MRI is “fat-signal-fraction”. After correction for confounding factors (eg. T2*-decay, etc) fat-signal-fraction is synonymous with fat-proton-density-fraction. Unfortunately, gold standard assays used to validate MRI provide estimates of fat-volume-fraction or fat-mass-fraction. The purpose of this work is to clarify fat-fraction definitions, and to estimate fat-volume-fraction and fat-mass-fraction from separated fat/water signals. Theory and experiment demonstrate that for fat, signal-fraction is equivalent to volume-fraction and mass-fraction. The same is not true, however, for other combinations of chemical species such as acetone and water, which require correction factors to determine volume or mass fraction.

fMRI Calibration

Room 323ABC                    10:30-12:30                                                                      Moderators: Catherine E. Chang and Peter Jezzard

10:30         212.       Quantification of CMRO2 and CBF Using Simultaneous NIRS and FMRI

Sungho Tak1, Jong Chul Ye1

1Bio and Brain Engineering, KAIST, Daejeon, Korea

This paper introduces an accurate technique to estimate the cerebral metabolic rate of oxygen (CMRO2) and cerebral blood flow (CBF) using simultaneously measured near infrared spectroscopy (NIRS) and blood oxygenation level dependent (BOLD) fMRI signals. Owing to simultaneous acquisition of both fMRI and NIRS, separate hypercapnia condition or arterial spin labeling (ASL) acquisition are not necessary to quantify CMRO2 and CBF, which greatly improves the accuracy of the proposed method. The dynamic coupling ratio of CBF changes to CMRO2 changes has been also investigated. Experimental results using finger tapping task showed that the activation pattern of CBF calculated using NIRS-SPM software is more specific to the primary motor cortex than fMRI BOLD and NIRS-HbR signal. Furthermore, the dynamic couple ratio coincides with the existing results from the literature.

10:42         213.       Evaluation of a New Quantitative BOLD Approach to Map Local Blood Oxygen Saturation

Thomas Christen1,2, Benjamin Lemasson1,3, Nicolas Pannetier1,2, Régine Farion1,2, Christoph Segebarth1,2, Chantal Rémy1,2, Emmanuel L. Barbier1,2

1Inserm, U836, Grenoble, F-38043, France; 2Université Joseph Fourier, Grenoble Institut des Neurosciences, UMR-S836, Grenoble, France; 3Oncodesign Biotechnology, Dijon, France

Recently, an in vivo MR approach – quantitative BOLD – was introduced to obtain blood volume fraction (BVf) and local blood oxygen saturation (lSO2) maps. The mesoscopic effect on T2* depends on both BVf and lSO2, but these two contributions are difficult to separate during data analysis. To improve the accuracy on the determination of lSO2, we introduce a different measurement scheme which combines a steady-state BVf measurement with standard B0 and T2 mapping. The proposed scheme was evaluated in healthy rats under an O2 challenge. Value of lSO2 are consistent with data from the litterature.

10:54         214.       Does Global Cerebral Oxygen Metabolism Change During Hypercapnia and Hypocapnia in Awake Humans?

Jean J. Chen1, G. Bruce Pike1

1McConnell Brain Imaging Centre, Montreal Neurological Institute, Montreal, Quebec, Canada

The effect of CO2 on cerebral metabolism is of great interest, since hypercapnia is routinely used in calibrated BOLD-based δCMRo2 estimation and assumes that CMRo2 remains unchanged during hypercapnia-induced blood flow increase. Certain anesthetized-animal studies, however, have put this claim under question, necessitating its verification in humans and under the conditions customary of calibrated BOLD. We report, for the first time, on steady-state global δCMRo2 measurements in awake humans during graded hypercapnia and hypocapnia. Our results show that under the mild levels of end-tidal CO2 changes commonly used in calibrated BOLD, there is negligible global δCMRo2.

11:06         215.       CO2 Breathing Suppresses Cerebral Metabolic Rate of Oxygen

Feng Xu1, Uma Yezhuvath1, Matthew R. Brier2, John Hart, Jr. 3, Michael A. Kraut4, Clair Moore2, Hanzhang Lu1

1University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA; 2University of Texas at Dallas, Dallas, TX, USA; 3University of  Texas at Dallas, Dallas, TX, USA; 4Johns Hopkins University, Baltimore, MD, USA

CO2 is highly potent in modulating cerebral blood flow. However the effect of CO2 on neuronal activity and brain energy consumption is not yet known. Here we used a novel technique to measure global cerebral metabolic rate of oxygen, CMRO2, during normocapnia and hypercapnia, and showed that 5% CO2 breathing can reduce the CMRO2 by 13±5% (n=8, p<0.001). We further used electroencephalography (EEG) to investigate which component of the neuron’s energy budget has changed, and found that the delta band in the EEG signal was enhanced by 18%, suggesting that brain was switched to a low-arousal state during CO2 breathing.

11:18         216.       CBF-CMRO2 Coupling in the Default Mode Network

Pan Lin1, Jorge Jovicich1, Simon Robinson1

1Center for Mind/Brain Sciences, University of Trento, Trento, Trentino, Italy

The Default Mode is a network of brain regions which show reduced blood flow (CBF) and BOLD signal in the task state relative to baseline, independent of the nature of the task. There has been controversy over the origin of these signal fluctuations, which overlap to some extent with regions affected by respiration rate variation. We show for the first time that the coupling ratio between cerebral blood flow and cerebral metabolic rate of oxygen consumption is the same in task-independent deactivation as in activation, and thereby consistent with a neuronal basis for deactivation of the Default Mode.

11:30         217.       Changes in Arterial Oxygen Tension with Evoked Stimulation in the Rat Somato-Sensory Cortex:  Implications for Quantitative FMRI

Alberto L. Vazquez1, Mitsuhiro Fukuda1, Seong-Gi Kim1

1Radiology, University of Pittsburgh, Pittsburgh, PA, USA

In an effort to investigate the changes in vascular and tissue oxygenation with evoked brain function, arterial, tissue and venous oxygen tension (and saturation) were measured in the rat somato-sensory cortex using oxygen micro-electrodes. Significant increases in the oxygen tension and saturation of pre-penetrating pial arterioles were observed. The largest increases in oxygen saturation were observed at the sampled small emerging pial veins. The observed steep oxygen tension and saturation gradient indicates that the quantification of the relative changes in CMRO2 from high-resolution BOLD fMRI data (hundreds of microns) will be underestimated.

11:42         218.       A Comparison of Physiologic Modulators of FMRI Signals

Hanzhang Lu1, Feng Xu1, Uma S. Yezhuvath1, Yamei Cheng1, Rani Varghese1

1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA

A critical prerequisite for fMRI to be possibly used for personalized disease diagnosis is that we have to understand and account for differences in fMRI signals across healthy subjects. Recently, much attention has been focused on the physiologic markers that can explain the inter-subject variations. Here we conducted visual-stimulation fMRI in a group of young, healthy controls and compared four potential modulators in explaining the variations in fMRI signals: baseline venous oxygenation, cerebrovascular reactivity, resting state BOLD signal fluctuation, and baseline CBF. It was found that these physiologic parameters in combination can explain up to 69% of the inter-subject variations.

11:54         219.       Comparison and Validation of FMRI Calibration Techniques

Rasmus Matthias Birn1, Daniel Handwerker1, Peter A. Bandettini1

1Laboratory of Brain and Cognition, National Institute of Mental Health, Bethesda, MD, USA

The amplitude of the BOLD response across the brain depends strongly on the variations in the underlying vasculature, making it difficult to determine subtle differences in neuronal activity between regions or subjects. In this study we test various calibration techniques designed to account for spatial variability in the vasculature, and compare their ability to pull out known subtle underlying variations in neuronal activity.

12:06         220.       An Intra-Subject Investigation of the BOLD Contrast Mechanism in Response to Visual Stimulation and Breath Hold at 1.5T, 3.0T and 7.0T: Insight Into the Extravascular Sensitivity, Resolution-Dependence and Vascular Origins of BOLD Contrast

Manus J. Donahue1, Hans Hoogduin2, Peter CM van Zijl3,4, Peter Jezzard1, Reinoud Pieter Harmen Bokkers2, Matthias JP van Osch5, Jaco J.M. Zwanenburg2, Peter Luyten2, Jeroen Hendrikse2

1Clinical Neurology, The University of Oxford, Oxford, UK; 2University Medical Center Utrecht, Utrecht, Netherlands; 3Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; 4FM Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA; 5Leiden University Medical Center, Leiden, Netherlands

B0-dependence of gradient-echo BOLD-fMRI contrast was investigated in the same subjects at 1.5T, 3.0T and 7.0T by performing (1) BOLD-fMRI (visual) in the presence of flow-dephasing gradients (b=100 s/mm2) at multiple TEs, (2) BOLD-fMRI (visual) at high (1.5x1.5x1.5mm3) and low (3.5x3.5x3.5mm3) spatial resolution, and (3) BOLD-fMRI (breath hold). Extravascular (EV) contributions to total BOLD ΔR2* were 45±13%, 70±11% and 92±19% at 1.5T, 3.0T and 7.0T, respectively, suggesting that BOLD fMRI performed at 7.0T is almost purely EV. Caution should be exercised when comparing total BOLD reactivity at different B0 due to different EV contributions.

12:18         221.       Physiological Noise Effects on the Flip Angle Selection in BOLD FMRI.

Jerzy Bodurka1, Peter Bandettini1,2

1Functional MRI Facility, National Institute of Mental Health, NIH, Bethesda, MD, USA; 2Section on Functional Imaging Methods, National Institute of Mental Health, NIH, Bethesda, MD, USA

Here we have considered theoretically and experimentally the physiological noise effects on the flip angle selection. We will shown that for given TR, temporal signal to noise ratio (TSNR=mean voxel time course signal/time course standard deviation)

 versus flip angle plots are significantly affected by the physiological noise. For situations where available SNR is high and physiological noise dominates over system/thermal noise the selection of Ernst angle does not results in large improvements in TSNR. In fact it is possible to select much smaller flip angle and have similar TSNR as for the Ernst angle, however smaller flip angle have important benefits of reducing possible inflow effect.

Molecular & Cellular Probes

Room 316BC                       10:30-12:30                                                       Moderators: Michael T. McMahon and Willem M. Mulder

10:30         222.       The Development of an MR Agent for Imaging of Malignant Micro-Calcification in Breast Cancer

Kumar R. Bhushan1, Elena Vinogradov2, Ananth J. Madhuranthakam3, Atshushi Takahashi4, John V. Frangioni1,2, Robert E. Lenkinski2

1Medicine, Beth Israel Deaconess Medical Center, Boston, MA, USA; 2Radiology, Beth Israel Deaconess Medical Center, Boston, MA, USA; 3Applied Science Laboratory, GE Healthcare, Boston, MA, USA; 4Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA

We have developed lanthanide-chelated bisphosphonate derivatives that are suitable MRI agents for imaging hydroxyapatite. An ultra-short echo time (UTE) sequence was used to image these agents in the environment of micro-calcification. We found that these compounds possess very high relaxivity in the adsorbed state. The combination of UTE and the newly developed MR agents demonstrate the successful high specificity and high sensitivity detection of calcified substances in vitro and in vivo. This study provides a foundation for the design and development of methods for high sensitivity MR detection of micro-calcifications within breast tumors.

10:42         223.       Fluorine-19 MR Molecular Imaging of Angiogenesis on Vx-2 Tumors in Rabbits Using α ν β 3-Targeted Nanoparticles

Jochen Keupp1, Shelton D. Caruthers2,3, Jürgen Rahmer1, Todd A. Williams3, Samuel A. Wickline3, Gregory M. Lanza3

1Philips Research Europe, Hamburg, Germany; 2Philips Healthcare, Andover, MA, USA; 3Washington University, St. Louis, MO, USA

Anti-angiogenic therapy in combination with established chemotherapy or radiation therapy has entered clinical practice for lung, colon and breast cancer. However, effectiveness of anti-angiogenic pre-treatment is substantially varying among patients. Given the high cost and severe side effects, there is a strong clinical need for enhanced patient stratification, which could be based on MRI of angiogenesis using targeted imaging agents. ανβ3-integrin targeted nanoparticle (NP) emulsions, labeled with R1-enhancing Gd-chelates, were previously shown to allow three-dimensional MR mapping of tumor angiogenesis in small animals. These studies were based on δR1 mapping from two image sets taken before and after NP injection. The present study shows, that the perfluorocarbon (PFC) core of the same targeted NP can be used as a 19F MR label to map angiogenesis around Vx-2 tumors (adenocarcinoma) in rabbits. With simultaneous 19F and 1H MR, diagnostic imaging is only required at a single time point post-injection injection and may offer the ability of direct absolute quantification.

10:54         224.       In Vivo Molecular MRI of Atherosclerotic Plaque Progression in Mice Using a Novel Elastin-Binding Contrast Agent

Marcus R. Makowski1, Ulrike Blume1, Andrea J. Wiethoff1, Christian Jansen1, Joel Lazewatsky2, Simon Robinson2, Rene M. Botnar3

1King’s College London BHF Centre of Research Excellence, Imaging Sciences Division, London, UK; 2Lantheus Medical Imaging, USA; 3King’s College London BHF Centre of Research Excellence, Imaging Sciences Division, UK

The extracellular matrix (ECM) plays a pivotal role in the pathogenesis of atherosclerosis and ECM remodeling. Elastin is an essential component of the ECM of the arterial vessel wall. Male ApoE -/- mice have been shown to reproducibly develop progressive atherosclerotic plaques in the innominate artery over a short period on a high fat diet (HFD). With the advent of a novel elastin binding contrast agent (BMS -753951) imaging of ECM formation in atherosclerosis has become feasible. In this study, we demonstrate the successful non-invasive assessment of alterations in atherosclerotic plaque size in an ApoE mouse model using serial MRI together with a novel elastin specific contrast agent. Molecular alterations, with regard to elastin formation in atherosclerosis can be differentiated using BMS-753951.

11:06         225.       MR Imaging of an Arachidonic Acid-Induced Mouse Model of Thrombosis Using an Activated Platelets-Targeted Paramagnetic Contrast Agent.

Ahmed Klink1,2, Eric Lancelot3, Sébastien Ballet3, Walter Gonzalez3, Christelle Medina3, Claire Corot3, Jean-Etienne Fabre4, Willem J.M Mulder1, Ziad Mallat2, Zahi A. Fayad1

1Translational and Molecular Imaging Institute, Mount Sinai School Of Medicine, New York, NY, USA; 2INSERM U689, Paris, France; 3Research Division, Guerbet, France; 4Atherothrombosis Laboratory, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Strasbourg, France

P975 is a paramagnetic MRI based contrast agent with specificity for activated platelets via a peptide that binds to the glycoprotein GPIIb/IIIa. This agent was used in an arachidonic acid-induced mouse model of thrombosis to visualize thrombi formation and monitor thrombogenic activity.

11:18         226.       in Vivo CEST Imaging Using Eu(III)-Water Molecule Exchange System

Tomoyasu Mani1,2, Osamu Togao1, Todd C. Soesbe1, Masaya Takahashi1, Allan Dean Sherry1,2

1Advanced Imaging Research Center, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA; 2Department of Chemistry, University of Texas at Dallas, Richardson, TX, USA

Chemical exchange saturation transfer (CEST) imaging has attracted considerable attention. Ln(III)-based exogenous CEST agents (PARACEST) can be used to enhance the sensitivity of CEST imaging. As part of a program to develop more effective agents, a newly designed Eu(III)-DOTA-tetraamide complex was applied in vivo. The CEST effect from this agent were somewhat smaller when the agent was dissolved in blood plasma at body temperatures (35-39 C) compared to when it was dissolved in pure water. No differences in CEST were observed at lower temperatures (20-27 C). CEST contrast in liver and kidney of mouse (20%) were successfully observed using low presaturation pulse (7µT) to avoid competitive inherent MT effects.

11:30         227.       Magnetization Transfer Detection of GFP: A New MRI Gene Reporter

Carlos J. Perez-Torres1, Cynthia A. Massaad2, Faridis Serrano2, Robia G. Pautler1,2

1Translational Biology and Molecular Medicine Program, Baylor College of Medicine, Houston, TX, USA; 2Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA

To visualize gene expression via any imaging modality, a reporter system needs to be instituted that causes sufficient contrast between the tissues where the gene is expressed compared to other tissues where the gene is not expressed. Green Fluorescent Protein (GFP) is a widely used molecular and gene expression marker. We report a technique to detect GFP by using Magnetic Resonance Imaging (MRI) through Magnetization Transfer Contrast (MTC). GFP was detected with MTC MRI both in vitro and in vivo. This system provides a flexible, non-invasive in vivo molecular imaging system that has the advantage of combining readily available materials.

11:42         228.       Chimeric Ferritin as a Reporter for MRI

Bistra Iordanova1, Clinton S. Robison1, Eric T. Ahrens1,2

1Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA; 2Pittsburgh NMR Center for Biomedical Research, Carnegie Mellon Univeristy, Pittsburgh, PA, USA

Several recent molecular MRI techniques utilize the iron storage protein ferritin as a probeless reporter. One of the practical limitations of ferritin as a reporter for MRI is that it is a relatively weak contrast agent, especially at lower magnetic field strengths. To enhance MRI sensitivity, we fixed its heavy and light subunit stoichiometry by engineering a fusion single-chain ferritin. In this study we show that the new ferritin chimera loads significantly more iron and exhibits higher transverse relaxation rates than wild type ferritin both in human cells and in mouse brain.

11:54         229.       In Vivo MR and PET Imaging of a Highly Sensitive Polymeric PARACEST Contrast Agent

Todd C. Soesbe1, Yunkou Wu2, Guiyang Hao3, Xiankai Sun1, A. Dean Sherry1,2

1Advanced Imaging Research Center, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA; 2Department of Chemistry, The University of Texas at Dallas, Dallas, TX, USA; 3Department of Radiology, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA

Chemical exchange saturation transfer (CEST) agents create contrast in MR images by exchanging their saturated lanthanide bound protons with those of bulk water. These agents have great potential to further extend the functional and molecular imaging capabilities of MR. Polymeric paramagnetic CEST (PARACEST) agents have recently been prepared by our group. The polymeric agents increase the CEST effect by creating a higher concentration of lanthanide ions at the target site. These agents offer an order on magnitude improvement in sensitivity which greatly reduces in vivo dose levels. The improved sensitivity of the polymeric agents also helps overcome the magnetization transfer (MT) effect due to endogenous macromolecules in tissue, which can mask the CEST effect. We present the first in vivo images of a polymeric Eu3+ PARACEST agent using a simple fast spin echo pulse sequence. We also show that this agent could be used for simultaneous PET/MR imaging by labeling the polymer with Cu-64.

12:06         230.       Rational Design of a High Relaxivity MR Probe

Luca Frullano1, Peter Caravan1

1Radiology, Massachusetts General Hospital, Charlestown, MA, USA

The synthesis and characterization of a new Gd-based contrast agent is described. A dual strategy of increasing inner-sphere and second-sphere hydration was used to design an agent with more than 150% higher relaxivity than other low molecular weight contrast agents. Relaxivity is unaffected by the presence of coordinating anions such as phosphate or citrate and the high relaxivity is maintained over a broad field range (0.5 – 9.4T). This complex also contains a pendant carboxylate for linkage of this contrast agent to a putative targeting moiety such as a peptide.

 

12:18         231.       Well-Defined, Multifunctional Nanostructures of a Paramagnetic Lipid and a Lipopeptide for Macrophage Imaging

Honorius M.H.F. Sanders1,2, Esad Vucic3, Nico A.J.M. Sommerdijk2, Enzo Terreno4, Francesca Arena4, Silvio Aime4, Klaas Nicolay1, Margaritta Dathe5, Zahi A. Fayad3, Willem J.M. Mulder3

1Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Brabant, Netherlands; 2Soft Matter Cryo-TEM Research Unit, Eindhoven University of Technology, Eindhoven, Brabant, Netherlands; 3Translational and Molecular Imaging Institute and Imaging Science Laboratories, Mount Sinai School of Medicine, New York, USA; 4Department of Chemistry IFM and Molecular Imaging Center, University of Torino, Torino, Italy; 5Leibniz Institute of Molecular Pharmacology, Berlin, Germany

In the field of targeted molecular imaging and therapy the pharmacokinetic profile as well as the tissue penetration potential of nanoparticulate formulations is of paramount importance. Hence, there is a great demand for nanostructures of which the final morphology and size can be judiciously controlled.

By controlling the ratio of two amphiphilic molecules, the paramagnetic lipid Gd-DTPA-DSA and P2fA2, a fluorscein labeled apolipoprotein E derived lipopeptide, we created a variety of well-defined multifunctional and nano-sized structures. NMRD-profiling disclosed excellent and tunable MRI properties, while in vitro experiments with macrophage cells demonstrated efficient uptake.

Methods for Spectroscopic Quantitation

Room 315                             10:30-12:30                                                                   Moderators: Sarah J. Nelson and Geoffrey S. Payne

10:30         232.       In-Vivo Measurement of Absolute Metabolite Concentrations Using the ERETIC Method

Susanne Heinzer-Schweizer1, Nicola De Zanche1,2, Matteo Pavan1, Giel Mens3, Urs Sturzenegger4, Anke Henning1, Peter Boesiger1

1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 2Department of Medical Physics , Cross Cancer Institute and University of Alberta, Edmonton, Canada; 3Philips Healthcare, Best, Netherlands; 4Philips AG Healthcare, Zurich, Switzerland

Absolute quantification is an indispensable tool to precisely determine metabolite changes. Calibration with ERETIC (Electric REference To access In vivo Concentrations), whereby a synthetic reference signal is injected during the acquisition of spectra, was used to determine quantitative in-vivo metabolite concentrations in volunteers. Brain 1H MRS spectra were acquired and cross-validated against the internal water reference method. The results of both calibration techniques were in good agreement in healthy tissue. In addition, the ERETIC setup was perfected by substitution of the electrical by an optical signal transmission line to eliminate fluctuations of the ERETIC signal intensity due to parasitic coupling.

10:42         233.       Simultaneous Localized in Vivo 1H and 15N MRS of Glutamine Synthesis in the Hyperammonaemic Rat Brain

Cristina Cudalbu1, Bernard Lanz1, Florence D. Morgenthaler1, Yves Pilloud1, Vladimir Mlynárik1, Rolf Gruetter1,2

1Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; 2Departments of Radiology, Universities of Lausanne and Geneva, Switzerland

A complementary approach to 13C MRS for studying glutamate and glutamine metabolism is 15N MRS during infusion of 15N labeled ammonia. The goal of this study was to use in vivo localized 15N MRS interleaved with in vivo 1H MRS to measure the glutamine synthesis rate under ammonia infusion in the rat brain. We obtained a net synthesis flux of 0.021±0.006µmol/min/g. By fitting the in vivo 5-15N Gln time course the apparent glutamine synthesis rate and the plasma FE of NH3 were 0.29±0.1µmol/min/g and 71±6%, respectively. Finally, the apparent neurotransmission rate was 0.26±0.1µmol/min/g.

10:54         234.       Measurement of Glutathione (GSH) Using a Standard STEAM Sequence with Optimized (TE, TM) Parameters: Spectral Simulation, Phantom, and Human Experiments at 3T

Shaolin Yang1, Yihong Yang1

1Neuroimaging Research Branch, National Institute on Drug Abuse, NIH, Baltimore, MD, USA

Glutathione (GSH) is a major intracellular antioxidant. Due to spectral overlap with other metabolites, spectral editing has been primarily employed to measure GSH. A recent report suggested resolving the GSH resonance at 2.54 ppm using a standard STEAM sequence with optimized (TE, TM) parameters. However, N-acetylaspartylglutamate (NAAG), which also yields proton resonances around 2.54 ppm, was ignored. In this study, we extended the (TE, TM) optimization originally proposed in that report by adding NAAG as another overlapping metabolites, and found optimized (TE, TM) parameters for resolved GSH measurement at 3T. Phantom and human experiments were conducted for verification.

11:06         235.       Simultaneous Quantitation of T2 and Concentration of Vitamin C and GSH in the Human Brain in Vivo Using Multiple Echo Time Double Editing with MEGA-PRESS  at 4 and 7 T

Uzay Emir1, Malgorzata Marjanska1, Dinesh Deelchand1, Pierre-Gilles Henry1, Ivan Tkac1, Melissa Terpstra1

1University of Minnesota, Minneapolis, MN, USA

Double Edited MEGA-PRESS spectra were detected at multiple TE in the human brain to measure T2 of Asc and GSH. Data from 22 subjects studied at 4 T were pooled to measure a 50 ms T2 for GSH (95% CI 41-62). The Asc T2 was not determined due to contamination by co-edited resonances. To our knowledge, this is the first time the T2 of GSH has been reported. Spectra measured at several TE in the human brain at 7 T suggest that this methodology can be utilized to measure the Asc and GSH T2 at 7 T.

11:18         236.       Measurement of N-Acetylaspartylglutamate in Human Brain by Difference Editing at 7.0 Tesla

Changho Choi1, Subroto Ghose2, Ivan Dimitrov1,3, Deborah Douglas1, Perry Mihalakos2

1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; 2Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA; 3Philips Medical Systems, Cleveland, OH, USA

N-acetylaspartylglutamate (NAAG) in human brain has been measured with difference editing at 7T. The C3 proton resonances (~2.5 ppm) of the aspartyl groups of NAAG and N-acetylaspartate (NAA) were differentiated using a 20 ms Gaussian radio-frequency (RF) pulse (bandwidth = 57 Hz) for selective excitation of the their coupling partners at 4.61 and 4.38 ppm, respectively. Symmetric carriers of the editing 180° pulse were applied to separate NAAG and NAA completely. In vivo measurement was conducted on the medial prefrontal and the left frontal lobes of a healthy volunteer. Assuming identical relaxation times between NAAG and NAA, the concentration of NAAG was estimated to be 1 and 2.3 mM for prefrontal and left frontal, respectively, with reference to NAA at 9 mM.

11:30         237.       GABA Concentration in Visual Cortex Correlates with Individual Differences in γ-Band Oscillation Frequency

Richard A. Edden1, Suresh Daniel Muthukumaraswarmy2, Derek K. Jones2, Jennifer B. Swettenham2, Krish D. Singh2

1Schools of Chemistry and Biosciences, Cardiff University, Cardiff, Wales, UK; 2CUBRIC, School of Psychology, Cardiff University, Cardiff, Wales, UK

GABA, the principle inhibitory neurotransmitter in the human CNS, plays an important role in the neuronal processes of the healthy brain, and altered GABAergic neurotransmission has been implicated in pathologies from epilepsy to bipolar disorder. This study presents a novel combination of edited MRS measurements of GABA with functional measurements of brain activity by magnetoencephalography and shows a strong correlation between GABA and γ-band oscillation frequency.

11:42         238.       Simplified 13C Metabolic Modeling for Simplified Measurements of Cerebral TCA Cycle Rate in Vivo

Julien Valette1, Fawzi Boumezbeur1, Vincent Lebon1,2

1CEA-NeuroSpin, Gif-sur-Yvette, France; 2CEA-MIRCen, Fontenay-aux-Roses, France

13C NMR spectroscopy is a unique tool to measure cerebral TCA cycle rate in vivo. The measurement relies on metabolic modeling of glutamate C3 and C4 enrichment time-courses during a 13C-glucose i.v. infusion. Classical metabolic models require as additional input functions the plasma glucose and 13C-glucose time-courses, as well as the knowledge of Michaelis-Menten kinetics parameters governing passage through the blood brain barrier. It is shown in the present work that metabolic modeling can be simplified in a manner that these additional inputs are not required anymore, significantly simplifying the measurement of cerebral TCA cycle rate in vivo.

11:54         239.       Phase Navigators for Localized MR Spectroscopy Using Water Suppression Cycling

Thomas Ernst1, Jikun Li2

1Medicine, University of Hawaii, Honolulu, HI, USA; 2Electrical Engineering, University of Hawaii

Magnetic resonance spectroscopy (MRS) is sensitive to subject motion, in part due to phase and frequency variations during movements. A novel water-suppression cycling scheme was developed that alternates between under-suppressed and over-suppressed residual water, and allows 1) phase and frequency correction of individual FIDs using the residual water signal, 2) restoration of signal losses due to incoherent averaging, and 3) near-complete attenuation of residual water. It is demonstrated that phase-correction, using the residual (cycled) water signal, can restore spectra with very poor signal-to-noise ratio (SNR) and line-width induced by subject motion.

12:06         240.       Versatile Fitting Tool for Simultaneous Modeling of Spectral Arrays Using Prior Knowledge Restrictions in Two Dimensions

Daniel Guo Quae Chong1, Johannes Slotboom2, Chris Boesch1, Roland Kreis1

1Department of Clinical Research, University of Be rn, Bern, Switzerland; 2Neuroradiology, Inselspital, Bern, Switzerland

A versatile fitting tool for 1D and 2D MRS data is introduced. It uses a hierarchical spectral model that allows for complex prior knowledge implementation. In the second dimension, constraints for common frequencies, widths or phases can be enforced, while predefined amplitude relations allow to fit further parameters, like T2 or T1. It was successfully used for a time series of spectra with varying concentration of a single metabolite, determination of T1 ‘s in a simulated saturation-recovery spectra, and 2DJ data.

12:18         241.       31P Spectroscopic Imaging of Human Brain at 7T

Jullie W. Pan1,2, Nikolai Avdievich1, Jonathan Knisely3, Hoby P. Hetherington1

1Neurosurgery, Yale University School of Medicine, New Haven, CT, USA; 2BME, Yale University School of Medicine, New Haven, CT, USA; 3Therapeutic Radiology, Yale University School of Medicine, New Haven, CT, USA

Because of reduced spectral overlap and sensitivity to B0 inhomogeneity, 31P MRSI is advantageous for whole brain studies. 31P MRS is also sensitive to chemical exchange, this aspect not widely utilized for human brain studies. The SNR limitation of 31P MRSI can be offset by acquiring data at 7T. We measured the T1s of PCr, ATP and Pi at 7T using a multi-tip IR sequence and a 3site exchange model. In brain tumor patients, 31P SI show dramatic reductions in PCr with normal ATP levels, arguing that the reduced PCr signal results from lower concentrations, not only chemical exchange differences.

Characterization of White Matter in Disease

Room 311                             10:30-12:30                                                                            Moderators: Kelvin O. Lim and Karen A. Tong

10:30         242.       White Matter NAA Levels and Very Long Chain Fatty Acid Levels in Asymptomatic Boys with X-Linked Adrenoleukodystrophy Undergoing Lorenzo’s Oil Therapy

Asif Mahmood1,2, Gerald V. Raymond1,2, Michael J. Moser3, Peter B. Barker2,3

1Neurology, Johns Hopkins University, Baltimore, MD, USA; 2Kennedy Krieger Institute, Baltimore, MD, USA; 3Radiology, Johns Hopkins University, Baltimore, MD, USA

Serial, yearly proton MRSI was performed in 58 asymptomatic boys with X-linked adrenoleukodystrophy (ALD) enrolled in a clinical trial of the dietary therapy “Lorenzo’s oil”. Metabolite ratios were examined for correlations with peripheral very long chain fatty acid (C26) levels. Significant negative correlations were found between posterior white matter NAA/Cho and NAA/Cr ratios and C26. These studies confirm preliminary results in a smaller number of subjects, which suggest that lack of control of C26 levels leads to axonal damage or dysfunction in the key white matter regions in ALD.

10:42         243.       Increased NAA Concentration in the Restless Legs Syndrome: Possible Link to Hypomyelination

Byeong-Yeul Lee1, Padmavathi Ponnuru2, James R. Connor2, Qing X. Yang1,3

1Bioengineering, The Penn State University, Hershey, PA, USA; 2Neurosurgery, The Penn State University, Hershey, PA, USA; 3Radiology, The Penn State University, Hershey, PA, USA

Iron deficiency has been known as a contributing factor for restless legs syndrome (RLS). To date, the relationship of iron deficiency and neurochemical changes in the dopaminergic brain structures has not been studied in vivo. The aim of present study was to investigate the neurochemical profiles in the RLS brain using in vivo 1H MRS as well as ex vivo myelin analysis of RLS autopsy brain tissue. We observed a highly significant increase in NAA concentration and decreased expression of myelin-related protein in RLS brain. These results support the hypothesis that brain iron deficiency may cause hypomyelination which leads to a NAA increase in RLS brain.

10:54         244.       Alteration of T2 Relaxation and NAA Concentration in Schizophrenia Evaluated in Frontal White Matter at 3 T

Nuran Tunc-Skarka1, Wolfgang Weber-Fahr1, Mareen Hoerst1, Susanne Englisch2, Christine Esslinger2, Dragos Inta2, Alexander Guttschalk2, Mathias Zink2, Gabriele Ende1

1Department Neuroimaging, Central Institute of Mental Health, Mannheim, Germany; 2Department of Psychiatry and Psychotherapy, Central Institute of Mental Health, Mannheim, Germany

There are several studies that found reduced NAA in schizophrenic patients. This could be an indication that NAA concentration or relaxation might be different due to pathological microstructure changes. The major problem of individual metabolite relaxation time estimation is the long measurement time. Nevertheless, only with the knowledge of individual relaxation time it is possible to evaluate absolute concentrations. In this study we wanted to estimate absolute metabolite concentrations of the frontal white matter in schizophrenic patients while evaluating individual T2 relaxation time and to compare with healthy controls. We found differences in NAA concentration and T2 relaxation time.

11:06         245.       Investigation of Tract-Specific Myelin Content Measures from a Population Averaged Myelin Water Fraction Atlas

Sean CL Deoni1

1Centre for Neuroimaging Sciences, London, UK

Here we report on the development of a whole-brain, population-averaged atlas of myelin content derived from in vivo measurements of the myelin water fraction. 14 healthy individuals were imaging using the mcDESPOT multi-component relaxometry technique, non-linearly coregistered to standard space and averaged. From the resulting whole-brain atlas we demonstrate white matter tract-specific measures and consider the future application of such an atlas for identifying disease-related change.

11:18         246.       Evaluation of Anatomical and Functional Connections Following Traumatic Brain Injury in Humans by Diffusion Tensor Imaging and Resting-State Functional Connectivity

Christine L. MacDonald1, Nicholas Hubbard1, Sanjeev Vaishnavi1, Adrian Epstein1, Abraham Snyder1, Stephanie Chleboun2, Joshua Shimony1, Marcus Raichle1, David Brody1

1Washington University, Saint Louis, MO, USA; 2Southern Illinois University Edwardsville, Edwardsville, IL, USA

Diffuse axonal injury is hypothesized to be the primary cause of cognitive deficits following traumatic brain injury (TBI). Currently clinical imaging modalities are not optimized to assess this pathology. 20 chronic TBI patients and 12 controls were scanned with diffusion tensor imaging and resting-state fMRI at 3T. Detailed neuropsychological assessments were performed the same day. Highly significant correlations were found between several aspects of cognitive performance and imaging abnormalities detected on DTI or resting-state fMRI analysis of functional connectivity. Conventional anatomical sequences did not reveal these pathologies. Thus, these advanced MRI techniques could be synergistically used to better assess TBI.

11:30         247.       Application of Diffusion Tensor Imaging to Better Understanding Pathogenesis of the Pelizaeus-Merzbacher Disease.

Jeremy J. Laukka1,2, Malek I. Makki3, James Y. Garbern1,4

1Neurology, Wayne State University, Detroit, Mi, USA; 2Radiology, Michigan State University, East Lansing, Mi, USA; 3Radiology, Wayne State University, Detroit, Mi, USA; 4Molecular Medicine and Genetics, Wayne State University, Detroit, Mi, USA

Twelve Pelizaeus-Merzbacher disease (PMD) patients with a range of PLP1 mutations were analyzed by DT-MRI. The radial (ëradial) and parallel (ë//) diffusivities, apparent diffusion constant (ADC) and fractional anisotropy (FA) were measured through several white matter tracts, including the corpus callosum and corticospinal tract. The most dramatic difference between PMD patients and controls was increased ëradial, most marked in the corpus callosum. Interestingly, ë// was also increased in the severely affected PMD patients, whereas in severely dysmyelinated rodents, the ëradial is reported to be normal to decreased. ë// in patients with PLP1 null mutations was relatively unaffected relative to controls.

11:42         248.       Microbleed Detection in Traumatic Brain Injury at 3T and 7T: Comparing 2D and 3D Gradient-Recalled Echo (GRE) Imaging with Susceptibility-Weighted Imaging (SWI)

Kathryn E. Hammond1,2, Janine M. Lupo1, Duan Xu1, Sri Veeraraghavan1, Hana Lee3, Adam Kincaid3, Dan B. Vigneron1,2, Geoffrey T. Manley3, Sarah J. Nelson1,2, Pratik Mukherjee1

1Radiology and Biomedical Imaging, University of California, San Francisco (UCSF), CA, USA; 2UCSF/UCB Joint Graduate Group in Bioengineering; 3Neurological Surgery, UCSF

The detection of microbleeds is important for the diagnosis and prognosis of traumatic brain injury (TBI). This study evaluated whether SWI improved microbleed detection over 2D or 3D GRE in 24 TBI patients scanned at 3T or 7T. The study reports that microbleeds were readily detectable in the short 2D GRE images, that few or no additional microbleeds were detected in the 3D GRE or SWI and that stretching in the SWI mislocated microbleeds. It concludes that the longer scan times required for 3D GRE and SWI may therefore not be necessary for clinical practice at high field.

11:54         249.       Analyzing White Matter Integrity Changes Associated with Posttraumatic Stress Disorder in Veterans

Wang Zhan1, Zhen Wang2,3, Charles Marmar2, Thomas Neylan2, Yu Zhang1, Susanne Mueller1, Marzieh Nezamzadeh1, Chris Ching1, Michael Weiner1, Norbert Schuff1

1Department of Radiology, University of California, San Francisco, San Francisco, CA, USA; 2PTSD Research Program, VA Medical Center, San Francisco, CA, USA; 3Shanghai Mental Health Center, Shanghai Jiao Tong University, Shanghai, China

Diffusion tensor imaging (DTI) technique is applied to analyze the white matter (WM) integrity alterations in war-related posttraumatic stress disorder (PTSD) in male veterans. Voxel-based group comparisons are made between PTSD veterans and age-matched healthy veterans controls. PTSD related WM degradations, measured by reduced fractional anisotropy (FA), are detected in WM tracts in prefrontal cortex (PFC) and anterior cingulate cortex (ACC). In the PTSD group, reduced FA is also found to be significantly correlated with increased PTSD severities, and the decreased volumes of hippocampal subfield CA3 and dentate gyrus (CA3&DG).

12:06         250.       White Matter Microstructure Abnormality in Autism Spectrum Disorders : A DTI Based Subdivided Corpus Callosum Study

Pei-Chin Chen1, Kun-Hsien Chou2, I-Yun Chen3, Chun-Yi Lo1, Hsuan-Hui Wang1, Ya-Wei Cheng3, Ching-Po Lin1,3

1Institute of Biomedical Imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan; 2Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan; 3Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan

Autism spectrum disorders (ASD) is a heterogeneously neurodevelopmental disorder, that is characterized by impaired social reciprocity, communication difficulties, and restricted interest. To observe the abnormal brain connectivity in ASD, the investigation of subdivision corpus callosum using DTI fiber tracking with fractional anisotropy (FA), can indicate the integrity of the fiber tracts. The ASD had greater FA in the Region 4 and 5 than healthy subject, the result indicated that the communication between bilateral hemispheres was abnormal in motor, somaesthetic areas. Previous studies indicated abnormal regulation of brain growth in ASD results from early overgrowth followed by abnormally slowed growth.

Advanced Sequences & Techniques

Room 313BC                       10:30-12:30                                                           Moderators: Sonia Nielles-Vallespin and Klaus Scheffler

10:30         251.       Young Investigator Award Finalist:  B0 and B1 Correction Using the Inherent Degrees of Freedom of a Multi-Channel Transmit Array

Jeremiah Aaron Heilman1, Jamal J. Derakhshan1, Matthew J. Riffe1, Natalia Gudino1, Jean Tkach1, Christopher A. Flask1, Jeffrey L. Duerk1, Mark A. Griswold1

1Case Western Reserve University, Cleveland, OH, USA

We present methods that capitalize on the inherent degrees of freedom in a mutli-channel transmission array to correct the effects of B0 and B1 variations within the context standard slice selective and chemically selective pulses. A new method called Parallel excitAtion for B-field insensitive fat Saturation preparaTion (PABST) utilizes the frequency and amplitude freedom to improve uniformity and efficacy of CHESS pulse fat saturation in the presence of off-resonance without increasing the length of the pulse or requiring iterative optimization. A similar technique, utilizing phase and amplitude freedoms to tailor the axis of rotation across the FOV, can correct for off-resonance effects in TrueFISP and potentially eliminate banding.

10:50         252.       Sampling Strategies for MRI with Simultaneous Excitation and Acquisition

Markus Weiger1, Klaas Paul Pruessmann2, Martin Tabbert3, Franek Hennel4

1Bruker BioSpin AG, Faellanden, Switzerland; 2Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 3Bruker BioSpin MRI GmbH, Ettlingen, Germany; 4Bruker BioSpin MRI GmbH, Germany

The concept of simultaneous excitation and acquisition (SEA) introduced with the SWIFT technique enables MRI of samples with very short T2 also under B1 constraints. Within this framework we suggest a number of improved sampling strategies, addressing reconstruction stability, SNR, and artefacts related to pulse errors. High-quality SEA images of short-T2 samples acquired at a bandwidth of 100 kHz are presented.

11:02         253.       A New Short TE 3D Radial Sampling Sequence: SWIFT-LiTE

Jang-Yeon Park1, Steen Moeller1, Ryan Chamberlain1, Michael Garwood1

1Center for Magnetic Resonance Research and Department of Radiology, University of Minnesota, Minneapolis, MN, USA

UTE imaging and SWIFT are techniques for imaging hard tissues with short T2 relaxation times on the order of a few tens to hundreds of microseconds. However, implementation of UTE and SWIFT on clinical MRI systems can be challenging due to unique hardware requirements. In some cases, achieving short TE < 1 ms (not ultrashort TE) is all that is required. This can be relatively easily accomplished with the new sequence introduced here, which is called SWIFT-LiTE (SWIFT with Limited TE). SWIFT-LiTE is a 3D radial sampling sequence and can effectively cover the short TE range of > ~0.5 ms.

11:14         254.       A Low Power Imaging Alternative to BSSFP

Walter R.T. Witschey1, Ari Borthakur2, Mark Elliott2, Erin Leigh McArdle2, Ravinder Reddy2

1Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, USA; 2Radiology, University of Pennsylvania, Philadelphia, PA, USA

Spin locked steady-state free precession (slSSFP) is shown to maintain a balanced gradient echo steady-state with significantly lower power than a bSSFP acquisition with similar contrast. The independence of locking power on the observable contrast is shown for MnCl2 doped samples in the motional narrowing regime. slSSFP was shown to mimic bSSFP contrast in knee tissues but the dependence on low frequency relaxation dispersion remains to be explored.

11:26         255.       Spin Locked Steady-State Free Precession Imaging

Walter R.T. Witschey1, Ari Borthakur2, Mark Elliott2, Abram Voorhees3, Ravinder Reddy2

1Biochemistry and Molecular Biophysics, University of Pennsylvania, Philadelphia, PA, USA; 2Radiology, University of Pennsylvania, Philadelphia, PA, USA; 3Siemens Medical Solutions USA, Inc., Malvern, PA, USA

A high SNR efficiency, fast imaging technique is described which makes use of spin locking pulses interleaved with short periods for data acquisition. The technique was implemented at low flip angle to obtain high resolution T2-weighted images at 7T and the resulting steady-state was shown to be nearly identical to bSSFP over a wide range of relaxation times.

11:38         256.       Sodium-MRI Using a Density Adapted 3D Radial Acquistion Technique

Armin Michael Nagel1, Frederik Bernd Laun1, Marc-André Weber2, Christian Matthies1, Wolfhard Semmler1, Lothar Rudi Schad3

1Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany; 2Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany; 3Computer Assisted Clinical Medicine, University Heidelberg, Mannheim, Germany

A density adapted 3D radial projection reconstruction pulse sequence (DA-3DPR) is presented that provides a more efficient k-space sampling than conventional 3D projection reconstruction sequences (3DPR). The gradients of the DA-3DPR sequence are designed such that the averaged sampling density in each spherical shell of k-space is constant. Benefits for low SNR applications are demonstrated with the example of sodium imaging. In simulations of the point-spread function, the SNR is increased by the factor 1.66. Using analytical and experimental phantoms, it is shown that the DA-3DPR sequence allows higher resolutions and is more robust in the presence of B0-inhomogeneities.

11:50         257.       3D Dynamic MRSI for Hyperpolarized 13C with Compressed Sensing and Multiband Excitation Pulses

Peder E. Z. Larson1, Simon Hu1, Michael Lustig2, Adam B. Kerr2, Sarah J. Nelson1, John Kurhanewicz1, John M. Pauly2, Daniel B. Vigneron1

1Radiology and Biomedical Imaging, University of California - San Francisco, San Francisco, CA, USA; 2Electrical Engineering, Stanford University, Stanford, CA, USA

We have developed and applied a compressed sensing acquisition and reconstruction scheme for repeated accelerated acquisitions for 3D dynamic time-resolved MRSI for hyperpolarized carbon-13 studies. This sequence also uses multiband RF excitation pulses to efficiently utilize the hyperpolarized magnetization. The compressed sensing exploits the spectral sparsity and temporal redundancy while the multiband pulses take advantage of the different metabolite concentrations in order to obtain dynamic serial 3D MRSI with a time resolution of 5 s over 50 seconds after injection of hyperpolarized [1-13C]-pyruvate.

12:02         258.       Accelerated Slice-Encoding for Metal Artifact Correction

Brian A. Hargreaves1, Wenmiao Lu2, Weitian Chen3, Garry E. Gold1, Anja C. Brau3, John M. Pauly4, Kim Butts Pauly1

1Radiology, Stanford University, Stanford, CA, USA; 2Electrical & Electronic Engineering, Nanyang Technological University, Singapore, Singapore; 3Applied Science Lab, GE Healthcare, Menlo Park, CA, USA; 4Electrical Engineering, Stanford University, Stanford, CA, USA

Techniques have recently been proposed to correct the susceptibility-induced distortions in MR images near metallic implants. The slice-encoding for metal artifact correction (SEMAC) method applies additional slice encoding, which almost completely corrects in-plane and through-plane distortions at a cost of additional scan time. Here we show that with a linear reconstruction SEMAC imaging can be performed with spin echo trains and both parallel imaging and partial Fourier imaging to provide flexible contrast in reasonable scan times.

12:14         259.       MR Imaging at Sub-Millisecond Frame Rates

Steven M. Wright1,2, Mary P. McDougall1,2

1Electrical and Computer Engineering, Texas A&M University, College Station, TX, USA; 2Biomedical Engineering, Texas A&M University, College Station, TX, USA

Spatial encoding using radiofrequency coils can provide extremely fast imaging speeds as the localization is not the result of a time integral of a gradient pulse. In this abstract the combination of Single Echo Acquisition (SEA) imaging and an echo-planar readout is demonstrated, resulting in 64 x 64 images obtained at frame rates exceeding 1000 images per second. Applications being investigated include imaging of extremely rapid flow, and the monitoring of the evolution of transverse magnetization during 2D RF pulses generated with EPI gradient trajectories by modifying the pulse sequence to enable a single image during the flyback period.

Image Analysis

Room 312                             10:30-12:30                                                                               Moderators: Qi Duan and Simon K. Warfield

10:30         260.       MR-Based Attenuation Correction for PET/MR

Matthias Hofmann1,2, Florian Steinke1, Ilja Bezrukov1,2, Armin Kolb2, Philip Aschoff2, Matthias Lichy2, Michael Erb2, Thomas Nägele2, Michael Brady3, Bernhard Schölkopf1, Bernd Pichler2

1Max Planck Institute for Biological Cybernetics, Tuebingen, Germany; 2Department of Radiology, University of Tuebingen, Tuebingen, Germany; 3Wolfson Medical Vision Laboratory, University of Oxford, Oxford, UK

There has recently been a growing interest in combining PET and MR. Attenuation correction (AC), which accounts for radiation attenuation properties of the tissue, is mandatory for quantitative PET. In the case of PET/MR the attenuation map needs to be determined from the MR image. This is intrinsically difficult as MR intensities are not related to the electron density information of the attenuation map. Using ultra-short echo (UTE) acquisition, atlas registration and machine learning, we present methods that allow prediction of the attenuation map based on the MR image both for brain and whole body imaging.

10:42         261.       High Resolution Phase Gradient Mapping as a Tool for the Detection and Analysis of Local Field Disturbances

Hendrik de Leeuw1, Peter Roland Seevinck1, Gerrit Hendrik van de Maat1, Chris J.G. Bakker1

1Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands

We have demonstrated a post processing technique -phase gradient mapping- that enables us to generate positive contrast of magnetically labeled substances. It furthermore can be used as a tool for the detection and analysis of local field inhomogeneities. The technique can be applied without loss of resolution, does not need phase unwrapping and allows simple error estimations. Phase gradient mapping provides quantitative values and may be expected to find application in many areas, e.g., in studies concerned with the quantification or characterization of field distortions due to contrast agents

10:54         262.       Limit of Detection of Localized Absolute Changes in CBF Using Arterial Spin Labeling (ASL) MRI

Iris Asllani1, Ajna Borogovac, Truman R. Brown, Joy Hirsch, John W. Krakauer

1PICS, Radiology, Columbia University, New York, NY , USA

In Arterial Spin Labeling (ASL) MRI, the partial volume effects (PVE) are exacerbated by the nonlinear dependency of the ASL signal on voxel tissue heterogeneity. We have developed a method that corrects for PVE in ASL. The method is based on a model that represents the voxel intensity as a weighted sum of pure tissue contribution where the weighting coefficients are the tissue’s fractional volume in the voxel. Here we show the feasibility of this method to quantify absolute changes in CBF. Results from data simulation as well as experimental model from stroke are presented.

11:06         263.       An Analytical Model of Diffusion and Exchange of Water in White Matter from Diffusion-MRI and Its Application in Measuring Axon Radii

Wenjin Zhou1, David H.  Laidlaw1

1Computer Science, Brown University, Providence, RI, USA

We present an analytical model of diffusion and water exchange in white matter to estimate axon radii. Direct measurement of important biomarkers such as the axon radii, density, and permeability are important for early detection of diseases. We use a model with two compartments between which there is exchange of water molecules. Our analytical formulas examine the derivation of axonal parameters that affect the signal attenuation of diffusion-MRI experiments. The model is fitted to Monte Carlo simulation data. The parameters recovered are compared with ground truth from simulation and prove the feasibility of recovering underlying axonal radii using the model.

11:18         264.       SMRI Complex Framework for Evaluating Relative Gray and White Matter Group Differences

Lai Xu1,2, Vince D. Calhoun1,2

1The MIND Research Network, Albuquerque, NM, USA; 2Electrical and Computer Engineering, The University of New Mexico, Albuquerque, NM, USA

In this study, we built a framework for jointly processing gray and white matter data which incorporates a complex-valued construction into source based morphometry (SBM) to identify the sources revealing relative gray and white matter group difference. The framework was applied to a large dataset from schizophrenia patients and healthy controls. Interestingly, some source patterns looked similar to functional MRI patterns which suggested structural brain information underlying functional areas might be identified. Our approach provides a way to jointly identify changes in both gray and white matter and may prove to be a useful tool to study the brain.

11:30         265.       Sensitive and Noise-Resistant Identification of Voxel-Wise Changes in Magnetization Transfer Ratio Via Cluster Enhancement and M-Estimator-Based Monte Carlo Simulation

Michael G. Dwyer1, Niels Bergsland1, Sara Hussein1, Jacqueline Durfee1, Bianca Weinstock-Guttman1,2, Robert Zivadinov1,2

1Buffalo Neuroimaging Analysis Center, State University of New York, Buffalo, NY, USA; 2The Jacobs Neurological Institute, State University of New York, Buffalo, NY, USA

We propose a sensitive and reliable means for automatically quantifying the volumes of significantly increasing and decreasing MTR in brain MRI over time. This method takes advantage of the newly developed threshold-free cluster enhancement (TFCE) technique to increase sensitivity without sacrificing specificity. It also utilizes a Monte Carlo simulation approach to ensure that results can be interpreted within a correct statistical framework. The method is validated via comparative analysis of a patient group with multiple sclerosis and a group of healthy volunteers

11:42         266.       A Method for Correcting Inter-Series Motion in Brain MRI for Auto Scan Plane Planning

Xiaodong Tao1, Sandeep Narendra Gupta1

1Visualization and Computer Vision Lab, GE Global Research Center, Niskayuna, NY, USA

Patient motion is a major problem in MR exams. We propose here an algorithm that relies on the known position and orientation of the anatomy at the beginning of a scan and uses fast three-plane localizers to update this just before image acquisition. The algorithm finds a rigid transform that best aligns the 3P localizers to the full initial volumetric localizer. This transform is then used to compute new patient-centric scan plane prescription. We have incorporated this approach in a clinical MR system and demonstrated its usefulness in automatically obtaining consistent imaging planes in brain exams in presence of motion.

11:54         267.       Development and Evaluation of a Quantitative Brain Atlas @1.5T and Its Application to MS

Veronika Ermer1, Heiko Neeb2, N. Jon Shah1,3

1Institute of Neurosciences and Biophysics, Research Centre Juelich, Juelich, Germany; 2RheinAhrCampus Remagen, University of Applied Sciences Koblenz, Remagen, Germany; 3Faculty of Medicine, Department of Neurology, RWTH Aachen University, JARA, Aachen, Germany

The use of standard brain atlases is well established in the MR community, but none of the commonly utilised standard brains or atlases provide quantitative information. Especially for human brain imaging, qMRI is an attractive method to study changes in the brain caused by diseases. Within the framework of qMRI, this work reports on the development of the first quantitative brain atlas for tissue water content. This atlas can be used as a reference for the comparison of the absolute water content of the brain of patients with pathological changes to that in healthy volunteers.

12:06         268.       Brain Tissue Segmentation Using Fast T1 Mapping

Wanyong Shin1, Geng Xiujuan1, Hong Gu1, Yihong Yang1

1Neuroimaging Research Branch, National Institute on Drug Abuse, Baltimore, MD, USA

In this study, an automated brain tissue segmentation method based on modeling of individual quantitative T1 values of brain tissues is proposed. To accomplish it, a fast T1 mapping using inversion recovery Look-Locker echo-planar imaging at a steady state (IR LL-EPI SS) with whole brain coverage is presented. This method is insensitive to instrumental settings and can be used to address specific patient populations and age-dependent groups.

12:18         269.       Efficient Anatomical Labeling by Statistical Recombination of Partially Label Datasets

Bennett Allan Landman1, John Anton Bogovic2, Jerry Ladd Prince2,3

1Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; 2Electrical and Computer Engineering, Johns Hopkins University, Baltimore, MD, USA; 3Biomedical Engineering, Johns Hopkins University, Balitmore, MD, USA

Manual labeling of medical imaging data is critical task for the assessment of volumetric and morphometric changes; however, even expert raters are imperfect and subject to variability. Existing techniques to combine data from multiple raters require that each rater generate a complete dataset. We propose a robust extension which allows for missing data, accounts for repeated tasks, and utilizes training data. With our technique, numerous raters can label small, overlapping portions of a large dataset, and rater heterogeneity can be robustly controlled while estimating a single, reliable label set. This enables “parallel processing” and reduces detrimental impacts of rater unavailability.

EDUCATIONAL COURSE
Atherosclerosis Imaging

Room 314                             10:30 – 12:30                                                                     Moderators:  Debiao Li and Orlando P. Simonetti

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Describe various plaque components in different stages of the atherosclerosis progression;

·   Recognize the relationship between atherosclerosis and cardiovascular disease;

·   Identify imaging characteristics for different plaque components; and

·   Design appropriate imaging protocols for atherosclerosis imaging.

 

10:30       Plaque Biology - No syllabus contribution at time of publication.
Sanjay Rajagopalan


10:55      
Current Applications/Clinical Trials

Chun Yuan

11:20       Non-Contrast Techniques

Zahi Adel Fayad

11:45       Targeted Contrast Techniques

Patrick M. Winter

12:20       Panel Discussion


GOLD CORPORATE MEMBER LUNCHTIME SYMPOSIUM
Siemens

Ballroom                              12:30 – 13:30                                                                                                                                                                                                                         

CLINICAL INTENSIVE COURSE
Case-Based Teaching II: Abdominal Pain

Room 310                             13:30 – 15:30                                                                                                        Moderator:  Elmar M. Merkle

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Describe the current role of MR in the work-up of patients with abdominal pain;

·   Apply new body MR techniques in their practice to shift patients with abdominal pain from the CT suite to the MR suite; and

·   Use multiparametric MRI for improved diagnosis of abdominal diseases.

 

13:30       Abdominal Trauma: Any Role for MR?
Scott B. Reeder


14:00      
MRI in Patients with Inflammatory Bowel Disease

Mukesh G. Harisinghani

14:30       Renal Stone Patients in the ER:  Is MR an Alternative?

Diego R. Martin

15:00       Pregnant Patients with Abdominal Pain

Ivan Pedrosa

SPECIAL INTEREST SESSION
Time-Resolved MRA

Room 313A                         13:30-15:30                                                                                Moderators: James C. Carr and Vivian S. Lee

13:30         270.       Time Resolved Angiography: Past, Present, and Future

Charles A. Mistretta1

1University of Wisconsin

13:54         271.       High Temporal and Spatial Resolution Time-Resolved 3D CE-MRA of the Hands and Feet

Clifton R. Haider1, James F. Glockner1, Anthony W. Stanson1, Stephen J. Riederer1

1Radiology, Mayo Clinic, Rochester, MN, USA

High spatial resolution arterial-only frames are desired in time-resolved 3D CE-MRA of the hands and feet. However, the increased spatial undersampling used for acceleration generally causes a reduction in image quality. In this work dedicated eight- and twelve-element peripheral vascular coil arrays were developed to maintain high image quality for accelerations greater than an order of magnitude (>10x). Results demonstrate high diagnostic image quality for high spatial and temporal resolution, bilateral 3D CE-MRA of the hands and feet.

14:06         272.       Highly Accelerated Contrast-Enhanced MR Angiography Using Ghost Imaging

Robert R. Edelman1,2, Ioannis Koktzoglou1,2

1Radiology, NorthShore University HealthSystem, Evanston, IL, USA; 2Radiology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA

Ghost MRA represents a fundamentally new approach for vascular imaging with potential applications for both non-contrast and contrast-enhanced angiography (CE-MRA). The method involves the creation of a ghost image which displays the vasculature with little or no signal contribution from background tissues. We compared conventional subtraction CE-MRA with Ghost CE-MRA in a series of healthy subjects using comparable image acquisition parameters. We also tested the hypothesis that Ghost imaging enables the use of much higher parallel acceleration factors (up to 13) than are feasible with standard phased array coils using the conventional CE-MRA approach.

14:18         273.       Radial Sliding Window Time Resolved MRA: Evaluation of Intrapulmonary Circulation Parameters in Pulmonary Arterial Hypertension

John J. Sheehan1, Hyun Jeong2, Amir Davarpanah3, Cormac Farrelly1, Randall Ramsy1, Sanjiv Shah4, Tim Carroll2, James C. Carr1,3

1Cardiovascular Imaging, Northwestern Memorial Hospital, Chicago, IL, USA; 2Biomedical Engineering, Northwestern University, Chicago, IL, USA; 3Cardiovascular Imaging, Northwestern University, Chicago, IL, USA; 4Cardiology, Northwestern Memorial Hospital, Chicago, IL, USA

Pulmonary arterial and venous transit times were measured by radial sliding window time-resolved MRA to calculate pulmonary blood volumes and correlated with ventricular volumetrics in patients with pulmonary arterial hypertension (PAH). Radial MRA allows high temporal resolution, free breathing MRA with good separation between arterial and venous phases. Intrapulmonary transit times (ITT) were prolonged in patients with PAH. ITT correlated directly with RVEDV/ESV, and inversely with RVEF. Radial MRA allows determination and separation of intrapulmonary transit times that are prolonged, and pulmonary blood volumes, which are raised in pulmonary arterial hypertension.

14:30         274.       Contrast Enhanced MRA with Retrospective Selection of Acceleration Factor

Bing Wu1, Richard Watts2, Anthony Butler1, Rick Millane1, Philip Bones1

1Department of Electrical can Computer Engineering, University of Canterbury, Chirstchurch, New Zealand; 2Department of Physics and Astronomy, University of Canterbury, Christchurch, New Zealand

A new time resolved contrast enhanced MR angiography method is proposed, which allows the desired temporal resolution to be selected in post processing and hence achieves an optimal trade-off between temporal resolution and SNR. To further improve the reconstruction SNR, subtraction of the background signal is incorporated to achieve a much smaller object support constraint. The utility of the method is demonstrated using in vivo data sets obtained from a healthy volunteer.

14:42         275.       MR Cerebral Angiography Using Arterial Spin Labeling for Dynamic Inflow Visualization and Vessel Selectivity

Weiying Dai1,2, Philip M. Robson1,2, Ajit Shankaranarayanan3, David C. Alsop1,2

1Radiology, Beth Israel Deaconess Medical Center, Boston, MA, USA; 2Radiology, Harvard Medical School, Boston, MA, USA; 3Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA

Digital subtraction X-ray angiography (DSA) is a widely used technique for the characterization of cerebral vessels. While MRI and CT can, in principle, provide angiographic information that could replace the riskier DSA study, these techniques typically lack the vessel selectivity and temporal resolution of DSA. Here we present the use of arterial spin labeling methods combined with balanced-SSFP acquisition to provide an MR angiographic exam more similar to DSA.

14:54         276.       Very Low Dose Time-Resolved MR Angiography

Gerhard Laub1, Randall Kroeker2, Derek Lohan3, Paul Finn3

1Siemens Medical Solutions USA, Los Angeles, CA, USA; 2Siemens Medical Solutions, Canada; 3David Geffen School of Medicine, UCLA

In view of NSF, we tested the feasibility of performing very low dose time-resolved 3D MR angiography in 10 patients and compared with standard dose contrast-enhanced MRA.

15:06         277.       HYPR-L0:  a Hybrid Technique for CE MRA with Extreme Data Undersampling Factors

Julia V. Velikina1, Alexey A. Samsonov

1Medical Physics, University of Wisconsin - Madison, Madison, WI, USA

We present a novel synergistic method for time-resolved image reconstruction from extremely undersampled data that utilizes independent acceleration mechanisms of non-Cartesian acquisition, parallel imaging, compressed sensing, and HYPR. The new technique is validated for applications to time-resolved contrast-enhanced angiography of the brain where it produces images with high spatial and temporal resolution and high SNR for the acceleration factors at which other reconstruction methods fail.

15:18         278.       Nonenhanced 3D Breast MRA Using FBI and Time-SLIP

Mitsue Miyazaki1,2, Pamera M. Otto3, Hitoshi Kanazawa4, Nobuyasu Ichinose4, Satoshi Sugiura4, Robert Anderson Anderson1

1Toshiba Medical Research Institute, Vernon Hills, IL, USA; 2MRI, Toshiba Medical Systems Corp, Otawara, Tochigi, Japan; 3Radiology, University of Texas at San Antonio, San Antonio, TX, USA; 4MRI, Toshiba Medical Systems Corp., Otawara, Tochigi, Japan

Breast Dynamic contrast-enhanced (DCE) MRA is becoming a standard examination tool for small lesion detection. This study presents an initial volunteer investigation of nonenhanced breast MRA using the Fresh Blood Imaging (FBI) and Time-Spatial Labeling Inversion Pulse (time-SLIP) sequences. FBI provides clear depiction of all vessels and time-SLIP provides time-course imaging of selective vessels branching from the mammary arteries.

Brain Tumor: Imaging Brain Tumor Treatment &  Response

Room 311                             13:30-15:30                                                                                     Moderators: Alberto Bizzi and Meng Law

13:30         279.       2008 ISMRM Grant Recipient:  Systematic Evaluation of Stereotatic Radiosurgery Effects in Metastasis and Acoustic Neurinomas Using MRI

Cristian Tejos1,2, M.E. Andia2,3, P. Besa4, J. Lorenzoni5, A. Vieria4, L. Meneses2,6, P. Irarrazaval1,2

1Department of Electrical Engineering, Pontificia Universidad Catolica de Chile, Santiago, Chile; 2Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Chile; 3Radiology Department, Pontificia Universidad Catolica de Chile, Santiago, Chile; 4Radiotherapy Department, Cancer Center, Pontificia Universidad Catolica de Chile, Santiago, Chile; 5Departamento de Neurocirugia, Pontificia Universidad Catolica de Chile, Santiago, Chile; 6Radiology Department, Pontificia Universidad Catolica de Chile , Santiago, Chile

13:50         280.       Apparent Diffusion Coefficient Measures on MR Correlate with Survival in Glioblastoma Multiforme

Gerard Thompson1, John Robert Cain1, Samantha Jane Mills1, Alan Jackson1

1Imaging Science and Biomedical Engineering, School of Cancer and Imaging Sciences, University of Manchester, Manchester, UK

Described in this work is a method for quantifying the change in apparent diffusion coefficient (ADC) which occurs across tissue boundaries in glioblastoma multiforme on diffusion-weighted imaging. The gradient of the change in ADC moving from peri-tumoural oedema into solid, enhancing tumour was found to correlate with length of survival (n=18; Kendall’s tau -0.401, p0.021; Cox’s Hazards Ratio 1.007 (1.001-1.014) p=0.032), whereas the ADC gradient measured from normal appearing white matter into peri-tumoural oedema did not (n=19; Kendall’s τ 0.164, p0.327; Cox’s Hazards Ratio 0.998 (0.998-1.008) p=0.695).

14:02         281.       A Fully Automated Method for Predicting Glioma Patient Outcome from DSC Imaging. a Second Reference to Histopathology?

Kyrre E. Emblem1,2, Frank G. Zoellner3, Atle Bjornerud1,4

1Department of Medical Physics, Rikshospitalet University Hospital, Oslo, Norway; 2The Interventional Centre, Rikshospitalet University Hospital, Oslo, Norway; 3Department of Assisted Clinical Medicine, University of Heidelberg, Mannheim, Germany; 4Department of Physics, University of Oslo, Oslo, Norway

We have assessed whether a fully automated, multi-parametric model for predicting outcome in glioma patients from dynamic susceptibility contrast MR imaging can be used as a second reference to pathologic findings. Based on automatically segmented tumor regions, 3D scatter diagrams of cerebral blood volume as a function of Ktrans were derived for each patient. A predictive model based on support vector machines was used to predict outcome in each patient using scatter diagrams and survival status of the remaining patients. Our results suggest that the proposed approach provides similar diagnostic accuracy values to histopathology when predicting patient outcome.

14:14         282.       Acute Effects of Bevacizumab on Glioblastoma Vascularity Assessed with DCE-MRI and Relation to Patient Survival

Weiting Zhang1, Teri N. Kreisl1, Jeff Solomon2, Richard C. Reynolds3, Danial R. Glen3, Robert W. Cox3, Howard A. Fine1, John A. Butman4

1Neuro-Oncology Branch, National Cancer Institute, NIH, Bethesda, MD, USA; 2Medical Numerics, Inc., Germantown, MD, USA; 3National Institute of Mental Health, NIH, USA; 4Radiology and Imaging Sciences, Clinial Center, NIH, USA

DCE-MRI was used to monitor the acute effects of Bevacizumab on physiologic measures of tumor vascularity, such as blood brain barrier permeability, represented as Ktrans. In addition, we relate these to progression free survival (PFS) and to overall survival (OS). Bevacizumab dramatically reduces Ktrans (46%) and enhancing tumor volume (39%) in recurrent GBMs within 96-hour of a single dose. However, tumors in which Bevacizumab resulted in larger decreases in Ktrans did not demonstrate an improved survival over those with smaller reductions in Ktrans. GBMs with larger baseline enhancing tumor volume and greater baseline Ktrans both predicted poorer PFS and OS.

14:26         283.       A Composite Model of the Parametric Response Map Predicts Survival Independent of Radiographic Response in Patients with High Grade Glioma

Craig J. Galban1, Thomas L. Chenevert1, Daniel A. Hamstra2, Charles R. Meyer1, Pia Sundgren1, Christina Tsien2, Theodore S. Lawrence2, Alnawaz Rehemtulla2, Timothy D. Johnson3, Brian D. Ross1

1Radiology, University of Michigan, Ann Arbor, MI, USA; 2Radiation Oncology, University of Michigan, Ann Arbor, MI, USA; 3Biostatistics, University of Michigan, Ann Arbor, MI, USA

A parametric response map composite model of the apparent diffusion coefficient (PRMADC) and relative cerebral blood flow (PRMrCBF) is predictive of treatment response in glioma patients independent of radiographic response (RR). Perfusion and diffusion MRI were performed on 44 patients pre and post-treatment. Survival analysis was employed on the population by stratifying based on RR, PRMADC, PRMrCBF and a composite of PRMADC and PRMrCBF (PRMADC-rCBF). Individually, PRM was closely associated to 10 week RR. A multivariate analysis showed a stronger dependence on PRM, most notably PRMADC-rCBF, than RR. This study provides a more accurate treatment response metric for cancer patients.

14:38         284.       R2* Response of Brain Tumors to Hyperoxic and Hypercapnic Respiratory Challenges at 3 Tesla

Andreas Müller1, Stefanie Remmele2, Ingo Wenningmann3, Frank Träber1, Roy König1, Hans Clusmann4, Hannes Dahnke5, Juergen Gieseke5, Sebastian Flacke1, Winfried A. Willinek1, Hans H. Schild1, Petra Mürtz1

1Department of Radiology, University Hospital Bonn, Bonn, Germany; 2Philips Research Europe, Hamburg, Germany; 3Department of Anesthesiology, University Hospital Bonn, Bonn, Germany; 4Department of Neurosurgery, University Hospital Bonn, Bonn, Germany; 5Philips Medical Systems, Hamburg, Germany

The R2* response to hyperoxic and hypercapnic respiratory challenges is of major diagnostic interest in oncology as it gives insight into tissue oxygenation and vasoreactivity. We determined the R2* response to elevated levels of O2 and CO2 in cerebral tumors at 3 Tesla. Different tumor regions show characteristically altered vessel function and reactivity. We present a robust and sensitive method to assess oxygenation changes and vasoreactivity in brain tumors. This additional information may support the selection and dosage of tumor therapies and may allow the non-invasive contrast-agent-free monitoring of treatment response.

14:50         285.       Functional Diffusion Maps Applied to FLAIR Abnormal Areas Are Valuable for the Clinical Monitoring of Recurrent Brain Tumors

Benjamin M. Ellingson1,2, Mark G. Malkin1,3, Scott D. Rand1,2, Devyani P. Bedekar1,2, Kathleen M. Schmainda1,2

1Translational Brain Tumor Program, Medical College of Wisconsin, Milwaukee, WI, USA; 2Department of Radiology, Medical College of Wisconsin, Milwaukee, WI, USA; 3Departments of Neurology and Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, USA

Functional diffusion maps (fDMs) involve calculating voxel-by-voxel changes in diffusivity in order to spatially localize and quantify changes in tumor cellularity. Traditionally, fDMs are applied to contrast-enhanced tumor regions exclusively. In the current study we have expanded the application of fDMs to FLAIR abnormal regions. Results suggest this technique provides additional insight into the growth and treatment response of both enhancing and non-enhancing brain tumors, along with reflecting the neurological status of the patient.

15:02         286.       Assessment of Anti-Angiogenic Treatment in Glioblastoma Using Arterial Spin-Labeling and Dynamic Susceptibility Contrast Perfusion MRI in a Phase II Trial

Mei-Yun Wang1, Wei-Ting Zhang1, Poe-zhou chen1, Thomas Benner1, Divya S. Bolar1, Tracy T. Batchelor2, Rakesh K. Jain3, A. Gregory Sorensen1

1Radiology, Massachusetts General Hospital, Boston, MA, USA; 2Neurology, Massachusetts General Hospital, Boston, MA, USA; 3Radiation Oncology, Massachusetts General Hospital, Boston, MA, USA

Angiogenesis is an essential step in the growth and spread of solid tumor, and advances in MRI now permit detection of the hemodynamic changes of glioblastoma after treatment. In the current study, arterial spin-labeling (ASL) and first-pass dynamic susceptibility contrast (DSC) perfusion MRI were used to assess the treatment effect of an anti-angiogenic agent AZD2171, a pan-VEGF receptor tyrosine kinase inhibitor, in a phase-II clinical trial. Our results suggest ASL is almost as sensitive as DSC in assessing rCBF changes of tumor and the tumor vascular normalization and reversal after anti-angiogenesis treatment.

15:14         287.       Intravoxel Water Diffusion Heterogeneity of Human High-Grade Gliomas

Thomas Kwee1, Craig Galban1, Marko Ivancevic1,2, Pia Sundgren1, Christina Tsien3, Larry Junck4, Benjamin Hoff1, Charles Meyer1, Brian Ross1, Thomas Chenevert1

1Department of Radiology, University of Michigan, Ann Arbor, MI, USA; 2Philips Healthcare, Cleveland, OH, USA; 3Department of Radiation Oncology, University of Michigan, Ann Arbor, MI, USA; 4Department of Neurology, University of Michigan, Ann Arbor, MI, USA

Diffusion-weighted signal decay of brain tissue is multi-exponential due to the presence of multiple intravoxel proton pools (IPPs) with different diffusion coefficients. This study investigated the intravoxel water diffusion heterogeneity (IDWH) of human high-grade gliomas (N=20), using the stretched-exponential model. IDWH was significantly higher in high-grade gliomas than in normal brain tissue, which potentially offers a new method for assessing tumor extent and evaluating therapeutic response. Correlation between tumor IDWH and overall tumor diffusion coefficient was strongly negative, suggesting that highly cellular tumors contain a lower number of distinct IPPs, while cystic/necrotic tumors contain a higher number of distinct IPPs.

Quantitative MRI of Fibrocartilage

Room 312                             13:30-15:30                                                                     Moderators: Garry E. Gold and Timothy J. Mosher

13:30         288.       T1ρ Imaging and Quantification of the Meniscus Using a T1ρ -Prepared Ultrashort TE (T1ρ -UTE) Sequence

Jiang Du1, Michael Carl2, Atsushi M. Takahashi2, Eric Diaz1, Christine B. Chung1, Eric Han2, Graeme M. Bydder1

1Radiology, University of California-San Diego, San Diego, CA, USA; 2Global Applied Science Laboratory, GE Healthcare Technologies, Menlo Park, CA, USA

Osteoarthritis is a multisystemic degenerative joint disease affecting not only articular cartilage, but also subchondral bone, synovium, the joint capsule and meniscii. Recently there has been increased interest in imaging and quantifying the impact of the disease on the meniscus. Meniscii appear low signal on the morphological images and accurate quantification may be challenging. Ultrashort TE (UTE) sequences with a TE of 8 ƒÝs provide high signal intensity of the meniscus, and improved confidence in quantification. Here we describe a UTE sequence designed to image and quantify T1ƒâ and T2* of the meniscus on a clinical 3T scanner.

13:42         289.       Variability of Meniscal T2* Calculations Using Ultra-Short Echo (UTE) Imaging

Matthew F. Koff1, Atsushi Takahashi2, Hollis Potter1

1Department of Radiology and Imaging, Hospital for Special Surgery, New York, NY, USA; 2Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA

The knee meniscus typically displays low signal on standard clinical images. Ultrashort echo (UTE) imaging creates contrast for meniscal visualization and T2* quantitation. This study evaluated the effects of UTE acquisition resolution and inter-echo timings on calculated T2* values. Ex-vivo sheep knees were scanned and the number of arms and inter-echo times of the radial sequence were varied. Higher resolution and longer inter-echo spaced images produced longer T2* values. The average maximum T2* difference from all methods was 1.2ms. This study will aid in the development of optimal UTE scanning parameters for clinical investigation of the meniscus.

13:54         290.       Delayed Contrast Enhanced MRI of Meniscus

Wei Li1, Robert R. Edelman1, Pottumarthi V. Prasad1

1Department of Radiology, Center of Advanced Imaging, NorthShore University HealthSystem, Evanston, IL, USA

A retrospective analysis of T10 and T1Gd in menisci, including inner and outer zones, was performed in 10 OA patients and 8 healthy subjects (HS). Data were acquired with a 3DLL sequence using ionic and non-ionic contrast agents. Compared to HS, the mean T10 of meniscus in OA was slightly higher, but T1Gd was lower. The meniscus showed a modest correlation with articular cartilage in T1Gd, with little difference in T1 between the two zones. There was a correspondence closed to 1:1 in T1Gd with the two agents. These findings collectively suggest minimal GAG based contrast distribution within the meniscus.

14:06         291.       Optimizing MR Signal Contrast of the TMJ Disk

Michael Carl1, Hatice T. Sanal2, Eric Diaz2, Jiang Du2, Olivier Maciej Girard2, Sheronda Statum2, Richard Znamirowski2, Christine Chung2

1GE Healthcare, Applied Science Lab, Milwaukee, WI, USA; 2Radiology, University of California, San Diego, CA, USA

The temporomandibular joint is a unique articulation that demonstrates both structural and functional complexity. These tissues comprised largely of short T2 components are challenging as conventional MR sequences are limited in their ability to detect signal from them, as well as produce contrast between the fibrocartilaginous disc and articular surfaces. In this study, we use a tissue specific algorithm that will optimize contrast based on knowledge of intrinsic MR properties of tissues and Bloch equations dictating signal and contrast. This approach to image optimization could be instrumental in improving diagnostic capabilities in the clinical setting.

14:18         292.       Mechanical and Biochemical Characterization of the Degenerated Rabbit Intervertebral Disc by MRI

Deva D. Chan1, Safdar N. Khan2, Xiaojing Ye3, Shane B. Curtiss3, Munish C. Gupta2, Eric Klineberg2, Corey P. Neu1

1Weldon School of Biomedical Engineering, Purdue University, West Lafayette, IN, USA; 2Orthopedic Surgery, University of California - Davis Medical Center, Sacramento, CA, USA; 3Center for Tissue Regeneration and Repair, University of California - Davis Medical Center, Sacramento, CA, USA

An intervertebral disc degeneration model in New Zealand white rabbit was characterized biochemically with delayed gadolinium enhanced MRI of cartilage (dGEMRIC) and mechanically with displacement-encoded stimulated echoes with fast spin echo readout (DENSE-FSE). Glucosaminoglycan content, as measured with dGEMRIC, was significantly decreased in degenerated discs, as expected and confirmed by histology. Deformations within the volume of the disc during cyclic compression demonstrated clear changes in mechanical behavior with degeneration.

14:30         293.       Assessing the Inververtebral Disc Via GagCEST

Wen Ling1, Galit Saar2, Ravinder R. Regatte3, Alexej Jerschow4, Gil Navon2

1CMRR, Univ. of Minnesota, Minneapolis, MN, USA; 2School of Chem., Tel Aviv Univ., Ramat Aviv, Tel Aviv, Israel; 3Dept. of Radiology, NYU, New York, NY, USA; 4Chem. Dept., NYU, NYU, NY, USA

Synopsis: The loss of the proteoglycans is thought to be an initiating event of disc degeneration. Therefore, the ability to detect these early events is of crucial importance to facilitate earlier intervention, to monitor the effectiveness of treatments, and to study the mechanism of disease progression. We demonstrate here the possibility of a MRI strategy based on glycosaminoglycan chemical exchange saturation transfer (gagCEST), which would allow one to detect the loss of proteoglycans within the disc. Our results show that gagCEST can be used to monitor early signs of disc degeneration.

14:42         294.       Sodium MRI of Intervertebral Disc Degeneration

Chenyang Michael Wang1, Erin McArdle2, Walter Witschey3, Mark Elliott2, Ravi Reddy2, Ari Borthakur2

1Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; 2Radiology, University of Pennsylvania; 3Biophysics and Molecular Biology, University of Pennsylvania

Intervertebral disc degeneration is a common and sometimes painful condition. The initial sign of intervertebral disc degeneration involves the breakdown of proteoglycans, and current diagnostic measure for the condition is not sensitive to it. Sodium MRI has previously been used to study proteoglycan depletion in articular cartilage. In this study, we conducted high-resolution sodium MRI on ex vivo bovine intervertebral discs samples, and correlated sodium MRI result with 1,9-dimethylmethylene blue proteoglycan assay results. Our results demonstrated the potential for sodium MRI to become a non-invasive diagnostic tool for early stage intervertebral disc degeneration.

14:54         295.       Correlation Between Apparent Diffusion Coefficient Values and Pfirrmann Grades of Lumbar Intervertebral Disc Degeneration

Hon J. Yu1, Shadfar Bahri1, Lutfi Tugan Muftuler1, Orhan Nalcioglu1, Vance Gardner2

1Tu & Yuen Center for Functional Onco-Imaging, University of California, Irvine, CA, USA; 2Orthopaedic Education and Research Institute of Southern California, Orange, CA, USA

The level of degeneration was graded on 5-level Pfirrmann classification system and its correlation with ADC values was investigated in vivo using 166 lumbar intervertebral discs (IVD). The ADC values from the whole IVD were obtained on a pixel-by-pixel basis and then grouped for each Pfirrman grade for comparison. The mean population values of ADC amongst the 5 groups differed significantly and showed an inversely proportional trend with respect to the grades (1: normal; 5: severe degeneration). A 5-bin histogram analysis of the ADC values exhibited a characteristic distribution of ADC values for each group, perhaps revealing different degenerative-related changes taking place in nucleus pulposus and annulus fibrosus of IVD.

15:06         296.       Self-Coregistered T and Sodium MRI of Intervertebral Discs

Chenyang Michael Wang1, Walter Witschey, Erin McArdle, Mark Elliott2, Ari Borthakur2, Ravi Reddy2

1Bioengineering, University of Pennsylvania, Philadelphia, PA, USA; 2Radiology, University of Pennsylvania

Intervertebral disc degeneration is a common and sometimes debilitating condition. Current diagnostic technique for intervertebral disc degeneration is not sensitive to the initial phase of degeneration, which involves the breakdown of proteoglycans. T1ρ is a non-invasive MRI technique that has been shown to be sensitive to interaction between macromolecules and bulk water. Sodium MRI has already been shown to be sensitive to proteoglycan change in tissue. In this study, we carried out sodium MRI and T1ρ MRI on ex vivo bovine intervertebral disc, and demonstrated linear correlation between the two measurements.

15:18         297.       Degeneration of the Long Biceps Tendon of the Shoulder: Comparison of MR Imaging with Gross Anatomy and Histology.

Florian M. Buck1, Holger Grehn2, Monika Hilbe3, Silvana Manzanell4, Juerg Hodler1

1Department of Radiology, Balgrist University Hospital, Zurich, Switzerland; 2Orthopedic Surgery, Balgrist University Hospital, Zurich, Switzerland; 3Institute of Veterinary Pathology, Vetsuisse Faculty, University of Zurich, Zurich, Switzerland; 4MSRU, Equine Hospital, Vetsuisse Faculty, University of Zurich, Zurich, ZH, Switzerland

Problem: Diagnosis of biceps tendinopathy in the shoulder is difficult (artifacts, complex anatomy, degeneration).  Method: Evaluation of tendon caliber and signal in MRI and comparison with gross anatomy and histology in cadaveric specimen. Results:  Agreement between gross anatomy and MRI was moderate to strong. Agreement between MRI and histology concerning the location of tendon degeneration was good. A diameter alteration always concurred with a tendon degeneration histologically. Conclusion:  Biceps tendon caliber changes are specific for tendinopathy but lack sensitivity. Signal changes are useful in the diagnosis of tendinopathy although none of the employed sequences in isolation demonstrated histological changes precisely.

EDUCATIONAL COURSE
Image Analysis

Room 315                             13:30 – 15:30                                 Moderators:  Douglas C. Noll, Henry Rusinek, and Simon K. Warfield

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Describe several basic image processing tasks, their basic algorithms, and tools for implementing these tasks;

·   Describe image data formats and DICOM, in particular, and how information is encoded into tags; and

·   Explain the fundamental aspects of image segmentation, registration, and shape-based analysis and know how to apply them in practice.

 

13:30       Welcome and Introduction
Douglas C. Noll


13:33      
Tagging Along with DICOM Format

Babak A. Ardekani

13:53       Software Tools & Resources at NIH: Overview of NITRC

David N. Kennedy

14:15       Algorithms and Software for Image Segmentation
               
Simon K. Warfield

14:40       Algorithms and Software for Image Coregistration - No syllabus contribution at time of publication.
               
James Gee

15:05       Analyzing DCE-MRI Data
               
Min-Ying Lydia Su

EDUCATIONAL COURSE
Fat Imaging & Quantification Image Analysis

Room 314                             13:30 – 15:30                                                                                                        Moderator:  Mark Schweitzer

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Compare advantages and disadvantages of various types of fat suppression and segmentation techniques; and

·   Describe the physiologic and pathophysiologic roles of localized fat deposits.

 

13:30       Techniques of Fat Suppression
Ian Cameron


13:50      
MRS of Fat

Robert E. Lenkinski

14:10       Fat Quantification in the Liver

Bachir Taouli

14:30       Whole Body Fat Segmentation - No syllabus contribution at time of publication.
               
Andrew Laine

14:50       Fat in the Musculoskeletal System
               
Mark Schweitzer

15:10       Discussion

CLINICAL INTENSIVE COURSE
MR Physics & Techniques for Clinicians

Room 313A                         16:00 – 18:00                                                                   Moderators:  Marcus Alley and Frank R. Korosec               

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Define and describe the fundamental principles of MR imaging, including the definition of spin magnetization, the Larmor relationship, relaxation phenomena, and the process of using the spin magnetization to produce an image;

·   Explain imaging pulse sequences based upon spin and gradient echoes, including fast spin-echo and echo planar techniques;

·   Design MR imaging protocols for diagnostic applications considering image contrast, spatial resolution, acquisition time, signal-to-noise ratio, and artifacts; and

·   Describe the principles of parallel imaging, high-field imaging, perfusion imaging, diffusion imaging, and functional MR imaging.


16:00       Spin Echo Imaging

R. Scott Hinks

16:40       Gradient Echo Imaging

                Brian A. Hargreaves

 

17:20       Fast Spin Echo Imaging

                Frank R. Korosec

Field Interactions & Safety

Room 323ABC                    16:00-18:00                                                                     Moderators: Azim Celik and Penny Anne Gowland

16:00         298.       Influence of Strong Static Magnetic Fields on Myocardial Mechanics: Evaluation Applying Ultra-Wideband Radar

Florian Thiel1, Mathias Hein2, Jürgen Sachs2, Ulrich Schwarz2, Tomasz Lindel1, Frank Seifert1

1Physikalisch-Technische Bundesanstalt (PTB), Berlin, Germany; 2Ilmenau University of Technology

ECG is excessively used for triggering MR data acquisition to image the heart. It is well established that the ECG is corrupted by the magneto-hydrodynamic effect (MHD). Hence, there is increasing difficulty to use the ECG for MR-triggering especially at B0-fields beyond 1.5 T. To investigate whether the myocardial contraction is also influenced by the static magnetic field, we propose a novel method, based on an ultra-wideband radar technique (UWB radar) to monitor the global myocardial dynamics inside a MR scanner.

16:12         299.       Effects of 7 Tesla MRI Examination on Postural Stability

Jens Matthias Theysohn1,2, Andreas K. Bitz1, Oliver Kraff1,2, Stefan Maderwald1,2, Marcus Gerwig3, Oliver Kastrup3, Dagmar Timmann3, Franz Schmitt4, Harald H. Quick1,2, Elke Ruth Gizewski1,2, Michael Forsting1,2, Mark E. Ladd1,2, Susanne C. Ladd1,2

1Erwin L. Hahn Institute for Magnetic Resonance Imaging, University Duisburg-Essen, Essen, Germany; 2Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany; 3Department of Neurology, University Hospital Essen, Essen, Germany; 4Siemens Healthcare, Erlangen, Germany

Ultra high-field MRI (7 Tesla and above) generates more temporary side-effects compared to 1.5T and 3T, e.g. dizziness. Postural stability was quantitatively measured before and after a 7 Tesla examination of the head. Twenty-five volunteers underwent a Romberg’s test. Stability with eyes closed was significantly reduced directly after the MR examination, but was fully recovered 15 minutes after examination. Physiological effects by orthostatic regulation were excluded. Stability results for tests with eyes open show no significant difference. The results show that exposition to a 7 Tesla examination causes only a temporary dysfunction or over-compensation of the vestibular system.

16:24         300.       Numerical Evaluation of SAR Within Whole-Body Pregnant Woman Models in MRI Birdcage Coil

Zhangwei Wang1, George X. Xu2, Victor Taracila1, Jason Jin1, Fraser J. Robb1

1GE Healthcare Coils, Aurora, OH, USA; 2Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA

Whole body pregnant woman models at different gestational stages were adopted to investigate the SAR variation at 1.5T. The highest SAR is occurred in the mother's peripheral tissues in all pregnancy phase. And the maximum local SAR of the fetus is below IEC limitation. The results show that the local maximum SAR1g and SAR10g can be better indications as limitation factor other than the whole body average SAR. Future work will be done by using more pregnancy stages and higher resolution models.

16:36         301.       Optimized Signal Intensity and T1r Based NMR Thermometry for Ultra-High Field RF Safety Applications

Devashish Shrivastava1, Timo Liimatainen1, Ute Goerke1, Jeramy Kulesa1, Timothy Hanson1, Shalom Michaeli1, J. Thomas Vaughan1

1CMRR, Radiology, University of Minnesota, Minneapolis, MN, USA

Good linear correlations were obtained between the core temperatures, and the 'optimized' signal intensities and the longitudinal magnetization relaxation rate constants in the rotating frame (i.e., T1r) in an in vivo porcine brain at 3 tesla (T). The correlations were obtained to measure RF heating induced temperatures with sub-degree Celsius accuracy in porcine brains at ultra-high fields.

16:48         302.       Real-Time Global and Local SAR Monitoring for Parallel Transmission Systems

Ingmar Graesslin1, Sven Biederer2, Bjoern Annighoefer3, Hanno Homann1, Henry Stahl1, Peter Vernickel1, Ulrich Katscher1, Dennis Glaesel4, Paul Harvey5

1Philips Research Europe, Hamburg, Germany; 2University of Lübeck, Lübeck, Germany; 3TU Hamburg-Harburg, Hamburg, Germany; 4Research Establishment for Applied Science, Wachtberg, Germany; 5Philips Healthcare, Best, Netherlands

A comprehensive RF safety concept for parallel transmission MRI systems can be realized by verifying the SAR limits before scanning and monitoring RF signals during scanning. However, using a pre-calculated safety margin over-estimates the actual SAR. This abstract extends the concept of pre-calculated safety margins with a real-time global and local SAR monitoring system. This new concept allows for a significantly increased permissible RF duty cycle and improves the detection of violations of SAR limits or any unsafe condition. The impact of patient motion on SAR is analyzed, and a scan termination in case of unsafe system operation is demonstrated.

17:00         303.       Safety and Initial Results with a Dedicated Human 7T Eye Coil

Peter A. Wassenaar1, Kathryn Richdale2, Katharine Teal Bluestein1, John Christoforidis3, Titus Lanz4, Michael Vincent Knopp1, Petra Schmalbrock1

1Radiology, The Ohio State University, Columbus, OH, USA; 2Optometry, The Ohio State University, Columbus, OH, USA; 3Ophthalmology, The Ohio State University, Columbus, OH, USA; 4Rapid MR International, LLC, Columbus, OH, USA

Ultra-high field MRI allows higher resolution for examination of the fine structures of the eye. This work focuses on the safety testing and implementation of a custom surface coil at 7T. A transmit head coil was used with a 4cm receive coil. Safety was insured through both active and passive decoupling. Testing indicated good homogeneity of the imaging region and signal drop off as expected for the coil diameter. Animal testing demonstrated that tissue heating did not exceed 0.3°C, even with high RF power. The use of a custom coil yielded high quality images of the human eye in vivo.

17:12         304.       RF Safety Assessment of a 7T Head Coil Using Thermal Modeling with Discrete Vessels

Astrid L.H.M.W. van Lier1, Cornelis A.T. van den Berg1, Dennis W.J. Klomp1, Bas W. Raaymakers1, Jan J.W. Lagendijk1

1Radiology, Radiotherapy, Nuclear Medicine, University Medical Center Utrecht, Utrecht, Netherlands

The RF safety assessment of a commercially available 7T head coil using thermal simulations with a discrete vessels model is shown. This model incorporates the heating of blood in the arteries and veins as it traverses through a heated volume, which is an addition to Pennes’ bio heat transfer equation. Comparing the maximum SAR with the maximum temperature rise within the head it was concluded that the restrictions based on volume integrated SAR calculations are over-conservative, which results in the sub-optimal imaging.

17:24         305.       Reduction of Implant RF Heating by Modification of Electric Field Distribution

Yigitcan Eryaman1, Haydar Celik1, Burak Akin1, Ergin Atalar1

1Electrical Engineering, Bilkent University, Ankara, Turkey

In this work, the optimum EM field that reduces the RF heating of implant leads is calculated. The resulting field also satisfies a given transmit target sensitivity constraint in an axial plane. Among infinite number of solutions satisfying these constraints, the one that minimizes the average SAR is presented. The field distribution which satisfies the electric field and the target transmit sensitivity constraints is realized by using a linearly polarized birdcage coil. Finally, heating experiments of resonant length wires is conducted by using linearly polarized and quadrature coils.

17:36         306.       Detecting Unsafe Device Coupling Using Reversed RF Polarization

William Overall1, Pascal Stang1, John Pauly1, Greig Scott1

1Electrical Engineering, Stanford University, Stanford, CA, USA

Patients with long-wire implants are ineligible for MR scans due to the risk of RF burns arising from RF fields coupling to their device. We propose the use of a low-power prescan to quantify the level of coupling and determine the burn risk for a particular patient in a particular scanner. This is accomplished through use of reversed RF polarization imaging, which produces images with signal proportional to RF coupling. Simulations and experimental data suggest that this technique can be reliably used to determine burn risk in a prescan setting.

17:48         307.       Characterization of the Relationship Between MR-Induced Distal Tip Heating in Cardiac Pacing Leads and the Electrical Performance of Novel Filtered Tip Assemblies

Robert S. Johnson1, Holly Moschiano1, Robert Stevenson1, Scott Brainard2, Sam Ye2, Joseph E. Spaulding1, Warren Dabney1

1Cardiac & Neurology, Greatbatch, Inc., Clarence, NY, USA; 2Cardiac & Neurology, Greatbatch, Inc., Plymouth, MN, USA

The impedance of inductor-capacitor band stop filters were characterized with impedance spectroscopy. If was found the impedance of the device was controllable with proper selection of the inductor and capacitor values. The filters were incorporated in implantable leads and the temperature rise of the distal end was measured during a MRI scan with an RF-intensive imaging protocol. The minimum heating was 9°C with the highest impedance filter and the maximum heating was 51°C with a control lead. Systematic changes in the lead configuration and location reduced the heating to near instrumentation noise level.

Microvascular Imaging in Cancer & Response Evaluation

Room 316A                         16:00-18:00                                                                Moderators: Jeffrey L. Evelhoch and Martin O. Leach

16:00         308.       Young Investigator Award Finalist:  Use of Cardiac Output to Improve Measurement of Tracer Input Function in Dynamic Contrast-Enhanced MRI

Jeff Lei Zhang1, Henry Rusinek1, Louisa Bokacheva1, Qun Chen1, Pippa Storey1, Vivian S. Lee1

1Radiology, New York University, New York, NY , USA

We present a new method for computing AIF from MR arterial signals using a constrained conversion that takes into account the subject¡¯s cardiac output. Monte Carlo simulations showed that by using the proposed method, the reproducibility of tumor perfusion parameters and renal function parameters was significantly improved (by at least a factor of three). Dynamic MR renography was repeated for volunteers on three separate days. We obtained similar results. The proposed method may be especially useful for analyzing repeated contrast-enhanced scans such as monitoring tumor therapy or ACE-inhibitor renography.

16:20         309.       Noninvasive Multimodality Imaging of the Tumor Microenvironment: Registered Dynamic 1H MRI and 18F PET Studies of a Preclinical Model of Tumor Hypoxia.

HyungJoon Cho1, Ellen Ackerstaff1, Sean Carlin1, Mihaela Lupu1, Ya Wang1, Asif Rizwan1, Joseph O'Donoghue1, Clifton Ling1, John Humm1, Pat Zanzonico1, Jason Koutcher1

1Memorial Sloan Kettering Cancer Center, New York, NY, USA

In vivo knowledge of the spatial distribution of viable, necrotic and hypoxic areas can provide prognostic information about the risk of developing metastases, the distribution of radiation sensitivity, and may possibly be used for localized dose escalation in radiation treatment. In this study, multimodality in vivo Magnetic Resonance Imaging (MRI) and Positron Emission Tomography (PET) imaging using stereotactic fiduciary markers in the Dunning R3327-AT prostate tumor was performed, focusing on the relationship between Dynamic Contrast-Enhanced (DCE)-MRI using Magnevist® (Gd-DTPA), and dynamic 18F-fluoromisonidazole (18F-Fmiso) PET. The non-invasive measurements were verified using tumor tissue sections stained for haematoxylin/eosin (H&E) and pimonidazole.

16:32         310.       Distinct Molecular Profiles Characterize Hypoxic Breast Tumor Regions Detected by Combined MRSI, Optical Imaging, and Imaging Mass Spectrometry

Erika R. Amstalden1, Tiffany R. Greenwood2, Zaver M. Bhujwalla2, Venu Raman2, Ronald M. A. Heeren1, Kristine Glunde2

1FOM Institute for Atomic and Molecular Physics, Amsterdam, Netherlands; 2JHU ICMIC Program, Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA

Breast tumors are characterized by spatially distinct hypoxic regions, which lead to radio- and chemoresistance and poor clinical outcome. Our goal is to identify to date unknown metabolites, small molecules, and proteins that, as a result of hypoxia-driven signaling pathways, have a high concentration in hypoxic regions. We combined 3D MRSI detection of metabolites with optical detection of hypoxic regions using hypoxia-driven fluorescence reporter and Imaging Mass Spectrometry (IMS) detection of undiscovered biomolecules in breast tumor models. Necrotic/hypoxic regions showed a markedly different molecular-metabolic profile compared to well-vascularized regions, which can provide molecular insights and differentiate these regions.

16:46         311.       3D Radial Multi Gradient Echo Dynamic MRI for Characterization of Microvasculature in Tumor Models Subjected to Respiratory Motion

Julien Vautier1,2, Melanie Heilmann3, Christine Walczak1,2, Joël Mispelter1,2, Andreas Volk1,2

1U759, INSERM, Orsay, France; 2Research Center, Institut Curie, Orsay, France; 3Computer Assisted Clinical Medicine, University Medicine, Mannheim, Germany

Preclinical dynamic MRI to characterize microvasculature in tumor models is typically performed with gradient- or spin-echo sequences and Cartesian k-space sampling which is not optimal for tumors subjected to respiratory motion. Radial k-space sampling, rather insensitive to motion, should be more appropriate. In this study, we have developed and validated a 3D radial multi gradient echo sequence. It allows for simultaneous measurement of T1 and T2* upon contrast agent administration at 1min30 time resolution. A first in vivo study comparing 3D Ktrans maps for two contrast agents of different molecular weights was performed on motion animated subcutaneous tumors in mice.

16:58         312.       High Resolution MR Angiography of Tumors Using Iron-Oxide Contrast Agent

Dmitri Artemov1, Yoshinori Kato1

1JHU ICMIC Program, Dept. of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA

Many forms of anticancer therapy target tumor vasculature and monitoring their effect with noninvasive imaging is one of the most important problems in cancer imaging. MR angiography (MRA) allows direct visualization of the tumor vasculature however its spatial resolution is limited by the method and only relatively large mature blood vessels can be imaged using current techniques. We propose to use SPIO-based blood pool contrast agents for susceptibility contrast enhanced MRA. These agents remain intravascular in the leaky tumor vasculature and provide improved visualization of small blood vessels due to the ’blooming effect’ in T2* weighted MR images.

17:10         313.       Early DCE-MRI Findings Predict Tumor Volume Changes

Edward Ashton1

1R&D, VirtualScopics, Inc, Webster, NY, USA

This study examines the relationship between early DCE-MRI findings and later changes in tumor burden as measured by structural CT or MRI for cancer patients undergoing anti-vascular or anti-angiogenic therapy. In particular, it addresses the question of whether reductions in blood flow and vascular permeability observed within the first two weeks of treatment are predictive of changes in tumor burden after 8 weeks. The data set includes 164 patients drawn from 13 clinical trials using a largely uniform data acquisition and analysis protocol. Results show a probability of tumor reduction of 70% in DCE-MRI responders vs. 26% for DCE-MRI non-responders.

17:22         314.       Serial Assessment of Perfusion Parameters in Patients with GBM Following Anti-Angiogenic Therapy

Emma Essock-Burns1,2, Janine M. Lupo1, Susan M. Chang3, Soonmee Cha1,3, Sarah J. Nelson1,2

1Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; 2UCSF/UCB Joint Graduate Group in Bioengineering, University of California, San Francisco, San Francisco, CA, USA; 3Department of Neurological Surgery, University of California, San Francisco, San Francisco, CA, USA

Perfusion parameters, derived from T1-weighted dynamic contrast enhanced imaging and arterial spin labeling, of tumor and normal brain tissue in patients with GBM were tracked for 6 months after receiving anti-angiogenic therapy. Kps, fBV, and CBF levels in the tumor region were seen to decrease significantly 6 months after treatment with noticeable changes within individual patients by 2 months after treatment. The results from this study suggest that perfusion imaging is a useful tool for assessing the effects of this therapy and possibly assisting early prediction of progression for patients with GBM.

17:34         315.       Early Detection of Response to Antiangiogenic Therapy in Metastatic Clear-Cell Renal Cell Carcinoma with ASL MRI

Ivan Pedrosa1, Philip Robson1, Rupal Bhatt2, David McDermott2, Michael B. Atkins2, David Alsop1

1Department of Radiology, Beth Israel Deaconess Medical Center, Boston, MA, USA; 2Department of Medicine, Division Hematology-Oncology, Beth Israel Deaconess Medical Center, Boston, MA, USA

Six patients with metastatic clear cell renal cell carcinoma (RCC) underwent arterial spin labeling (ASL) magnetic resonance imaging (MRI) before and 1 week after initiation of therapy with sorafenib and bevacizumab. Mean tumor perfusion at 1 week into therapy (80 ± 64 ml/100 g/min) was significantly lower than the tumor perfusion at baseline (176 ± 107 ml/100 g/min)(p=0.02, paired t-test) whereas there was no significant decrease in measured tumor size at 1 week (p=0.06, paired t-test). ASL MRI detects changes in the vascularity of RCC metastasis as soon as 1 week into therapy with sorafenib and bevacizumab.

17:46         316.       DCE-MRI Summary and Heterogeneity Statistics Predict Response to Combined Chemo- And Anti-VEGF Therapy

Chris James Rose1, James Patrick O'Connor1, Yvonne Watson1, Caleb Roberts1, Giovannni A. Buonaccorsi1, Susan Cheung1, Brandon Whitcher2, Gordon Jayson3, Alan Jackson1, Geoffrey J. Parker1

1Imaging Science and Biomedical Engineering, School of Cancer and Imaging Sciences, The University of Manchester, Manchester, UK; 2MRI Modelling, Clinical Imaging Centre, GlaxoSmithKline, London, UK; 3Cancer Research UK Dept. of Medical Oncology, The Christie, Manchester, UK

In the context of clinical trials of anti-cancer therapies, there is limited evidence that biomarkers derived from DCE-MRI and tracer kinetic modelling have predictive value. It has been speculated that intratumoural spatial heterogeneity—neglected by conventional analyses—may carry useful information. We applied spatial heterogeneity analysis to a clinical trial of combined chemo- and anti-VEGF therapy. Multiple regression and correlation analyses revealed a statistically significant (p ≤ 0.001) correlation between median Ktrans and spatial heterogeneity of ve maps—measured before treatment at baseline—and reduction in tumour size measured after five two week cycles, indicating that treatment response can be predicted at baseline.

Go with the Flow

Room 312                             16:00-18:00                                                                        Moderators: Jelena Bock and Georg M. Bongartz

16:00         317.       Flow Assessment Over All Heart Valves Simultaneously Using 3D Velocity-Encoded MRI with Retrospective Valve Tracking

Jos J.M. Westenberg1, Stijntje D. Roes1, Sebastiaan Hammer2, Pieter J. van den Boogaard1, Nina Ajmone Marsan3, Jeroen J. Bax3, Johan H.C. Reiber1, Albert de Roos1, Rob J. van der Geest1

1Radiology, Leiden University Medical Center, Leiden, Netherlands; 2Internal Medicine, Leiden University Medical Center, Leiden, Netherlands; 3Cardiology, Leiden University Medical Center, Leiden, Netherlands

Conventional 2-dimensional one-directional through-plane velocity-encoded MRI not only extents imaging time when the flow through all heart valves needs to be studied sequentially, but also shows low agreement in net flow volume between the four valves. Three-dimensional three-directional velocity-encoded MRI with retrospective valve tracking during offline analysis is introduced for simultaneous flow assessment at all four heart valves in less than 5 minutes scan time. This technique is applied to 16 volunteers without valve regurgitation and 29 patients with valve regurgitation. The net flow volumes show good agreement between the valves. Regurgitation and net flow can be quantified accurately.

16:12         318.       Pressure Gradient Wave Propagation in the Left Atrium and Left Ventricle During Early Diastole

June Cheng Baron1, Ben Esch2, Jessica Scott2, Mark Haykowsky3, Ian Paterson4, Richard Thompson1

1Biomedical Engineering, University of Alberta, Edmonton, AB, Canada; 2Cardiovascular Physiology and Rehabilitation Laboratory, University of British Columbia, Vancouver, BC, Canada; 3Physical Therapy, University of Alberta, Edmonton, AB, Canada; 4Division of Cardiology, University of Alberta, Edmonton, AB, Canada

Pressure gradients are an appealing measure of diastolic function because they provide a direct assessment of the forces responsible for driving blood flow, and have now been reported in several clinical studies. While pressure gradients are commonly expressed in terms of a peak pressure difference over space at a single point in time they vary considerably over time and space, with unique patterns in the atrium and ventricle. We show, for the first time, that pressure gradients, calculated using phase contrast MRI, present as distinct ventricular and atrial waves with characteristic speeds, directions and amplitudes.

16:24         319.       4D Flow of the Whole Heart and Great Vessels Using a Real Time Self Respiratory Gating Technique: A Validation Study.

Sergio Andres Uribe Arancibia1, Philipp Beerbaum1, Allan Rasmusson2, Thomas Sorensen2, Reza Razavi1, Tobias Schaeffter1

1Division of Imaging Sciences, King's College London, London, UK; 2Department of Computer Science, University of Aarhus, Aarhus, Denmark

In this study we propose to validate a 4D flow technique that acquires data on the whole heart and great vessels using a self-respiratory gating technique. The method allows retrospective flow quantification from data obtained in a single free breathing scan. In 15 volunteers, the method was compared with 2D flows and with a 4D flow data obtained without respiratory gating. Result showed an excellent agreement with the clinically used 2D sequence. When applied in a congenital heart patient the technique showed to be very valuable for retrospective analysis of flow in any arbitrary plane and direction.

16:36         320.       PC VIPR for Comprehensive Cardiovascular Evaluation in Congenital Heart Disease

Christopher J. François1, Elizabeth K. Nett2, Benjamin R. Landgraf1, Kevin M. Johnson2, Shardha Srinivasan3, John Carter Ralphe3, Darren P. Lum1, Oliver Wieben2

1Radiology, University of Wisconsin, Madison, WI, USA; 2Medical Physics, University of Wisconsin, Madison, WI, USA; 3Pediatric Cardiology, University of Wisconsin, Madison, WI, USA

This study demonstrates the feasibility of using phase contrast (PC) vastly undersampled isotropic projection reconstruction (VIPR) for the evaluation of patients with congenital heart disease. The scan is completed during free breathing and provides coverage of the whole chest with isotropic spatial resolution. The data are reconstructed as (1) magnitude images, (2) angiograms, and (3) cine velocity vector fields to quantify flow and other hemodynamic parameters, thereby providing comprehensive information from a single scan. Because PC VIPR does not require the use of contrast material, this sequence can be performed in patients in whom the administration of Gd-based contrast material is not considered safe.

16:48         321.       Analysis of Aortic Hemodynamics After Treatment for Coarctation Using Flow-Sensitive 4D MRI at 3T

Alex Frydrychowicz1, Daniel Hirtler2, Raoul Arnold2, Alexander Berger1, Aurelien F. Stalder1, Jelena Bock1, Andreas Harloff3, Mathias Langer1, Jürgen Hennig1, Michael Markl1

1Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany; 2Pediatric Cardiology, University Hospital Freiburg, Freiburg, Germany; 3Neurology, University Hospital Freiburg, Freiburg, Germany

Surgical repair of aortic coarctation can lead to severe secondary complications such as re-stenosis and aneurysms. It was the aim of this study to investigate the influence of aortic flow alterations on the formation of secondary complications in 24 patients after coarctation repair by means of time-resolved 3-directional flow-sensitive 3D MRI at 3T. 3D visualization using time-resolved particle traces and streamlines revealed the different extent of altered flow patterns associated with the post surgical status of the patient. Characteristic changes in 3D flow patterns hint towards a hemodynamic contribution to the otherwise multifactorial etiology of complications associated with aortic coarctation.

17:00         322.       Phase Contrast Ultra Short TE; a More Reliable Technique for Measurement of High Velocity Turbulent Stenotic Jets

Kieran O'Brien1, Saul Myerson2, Brett Cowan1, Alistair Young1, Matthew Robson2

1University of Auckland, Auckland, New Zealand; 2University of Oxford, Oxford, UK

The reliability of phase contrast (PC) magnetic resonance velocity measurements in high velocity stenotic jets has been questioned. The best method to reduce errors due to intravoxel dephasing is to shorten the TE; however, in conventional Cartesian PC sequences the TE cannot be shortened adequately for reliable clinical diagnosis. We present an alternative technique that utilizes velocity-dependent selective-slice-excitation and centric-radial readout trajectories to minimize TE. Velocity measurement occurs over the shortest time window resulting in reduced intravoxel dephasing and better agreement with a high velocity (~10m/s) stenotic phantom. Clinical feasibility was demonstrated in a patient with aortic stenosis.

17:12         323.       Three-Dimensional Assessment of Wall Shear Stress Distribution in the Carotid Bifurcation

Michael Markl1, Felix Wegent2, Simon Bauer1, Aurelien F. Stalder1, Alex Frydrychowicz1, Cornelius Weiller2, Martin Schumacher3, Andreas Harloff2

1Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany; 2Neurology, University Hospital Freiburg, Freiburg, Germany; 3Neuroradiology, University Hospital Freiburg, Freiburg, Germany

Flow sensitive MRI for the in-vivo quantification of 3D blood-flow and derived vessel wall parameters may provide an enhanced understanding of flow-mediated arterial atherogenesis in the carotid arteries. We evaluated the normal distribution of segmental wall shear stress in 32 normal volunteers based flow-sensitive 4D MRI for full hemodynamic information on 3D blood flow. Analysis of vectorial wall shear stress (WSS) identified carotid segments potentially predisposed to the development of atherosclerosis. Posterior regions demonstrated a high incidence of low absolute WSS and high oscillatory shear index (OSI) offering a potential explanation why carotid stenosis predominantly develops in the ICA bulb.

17:24         324.       Time-Resolved Blood Flow Quantification Without Gating

Michael C. Langham1, Jeremy Magland1, Felix W. Wehrli1

1Radiology, University of Pennsylvania, Philadelphia, PA, USA

In MRI, gated phase-contrast (PC)-MRI is the standard approach to resolving pulsatile blood flow but arrhythmia (which is normal) can significantly affect accuracy and reproducibility since each phase-encoding takes one heartbeat. We describe a flow quantification technique with velocity-encoded projections where reference image is used to remove signals from the background, e.g. tissue, prior to taking phase difference. The projection method achieves temporal resolution of 20 ms without gating (prospective or retrospective). We demonstrate the technique by time-resolving the triphasic pulsatile blood flow in femoral artery of healthy subjects and show that results are consistent with PC-MRI.

17:36         325.       Evidence Across CMR Sites and Systems of Phase-Contrast Background Velocity Offsets Requiring Correction for Accurate Regurgitant or Shunt Flow

Peter D. Gatehouse1, Marijn P. Rolf2, Martin J. Graves3, Mark B. Hofman2, John Totman4, Beat Werner5, Rebecca Quest6, Yingmin Liu7, Jochen von Spiczak8, Matthias Dieringer9, Juerg Schwitter10, Jeanette Schulz-Menger9, David N. Firmin1, Philip J. Kilner1

1Royal Brompton Hospital, London, UK; 2VU Medical Center, Amsterdam, Netherlands; 3Addenbrooke's Hospital, Cambridge, UK; 4King's College, London, UK; 5Kinderspital, Zurich, Switzerland; 6Imperial College, London, UK; 7University of Auckland, New Zealand; 8University and ETH, Zurich, Switzerland; 9Charité Universitätsmedizin, Berlin, Germany; 10University Hospital, Zurich, Switzerland

Velocity offset errors are often reported to damage reliability of cardiac shunt and regurgitation by phase-contrast, hence this inter-site inter-scanner measurement of velocity errors to find out how widespread the problem might be.

17:48         326.       In Vivo Assessment of Carotid Wall Shear Rate Using Spiral Fourier Velocity Encoding

Joao Luiz Azevedo Carvalho1,2, Jon Fredrik Nielsen2,3, Krishna Shrinivas Nayak2

1Electrical Engineering, University of Brasilia, Brasilia, DF, Brazil; 2Electrical Engineering, University of Southern California, Los Angeles, CA, USA; 3Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA

Wall shear stress is believed to influence the development of atherosclerosis, but there is currently no gold standard for its in vivo measurement. High-resolution phase contrast is inadequate due to partial volume effects, long scan-times, and low SNR. We evaluate the use of spiral Fourier velocity encoding for assessing wall shear rate in the carotid arteries. The shear rate is estimated using the method described by Frayne and Rutt MRM 34:378-387, which estimates the velocity profile within a voxel from its velocity distribution. The proposed method is validated using simulated data from computational fluid dynamics, and demonstrated in vivo at 3T.

Spectroscopic Imaging & Excitation

Room 315                             16:00-18:00                                                          Moderators: Daniel M. Spielman and Melissa J. Terpstra

16:00         327.       Short TE (15ms) Spectroscopic Imaging of the Human Brain at 7T Using Transceiver Arrays and B1 Shimming Based Localization

Hoby Patrick Hetherington1, Andrey M. Kuznetsov1, Nikolai I. Avdievich1, Jullie W. Pan1

1Neurosurgery, Yale University, New Haven, CT, USA

The presence of ultra high field systems (7T) dating from late 1990s, there have been few reports of their use in spectroscopic imaging (SI) studies. This limitation is due to the inherent disadvantages of high field which result in a 5-12 fold increase in power deposition at 7T in comparison to 3T. These problems become especially severe when in–plane volume localization is used for SI. To overcome these limitations we have developed a short TE (15ms) SI sequence utilizing an 8 element 7T transceiver array and a B1 shimming based method for in-plane localization.

16:12         328.       Spectroscopic Imaging Using Wideband Parallel RF Excitation at 7T

Borjan Aleksandar Gagoski1, Kawin Setsompop2, Joonsung Lee1, Vijay Alagappan2, Michael Hamm3, Axel vom Endt3, Lawrennce Wald4,5, Elfar Adalsteinsson5,6

1Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA; 2A. A. Martinos Center for Biomedical Imaging, MGH, Charlestown, MA, USA; 3Siemens Medical Solutions, Charlestown, MA, USA; 4A. A. Martinos Center for Biomedical Imaging, Department of Radiology, MGH, Charlestown, MA, USA; 5Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA, USA; 6Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge,, MA, USA

pTx mitigation excitation over a 600Hz spectral bandwidth and a 3 cm thick slab, preceded by pTx Gaussian-shaped pulses for water suppression was used in a chemical shift imaging acquisitions. The goal of this work is to demonstrate that compared to the regular birdcage (BC) mode excitation, the proposed pTx wideband excitation provides spatial uniformity of metabolite signals in a spectroscopy phantom containing physiological brain metabolite concentrations.

16:24         329.       1H NMR Spectroscopy in the Human Brain in Vivo at 9.4 Tesla: Initial Results

Dinesh K. Deelchand1, Pierre-Francois Van de Moortele1, Gregor Adriany1, Peter Andersen1, Kamil Ugurbil1, Pierre-Gilles Henry1

1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA

We report initial 1H NMR spectroscopy results in the human brain in vivo at 9.4 Tesla despite several challenges for human studies at ultra high-field. The increase in signal-to-noise and spectral dispersion has allowed quantification of at least 15 metabolites with greater precision. As expected, the T1 relaxation time was increased and T2 relaxation time was reduced at 9.4 Tesla.

16:36         330.       Spectroscopic SWIFT

Djaudat Idiyatullin1, Curt Corum1, Steen Moeller1, Jutta Ellermann2, Michael Garwood1

1CMRR, University of Minnesota, Minneapolis, MN, USA; 2Radiology, University of Minnesota, Minneapolis, MN, USA

The ability to obtain chemical shift information is often needed and advantageous in MRI. This work describes a new 3D and 4D spectroscopic SWIFT technique involving an intrinsic frequency dimension. In addition to providing chemical shift information, spectroscopic SWIFT can be used to reduce blurring which normally occurs in radial imaging due to frequency shifts. The presented method can be used for spectroscopy of human tissue having transverse relaxation times, T2, in microsecond time scale. As examples of applications, fat-water separation, imaging near metallic implants, and short T2 mapping are illustrated and discussed.

16:48         331.       Accelerated Proton Echo-Planar Spectroscopic Imaging Using Parallel Imaging and Compressed Sensing

Ricardo Otazo1, Daniel K. Sodickson1, Akio Yoshimoto2, Stefan Posse2,3

1Center for Biomedical Imaging, NYU School of Medicine, New York, NY, USA; 2Electrical and Computer Engineering Department, University of New Mexico, Albuquerque, NM, USA; 3Department of Neurology, University of New Mexico, Albuquerque, NM, USA

Compressed sensing and parallel imaging are combined into a single joint reconstruction to accelerate Proton Echo Planar Spectroscopic Imaging (PEPSI). The method exploits the joint sparsity in the sensitivity-encoded images to achieve higher accelerations than for coil-by-coil compressed-sensing or parallel imaging alone. We demonstrate the feasibility of simulated 4-fold acceleration for human brain PEPSI using a standard 12-channel array coil.

17:00         332.       Gradient Offset Independent Adiabatic Pulses for High-Field MR Spectroscopy on Clinical Scanners

Ovidiu Cristian Andronesi1, Saadallah Ramadan2, Eva Maria Ratai1, Dominique Jennings1, Carolyn Mountford2, A. Gregory Sorensen1

1Martinos Center for Biomedical Imaging, Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA; 2Center for Clinical Spectroscopy, Department of Radiology, Brigham & Women’s Hospital, Harvard Medical School, Boston, MA, USA

Adiabatic pulses are necessary to mitigate chemical shift artifact and rf inhomogeneity at high-field MRS, but often they need longer durations (≥ 5 ms) and higher rf strengths (> 1 kHz) that limits their application in-vivo. Gradient offset independent adiabatic (GOIA) pulses have been proposed [1] as an elegant solution to reduce these requirements while effectively increasing the excitation bandwidth (> 20 kHz). Despite of the benefits, their use on clinical scanners has not been widespread. Here we report on a new class of GOIA pulses derived from WURST [3] adiabatic pulses that provide accurate localization and increased SNR at 3T and 7T.

17:12         333.       Application of HSn Low Peak B1 Adiabatic Refocusing Pulses to Hyperpolarized 13C Spectroscopic Imaging

Simon Hu1,2, Peder E. Larson1, Adam B. Kerr3, Douglas A. Kelley4, James Tropp4, John M. Pauly3, John Kurhanewicz1,2, Daniel B. Vigneron1,2

1Dept. of Radiology and Biomedical Imaging, University of California, San Francisco, CA, USA; 2UCSF & UCB Joint Graduate Group in Bioengineering, San Francisco, CA, USA; 3Dept. of Electrical Engineering, Stanford University, Stanford, CA, USA; 4GE Healthcare, San Francisco, CA, USA

In order to develop methods for human studies, we modified a previously reported double spin-echo hyperpolarized 13C spectroscopic imaging sequence by using stretched hyperbolic secant refocusing pulses instead of standard hyperbolic secant pulses. The previous pulses used in animal model studies had a nominal B1 of 1.7 gauss, which was achievable with small coils but not with human coils. We designed new pulses with a nominal B1 of 0.4 gauss, which we validated in simulations, phantom experiments, and in vivo.

17:24         334.       Diffusion-Weighted Line-Scan Echo-Planar Spectroscopic Imaging for Improved Accuracy in Metabolite Diffusion Imaging

Yoshitaka Bito1, Koji Hirata1, Toshihiko Ebisu2, Yuko Kawai3, Yosuke Otake1, Satoshi Hirata1, Toru Shirai1, Yoshihisa Soutome1, Hisaaki Ochi1, Masahiro Umeda3, Toshihiro Higuchi4, Chuzo Tanaka4

1Central Research Laboratory, Hitachi, Ltd., Kokubunji-shi, Tokyo, Japan; 2Neurosurgery, Nantan General Hospital, Kyoto, Japan; 3Medical Informatics, Meiji University of Integrative Medicine, Kyoto, Japan; 4Neurosurgery, Meiji University of Integrative Medicine, Kyoto, Japan

A diffusion-weighted line-scan echo-planar spectroscopic imaging (DW-LSEPSI) technique to improve accuracy in measuring diffusion-weighted images of metabolites is developed.@The most challenging issue to improve accuracy is to reduce motion artifact induced by cardiac pulsation and respiratory. The developed technique uses line-scan technique and echo-planar technique to reduce the influence of phase errors caused by such motions during diffusion time. Acquisition of accurate diffusion-weighted image and ADC maps of metabolites is demonstrated by applying this technique to a phantom and a rat brain in vivo.

17:36         335.       Improving Spatial Localization in MR Spectroscopic Imaging with PSF-Choice

Lawrence Patrick Panych1,2, Joseph R. Roebuck3, Robert V. Mulkern2,4, Yi Tang1,2, Bruno Madore1,2, Nan-kuei Chen5

1Radiology, Brigham and Women's Hospital, Boston, MA, USA; 2Radiology, Harvard Medical School, Boston, MA, USA; 3Radiology, University of Texas Medical Branch, Galveston, TX, USA; 4Radiology, Children's Hospital, Boston, MA, USA; 5Brain Imaging and Analysis Center, Duke University, Durham, NC, USA

The purpose of this work was to improve the point-spread-function (PSF) of MR spectroscopic imaging (MRSI) to avoid corruption from neighboring voxels. PSF-Choice, a method that uses RF manipulation to shape the PSF in phase-encoding directions, was implemented. Evaluation of the method in extensive phantom experiments was conducted. In addition, an implementation of this method is reported for MRSI of the prostate, where it is demonstrated that, in 13 of 16 pilot prostate MRSI scans, intra-voxel spectral contamination from lipid is significantly reduced compared to a standard phase-encoding MRSI method.

17:48         336.       Enhanced Polyamine Detection at 7T as a Possible in Vivo Biomarker for Prostate Cancer

Dennis Klomp1, Tom Scheenen2, Jack van Asten2, Vincent Boer1, Peter Luijten1

1Radiology, University Medical Center Utrecht, Utrecht, Netherlands; 2Radiology, Radboud University Nijmegen, Medical Center, Netherlands

Additional biological markers may improve prostate cancer diagnoses. In this work we demonstrate the use of chemical shift selective refocusing to substantially enhance the polyamine marker in vivo at a field strength of 7T.

Multiple Sclerosis - Clinical Applications

Room 310                             16:00-18:00                                                                   Moderators: Nicola de Stefano and Massimo Filippi

16:00         337.       High Resolution Magnetization Transfer Imaging at 7T

Olivier E. Mougin1, Ali al-Radaideh1, Ron Coxon1, Emma C. Tallantyre2, Matthew J. Brookes1, Nikos Evangelou3, Penny A. Gowland1

1Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, Nottinghamshire, UK; 2Departement of Clinical Neurology, Medical School, University of Nottingham, Nottingham, Nottinghamshire, UK; 3School of Medical & Surgical Sciences, University of Nottingham, Nottingham, Nottinghamshire, UK

High resolution (1x1x1mm3) MTR scans have been acquired at 7T using a novel imaging sequence. The MTR contrast has been compared between 7 and 3T, showing a greater grey matter (GM) / white matter (WM) contrast to noise ratio at 7T, providing a good delineation of WM lesions at high resolution with the MTR contrast. The sequence is being used to study white matter changes in MS patients.

16:12         338.       Regions of Reduced Cortical Magnetization Transfer Ratio Detected in MS Patients Using Surface-Based Techniques

Mishkin Derakhshan1, Zografos Caramanos1, Sridar Narayanan1, Donald Louis Collins1, Douglas Lorne Arnold1

1Montreal Neurological Institue, McGill University, Montreal, QC, Canada

The multiple sclerosis imaging community still struggles with the in vivo detection of cortical grey matter lesions. In this abstract we quantified the extent of subpial decreases of magnetization transfer ratio of the cortical grey matter, which may indicate regions of cortical demyelination, in groups of MS patients and healthy controls. To increase our sensitivity, we exploited the knowledge gained from pathological studies of the unique geometry of these lesions, and carried out our analyses on two-dimensional parametric surface models of the cortex, instead of the three-dimensional voxel-wise analyses traditionally used.

16:24         339.       Optimisation of 7T Double-Inversion Recovery (DIR) Imaging to Improve Detection of MS Lesions In Vivo

Jennifer Elizabeth Dixon1, Paul S. Morgan2,3, Matthew J. Brookes1, Ali M. Al-Radaideh1, Emma C. Tallantyre4, Nikos Evangelou4, Peter G. Morris1

1Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, Nottinghamshire, UK; 2Radiology & Radiological Science, Medical University of South Carolina, Charleston, SC, USA; 3Academic Radiology, University of Nottingham, Nottingham, Nottinghamshire, UK; 4Department of Clinical Neurology, University of Nottingham, Nottingham, Nottinghamshire, UK

DIR sequences have proved useful in the detection of cortical MS lesions. However, the inherently low SNR of this sequence suggests the importance of developing it at higher field. This requires the determination of inversion times to provide the desired contrast between grey matter, white matter and CSF, and must address the effects of variation in flip angle due to B1 inhomogeneity at 7T, as well as reduce the TR to obtain clinically acceptable scan times. We use this theory to produce high-resolution images acquired at 7T, which show clearly areas of signal hyperintensity associated with MS lesions

16:36         340.       Detection of Cortical Lesions in Multiple Sclerosis Using FLAIR, DIR and Ultra High Field MPRAGE

Emma Clare Tallantyre1, Jennifer E. Dixon2, Matthew J. Brookes2, Ali Al-Radaideh2, Paul S. Morgan3,4, Nikos Evangelou1, Peter G. Morris2

1Clinical Neurology, Nottingham University, Nottingham, UK; 2Sir Peter Mansfield MR Centre, Nottingham University, Nottingham, UK; 3Radiology & Radiological Sciences, Medical University of South Carolina, Charleston, USA; 4Academic Radiology, Nottingham University, Nottingham, UK

Objective: To investigate whether cortical MS lesions detected using 3T DIR are also seen using ultra high field (7T) MRI. Methods: MR imaging at 3T and 7T of 11 MS patients and 8 controls.  Results: DIR was susceptible to artefact in controls. A proportion of cortical lesions identified on 3T DIR appear to be genuine. However, enhanced spatial resolution of 7T MPRAGE better determines the anatomical location of lesions and some cortical hyperintensities on 3T DIR seem to arise from extracortical blood vessels. Conclusions: Ultra high field MRI increases sensitivity and specificity in the detection of cortical lesions.

16:48         341.       Evaluation of Cortical Lesions Conspicuity in Multiple Sclerosis: 7T Vs 3T MRI

Caterina Mainero1, Thomas Benner1, Amy Radding1, Rikke Jensen2, Andre van der Kouwe1, R P. Kinkel2, Bruce R. Rosen1

1A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA; 2Neurology, Beth Israel Deaconess Medical Center, Boston, MA, USA

In this study we assessed the use of 7T MRI to (1) visualize cortical lesions, including all histopathological types, in patient with multiple sclerosis (MS); (2) characterize the contrast properties of cortical lesions including T2*, T2, T1, and phase images to assess which MR contrasts are more sensitive to cortical pathology; (3) compare the ability of the 7T images that showed higher contrast for cortical plaques with that from 3T in disclosing cortical MS pathology. 7T MRI, and particularly FLASH-T2* scans, showed greater potential than 3T MRI not only in detecting cortical lesions but also in characterizing them as described histopathologically.

17:00         342.       High Resolution In-Vivo and Post-Mortem R2* and Phase Images of Multiple Sclerosis Lesions at 7 T

Bing Yao1, Francesca Bagnato1, Hellmut Merkle1, Peter van Gelderen1, Fredric K. Cantor1, Joan Ohayon1, Henry McFarland1, Jeff H. Duyn1

1NINDS, National Institutes of Health, Bethesda, MD , USA

R2* and phase images have been exploited to investigate brain tissue microstructure. In this study, MS patients and brain specimens of an MS deceased patient were imaged using a 7 T MR scanner and the R2* and phase images were investigated. Heterogeneity appearances of the MS lesions are found in the high resolution R2* and phase images, for both in-vivo and extra-vivo tissues. We here aim at providing new insights on the major sources that contribute to the MRI contrast in MS lesions.

17:12         343.       Demyelination and Remyelination in New Multiple Sclerosis Lesions: Insights from Serial Myelin Water Imaging

Cornelia Laule1, Irene M. Vavasour1, Shannon H. Kolind2, Burkhard Maedler3, Anthony L. Traboulsee4, Penny Smyth4, Alex Rauscher1, John Hooge4, Virginia Devonshire4, Joel Oger4, Wayne Moore5, David KB Li1,4, Alex L. MacKay1,2

1Radiology, UBC, Vancouver, BC, Canada; 2Physics & Astronomy, UBC, Vancouver, BC, Canada; 3Philips Healthcare, Vancouver, BC, Canada; 4Neurology, UBC, Vancouver, BC, Canada; 5Pathology & Laboratory Medicine, UBC, Vancouver, BC, Canada

Histological studies show cycles of demyelination and remyelination occur in multiple sclerosis (MS) lesions. MR measures of myelin water fraction (MWF), water content (WC) and geometric mean T2 (GMT2) measured by multi-echo T2 relaxation provide insight into the myelination state of MS lesions.We utilized a 3D T2 relaxation sequence to follow MWF, WC, GMT2 and also measured T1 on a monthly basis to elucidate the time course of pathological changes in new MS lesions. The behaviour of new lesions varied between subjects, with some lesions showing recovery. WC and MWF can monitor the evolution of demyelination and remyelination in MS.

17:24         344.       Whole-Brain Voxel-Wise Analysis of Myelin Water Volume Fraction in Multiple Sclerosis

Sean CL Deoni1

1Centre for Neuroimaging Sciences, London, UK

The ability to distinguish affected, but normal appearing, white matter tissue has significant clinical application to MS and other de-myelinating disorders. Currently, this may be accomplished using histogram analysis, but at the expense of spatial information. Here we demonstrate a patient-specific approach, involving the comparison of voxel-wise myelin volume fraction values, obtained using the mcDESPOT multi-component relaxometry technique, to a reference population-matched atlas. We demonstrate the ability to visualize areas of significantly reduced myelin fraction within tissue that appears normal on conventional T1 or T2 weighted scans.

17:36         345.       Differentiation of Pathological Processes and Clinical Forms in Multiple Sclerosis: A Tract Based Spatial Statistics Study.

Salem Hannoun1,2, Francoise Durand-Dubief1,3, Danielle Ibarrola2, Jean Christophe Comte2, Christian Confavreux3, Dominique Sappey-Marinier1,2

1CREATIS-LRMN, UMR5220 CNRS & U630 INSERM & Université de Lyon, Bron, France; 2CERMEP-Imagerie du vivant, Bron, France; 3Hopital Neurologique, Groupement Hospitalier Est, Bron, France

his study aims to characterize the pathological processes and differentiate the clinical forms of multiple sclerosis (MS) patients using tract based spatial statistics (TBSS). Significant decreases of FA values were observed in numerous white matter regions of MS patients (SP, PP and RR forms) when compared to control subjects. These decreases were also more pronounced when comparing patients with more advanced forms (SP and PP) to RR patients while no significant differences were observed between SP and PP groups. This technique constitutes an important new tool to follow the disease progression and better characterize the alterations extent between patients clinical status.

17:48         346.       Application of Lesion Probability Maps to Predict Progression in Primary-Progressive Multiple Sclerosis: A 10-Year Multi-Centre Study

Benedetta Bodini1, Marco Battaglini2, Nicola De Stefano2, Zhaleh Khaleeli1, Frederik Barkhof3, Bruno Brochet4, Vincent Dousset5, Massimo Filippi6, Xavier Montalban7, Chris Polman3, Marco Rovaris6, Alex Rovira7, Jaume Sastre-Garriga7, David H. Miller8, Rebecca Samson8, Olga Ciccarelli1, Alan J. Thompson1

1Dept. of Brain Repair and Rehabilitation, Institute of Neurology, UCL, London, UK; 2Dept. of Neurological and Behavioural Sciences, University of Siena, Siena, Italy; 3Department of Radiology, MS Center, VU University Medical Centre, Amsterdam, Netherlands; 4Hopital Pellegrin, Centre Hospitalier Universitaire, Bordeaux, France; 5Bordeaux Neuroscience Institute, University Victor Segalen, Bordeaux, France; 6Neuroimaging Research Unit, San Raffaele Scientific Institute, Milan, Italy; 7Depts. of Neuroimmunology and Radiology, Hospital Vall d’Hebron, Barcelona, Spain; 8Dept. of Neuroinflammation, Institute of Neurology, UCL, London, London, UK

The aim of this study was to assess whether the spatial distribution of T2 lesions predicted long-term progression in primary progressive multiple sclerosis (PPMS). To clarify this issue, we applied Lesion Probability Map, a novel technique, to a large cohort of PPMS patients followed-up over 10 years. We found that the spatial distribution of T2 lesions at baseline was relevant in predicting the risk of long-term progression. In particular, lesions in the motor and associative tracts correlated with more rapid clinical progression. We confirmed that male gender was associated with a worse long-term prognosis.

Neurochemical Modeling & Profiling of Brain Metabolism

Room 311                             16:00-18:00                                                                                  Moderators: In-Young Choi and Ivan Tkac

16:00         347.       Multimodal NMR Assessment of Erythropoietin as a Neuroprotective Agent Following Hypoxia-Ischemia on P3 Pup Rat Brain

Yohan van de Looij1,2, Alexandra Chatagner1, Nicolas Kunz1,2, Petra S. Hüppi1, Rolf Gruetter3,4, Stéphane V. Sizonenko1

1Division of Child Growth & Development, Department of Pediatrics, University of Geneva, Geneva, Switzerland; 2Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 3Laboratory for Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne , Lausanne, Switzerland; 4Department of Radiology, University of Geneva and Lausanne, Switzerland

The 3-day old rat (P3) shares some similarities in terms of cerebral development to the very preterm infant. Animal models of periventricular leukomalacia (most important cerebral alteration after premature birth) can be achieved by Hypoxia-Ischemia (HI). Here we investigated the neuroprotective effect of EPO in a model of neonatal HI injury in the P3 rat pup using DTI, MRS and immunohistochemistry. EPO appears able to reduce tissue loss and white matter injuries but it retains compromised metabolism consistent with incomplete recovery from EPO, giving a highly relevant new insight in the neuroprotective effect of EPO.

16:12         348.       Neurochemical Profile of the Mouse Hypothalamus Using 1H MRS at 14.1T

Hongxia Lei1,2, Carole Poitry-Yamate1, Frederic Preitner3, Bernard Thorens3, Rolf Gruetter1,4

1Ecole Polytechnique Federale de Lausanne, Lausanne, Vaud, Switzerland; 2Radiology, University of Lausanne , Lausanne, Vaud, Switzerland; 3Institute of Physiology, University of Lausanne , Lasuanne, Vaud, Switzerland; 4Radiology, University of Geneva, Geneva, Switzerland

MRS of hypothalamus in mice is very challenging due to its small volume and deep structure. In present study, we examine the feasibilities of 1H MRS of the hypothalamus in GLUT8 knockout mice at 14.1T. The quality spectra resulted in nearly 20 metabolites, so called the neurochemical profile of the mouse hypothalamus.

16:24         349.       1H MRS of the Visual Cortex Under Chronic Ocular Hypertension

Kevin C. Chan1,2, Kwok-fai So3, Ed X. Wu1,2

1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China; 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China; 3Department of Anatomy, The University of Hong Kong, Hong Kong SAR, China

This study aims to employ in vivo 1H MRS to monitor the metabolic changes in the visual cortex in an experimental model of chronic glaucoma. Five Sprague-Dawley rats were prepared to induce ocular hypertension unilaterally in the right eye by photocoagulating the episcleral and limbal veins using an argon laser. 1H MRS was performed to each side of the visual cortex 6 weeks after laser treatment. The results of this study suggest that glaucoma is associated with alterations in the metabolism of choline-containing compounds in the normally-appearing visual cortex. Measurement of the Cho:Cr reduction in the visual cortex may be a noninvasive biomarker for the disease.

16:36         350.       Proton MRS Investigation of Human Glioma Models in Nude Mice at 14.1 T

Vladimir Mlynarik1, Cristina Cudalbu1, Virginie Clément2, Denis Marino2, Ivan Radovanovic2, Rolf Gruetter1,3

1Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Dept. of Genetic Medicine and Development, University of Geneva School of Medicine, Geneva, Switzerland; 3Departments of Radiology, Universities of Lausanne and Geneva

Injecting separated fresh or cultured human glioma-initiating cells into brain of nude mice produced tumors having two different phenotypes. The tumors from cultured cells grew fast and showed necrosis and Gd enhancement, while the gliomas from fresh cells grew slowly and showed no necrosis and very little Gd enhancement. Proton localized spectroscopy at 14.1 Tesla revealed different metabolic profiles in the two types of tumors. Characteristic changes of metabolite concentrations were observed in the brain tissue near the injection site of the cultured glioma-initiating cells before solid tumors were detected by MRI.

16:48         351.       Redox Dependence and Compartmentation of [13C]Pyruvate in the Brain of Deuterated Rats Bearing Implanted C6 Gliomas

Tiago Brandao Rodrigues1, Pilar Lopez-Larrubia1, Sebastián Cerdán1

1LISMAR, Instituto de Investigaciones Biomédicas CSIC, Madrid, Spain

We investigated the redox dependence and compartmentation of the pyruvate pool in the brain of partially deuterated rats bearing C6 gliomas. The rats were infused with [1-13C]glucose and [2-13C]pyruvate or [U-13C3]lactate. The relative amounts of [3-13C]lactate derived from glucose to the [2-13C] or [U-13C3]lactate isotopomers derived from monocarboxylates decreased in the order contralateral>ipsilateral>tumor regions, revealing a progressive reduction in glycolysis for regions containing increasing endogenous lactate concentrations. Deuterated animals bearing C6 tumors, infused with [1-13C]glucose and [2-13C]pyruvate, showed different deuterium enrichments in the methyl groups of cerebral [3-13C] and [2-13C]lactate, revealing a slow mixing of the [3-13C] and [2-13C]pyruvate precursors in the 2H exchange timescale of their methyl groups.

17:00         352.       In Situ 3D MR Metabolic Imaging of Microwave-Irradiated Rodent Brain: A New Tool for Metabolomics Research

Robin A. de Graaf1, Golam MI Chowdhury1, Peter B. Brown1, Douglas L. Rothman1, Kevin L. Behar1

1MRRC, Yale University, New Haven, CT, USA

High-resolution and high-sensitivity MR imaging and spectroscopy on microwave-irradiated rat brain is demonstrated. Structural integrity and metabolic stability are confirmed for at least 12 hours through the use of DTI and T2-weighted MRI and 1H MRS. 1H MR spectra of microwave-irradiated rat brain are indistinguishable from in vivo 1H MR spectra. When combined with in vivo infusion of 13C-labeled compounds, the in situ 1H MRSI data allows the detection of metabolic fluxes at high spatial resolution.

17:12         353.       Quantification of Brain Glycogen Concentration and Turnover Through Localized 13C NMR of Both the C1 and C6 Resonance

Ruud Bernardus van Heeswijk1, Florence D. Morgenthaler1, Lijing Xin1, Rolf Gruetter1,2

1Center for BioMedical Imaging (CIBM), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, VD, Switzerland; 2Departments of Radiology, Universities of Lausanne and Geneva, Lausanne and Geneva, Switzerland

Brain glycogen concentration and turnover were determined in vivo in the rat by simultaneously monitoring both the C1 and C6 resonances with 13C NMR. These resonances lie 3.9 kHz apart at 9.4 T, so to prevent a chemical shift displacement artifact a sequence based on the Fourier series window was implemented. After bringing the C1 resonance in steady state through 'pre-labeling' with 1-13C1 glucose, an acute infusion of 1,6-13C2 glucose was used to label the C6 resonance of glycogen and so estimate its turnover time, while the C1 resonance was used to monitor for concentration changes.

17:24         354.       17O T1/T2* Tissue-Relaxation Rates with Anatomical Contrast in the Rat Brain at 16.4 T

Hannes M. Wiesner1, David Z. Balla1, Rolf Pohmann1, Wei Chen2, Kamil Ugurbil2, Kamil Uludag1

1High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tübingen, Germany; 2Radiology, Center for Magnetic Resonance Research, University of Minnesota Medical School, Minneapolis, MN, USA

The direct NMR detection of 17O benefits particularly from higher field strengths and is a promising tool in the study of cerebral oxygen metabolism. The aim of this study was to acquire anatomical MRS images of H217O at natural abundance concentration in the rat head at 16.4 Tesla. Intra-cortical contrast and differences in tissue-specific relaxation of brain and muscle tissue were found, enabling optimizations in contrast and sensitivity. Based on these results implications on the spatial specificity of oxygen consumption (CMRO2) measurements using 17O2-enriched gas will be discussed.

17:36         355.       Effect of Short- And Long-Term Type 1 Diabetes on the Neurochemical Profile in STZ-Induced Diabetic Rats at 9.4 T

Wen-Tung Wang1, Sang-Pil Lee2,3, Irina Smirnova4, In-Young Choi1,5

1Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS, USA; 21Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS, USA; 32Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA; 4Department of Physical Therapy and Rehabilitation Sciences, University of Kansas Medical Center, Kansas City, KS, USA; 52Department of Neurology, Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA

The neurological consequences of diabetes mellitus were assessed during short- and long-term streptozotocin-induced diabetes in the rat brain. Early yet subtle changes of neurochemical contents in the streptozotocin(STZ)-induced diabetes were detected using in vivo ultra-short echo time 1H MRS at 9.4 T. Acute hyperglycemia led to significant changes in alanine, ß-hydroxybutyrate, glutamine, myo-inositol, lactate, taurine, and choline compounds (GPC+PCho). While glutamine showed a transient increase during the short-term hyperglycemic period, others maintained persistent changes through the chronic stage. Four weeks after the STZ-injection, aspartate, glutathione and N-acetylaspartate started to show significant decreases, indicating increased oxidative stress and neuronal loss during the disease progression.

17:48         356.       Dynamic Metabolic Modeling of [2-13C]Acetate Metabolism in the Rat Brain<

Alexander A. Shestov1, Dinesh K. Deelchand1, Pierre-Gilles Henry1

1Radiology, University of Minnesota Medical School, Minneapolis, MN, USA

Carbon-13 MRS combined with metabolic modeling allows measurement of metabolic rates in vivo. Most 13C metabolic modeling studies have been performed using 13C-glucose as the infused substrate. Acetate, a glial-specific substrate, is an attractive alternative to glucose for the study of neuronal-glial interactions. Here we report kinetic parameters for acetate transport and utilization, as well as dynamic metabolic modeling of glutamate and glutamine 13C turnover curves obtained during 13C-acetate infusion with a two-compartment neuronal-glial model.

HARDI & Higher Order Descriptions of Diffusion

Room 316BC                       16:00-18:00                                                                       Moderators: Daniel Alexander and Mariana Lazar

16:00         357.       Orientationally Invariant Axon-Size and Density Weighted MRI

Daniel C. Alexander1, Penny L. Hubbard2, Matt G. Hall1, Elizabeth A. Moore3, Maurice Ptito4, Geoff J. M. Parker2, Tim B. Dyrby5

1Centre for Medical Image Computing, Dept. Computer Science, UCL (University College London), London, UK; 2Imaging Science and Biomedical Engineering, School of Cancer and Imaging Sciences, University of Manchester, Manchester, UK; 3Best, Philips Healthcare, Eindhoven, Netherlands; 4School of Optometry, University of Montreal, Montreal, Canada; 5Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital, Copenhagen, Denmark

We present a diffusion MRI technique for mapping correlates of the axon size and density in white matter over the whole brain. Unlike previous techniques, the method does not require prior knowledge of the fibre direction. Results from a perfusion fixated monkey brain agree with histological data in the literature. Further results from in vivo human brain data, acquired in less than one hour on a standard system, also show the expected trends.

16:12         358.       How Many Diffusion Gradient Directions Are Required for HARDI?

J-Donald Tournier1,2, Fernando Calamante1,2, Alan Connelly1,2

1Brain Research Institute, Florey Neuroscience Institutes (Austin), Melbourne, Victoria, Australia; 2Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia

While the number of DW directions required for DTI has been extensively studied, the equivalent studies have not been performed for HARDI. However, due to the large number of directions inherent in HARDI acquisitions, this information is crucial to keep scan times practical. In this study, we use sampling theory to determine the minimum number of DW directions required for HARDI experiments, independent of the particular algorithm used to estimate fibre orientations. Results obtained at b = 3000s/mm2 indicate that 45 directions are required to adequately characterize the angular frequency information contained in the DW signal.

16:24         359.       Diffusion Kurtosis Imaging (DKI) Reveals an Early Phenotype (P30) in a Transgenic Rat Model for Huntington’s Disease

Ines Blockx1, Marleen Verhoye1,2, Geert De Groof1, Johan Van Audekerke1, Kerstin Raber3, Dirk Poot2, Jan Sijbers2, Stephan von Horsten3, Annemie Van der Linden1

1Bio-Imaging Lab, University of Antwerp, Antwerp, Belgium; 2Vision Lab, University of Antwerp, Antwerp, Belgium; 3Experimental Therapy, Friedrich-Alexander University, Erlangen, Germany

The transgenic rat model for Huntington’s Disease (HD) resembles the late-onset form, exhibiting a behavioral phenotype with emotional disturbance, motor deficits, and cognitive decline. We used Diffusion Kurtosis Imaging (DKI) to study very young (P15-P30) HD rats and controls. In white matter of P30 HD pups we observed a significantly decreased fractional anisotropy and increased axial kurtosis as compared to controls. In grey matter of P30 HD pups axial kurtosis was significantly increased as well as Mean Kurtosis. The DKI changes we detected in HD pups, suggests that neurodegenerative processes of HD also involves neurodevelopment defects already detectable at P30.

16:36         360.       In Vivo Imaging of Kurtosis Tensor Eigenvalues in the Brain at 3 T

Eric Edward Sigmund1, Mariana Lazar1, Jens H. Jensen1, Joseph A. Helpern1

1Radiology, New York University, New York, NY , USA

Diffusion kurtosis imaging (DKI) quantifies the well-known non-gaussianity of apparent diffusion in biological tissue, and its directionally averaged mean kurtosis (MK) has potential clinical utility in the brain. However, the complete rank-4 kurtosis tensor contains more information that may be reduced, as in diffusion tensor diagonalization, to characteristic properties. The present study applies the recently described spectral decomposition to derive the eigenvalues/eigentensors of the kurtosis tensor, and resolve them spatially in a full brain 3 T DW-MRI scan. Maps of kurtosis eigenvalues and composite “eigensurfaces” derived from eigentensor projections present new contrast, potentially involving fiber crossing and barrier-density anisotropy.

16:48         361.       Detection of Brain Maturation - DTI with Different B-Values Versus Diffusion Kurtosis Imaging

Matthew Man Hin Cheung1,2, Ed X. Wu1,2

1Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China; 2Laboratory of Biomedical Imaging and Signal Processing , The University of Hong Kong, Hong Kong SAR, China

This study aims to investigate the effects of different b-values in detecting microstructural changes during well-controlled rodent brain maturation. The results are also compared to the diffusion kurtosis indices obtained by diffusion kurtosis imaging (DKI) that characterizes the restricted diffusion by fitting multiple b-value DW measurements to a quadratic-exponential model. The results indicate that the b-value for optimal DTI detection of microstructural changes depends on the specific physiological or pathological processes targeted. High-order diffusion imaging, such as DKI, is therefore essential for more robust MR diffusion characterization of neural tissues.

17:00         362.       Super-Resolving Patches in Diffusion MRI Using Canonical Fibre Configurations

Simon Jeremy Damion Prince1, Daniel C. Alexander1

1Computer Science, University College London, London, UK

We aim to improve the spatial resolution of fibre-orientation estimates in diffusion MRI by learning a prior over 3x3x3 voxel patches that assumes self-similarity across scale. In training we align and cluster patches of fibre orientations from a larger scale using a mixture of Watsons model. The resulting canonical fibre configurations describe homogenous regions, bending, fanning etc. To super-resolve, we find the canonical patch and mean orientation, diffusivity and volume fraction that best describe the voxel measurements. We compare our results to nearest-neighbour interpolation and demonstrate that it is possible to successfully determine sub-voxel structure.

17:12         363.       Model-Based Residual Bootstrap of Constrained Spherical Deconvolution for Probabilistic Segmentation and Tractography

Hamied Ahmad Haroon1, David M. Morris1, Karl V. Embleton1,2, Geoff J. Parker1

1Imaging Science and Biomedical Engineering, School of Cancer and Imaging Sciences, The University of Manchester, Manchester, England, UK; 2School of Psychological Sciences, The University of Manchester, Manchester, England, UK

Here we describe the application of model-based residual bootstrapping to the analysis of HARDI data using constrained spherical deconvolution. We demonstrate that the method is able to provide estimates of the probability of finding different fiber configurations within the brain. These distributions of fiber orientations may then be used directly as PDFs across each configuration for probabilistic tractography. This method provides a means by which the microstructural complexity of tissue, as reflected in the HARDI diffusion signal, may be characterised, naturally accounting for the underlying tissue microscopic complexity, macroscopic partial volume, and data noise levels.

17:24         364.       Diffusion Propagator Imaging: A Novel Technique for Reconstructing the Diffusion Propagator from Multiple Shell Acquisitions

Maxime Descoteaux1, Jean-François Mangin1, Cyril Poupon1

1NeuroSpin, IFR 49, CEA Saclay, Gif-sur-Yvette, France

We present a simple and linear analytical diffusion propagator solution using spherical Laplace's equation. The reconstruction is possible from only two b-value HARDI acquisitions and less than 100 diffusion measurements.

17:36         365.       Practical Crossing Fiber Imaging with Combined DTI Datasets and Generalized Reconstruction Algorithm

Fang-Cheng Yeh1, Van Jay Wedeen2, Wen-Yih Isaac Tseng1,3

1Center for Optoelectronic Biomedicine, National Taiwan University College of Medicine, Taipei, Taiwan; 2MGH Martinos Center for Biomedical Imaging, Harvard Medical School, Charlestown, MA, USA; 3Department of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan

We present a clinically feasible sampling scheme which combines two DTI datasets to achieve higher angular resolution. The performance and accuracy of the proposed scheme was examined in comparison with q-ball imaging method.

17:48         366.       Restriction Spectrum Imaging (RSI): A New Method for Resolving Complex Tissue Microstructures in Diffusion MRI

Nathan S. White1, Trygve B. Leergaard2, Alex de Crespigny3,4, Anders M. Dale5

1Cognitive Science, University of California, San Diego, La Jolla, CA, USA; 2Centre for Molecular Biology and Neuroscience, University of Oslo, Norway; 3Radiology and Neurosciences, Massachusetts General Hospital, Harvard University; 4Department of Clinical Neurology, Oxford University, UK; 5Neurosciences and Radiology, University of California, San Diego, La Jolla, CA, USA

We present a new model-based analysis method for diffusion MRI called Restriction Spectrum Imaging (RSI). Traditional model-based deconvolution methods assume all fibers in a given voxel are composed of the same biological components and thus have identical water restriction properties. In RSI, the tissue is modeled using a spectrum of both oriented and non-oriented diffusion components with different water restriction scales. Both the volume fraction and 3D orientation of each individual component can be derived in each voxel using linear estimation methods. RSI may provide a more complete characterization of tissue with complex neuromorphologies.

B1 Mapping: What's Your Angle?

Room 314                             16:00-18:00                                                                      Moderators: Adam B. Kerr and Rudolf Stollberger

16:00         367.       Very Fast Multi Channel B1 Calibration at High Field in the Small Flip Angle Regime

Pierre-Francois Van de Moortele1, Kamil Ugurbil1

1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA

We describe a fast method to estimate transmit B1 profiles in multi channel transceiver arrays in the small flip angle regime within about 1 minute of data acquisition. Despite of expected residual biases, it was possible to obtain excellent B1 Shim results based on these estimated B1 maps. Further investigation will help determining if this fast B1 estimation, which can cover the whole brain in less than 3 minutes with 40 slices, could become part of common scanner calibration routines, such as B0 mapping, for integrating transmit B1 adjustment in standard MR sesions at high field.

16:12         368.       Eigenmode Analysis of Transmit Coil Array for SAR-Reduced B1 Mapping and RF Shimming

Kay Nehrke1, Peter Börnert1

1Philips Research Europe, Hamburg, Germany

The B1 transmit field inhomogeneity represents a serious problem in whole-body high field MRI (>3T). B1 shimming based on measured B1 maps is a promising approach to cope with this problem and represents the primary application for parallel transmission at this point in time. However, B1 mapping is still an error-prone and time consuming process, potentially resulting in a SAR issue caused by the shimmed RF pulse and the mapping scan itself. In the present work, an eigenmode analysis of the transmit sensitivities is employed to accelerate the B1 mapping process and reduce the SAR of the shimmed RF pulses.

16:24         369.       Precise and Robust B1+ Characterization of Transmit Coil Arrays

Martin Janich1,2, Olaf Dössel1, Sascha Köhler2, Johannes Schneider2, Peter Ullmann2

1Institute of Biomedical Engineering, University of Karlsruhe, Karlsruhe, Germany; 2Bruker BioSpin MRI GmbH, Ettlingen, Germany

A common approach to B1+ characterization of TX-arrays involves transmitting with different combinations of array elements in order to improve SNR. TX-element combination can be employed in a more sophisticated manner when using a B1+ mapping method based on saturation and excitation pulses. The saturation can be performed with a single transmit element and the excitation with a B1+-shimmed combination. The present study proposes improvements to the common combined transmission approach for TX-array B1+ mapping as well as for the saturation-based technique. The performance of the improved techniques was experimentally compared to the classical single-element B1+ mapping approach.

16:36         370.       Extended Multi-Flip-Angle Approach: A 3D B1unit+ Mapping Method for Inhomogeneous Fields

Hans Weber1, Dominik Paul1, Maxim Zaitsev1, Jürgen Hennig1, Dominik von Elverfeldt1

1Dept. of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany

Comprehensive characterization of an RF resonator is given by a quantitative and spatial analysis of its magnetic field produced per unit current (B1unit+). In this study, we present an extension of the multi-flip-angle approach which allows mapping of inhomogeneous B1unit+ fields in three dimensions over a large dynamic range. To demonstrate its superiority over the commonly-used conventional double-angle method, a comparison between both is given.

16:48         371.       Targeted B1+ Mapping Using 3D Reduced Field-Of-View Catalyzed Double-Angle Method

Dingxin Wang1, Sven Zuehlsdorff2, Reed Omary1, Andrew Larson1

1Departments of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, USA; 2Siemens Medical Solutions USA, Inc., Chicago, IL, USA

This study proposes a targeted B1+ mapping technique using 3D reduced FOV catalyzed double angle method (DAM). This method is based on 3D catalyzed DAM which allows a short TR for fast B1+ mapping by introducing catalyzation pulses at the end of each repetition cycle of DAM to drive the ratio of the ending longitudinal magnetizations (for the two different flip angle excitations) to unity. This method employs an inner volume 3D turbo spin echo (TSE) sequence to limit the FOV and thereby to shorten imaging time.

17:00         372.       Actual Flip Angle Imaging: From 3D to 2D

Xiaoping Wu1, Dinesh Kumar Deelchand1, Vasily L. Yarnykh2, Kâmil Ugurbil1, Pierre-François Van de Moortele1

1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA; 2Department of Radiology, University of Washington, Seattle, WA, USA

Recently, actual flip angle imaging (AFI) has been introduced as an efficient, fast 3D flip angle (FA) mapping technique. In some circumstance, a 2D version would be preferable (e.g., 2D Parallel Transmission) since it would require a significantly shorter acquisition time. Although in the original 3D version the FA calculation in AFI does not need to take into consideration the impact of slice profiles, this is however not the case when a 2D slice selective version of the same approach is considered, especially with regard to T1 sensitivity. Therefore, the purpose of this study was to evaluate the properties and feasibility of 2D AFI FA mapping where 2D (instead of 3D) image signals are used for FA calculations, using the equation that was derived for the 3D AFI FA mapping. For this purpose, we performed phantom experiments at 9.4 T, together with simulations, to study the relationship between 2D and 3D AFI FA values for different T1's.

17:12         373.       Quantitative Comparison of B1+ Mapping Methods for 7T Human Imagning

Jason E. Moore1, Marcin Jankiewicz1,2, Huairen Zeng1,2, Adam W. Anderson1,3, Malcolm J. Avison1,3, E Brian Welch1,4, John C. Gore1,3

1Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; 2Department of Radiology, Vanderbilt University; 3Department of Biomedical Engineering, Vanderbilt University; 4Philips Healthcare, Cleveland, OH, USA

B1+ / flip angle mapping results from double-angle, pulsed steady state, and gradient echo series techniques are compared using a dielectric phantom in a 7T human MR system. Under such conditions, B1+ maps are found to vary significantly (~50%) across protocols.

17:24         374.       Optimization of a Low-Flip-Angle Phase-Based 3D B1 Mapping Technique for High Field Applications

Pippa Storey1, Graham C. Wiggins1, Davide Santoro1, Daniel K. Sodickson1

1NYU School of Medicine, New York, NY , USA

A rapid 3D low-flip-angle phase-based method for B1 measurement was originally proposed by Mugler for transmit calibration in hyperpolarized helium studies and also tested as a B1 mapping technique in protons at 1.5T. We explore ways to optimize the sensitivity and accuracy of the technique for high field applications, and present B1 maps of the thighs at 3T and the brain at 7T.

17:36         375.       A Simple and Fast Flip Angle Calibration Method

Sofia Chavez1, Greg Stanisz2

1Imaging Research, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; 2Sunnybrook Health Sciences Centre, Canada

A simple flip angle calibration method is introduced. It relies on the quasi-linear characteristics of the signal vs flip angle curve for a spoiled gradient recalled echo at large flip angles and for short repetition time. A straight-line extrapolation is used to determine the signal null point, occurring for a true flip angle of 180°. The data at each pixel is fit to yield a map of the flip angle calibration factor (k). The resulting k map is shown to be in good agreement with that resulting from the standard double angle method in a much shorter acquisition time.

17:48         376.       A Noise Analysis of Flip Angle Mapping Methods

Glen Morrell1,2, Matthias Schabel2

1Radiology Department, University of Utah Health Sciences Center, Salt Lake City, UT, USA; 2Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT, USA

Error analysis of four methods of flip angle mapping was performed by explicit calculation of the probability density functions of the flip angle estimates given corruption of the measured MR signals by Gaussian white noise. The methods investigated were double angle gradient recalled echo, double angle spin echo, “actual flip angle” imaging, and a phase sensitive technique. The phase sensitive technique is shown to be superior to other methods, with lower mean bias and lower variance of the flip angle estimate.

CS++: Compressed Sensing & Beyond

Room 313BC                       16:00-18:00                                                                  Moderators: Pablo Irarrazaval and Krishna S. Nayak

16:00         377.       Accelerating SENSE Using Distributed Compressed Sensing

Dong Liang1, Kevin f. King2, Bo Liu3, Leslie Ying1

1Dept. of Electrical Engineering and Computer Science, Univ. of Wisconsin-Milwaukee, Milwaukee, WI, USA; 2Global Applied Science Lab, GE Healthcare, Waukesha, WI, USA; 3MR Engineering, GE Healthcare, Waukesha, WI, USA

Most existing methods apply compressed sensing (CS) to parallel MRI as a regularized SENSE reconstruction, where the regularization function is the L1 norm of the sparse representation. However, the CS conditions such as incoherence are not necessarily satisfied. To address the issue, a method is proposed which first reconstructs a set of aliased images from all channels simultaneously using distributed CS (DCS), and then the final image using Cartesian SENSE. The results on a set of eight-channel data show that the proposed method is able to achieve a higher reduction factor than the existing methods.

16:12         378.       Distributed Compressed Sensing for Accelerated MRI

Ricardo Otazo1, Daniel K. Sodickson1

1Center for Biomedical Imaging, NYU School of Medicine, New York, NY, USA

A framework for combining parallel imaging with compressed sensing is presented using the theory of distributed compressed sensing which extends compressed sensing to multiple sensors using the principle of joint sparsity. We present a greedy reconstruction algorithm named JOMP (Joint Orthogonal Matching Pursuit) that uses intra- and inter-coil correlations to jointly sparsify the multi-coil image instead of sparsifying the individual images. We show that for a sufficient number of coils, the number of measurements required by JOMP-PMRI to reconstruct a truly sparse image is very close to the image sparsity level. The performance of JOMP-PMRI with compressible images is assessed with a simulated brain image to show feasibility of higher accelerations with increasing number of coils.

16:24         379.       L1 SPIR-IT: Autocalibrating Parallel Imaging Compressed Sensing

Michael Lustig1, Marcus Alley2, Shreyas Vasanawala2, David L. Donoho3, John Mark Pauly1

1Electrical Engineering, Stanford University, Stanford, CA, USA; 2Radiology, Stanford University; 3Statistics, Stanford University

A detailed approach of combining auto-calibrating parallel imaging (acPI) with compressed sensing (CS) is presented. The acquisition and the reconstruction are carefully optimized to meet the requirements of both methods in order to achieve highly accelerated robust reconstructions. Poisson-disc sampling distribution is used to achieve the required incoherency for CS and uniform density for acPI. A novel L1-wavelet penalized, iterative reconstruction (L1 SPIR-iT) is used to enforce consistency with the calibration and data acquisition, and in addition, joint sparsity of the reconstructed coil images. High quality in vivo, 5-fold accelerated reconstruction using only 4 coils is demonstrated.

16:36         380.       L1-Norm Regularization of Coil Sensitivities in Non-Linear Parallel Imaging Reconstruction

Carlos Fernández-Granda1,2, Julien Sénégas3

1École des Mines, Paris, France; 2Universidad Politécnica de Madrid, Spain; 3Philips Research Europe, Hamburg, Germany

Joint estimation of the coil sensitivities and the image in parallel imaging can suppress aliasing more effectively than methods based on low-resolution sensitivity estimates. We propose a joint estimation approach related to Compressed Sensing that exploits the sparsity of the coil sensitivities in k-space and in a base of Chebyshev polynomials within a greedy scheme to solve the ill-posed reconstruction problem. In vivo data reconstructions are presented and compared to results obtained with Generalized SENSE and Joint SENSE.

16:48         381.       SPArse Reconstruction Using a ColLEction of Bases (SPARCLE)

Ali Bilgin1,2, Onur Guleryuz3, Theodore P. Trouard2,4, Maria I. Altbach2

1Electrical and Computer Engineering, University of Arizona, Tucson, AZ, USA; 2Dept. of Radiology, University of Arizona, Tucson, AZ, USA; 3Dept. of Electrical Engineering, Polytechnic Institute of NYU, Brooklyn, NY, USA; 4Biomedical Engineering, University of Arizona, Tucson, AZ, USA

We introduce a new sparse reconstruction framework where sparsity is enforced in a collection of bases rather than a single one. Results indicate that this new framework yields significantly improved reconstruction quality.

17:00         382.       Ultra-High Resolution 3D Upper Airway MRI with Compressed Sensing and Parallel Imaging

Yoon-Chul Kim1, Shrikanth S. Narayanan1, Krishna S. Nayak1

1Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA, USA

Ultra-high resolution 3D imaging of the vocal tract can provide insight into the shaping that occurs during complex speech articulation. The combined use of compressed sensing (CS) and parallel imaging is investigated to maximize spatial resolution while maintaining scan-time appropriate for a single sound production task (~7 seconds). Compared to conventional reconstructions, boundary depiction was improved by using high-resolution phase constraints, sensitivity encoding, and regularization based on total variation and the l1-norm of the wavelet transform. Eight-fold acceleration was achieved leading to 1.33x1.33x1.33 mm3 resolution and 7-second scan time.

17:12         383.       Highly-Accelerated First-Pass Cardiac Perfusion MRI Using Compressed Sensing and Parallel Imaging

Ricardo Otazo1, Daniel Kim1, Daniel K. Sodickson1

1Center for Biomedical Imaging, NYU School of Medicine, New York, NY, USA

Compressed sensing and parallel imaging are combined into a single joint reconstruction paradigm named k-t Parallel-Sparse for highly accelerated first pass cardiac perfusion imaging. The method exploits the joint sparsity in the sensitivity-encoded images to achieve higher accelerations than for coil-by-coil sparsity alone, and it does not require dynamic training data. We demonstrate the feasibility of high in vivo acceleration factors of 8 and 12 and assess the effect of respiratory motion.

17:24         384.       Motion Estimated and Compensated Compressive Sensing Dynamic MRI Under Field Inhomogeneity

Hong Jung1, Jaeseok Park2, Jong Chul Ye3

1KAIST, Daejon, Korea; 2Yonsei Univ. medical center, Korea; 3KAIST, Korea

Recently, we proposed a compressed sensing dynamic MR technique called k-t FOCUSS that extends the conventional k-t BLAST/SNESE by exploiting the sparsity of x-f signal. Especially, we found that when a fully sampled reference frame is available more sophisticated prediction methods such as RIGR and motion estimation and compensation (ME/MC) can significantly sparsify the residual and improve the overall reconstruction quality. Among these, ME/MC is especially useful since it can be used for arbitrary trajectories such as radial and spiral. However, our extensive experiments with non-cartesian trajectory have demonstrated that there exist technical issues in applying the ME/MC to non-cartesian trajectory due to the field inhomogeneities. This paper showed that if the ME/MC is done in magnitude image domain and the lost phase is compensated from the current frame estimate, the field inhomogeneity problem can be significantly alleviated. Furthermore, we showed that the introduction of half-pel ME/MC and intra block mode within the estimation loop can improve the overall reconstruction quality of compressed sensing dynamic MRI.

17:36         385.       Fast Relaxation Parameter Mapping from Undersampled Data

Mariya Doneva1, Christian Stehning2, Peter Börnert2, Holger Eggers2, Alfred Mertins1

1University of Luebeck, Luebeck, Germany; 2Philips Research Europe, Hamburg, Germany

The quantitative assessment of MR parameters like T1, T2, ADC, etc. requires the acquisition of multiple images of the same anatomy, which results in long scan times. However, these data can be described by a model with only a few parameters and in that sense they are highly compressible. Thus, Compressed Sensing (CS) could be applied to accelerate the data acquisition. In this work we introduce a model-based reconstruction from undersampled data, which performs simultaneous image reconstruction and parameter mapping and demonstrate it for the example of T1 mapping.

17:48         386.       Quality Index for Detecting Reconstruction Errors Without Knowing the Signal in L0-Norm Compressed Sensing

Carlos A. Sing-Long1,2, Cristian A. Tejos1,2, Pablo Irarrazaval1,2

1Departamento de Ingenieria Electrica, Pontificia Universidad Catolica de Chile, Santiago, R.M., Chile; 2Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, R.M., Chile

Compressed Sensing allows reconstructing signals, if they are sparse in some representation, from some of its Fourier coefficients. The reconstruction conditions are stated in terms of the support size of the signal. Since it is generally unknown, it is impossible to determine if there are reconstruction errors due to high undersampling rates. Our work introduces a modified fixed-point solver for a continuous approximation of the l0-norm and an index which shows high correlation with the reconstruction error. This index does not need any a priori information and may be used to determine if the undersampling rate needs to be reduced.

BRONZE CORPORATE MEMBER SYMPOSIUM
Bayer Healthcare

Room 312                             18:15 – 19:45                                                                                                                                                                                                                         

BRONZE CORPORATE MEMBER SYMPOSIUM
Bracco
Navigating the Brave New World: Practical Protocols for Contrast Enhanced MR Imaging

Room 315                             18:15 – 19:45                                                                                                                                                                           


SUNRISE EDUCATIONAL COURSE
Image Reconstruction

Room 314                             07:00 – 08:00                                         Moderators:  Peter Börnert, Klaas Pruessmann, and Jeffrey Tsao

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Describe the main steps involved in efficient non-Cartesian image reconstruction;

·          Formulate a generalized signal model incorporating gradient encoding, coil sensitivity and B0 inhomogeneity;

·          List the pros and cons of Cartesian and non-Cartesian parallel MRI;

·          Compare compressed sensing, HYPR, and k-t BLAST with respect to their use of prior knowledge;

·          Describe the principles of separating water and fat signals; and

·          Name three differentn approaches for motion correction and appraise their potential to become routine methods.

 

Parallel Imaging

07:00        
Parallel Imaging Reconstruction I:  Cartesian

                  Michael Schacht Hansen

                                                     

07:30         Parallel Imaging Reconstruction II:  Non-Cartesian

                  Chunlei Liu

SUNRISE EDUCATIONAL COURSE
Safety Update

Room 320                             07:00 – 08:00                                                          Moderators:  Penny A. Gowland and Roger Luechinger

Educational Objectives:
Upon completion of this session, participants should be able to:

·          Explain the issues involved in setting the SAR limit for a pulse sequence;

·          List the causes of PINS and how coils are designed to prevent it;

·          Describe standards related to medical implants in the MR environment;

·          Describe causes of accidents and preventative measures in the MR environment; and

·          Explain risks and minimization of acoustic noice in the MR environment.

 

07:00         Interactions of Tissues with Low Frequency Magnetic Fields

                  Blaine A. Chronik

 

07:30         Gradient Coil Design

                  Daniel J. Schaefer

SUNRISE EDUCATIONAL COURSE
Quantitative Neuroanatomic & Functional Image Assessment

Room 316A                         07:00 – 08:00                                                               Moderators:  Peter A. Bandettini and Carlo Pierpaoli

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Assess the challenges and obstacles involved with quantitative assessment of anatomic and functional MRI data;

·          Describe the necessary steps to perform group comparisons of anatomic data;

·          List the neuronal, scanner-related, and physiological factors that influence the fluctuations in fMRI data;

·          Explain the neuronal, scanner-related, and physiological factors that influence the magnitude of the activation-induced fMRI signal change;

·          Describe the methods by which fMRI activation-related signal may be calibrated; and

·          List the methods by which fMRI resting state data can be filtered such that only neuronally related signal changes remain.

 

07:00         BOLD Activation Calibration

                  Thomas Liu

SUNRISE EDUCATIONAL COURSE
Mobile Lipids in Disease

Room 313A                         07:00 – 08:00                                                                  Moderators:  Carles Arús and Edward J. Delikatny

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Recognize the various ML resonances detectable in the 1H NMR spectral pattern of a tissue or organ;

·          Select optimal acquisition conditions to detect ML resonances and appreciate their possible variation in biological samples;

·          Describe the possible biochemical origins of ML;

·          List possible causes for qualitative and quantitative changes in ML pattern;

·          Interpret qualitative and quantitative changes in the ML pattern of cells and tissues; and

·          List possible clinical applications of in vivo ML detection for disease diagnosis, staging and response to therapy.

ML Compartment Studies in Model Systems, Cells and In Vivo by NMR and Other Methods

07:00         Mobile Lipid Accumulation as Stress Response

                  Edward J. Delikatny

 

07:20         ML in Model Systems and Plama/Serum: Michelles, Lipoproteins

                  Alkystis Phinikaridou

07:40         Relaxation and Diffusion Measurements In Vitro, Ex Vivo and In Vivo

                  Chantal Rémy

SUNRISE EDUCATIONAL COURSE
MRI Applications for Tissue Engineering

Room 311                             07:00 – 08:00                                                                                               Moderator:  Richard G. S. Spencer

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Define what is meant by tissue engineering;

·          Appreciate the current status of the field of tissue engineering, including several of the products currently on the market;

·          Recognize some of the current approaches to development of tissue-engineered constructs;

·          Describe the role of MR in certain current tissue engineering studies; and

·          Identify further opportunities for application of MR to problems in tissue engineering.

07:00         Three Decades of MRI and MRS of Bioartificial Liver

                  Jeffrey M. Macdonald

 

07:30         Optical Spectroscopy of Engineered Connective Tissues: Mapping Molecular Components

                  Nancy Pleshko

SUNRISE EDUCATIONAL COURSE
Clinical Science for Physicists & Engineers

Room 313BC                       07:00 – 08:00                                                      Moderators:  Vivian S. Lee, Tim Leiner, and Bachir Taouli

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Identify basic anatomy and physiology of the central nervous system, kidney, liver, cardiac, vascular and musculoskeletal systems;

·          Describe the process and diagnosis of stroke and white matter formation and damage;

·          Explain kidney and liver anatomy and function and how MRI can be used to evaluate these organs;

·          Describe basic cardiac physiology and the consequences of coronary artery disease and heart failure;

·          Describe the process of bone and cartilage formation and degeneration; and

·          Appraise unmet clinical needs that could potentially be solved by physicists and engineers.

 

07:00         Liver Function and Failure

                  Bachir Taouli

 

07:30         Kidney Function and Failure

                  Diego R. Martin

SUNRISE EDUCATIONAL COURSE
Cardiovascular Disease or Problem-Based Teaching & Practical Protocols

Room 316BC                       07:00 – 08:00                                                                 Moderators:  Victor A. Ferrari and Stefan G. Ruehm

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Critique the strengths and limitations of current cardiovascular MRI techniques when applied to clinical diagnostic testing;

·          Compare coronary MR and CT angiography at 1.5 and 3T field strengths and how practical these approaches currently are;

·          Describe the etiologies of right heart failure, and the clinical applications of MR techniques to evaluate these disorders, especially the assessment of right heart function;

·          Compare the current clinical techniques for assessment of ischemic heart disease and the use of MR methods for assessment of ischemia, perfusion reserve, and viability;

·          Appraise the potential clinical applications of 7T cardiovascular MRI and the technical challenges that will need to be resolved for wider application of the technique; and

·          Evaluate how the attendee’s current approaches to these diseases may need to be modified based on expert advise.

Right Heart Failure

07:00        
Congenital Heart Disease

                  Jean-Paul Vallée

 

07:15         Pulmonary Hypertension - No syllabus contribution at time of publication.

                  Gautham Reddy

 

07:30         Arrhythmogenic Right Ventricular and Other Cardiomyopathies

                  Harikrishna Tandri

 

07:45         Techniques for Right Heart Cardiac Function

                  Daniel B. Ennis

SUNRISE EDUCATIONAL COURSE
MRI & MRS of the Mouse Brain: Techniques & Applications

Room 312                             07:00 – 08:00                                                                     Moderators:  Jeffry R. Alger and Afonso C. Silva

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Identify hardware/software configurations that are needed to perform anatomical imaging, diffusion tensor imaging, functional imaging, and magnetic resonance spectroscopy in the mouse brain;

·          Recognize the constraints associated with the small size of the mouse body and brain and how to achieve stable physiology of the animals during the MRI/MRS experiments;

·          Define how to perform anatomical imaging, diffusion tensor imaging, functional imaging, and magnetic resonance spectroscopy in the mouse brain;

·          Describe the anatomical or physiological properties that can be measured with MRI in mouse brain; and

·          Identify significant biomedical findings that have been obtained through mouse brain neuroimaging using anatomical imaging, diffusion tensor imaging, functional imaging, and magnetic resonance spectroscopy.

Diffusion Tensor Imaging

07:00         Techniques for Diffusion Tensor Imaging in Mouse Brain
                 
Jiangyang Zhang

07:30         Diffusion Tensor Imaging of Multiple Sclerosis Models
                  Sheng-Kwei Victor Song

 

SUNRISE EDUCATIONAL COURSE
(Clinical Intensive Course Option)
Unsolved Problems in MSK MRI:  What Do We Know and What Don’t We Know?

Room 310                             07:00 – 08:00                                                                         Moderators:  Juerg Hodler and Hollis G. Potter

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Avoid over-diagnosis and over-treatment when performing MR imaging of the lumbar spine, rotator cuff, wrist, and knee;

·          Describe the current developments potentially leading to more precise diagnosis of abnormalities in the lubar spine, rotator cuff, wrist, and knee; and

·          List six (6) pitfalls which lead to over- or under-diagnosis in the lumbar spine, rotator cuff, wrist, and knee.

Pain Related to Rotator Cuff Abnormalities

07:00         MR Findings without Clinical Significance

                  Jenny Bencardino

                                                     

07:30         Clinical Abnormalities not Detectable on MR Images

                  Lynne S. Steinbach

SUNRISE EDUCATIONAL COURSE
(Clinical Intensive Course Option)
Hot Topics in Body MRI

Room 315                             07:00 – 08:00                                                                                                          Moderator:  Clare Tempany

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Compare the potential utility of the various methods for pulmonary MRI including proton-based techniques and hyperpolarized gas MRI;

·          Protocol and interpret MRI examinations for the evaluation of rectal cancer and non-neuro fetal abnormalities;

·          Describe the techniques for MRI guided interventions including vascular and non-vascular interventions;

·          Identify patients and clinical situations in which whole body MRI for cancer evaluation and lymph node detection would be appropriate, and protocol and interpret the examinations.

 

07:00         MRI of Rectal Cancer

                  Regina G. H. Beets-Tan

                                                     

07:30         Non-Neuro Fetal MRI

                  Ann M. Johnson

PLENARY LECTURES
What Did We Learn from NSF?

Ballroom                              08:15-09:30                                                                      Moderators: Georg M. Bongartz and Vivian S. Lee

08:15         387.       GBCAs and NSF: Why Did It Happen and What Have We Learned?

Jeffrey C. Weinreb 1

1Yale University School of Medicine, New Haven, CT, USA

The association between GBCAs and NSF has led the medical community to ask, “Why did it happen and what have we learned? A confluence of factors conspired to cause a lag in identifying this association, including the perceived advantage compared with iodinated agents in CIN, high dose CE-MRA, physician engagement, record keeping, pharmcovigilance infrastructure, and new dialysis regimens. < 500 cases of NSF are reported, and severe forms occur only in patients with AKI or severe to end-stage CKD, usually on dialysis. Most “high risk” patients do not develop NSF, and the number of new cases

has dropped precipitously since 2007.

08:40         388.       The Fibrocyte's Role in NSF

Richard H. Gomer 1

1Rice University, Houston, TX, USA

In fibrotic lesions such as those associated with NSF, some monocytes enter the tissue and differentiate into fibroblast-like cells called fibrocytes. The plasma protein Serum Amyloid P (SAP) inhibits fibrocyte differentiation, and SAP injections can inhibit fibrosis in animal models. The exposure of some renallyinsufficient patients to gadolinium-containing MRI contrast agents such as Omniscan has been associated with the development of NSF. We found that in cell culture, Omniscan inhibits the ability of SAP to inhibit the differentiation of human monocytes into fibrocytes, suggesting a possible mechanism of how a MRI contrast agent can be associated with a disease.

09:05         389.       Consequences Following NSF - Imaging Options in CKD Patients

Giles H. Roditi 1

1Glasgow Royal Infirmary, Glasgow, Scotland, UK

We must now identify 'at risk 'patients for whom high quality MRI without contrast will often suffice, if not then alternative imaging options must be explored. Vascular disease is the major area of concern since it is the main disease burden and a source of high contrast dose for MRA, hence non-contrast MRA has had a resurgence. Ultrasound is useful for carotid disease but less successful for other vascular territories. CTA can be employed in patients on dialysis but has the problem of contrast nephropathy for those not yet dialysis dependent, the danger of which is likely greater than that of low dose cyclic GBCA enhanced MRA.

CLINICAL INTENSIVE COURSE
Sports Imaging: Elbow

Room 310                             10:30-12:30                                                                                                      Moderator:  Timothy J. Mosher

10:30         Optimization of Elbow MRI Technique and Normal Anatomy

                  James M. Linklater

                                                     

11:10         Imaging of Elbow Internal Derangement

                  Russell C. Fritz

                                                     

11:50         Case-Based Learning

                  Kathryn J. Stevens

Transmit Array Technology

Room 312                             10:30-12:30                                                                               Moderators: Peter Ullmann and Yudong Zhu

10:30         390.       8-Channel Eigenmode Tx-Array at 3T for Tx-SENSE

Scott B. King1, Jarod Matwiy1, Mike J. Smith1, Ulrich Fontius2, Franz Schmitt2, Boguslaw Tomanek3

1National Research Council of Canada, Institute for Biodiagnostics, Winnipeg, Manitoba, Canada; 2Siemens AG, Erlangen, Germany; 3National Research Council of Canada, Institute for Biodiagnostics (West), Calgary, Alberta, Canada

Tx-array elements that have B1 field distributions that are completely orthogonal may allow the complimentary effect of Rx-array data compression but on the transmit side for Tx-SENSE applications, minimizing the number of transmit channels required to achieve a certain Tx-SENSE reduction factor. Here we report on an eigenmode Tx-array solution that generates 8-channel orthogonal B1 fields used in conjunction with an 8-channel transmitter MRI system for Tx-SENSE MRI.

10:42         391.       Clinical Imaging at 7T with a 16 Channel Whole Body Coil and 32 Receive Channels

J Thomas Vaughan1, Carl Snyder1, Lance Delabarre1, Jinfeng Tian1, Gregor Adriany1, Peter Andersen1, John Strupp1, Kamil Ugurbil1

1Radiology, University of Minnesota, Minneapolis, MN, USA

Reported is the first demonstration of “clinical mode” whole body imaging at 7T, using a body coil for best uniformity together with local receivers for improved sensitivity. Body imaging at 7T however requires new technology and methods to mitigate the severe RF artifacts encountered by conventional approaches. To achieve safe and successful body images, an actively detuned, 16-channel TEM body coil was used together with a pair of 8 channel receive arrays. B1 shimming was employed to optimize the RF field over the ROI. 32 combined channels from the body coil and the receive arrays were used to maximize signal.

10:54         392.       In-Vivo RF Power-Controlled B1 Shimming with Tx/Rx Array and with Tx Array Combined Rx Only Coil Without B1 Measurements

Tamer S. Ibrahim1, Yik-Kiong Hue, Lin Tang2, Tiejun Zhao3, Fernando E. Boada, Howard J. Aizenstein

1Bioengineering and Radiology, University of Pittsburgh, Pittsburgh, PA, USA; 2University of Oklahoma; 3Siemens Medical Solutions

Several major obstacles have dampened wide implementation of multi-transmission methods including requirements to have the knowledge of how the RF fields produced by current MRI coils/arrays behave in every imaged subject using B1 field measurement/mapping prior to performing the multi-transmission experiment. This work aims overcoming this subject-dependence issue while maintaining a high-SNR intact through the development of subject-insensitive multi-transmit arrays with receive-only inserts.

11:06         393.       7 Tesla Transmit-Receive Array for Carotid Imaging: Simulation and Experiment

Graham Wiggins1, Bei Zhang1, Qi Duan1, Riccardo Lattanzi1, Stephan Biber2, Bernd Stoeckel3, Kellyanne McGorty1, Daniel K. Sodickson1

1Radiology, Center for Biomedical Imaging, NYU School of Medicine, New York, NY, USA; 2Siemens Healthcare, Erlangen, Germany; 3Siemens Medical Solutions USA Inc., New York, NY, USA

Full wave electromagnetic simulations were used to explore design options for a 4-element transmit and 8 element receive array for imaging the carotid arteries in humans at 7 Tesla. By phasing the excitation of the transmit elements, B1+ excitation efficiency at the depth of the carotids was improved. The simulations suggested shifting the transmit and receive elements relative to each other to account for the twisting B1+ and B1- fields at 7T. A carotid array was constructed based on these observations, and was compared to a similar receive array at 3 Tesla. Substantial SNR gains were observed.

11:18         394.       An Eight-Channel Phased Array RF Coil for Spine MR Imaging at 7 Tesla

Oliver Kraff1,2, Stefan Kruszona1,2, Andreas K. Bitz1,2, Stephan Orzada1,2, Stefan Maderwald1,2, Lena C. Schaefer1,2, Irina Brote1,2, Mark E. Ladd1,2, Harald H. Quick1,2

1Erwin L. Hahn Institute for MRI, Essen, Germany; 2Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, Germany

A transmit/receive RF array, build of eight overlapping loop coils, has been developed for imaging the human spine at 7T. We characterize this prototype in simulations and bench measurements as well as in phantom and in vivo measurements. Numerical simulations were performed for design optimization as well as safety validation. In vivo images show a good excitation along the spine over a 40 cm FOV. Anatomic details such as the vertebral bodies, the dens, or the longitudinal ligaments are well visualized. Our results indicate that this phased array coil could open a promising new application field in 7T clinical research.

11:30         395.       Vector Iterative Pre-Distortion: An Auto-Calibration Method for Transmit Arrays

Pascal Pawel Stang1, Adam Kerr1, William Grissom1, John Mark Pauly1, Greig Cameron Scott1

1Electrical Engineering, Stanford University, Stanford, CA, USA

Transmit arrays hold growing promise for MRI by enabling improved safety, RF homogeneity, selectivity, and pulse acceleration. Yet, achieving good performance with complex Transmit-SENSE pulses requires that array channels be characterized, closely calibrated, and decoupled. We propose Vector Iterative Pre-distortion (VIP), a multi-channel iterative correction method which pre-distorts RF amplifier input to achieve desired output at the coil. VIP uses current sensor feedback to detect and correct errors in the transmit path yielding substantially improved RF fidelity. We successfully demonstrate VIP as general method for correcting non-ideal transmit path performance, and show improved Transmit-SENSE results when using the method.

11:42         396.       Variable Power Combiner for a 7T Butler Matrix Coil Array

Pedram Yazdanbakhsh1, Markus Fester2, Ralph Oppelt3, Andreas Bitz4, Oliver Kraff4, Stephan Orzada4, Mark E. Ladd4, Klaus Solbach1

1High Frequency Technique, University Duisburg-Essen, Duisburg, NRW, Germany; 2Siemens Medical Solutions, Erlangen, Germany; 3Siemens Corporate Technology, Erlangen, Germany; 4Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany

Butler matrix networks are used for the excitation of phase modes of MRI coil arrays. The standard excitation method is to connect each power amplifier output to one of the (input) mode ports of a Butler matrix. This allows all phase modes of the coil array to be excited at equal power level. However, not all modes are equally useful, since the lowest-order CP mode is the dominant mode, while higher modes are less important to excite and CP- modes may be completely unnecessary to excite. In this work an eight-channel variable power combiner has been designed and fabricated using an 8×8 Butler Matrix network to excite the coil array in a 7 T MRI system.

11:54         397.       7T Current-Mode Class-D (CMCD) RF Power Amplifier

Natalia Gudino1, Jeremiah A. Heilman2, Matthew J. Riffe3, Chris A. Flask4, Mark A. Griswold4

1Biomedical Engineering , Case Center for Imaging Research, Cleveland, OH, USA; 2Physics , Case Center for Imaging Research, Cleveland, OH, USA; 3Biomedical Engineering, Case Center for Imaging Research, Cleveland, OH, USA; 4Radiology, Case Center for Imaging Research, Cleveland, OH, USA

We present preliminary results of the first, to our knowledge, an on-coil class D, current mode (CDCM) amplifier for 7T applications. High efficiency, intrinsic decoupling and the elimination of high power RF cables make this configuration promising for building a 7T array parallel RF transmission We successfully obtained an axial image of a saline phantom using a multislice FLASH sequence in a 7T Bruker Biospec scanner. We think this represents a promising advance for high field multichannel transmit arrays.

12:06         398.       Frequency Offset Cartesian Feedback Control System for MRI Power Amplifier

Marta Gaia Zanchi1, John Mark Pauly1, Greig Cameron Scott1

1Electrical Engineering, Stanford University, Stanford, CA, USA

We present a Cartesian feedback system based on complex baseband loop driver amplifiers to control the radiofrequency signal generated by MRI power amplifiers. By shifting the control baseband frequencies far away from DC, our system eliminates the quadrature excitation ghosts and unmodulated LO leakage—caused by baseband mismatches and DC offsets—that can affect power amplifier control systems based on the classic Cartesian feedback method.

12:18         399.       Transmit B1 Field Pattern Control Using RF Current Source Technique

Wonje Lee1, Eddy B. Boskamp1, Thomas Grist2, Krishna Kurpad2

1GE Healthcare, Waukesha, WI, USA; 2Radiology, University of Wisconsin - Madison

In this work a two-channel parallel excitation system incorporating an RF current source technology is described and its practical use is demonstrated at 3T in a head size volume transmit coil. The B1 field pattern was successfully controlled by the current source integration without using any other decoupling strategies, which has the potential to improve parallel transmit systems by forcing the drive currents into current elements in load dependent transmit environments at high fields.

NSF & Functional Renal

Room 316A                         10:30-12:30                                                                      Moderators: Diego R. Martin and Jeffrey Weinreb

10:30         400.       2008 ISMRM Grant Recipient:  The Biodistribution of [153Gd]Gd-Labeled DTPA-BMA and DOTA in a Transgenic Mouse Model of Renal Failure Differs Greatly from Wild-Type Mice

Thaddeus J. Wadas1, Christopher D. Sherman1, Jeffrey H. Miner2, Jeffrey J. Brown2, James R. Duncan1, Carolyn J. Anderson1

1Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, MO, USA; 2Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA

10:50         401.       Postmortem ICP-MS and MR Analysis of Gadolinium Concentration and Distribution in Three Confirmed NSF Cases

Peter Caravan1, Aashiyana Koreishi2, Jonathan Kay3

1Radiology, Massachusetts General Hospital, Charlestown, MA, USA; 2Pathology, Massachusetts General Hospital, Boston, MA, USA; 3Rheumatology, Massachusetts General Hospital, Boston, MA, USA

Nephrogenic systemic fibrosis (NSF) is a debilitating fibrosing disorder that can occur in renally compromised patients and has been linked to gadolinium (Gd) based contrast agents. We analyzed autopsy tissue from 3 confirmed NSF subjects. Gd was quantifiable in all tissues assayed and very high concentrations of Gd were observed in the kidney and the heart. High resolution relaxation time (T1, T2, T2*) maps suggest a heterogeneous distribution in kidney cortex. In the heart, the Gd had little T1 effect but a strong T2* effect suggesting an insoluble deposit and/or sequestration inside an endosome.

11:02         402.       Incidence of Nephrogenic Systemic Fibrosis (NSF) in Dialysis Patients Receiving Either a Standard or a High-Relaxivity Gadolinium Chelate Contrast Agent: A Single Center Study

Saravanan Kokila Krishnamoorthy1, Diego Martin1, Khalil Nabeel Salman1, Bobby Kalb1, John Carew2, Philip Andrew Martin3, Kenneth Kokko4, Christian Larsen5, Thomas Pearson5

1Department of Radiology, Emory University, Atlanta, GA, USA; 2Department of Biostatistics and Bioinformatics, Emory University, Atlanta, GA, USA; 3University of West Georgia, Carrollton, GA; 4Department of Medicine, Emory University, Atlanta, GA, USA; 5Department of Surgery, Emory University, Atlanta, GA, USA

Retrospective single center study measuring the incidence of Nephrogenic Systemic Fibrosis (NSF) in dialysis patients who were administered either gadodiamide or gadobenate dimeglumine. Mean cumulative dose of gadodiamide was 0.16 mmol/kg in 312 patients and 8 (2.6%) developed NSF. Mean cumulative dose of gadobenate dimeglumine was 0.11 mmol/kg in 603 patients and none developed NSF. The cause for this difference is not determined definitively but our results show that a change to a low dose higher relaxivity gadolinium chelate can significantly reduce NSF incidence and that the incidence in dialysis patients is less than 1 in 603 in our patients.

11:14         403.       Risk Factors for NSF: A Meta-Analysis

Honglei Zhang1, Giles H. Roditi2, Rochelle Morgan1, Martin R. Prince1,3

1Radiology, Weill Medical College of Cornell University, New York, NY, USA; 2Radiology, Glasgow Royal Infirmary, Glasgow, UK; 3Radiology, Columbia College of Physicians and Surgeons, New York, NY, USA

From 260 NSF patients in 59 published papers, this meta-analysis explores the risk factors and demonstrates how risk can be minimized. It appears that eliminating even a single risk factor, such as the use of high dose can reduce NSF incidence/risk at least 10-fold. Elimination of multiple risk factors for example by using single dose GBCA, dialyzing dialysis patients with 24 hours following GBCA administration, avoiding GBCA in acute renal failure, avoiding non-ionic GBCA in renal failure patients can reduce NSF risk by orders of magnitude thereby allowing safe GBCA enhanced MRI in most patients.

11:26         404.       Non-Contrast Enhanced Renal MR Angiography Using NATIVE TrueFISP – Initial Experience for Clinical Imaging of Patients with Renovascular Disease

Stephen J. Gandy1, Prasad Guntur Ramkumar2, Shelley A. Waugh1, R Stephen Nicholas1, Andrew W. Taylor2, Xiaoming Bi3, Peter Weale3, J Graeme Houston2

1NHS Tayside Medical Physics, Ninewells Hospital, Dundee, Angus, UK; 2NHS Tayside Clinical Radiology, Ninewells Hospital, Dundee, Angus, UK; 3Cardiovascular Research and Development, Siemens Medical Solutions, Chicago, IL, USA

The study aim was to compare a new steady-state gradient echo non-contrast MR angiography (NCE-MRA) sequence with contrast enhanced MRA (CE-MRA) for renal artery imaging. Fifty patients with suspected renovascular disease were scanned using non-contrast (NATIVE TrueFISP) and CE-MRA sequences. Resulting maximum intensity projection (MIP) images were compared and scored by two observers. Qualitative analysis revealed that NCE-MRA and CE-MRA were virtually equivalent for renal artery visualisation. Intra- and inter-observer scoring agreement was k=0.91 and 0.70 respectively. In conclusion, this NCE-MRA technique is comparable to CE-MRA and may provide an alternative for imaging patients at risk of Nephrogenic Systemic Fibrosis.

11:38         405.       Understanding Renal DTI at 3T: FA and MD Changes with Water Loading

Hersh Chandarana1, Vivian S. Lee1, Irina Barash2, Eric E. Sigmund1

1Radiology, NYU Langone Medical Center, New York, NY, USA; 2Nephrology, NYU Langone Medical Center, New York, NY, USA

Diffusion tensor imaging allows non-invasive evaluation of renal structure and function. Renal medulla has been shown to have higher fractional anisotropy (FA) compared to cortex, but it is unclear if medullary FA is predominantly a measure of tubular structural arrangement or if it is significantly influenced by tubular flow. We examined changes in renal FA prior to and in response to water loading. Our study demonstrates a trend to faster, more isotropic diffusion with water loading. Since water-loading is known to increase tubular flow, these results suggest that tubular flow plays little or no role in baseline medullary diffusion anisotropy.

11:50         406.       Kidney Stiffness Measured in an Animal Model of Unilateral Renal Arterial Stenosis Using 2D MR Elastography

Lizette Warner1, Meng Yin2, Richard L. Ehman2, Lilach Orly Lerman3

1Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, USA; 2Department of Radiology, Mayo Clinic, Rochester, MN, USA; 3Department of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA

Magnetic Resonance Elastography (MRE) is a modified phase contrast MRI technique for quantitatively assessing the mechanical properties of soft tissue by visualization of propagating shear waves. Both fibrosis and turgor may affect the mechanical properties of tissue and in the kidney may threaten the viability and ultimately lead to kidney failure. We have previously shown in a swine model of renal arterial stenosis, the stenotic kidney exhibits moderate but significant interstitial fibrosis. We quantitatively determine with 2D MRE in vivo the effect of renal arterial stenosis on the mechanical properties of swine kidney.

12:02         407.       Effects of Ischemia-Reperfusion Injury on 23Na Relaxation Times and Its Implications on Quantification of Corticomedullary Sodium Concentration by 23Na MRI

Bharath Atthe1, Andriy Babsky1, Navin Bansal1

1Radiology, Indiana University School of Medicine, Indianapolis, IN, USA

23Na MRI and MRS are applied to evaluate the effects of renal ischemia and reperfusion on 23Na MRI signal intensity (SI), relaxation times and [Na+] in the medulla and cortex of rat kidney. 23Na relaxation times were found to be similar in renal medulla and cortex in the normal kidney. Ischemia caused a significant decrease in the relaxation times which affected the calculation of [Na+] from MRI data. However, the changes in relaxation times for the medulla and cortex were identical, thus the medulla to cortex 23Na SI ratio represents [Na+] ratio in the two compartments during ischemia and reperfusion.

12:14         408.       Estimating GFR from Early (Uptake) Portion of DCE MRI Renal Data, Using a 3-Compartment Model,  Improves Reproducibility and May Eliminate Need for Cortical Segmentation.

Paul S. Tofts1,2, Marica Cutajar1,3, Iosif Mendichovszky3, Isky Gordon3

1Brighton and Sussex Medical School, Brighton, Sussex, UK; 2Institute of Neurology, University College London, London, UK; 3Institute of Child Health, University College London, UK

No synopsis available.

Preclinical & Human Studies of Tumor Therapy Response

Room 315                             10:30-12:30                                                                  Moderators: Kristine Glunde and N. R. Jagannathan

10:30         409.       Edema Control by Anti-VEGF Therapy Prolongs Survival Despite Persistent Tumor Growth in Mice

Christian T. Farrar1, Walid Kamoun2, Carsten D. Ley2, Young R. Kim1, Guangping Dai1, Bruce R. Rosen1, Rakesh K. Jain2, A. Gregory Sorensen1

1Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Charlestown, MA, USA; 2Edwin L. Steele Laboratory, Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, USA

Recent clinical trials of anti-vascular endothelial growth factor (VEGF) agents for glioblastoma showed promising progression-free and overall survival rates. However, it is unclear whether this is due to anti-tumor or anti-edema effects of these agents. Thus the mechanisms leading to improved survival in patients remain unclear. Our goal was to determine whether alleviation of edema by anti-VEGF agents alone, without affecting tumor growth, could increase survival in mice. Here we examine in detail the impact of cediranib treatment on tumor growth, tumor blood volume, vessel caliber, edema, and permeability in a U87 mouse brain tumor model. In addition, we validate the MRI biomarkers of tumor angiogenesis with histology, optical microscopy, and wet-dry weight measurement methods.

10:42         410.       Noninvasive Therapeutic Evaluation on Rodent Liver Tumor Treated with Vascular Disrupting Agent: Multiparametric Magnetic Resonance Imaging in Correlation with Microangiography and Histology

Huaijun Wang1, Junjie Li1, Feng Chen1, Yicheng Ni1

1Catholic University of Leuven, Leuven, East Flanders, Belgium

This study aimed to document tumoricidal events after a vascular targeting agent ZD6126 in rodent liver tumors with clinical MRI in correlation with postmortem microangiography and histopathology. Rhabdomyosarcomas in rat liver were treated with i.v. injection of ZD6126. Therapeutic outcomes were evaluated morphologically and functionally with 1.5T MRI. Diffusion-weighted imaging and dynamic contrast-enhanced MRI successfully monitored vascular shutdown by ZD6126 at 1h after treatment, prior to the advent of morphological change of tumor size at 48h, which were verified with microangiography and histopathology. Clinical MRI allowed monitoring of ZD6126-related vascular shutdown, necrosis, and neovascularization of liver tumors in rats.

10:54         411.       Vessel Size Index MRI for Evaluating the Effects of Multiple Anti-Angiogenic Therapies in Sequence

Sharon E. Ungersma1, Glenn Pacheco2, Anil Bagri1, Shang-Fan Yu2, Andrew Mcgeehan2, Sarajane Ross2, Richard AD Carano1

1Tumor Biology & Angiogenesis, Genentech, South San Francisco, CA, USA; 2Translational Oncology, Genentech, South San Francisco, CA, USA

In vivo imaging of tumors treated with anti-angiogenic agents can reveal information about therapeutic effects on tumor vasculature. Vessel size index (VSI) MRI uses a USPIO contrast agent to determine the blood volume, mean vessel size, and Q (a parameter related to vessel density) for each voxel. We used VSI MRI to examine the effects of two potential therapies in sequence: anti-VEGF, an antibody to vascular endothelial growth factor, and anti-NRP1B, an anti-angiogenic agent believed to inhibit vessel maturation. The VSI technique detected significant reductions in vascular parameters that indicated an advantage to dosing with anti-NRP1B before anti-VEGF.

11:06         412.       Assessment of Vascular Remodelling During Antiangiogenic Tumor Therapy Using DCE-MRI and Vessel Size Imaging

Stefan Zwick1, Ralph Strecker2, Moritz Palmowski3, Peter Gall4, Valerij Kiselev4, Arne Hengerer2, Wolfhard Semmler1, Fabian Kiessling3

1Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany; 2HealthCare Sector, Siemens AG, Erlangen, Germany; 3Department of Experimental Molecular Imaging, RWTH-Aachen University, Aachen, Germany; 4Department of Diagnostic Radiology, University Hospital Freiburg, Freiburg, Germany

To assess vascular remodelling in tumors during antiangiogenic therapy DCE-MRI and vessel size imaging were performed. Tumor bearing nude mice were treated with a multitargeted tyrosine kinase inhibitor and investigated before and after treatment. The decrease of A and increase of kep in treated compared to untreated tumors clearly showed therapy response. The mean vessel size measured by vessel size imaging significantly increased in treated as compared to untreated tumors. Results of both methods are in excellent agreement with histology. Thus, DCE-MRI and vessel size imaging were able to assess vascular remodelling during antiangiogenic tumor therapy.

11:18         413.       Measurement of the Increase in Vessel Size Induced by a Vascular Disrupting Agent in Orthotopic Prostate Tumours Using Vessel Size Imaging

Simon Walker-Samuel1, Jessica K. Boult1, Lesley D. McPhail1, Simon P. Robinson1

1Cancer Research UK Clinical Magnetic Resonance Research Group, Institute of Cancer Research, Sutton, Surrey, UK

In this study, susceptibility MRI with ultra-small paramagnetic iron oxide (USPIO) was used to estimate the vessel size index (VSI) in orthotopic PC3 prostate tumours following treatment with ZD6126, a vascular disrupting agent. It was found that orthotopic tumours exhibited larger vessels than typically found in ectopic (subcutaneous) tumour xenograft models (VSI = 65±25ìm), and that this significantly increased following treatment with ZD6126 (post-treatment VSI = 122±36ìm, p<0.05). An excellent correspondence was found with histological measurements of vessel size. This study highlights the potential use of VSI as a biomarker for assessing vascular architecture and response to vascular disrupting agents.

11:30         414.       Can DCE MRI Predict Risk of Treatment Failure in Early-Stage Favorable-Prognosis Cervical Cancer Patients?

Nina A. Mayr1, William T.C. Yuh2, Hualin Zhang1, Lanchun Lu1, Joe F. Montebello1, Steffen Sammet2, Guang Jia2, Jeffrey M. Fowler3, Kyle Porter4, David Jarjoura4, Jian Z. Wang1

1Radiation, The Ohio State University, Columbus, OH, USA; 2Radiology, The Ohio State University, Columbus, OH, USA; 3Obstetrics & Gynecology, The Ohio State University, Columbus, OH, USA; 4Biostatistics, The Ohio State University, Columbus, OH, USA

Despite favorable prognosis, many low risk cervical cancer patients ultimately fail therapy. The purpose of this study was to assess, if DCE MRI can predict poor treatment outcome in patients with otherwise favorable clinical prognosis judged by gold-standard clinical criteria. DCE MRI predicts treatment failure early in otherwise favorable-prognosis cervical cancer patients and provides a therapeutic window to modify the treatment strategies that can have profound impact to the long term outcome. This predictive ability is likely related to DCE MRI’s ability to indentify and analyze the subregions of the heterogeneous tumor that likely represent tumor cells resistant to treatment.

11:42         415.       Combining DCE-MRI and Microbubble Ultrasound to Evaluate Response to Sunitinib in Patients with Renal Cell Carcinoma

Colleen Bailey1,2, Ross Williams2, Gord Lueck2, Mostafa Atri3, Peter N. Burns1,2, Greg J. Stanisz1,2, Georg A. Bjarnason4

1Medical Biophysics, University of Toronto, Toronto, ON, Canada; 2Imaging Research, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; 3Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, ON, Canada; 4Medical Oncology, Sunnybrook Health Sciences Centre, Toronto, ON, Canada

Patients with renal cell carcinoma were treated with the drug Sunitinib and examined by DCE-MRI and contrast-enhanced ultrasound. DCE-MRI provided the volume transfer constant, Ktrans, and the extravascular extracellular volume fraction ve. Disruption-replenishment provided the relative blood volume change. Combining the information from both imaging techniques provides a fuller picture of the tumour response to treatment.

11:54         416.       Potential of Choline SNR, Tumor Volume and Diameter in the Assessment of Response of Locally Advanced Breast Cancer Patients Using Sequential MRSI and MRI

Karikanni Kalathil A. Danishad1, Uma Sharma1, Rani Gupta Sah1, Vurthaluru Seenu2, Rajinder Parshad2, Naranamangalam R. Jagannathan1

1Department of NMR and MRI Facility, All India Institute of Medcial Sciences, New Delhi, Delhi, India; 2Department of Sugical Disciplines, All India Institute of Medcial Sciences, New Delhi, Delhi, India

Sequential MRSI [before therapy and after I, II and neo-adjuvant chemotherapy (NACT)] was carried out in 30 breast cancer patients to evaluate the potential of signal-to-noise ratio of choline (ChoSNR), tumor volume and diameter to predict tumor response. Changes in these parameters revealed significant decrease in ChoSNR after I NACT compared to pre-therapy in responders than non-responders. Sensitivity to detect responders using ChoSNR was 85.7% with 91% specificity while 100% sensitivity for volume and diameter but with reduced specificity (73% and 81.8%). When all the three parameters were combined, 100%sensitivity, 82% specificity with 87.5% PPV and 100% NPV was achieved.

12:06         417.       Choline Metabolites as Biomarkers for Predicting Response to Neoadjuvant Chemotherapy in Local Advanced Breast Cancer Patients

Maria Dung Cao1, Beathe Sitter1, Tone Frost Bathen1, Per E. Lønning2,3, Steinar Lundgren1,4, Ingrid Susann Gribbestad1

1Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; 2Department of Oncology, Haukeland University Hospital, Bergen, Norway; 3University of Bergen, Bergen, Norway; 4Department of Oncology, St.Olavs University Hospital, Trondheim, Norway

The presence and change in the composite choline signal detected in MR spectra has been suggested as a biomarker for breast cancer diagnosis and treatment monitoring. The purpose of this study was to evaluate quantitative changes in the level and composition of the choline-containing metabolites (tCho) prior to and after treatment with doxorubicin monotherapy in 30 patients with breast cancer. Our study suggests that quantitative changes in different choline profiles may be related to breast cancer treatment response.

12:18         418.       Noninvasive Detection of Carboxypeptidase G2 Activity in Vivo using 19F 3D CSI

Yann Jamin1, Lynette Smyth1, Simon P. Robinson1, Thomas R. Eykyn1, Caroline J. Springer1, Martin O. Leach1, Geoffrey S. Payne1

1Institute of Cancer Research and Royal Marsden NHS trust, Sutton, UK

Carboxypeptidase G2 (CPG2) is a bacterial enzyme used in cancer chemotherapy to activate selectively non toxic prodrugs into potent cytotoxics in tumors. We demonstrate that 19F 3D CSI can be used in combination with a surface coil to monitor dynamically and quantitatively the CPG2-mediated conversion of the reporter probe 3,5-difluorobenzoyl-L-glutamic acid (3,5-DFBGlu) into 3,5-difluorobenzoic acid (3,5-DFBA). This method could provide important information on the level of CPG2 activity in patient undergoing CPG2-based therapy.

MRA:  Low Dose to No Dose

Room 313A                         10:30-12:30                                                                            Moderators: Ruth P. Lim and Mitsue Miyazaki

10:30         419.       Critical Concentration of Contrast Agents for Quantification of Enhancement: Another Reason for Dose Reduction

Abbas Nasiraei Moghaddam1, Reza Habibi1, Tariq Balawi1, J. Paul Finn1

1Radiology, UCLA, Los Angeles, CA, USA

Dose-minimization in CEMRA not only increases the safety measure in clinical practice but also keeps the relation between the image enhancement and contrast agent concentration in the linear range. This linearity is required for applications such as quantitative perfusion imaging and prediction of contrast agents’ dynamics in MR angiography, using the theory of linear time-invariant systems. In this study we introduce the “critical” concentration up to which the signal intensity is a linear function of [Gd]. We also show in the routine range of flip angles the obtained enhancement is robust against RF filed inhomogeneity. Experimental verification is also presented.

10:42         420.       Feasibility of Combined Low-Dose (0.07mmol/kg) Continuous Table Movement MRA of the Peripheral Vessels with Ultra-Low Dose (0.03mmol/kg) TWIST-MRA of the Calf Station

Henrik Jakob Michaely1, Matthias Voth1, Stefan Haneder1, Stefan Oswald Schoenberg1

1Institute of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Mannheim, Germany

At 3.0T peripheral continuous table movement MRA with 0.07mmol/kg gadobutrol and TWIST MRA with 0.03mmol/kg can be acquired in a single session with good image quality.

10:54         421.       SNR Optimized Contrast-Enhanced MRA of the Peripheral Vasculature Using Patient Specific Timing Parameters:  Comparison  Between High and Conventional Relaxivity Contrast Agents in Patient Suspected of Arterial Occlusive Disease

George Rachid de Oliveira1, Earl Michael Chester2, Gregory Wilson1,3, Jeffrey H. Maki1,4

1Radiology, University of Washington, Seattle, WA, USA; 2Medicine, University of Washington, Seattle, WA, USA; 3Radiology, Philips Healthcare, Cleveland, OH; 4Radiology, Puget Sound VA Health Care System, Seattle, WA, USA

The objective was to compare qualitative and quantitative peripheral MRA (pMRA) image quality with different dose high vs. conventional relaxivity contrast agents (HRCA vs. CRCA). SNR and timing optimized 3 station pMRA was performed using similar doses (~0.2 mmol/kg) of HRCA vs. CRCA, as well as a smaller dose (~0.1 mmol/kg) of HRCA. No statistically significant qualitative or quantitative differences were observed between same dose HRCA and CRCA. Furthermore, no differences were observed between 0.2 and 0.1 mmol/kg dosing for HRCA, suggesting low dose HRCA is equivalent to high dose CRCA, and increasing HRCA dose has little benefit for pMRA.

11:06         422.       Effect of Flip Angle Evolution on Flow Sensitivities in ECG-Gated Fast Spin Echo MRA Methods at 3T

Iliyana P. Atanasova1,2, Pippa Storey1, Ruth P. Lim1, Jian Xu1, Qin Chen3, Andrew Laine2, Vivian S. Lee3

1Department of Radiology , New York University Medical Center, New York, USA; 2Columbia University, New York, USA; 3Department of Radiology, New York University Medical Center, New York, USA

ECG-gated 3D fast spin-echo based techniques, which exploit differences in arterial and venous flow during systole and diastole, have been developed for non-contrast-enhanced MRA. We investigate the flow sensitivity of fast spin echo with constant (CFL) versus variable flip angle (VFL) echo-train evolutions at different stations of the peripheral vasculature. Out data demonstrate that velocity sensitivities depend on the flip angle magnitude, with shorter sensitivity range for lower flip angles. With the VFL approach near complete signal void occurs for velocities as low as 5 cm/s, which renders the technique suboptimal for imaging vessels where diastolic flow exceeds this threshold.

11:18         423.       Non Contrast MRA of the Hand in Patients with Raynauds Disease Using Flow Sensitized Dephasing Prepared SSFP

John J. Sheehan1, Zhaoyang Fan2, James C. Carr1,2, Debiao Li2

1Cardiovascular Imaging, Northwestern Memorial Hospital, Chicago, IL, USA; 2Cardiovascular Imaging, Northwestern University, Chicago, IL, USA

This study assessed the diagnostic quality and accuracy of a flow-sensitized dephasing (FSD)-prepared SSFP MRA in patients with Raynauds disease. The FSD method acquires a bright-artery scan using ECG-triggered SSFP and a dark-artery scan using ECG-triggered, FSD-prepared SSFP. Subtraction of the two results in bright arteries. Comparison revealed better quality grades for the FSD NC-MRA compared to contrast MRA . FSD identified 95% of luminal narrowings and all arterial occlusions. FSD of the hand in patients with Raynauds compares favorably with contrast enhanced MRA demonstrating in many cases improved resolution and visualization of normal and vasospastic vessels.

11:30         424.       Non-Invasive Assessment of Transstenotic Pressure Gradients Utilizing 3D Phase Contrast MRA: Validation Against Endovascular Pressure Measurements in a Porcine Study

Thorsten Alexander Bley1, Kevin M. Johnson2, Oliver Wieben2, Christopher J. Francois1, Scott B. Reeder1, Mark L. Schiebler1, Darren P. Lum1, Thomas M. Grist1

1Radiology, University of Wisconsin - Madison, Madison, WI, USA; 2Radiology and Medical Physics, University of Wisconsin - Madison, Madison, WI, USA

This study evaluates noninvasive assessment of transstenotic pressure gradients (TSPG) utilizing phase contrast with vastly under sampled isotropic projection reconstruction (PC VIPR) MRA for quantification of renal artery stenosis (RAS) in a porcine model. TSPG over surgically created bilateral RAS in 11 swine were compared to invasive endovascular pressure measurements obtained with pressure sensing guidewires. Excellent correlation of TSPG assessed with PC VIPR and the gold standard were found (Pearson correlation coefficient of 0.977), indicating the feasibility of this novel method for noninvasive assessment of the hemodynamic severity of RAS.

11:42         425.       B1 Inhomogeneity in the Thigh at 3T and Implications for Peripheral Vascular Imaging

Pippa Storey1, Vivian S. Lee1, Daniel K. Sodickson1, Davide Santoro1, Bei Zhang1, Ruth P. Lim1, Iliyana P. Atanasova1, David R. Stoffel1, Qun Chen1, Graham C. Wiggins1

1NYU School of Medicine, New York, NY , USA

Signal loss in the proximal right femoral artery is evident to some degree on contrast-enhanced MR angiograms, and to a greater extent on non-contrast MRA. Using 3D B1 mapping and RF field simulations, we show that the B1 profile exhibits a rotational symmetry in the thighs, with minima on the anterior medial side of the right leg, and the posterior medial side of the left leg. The fact that the proximal right femoral artery coincides with a B1 minimum explains the signal loss. We investigate the use of dielectric pads and a coupling coil to mitigate the problem.

11:54         426.       Ungated Ghost MR Angiography

Ioannis Koktzoglou1, Robert R. Edelman1

1Department of Radiology, NorthShore University HealthSystem, Evanston, IL, USA

We present a novel contrast mechanism for creating MR angiograms on the basis of ghost artifacts originating from pulsatile arterial flow. The method, which we call “Ghost MRA”, is amenable to numerous pulse sequences and does not require cardiac synchronization or image subtraction to suppress background tissue.

12:06         427.       Non-Contrast-Enhanced Flow-Independent Peripheral Angiography with Magnetization-Prepared IDEAL Balanced-SSFP

Tolga Çukur1, Ann Shimakawa2, Huanzhou Yu2, Brian A. Hargreaves1, Bob S. Hu3, Dwight G. Nishimura1, Jean H. Brittain2

1Stanford University, Stanford, CA, USA; 2Applied Science Laboratory, GE Healthcare, USA; 3Palo Alto Medical Foundation, USA

There has been renewed interest in non-contrast-enhanced angiography due to the recent discovery of the link between the use of gadolinium-based contrast agents and nephrogenic systemic fibrosis. Because most non-contrast-enhanced techniques rely on blood flow, the reliability of the generated contrast is compromised in cases of slow flow, such as occluded vessels. On the other hand, flow-independent angiography only relies on the inherent T1, T2 and chemical shift differences of the tissues. 3D complex-sum IDEAL balanced-SSFP can reliably suppress the fat signal. Meanwhile, frequent magnetization preparation coupled with parallel imaging can reduce the long-T1 and muscle signal without compromising the scan efficiency.

12:18         428.       Flow Saturation Inversion Recovery Non-Contrast-Agent MR Angiography for Lower Extremity

Mitsuharu Miyoshi1, Naoyoki Takei1, Tetsuji Tsukamoto1

1Japan Applied Science Laboratory, GE Yokogawa Medical Systems Ltd., Hino, Tokyo, Japan

For arterial/venous separation, Non-Contrast-Agent MR Angiography (NCA-MRA) often uses image subtraction, which is sensitive to patient motion. In this paper, Flow Saturation Inversion Recovery (FS-IR) pulse is used to eliminate subtraction. Three volunteer images of popliteal artery and trifurcation were compared between subtraction method and FS-IR. Signal intensity and scanning time of FS-IR is 66% and 89% of subtraction method, respectively. Large arteries were depicted in both methods. However, small arteries were depicted well in subtraction method because of higher signal intensity. FS-IR method could eliminate subtraction and it was an effective method for NCA-MRA.

The Addictive Brain

Room 311                             10:30-12:30                                                                          Moderators: Dieter Meyerhoff and John D. Port

10:30         429.       Altered Resting-State Default Mode Network Connectivity in Adults Prenatally Exposed to Alcohol

Priya Santhanam1, Zhihao Li1, Mary Ellen Lynch2, Claire D. Coles2, Xiaoping Hu1

1Biomedical Engineering, Georgia Institute of Technology/ Emory University, Atlanta, GA, USA; 2Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA

As the default mode network (DMN) has not been previously examined in a population with prenatal alcohol exposure (PAE), the current study examined resting state connectivity in DMN in two PAE groups versus healthy controls. The time course seed, used for cross-correlation, was taken from anterior cingulate region of deactivation during a cognitive task. Resting state synchrony of DMN was lower in both PAE groups as compared to controls (p=0.019 and p=0.027 for dysmorphic and non-dysmorphic, respectively); however, deactivation during cognition was not significantly different. Results imply PAE may be affecting connectivity at rest (baseline arousal) but not task-related arousal.

10:42         430.       Prenatal Cocaine Exposure Alters Ventromedial Prefrontal Activity Associated with Emotion Regulation

Zhihao Li1, Priya Santhanam1, Claire D. Coles2, Mary Ellen Lynch2, Stephan Hamann3, Xiaoping Hu1

1Biomedical Engineering, Emory University & Georgia Institute of Technology, Atlanta, GA, USA; 2Psychiatry and Behavioral Sciences, Emory University, Atlanta, GA, USA; 3Psychology, Emory University, Atlanta, GA, USA

Prenatal cocaine exposure (PCE) is associated with arousal dysregulation but the neurobiological bases have not been well investigated yet. The present fMRI data showed that PCE subjects could not increase their ventromedial prefrontal activation in excerting emotional suppression, which complemented previous findings about altered amygdala emotional responses in PCE subjects.

10:54         431.       Greater Than Age-Related Decline in Temporal and Occipital Cortices of Methamphetamine Users

Helenna Nakama1, Ryan Shimotsu2, Thomas Ernst3, George Fein2, Linda Chang3

1Department of Psychiatry, University of Hawaii at Manoa, Honolulu, Hi, USA; 2Neurobehavioral Research, Inc., Honolulu, Hi, USA; 3John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, Hi, USA

Methamphetamine (METH) use can lead to brain gray matter deficits. However, the effect of aging on gray matter volumes has not been studied. Structural MRI was performed in 44 METH users and 34 controls subjects. METH users had a 5 to 8-fold greater age-related decline in temporal and occipital lobe gray matter volumes than healthy non-drug users. These findings suggest that METH users may be more vulnerable to age-related atrophic changes, which might contribute to greater age-related cognitive decline, including dementia.

11:06         432.       Disrupted Midbrain-Thalamus Functional Connectivity in Cocaine Abusers

Dardo Tomasi1, Nora D. Volkow2, Ruiliang L. Wang1, Jean H. Carrillo1,3, Thomas Maloney1, Nelly Alia-Klein1, Patricia A. Woicik1, Frank Telang1, Rita Z. Goldstein1

1Medical Department, Brookhaven National Laboratory, Upton, NY, USA; 2National Institute on Drug Abuse, National Institute on Health, Bethesda, MD, USA; 3Department of Computer Science, SUNY , Stony Brook, NY, USA

Chronic cocaine use decreases brain dopamine activity. However the functional effects of this disruption are largely unknown. We used fMRI and seed-voxel correlation analyses to study brain activation to a cognitive-emotional (drug Stroop-like; DS) task and the functional connectivity (fcMRI) between midbrain and forebrain. Cocaine abusers had lower DS activation in the thalamus and lower fcMRI between the thalamus and midbrain than controls, consistently with dopaminergic neuroadaptations resulting from repeated cocaine use. These findings suggest that lower subcortical recruitment and larger cortical recruitment is mediated by abnormal fcMRI of catecholamine (dopamine and noradrenaline) pathways in cocaine abusers.

11:18         433.       Acute Ethanol Alters GABA and MyoInositol in Human Brain

Graeme F. Mason1, June Watzl2, Stuart Weinzimer3, Gerard Sanacora, Elizabeth Guidone, Ismene L. Petrakis, Douglas L. Rothman4, John H. Krystal

1Diagnostic Radiology and Psychiatry, Yale University, School of Medicine, New Haven, CT, USA; 2Diagnostic Radiology, Yale University, School of Medicine, New Haven, CT, USA; 3Pediatrics, Yale University, School of Medicine, New Haven, CT, USA; 4Diagnostic Radiology & Biomedical Engineering, Yale University, School of Medicine, New Haven, CT, USA

Ethanol is known to potentiate GABA receptors and inhibit glutamate receptors in the brain. We hypothesized that ethanol would alter brain GABA and possibly glutamate levels in a time-dependent manner. Intravenous infusions of ethanol were performed during J-edited MRS measurements of GABA and other compounds in the occipital lobe. GABA and myoinositol were reduced significantly during the infusion, glutamate rose transiently and returned to starting levels, and no changes were seen in tissue water, total creatine, choline, or other metabolites. Brain ethanol closely tracked the breath alcohol, while venous ethanol lagged.

11:30         434.       Glutamate Alterations in Alcohol Dependent Patients During Early Detoxification

Gabriele Ende1, Nuran Tunc-Skarka1, Wolfgang Weber-Fahr1, Mareen Hoerst1, Matthias Ruf1, Monika Uhrig1, Derik Hermann2, Karl Mann2

1Neuroimaging, Central Institute of Mental Health, Mannheim, Germany; 2Department of Addictive Behavior and Addiction Medicine, Central Institute of Mental Health

The purpose of this study is to determine whether there are significant changes in glutamate concentrations in the anterior cingulate gyrus and frontal white matter in alcohol dependent patients during early detoxification in comparison to healthy controls and whether these changes parallel deficits in NAA and tCho concentrations. Alcoholic patients during early detoxification show reduced levels of Glu in fWM in addition to reduced tNAA and tCho. A rather weak correlation of Glu values acquired at TE = 30 and TE =80 ms gives rise to the suspicion that the separation of Glu from Gln and GABA is not reliable.

11:42         435.       Negative Correlation Between Medial Frontal Activity During Inhibitory Control and Impulsiveness in Abstinent Heroin Dependents: An FMRI Study

Li-ping FU1,2, Zhi-tong ZOU3, Shi-jiang LI4, Guo-hua BI1, Yan WANG3, En-mao YE1, Lin MA3, Zheng Yang1

1Beijing Institute of Basic Medical Science, Beijing, China; 2Radiology, Peking University Shougang Hospital , Beijing, China; 3Radiology, General Hospital of People's Liberation Army of China; 4Biophysics, Medical College of Wisconsin, Milwaukee, WI, USA

Impulsiveness is a hallmark of addiction. In this study, we combined the neurobiological method (fMRI) and laboratory performance (BIS-11) to explore the rapid-response impulsivity in abstinent heroin dependents. A significant negative correlation between the non-planning score of BIS-11 and the activation of bilateral cingulated cortex (CC) and medial frontal gyrus (mFG) was detected, which indicates that the CC and mFG may be the most sensitive brain areas to the neurotoxicity of heroin and the lack of self-control and intolerance of cognitive complexity reflected by the high BIS-scores contributes, at least partly, to the persistent neural dysfunction.

11:54         436.       [1-13C] Acetate MRS to Study Glial Glutamate Dysfunction in Methamphetamine Users

Napapon Sailasuta1, Kent Harris1, Osama Abulseoud2, Brian Ross1

1HMRI, Pasadena, CA, USA; 2U of Southern California, Los Angeles, CA, USA

13C MRS studies of glial glutamate metabolism in abstinent methaphetamine users via C1-acetate infusion.

12:06         437.       Brain Reactivity to Smoking-Related Cues During Tobacco Abstinence: An FMRI Study.

Amy C. Janes1, Blaise deB Frederick1, Sarah Richardt1, Caitlin Burbridge1, Emilio Merlo-Pich2, Perry F. Renshaw1, A. Eden Evins3, Maurizio Fava3, Marc J. Kaufman1

1Brain Imaging Center, McLean Hospital, Belmont, MA, USA; 2Psychiatry-CEDD, GlaxoSmithKline, Verona, Italy; 3Massachusetts General Hospital, Boston, MA, USA

Nicotine replacement therapies (NRT) reduce smoking withdrawal symptoms but not cue-induced craving. We used blood oxygen level dependent (BOLD) functional MRI (fMRI) to characterize brain responses to smoking-related cues prior to and during NRT-maintained abstinence. BOLD response patterns were comparable to previously reported findings in smoking-cue fMRI studies but anatomical distributions differed based on smoking status. Nigrostriatal activation was greater in smokers in the abstinent versus pre-abstinent state. Since in abstinence, this circuit participates in drug seeking reinstatement, our findings suggest that treatments that modulate nigrostriatal activity may reduce cue-induced brain activations and craving, and may improve smoking cessation outcomes.

12:18         438.       Live Brain MRI Detection of Glia Activation by Psychostimulant Exposure

Christina H. Liu1, Jia Q. Ren, Pradeep G. Bhide2, Philip K. Liu3

1Radiology, Massachusetts General Hospital, Charlestown, MA, USA; 2Neurology, Massachusetts General Hospital, USA; 3Radiology, Massachusetts General Hospital, USA

Electrophysiological data from cell cultures or brain slice preparations show that an important component of drug abuse is the interaction that occurs between glia and neurons. While most addiction research has focused on the molecular adaptation of neurons, our understanding in glial response to psychostimulants at the transcriptional level is very limited. Here we report an MR imaging technique that allows us to identify vulnerable brain regions to glia activation after acute or chronic exposure to amphetamine in live animals. This technique will facilitate and broaden our understanding on molecular processes at transcription level that attribute to drug addiction.

Thermal Therapy & Focused Ultrasound

Room 323ABC                    10:30-12:30                                                        Moderators: Kagayaki Kuroda and Nathan J. McDannold

10:30         439.       Bio-Functional Magnetic Nanoparticles for MR Monitoring and Localized Hyperthermic Treatment of Cancer

Panagiotis G. Kyrtatos*1,2, Michael R. Loebinger*3, Anthony N. Price1, Mathew Kallumadil4,5, Paul Southern4,6, Quentin A. Pankhurst4,6, Sam M. Janes3, Mark F. Lythgoe2,7

1Centre for Advanced Biomedical Imaging , UCL Institute of Child Health and UCL Department of Medicine, London, UK; 2RCS Unit of Biophysics, UCL Institute of Child Health, London, UK; 3Centre for Respiratory Research, University College London; 4London Centre for Nanotechnology; 5Davy-Faraday Research Laboratories, The Royal Institution  of Great Britain, London, UK, *equal contribution to this work; 6Davy-Faraday Research Laboratories, The Royal Institution of Great Britain, London, UK, *equal contribution to this work; 7Centre for Advanced Biomedical Imaging, UCL Institute of Child Health and UCL Department of Medicine, London, UK

Lung cancer is the biggest cancer killer. Recent evidence suggests that stromal tissue within cancers can be mesenchymal stem cell (MSC) derived. Superparamagnetic iron oxide nanoparticles (SPIO) offer attractive possibilities in biomedicine as they can be utilized for MR imaging and targeted localized hyperthermia by application of RF magnetic field. The long term aim of our study is to utilize the tumor-homing capacity of MSCs to deliver a payload of nanoparticles for targeted hyperthermia and non-invasive MR monitoring of therapy. Here we present preliminary data on particle heating using a custom-made RF applicator, MSC labeling and tumor imaging.

10:42         440.       Endocavitary Phased Array Applicator of Therapeutic Ultrasound with an Integrated Opposed-Solenoid Coil for High Resolution MRI-Guided Thermotherapy: An in Vivo Study

Mihaela Rata1,2, Francois Cotton3,4, Christian Paquet5, Vlad Birlea1, Michael Bock6, Rares Salomir1

1INSERM U556, Lyon, France; 2UCBL Lyon 1, Lyon, France; 3UCBL  Lyon 1, Lyon, France; 4CHU Lyon Sud, Radiology Department , Lyon, France; 5National Veterinary School, Lyon, France; 6DKFZ, Heidelberg, Germany

High intensity contact ultrasound (HICU) under MRI guidance may provide minimally invasive treatment of endocavitary digestive tumors (colon/rectum). In this study, opposed-solenoid receiver-only coils were integrated into an endoscopic phased array ultrasound probe to offer high resolution MRI guidance of thermotherapy. The improvement of the image quality and temperature monitoring and control using this device has been investigated in- vivo, on a clinical 1.5T. The comparison endocavitary/external standard coils (voxel: 0.88 x 0.88 x 8 mm3) showed a sensitivity gain up to a factor 4, at the limit of the cooling balloon. Infra-millimeter resolution became feasible for fast MR thermometry while providing an excellent SDT. The endoscopic device was actively operated under automatic temperature control, demonstrating accurate performance.

10:54         441.       Fast Imaging Sequence for Temperature Monitoring in Moving Objects

Bruno Madore1, Jing Yuan1, Chang-Sheng Mei1, Lawrence P. Panych1

1Department of Radiology, Harvard Medical School, Brigham and Women's Hospital, Boston, MA, USA

A novel approach to monitor both motion and temperature in moving organs is presented. The technique is based on an SSFP sequence modified to be tolerant but yet sensitive to resonance frequency variations, such as those created by temperature. A phantom moving over a 2-cm range with a period of about 5 s, typical of the motion expected in the liver during free breathing, was imaged with a temporal resolution of 500 ms to resolve the motion. After registration, temperature curves and images comparable (although visibly degraded) to the static case were obtained.

11:06         442.       Three Dimensional Motion Compensation for Real-Time MRI Guided Focused Ultrasound Treatment of Abdominal Organs

Mario Ries1, Baudouin Dennis De Senneville1, Gregory Maclair1, Max O. Köhler2, Bruno Quesson1, Chrit Moonen1

1UMR 5231, CNRS/Université Bordeaux 2, Laboratory for Molecular and Functional Imaging, Bordeaux, France; 2Philips Healthcare, Vantaa, Finland

A method for real-time 3D positioning of a High Intensity Focused Ultrasound (HIFU) beam onto a moving target with simultaneous temperature monitoring is presented as a step towards MR-guided HIFU for the ablation of tumors in abdominal organs under free-breathing conditions. The feasibility of the proposed method is demonstrated with phantom experiments and an in-vivo ablation of a pig kidney.

11:18         443.       Advances in Real-Time MR Temperature Mapping of the Human Heart

Sebastien Roujol1, Baudouin denis de Senneville1, Gregory Maclair1, Silke Hey1, Pierre Jais1, Chrit Moonen1, Bruno Quesson1

1CNRS/Université Bordeaux 2, Laboratory for Molecular and Functional Imaging, Bordeaux, France

A method for monitoring the temperature evolution in the heart muscle at each cardiac cycle is presented. Cardiac triggering and navigator-based slice tracking for respiratory compensation were combined with image registration and with modeling of motion-related susceptibility changes. With this approach, temperature images were updated approximately each cardiac cycle (1 second) and the resulting median value of the temperature standard deviation in the septum ranged between 1  and 5 C for all volunteers (N=19). This rapid temperature imaging could be used for monitoring radiofrequency catheter ablations.

11:30         444.       Reference-Less MR Thermometry Using Iteratively-Reweighted L1 Regression

William Allyn Grissom1, Michael Lustig2, Viola Rieke, Andrew B. Holbrook3, John B. Pauly2, Kim B. Butts-Pauly

1Electrical Engineering and Radiology, Stanford University, Stanford, CA, USA; 2Electrical Engineering, Stanford University, Stanford, CA, USA; 3Bioengineering, Stanford University, Stanford, CA, USA

Conventional reference-less thermometry techniques derive baseline phase images using least-squares polynomial regression performed on image phase during thermotherapy. Because least-squares regression is sensitive to outliers, i.e., the phase within the hot spot, the hot spot must be masked out of this regression, so its location must be known or tracked. We propose a new thermometry method that uses reweighted-L1 polynomial regression to prevent hot spot bias, obviating the need for masking or tracking. The method is therefore more robust to motion than conventional reference-less thermometry, and requires less user interaction.

11:42         445.       3-D MR Temperature Imaging with Model Predictive Filtering Reconstruction

Nick Todd1, Allison Payne2, Dennis Parker3

1Physics, University of Utah, Salt Lake City, UT, USA; 2Mechanical Engineering, University of Utah, Salt Lake City, UT, USA; 3Radiology, University of Utah, Salt Lake City, UT, USA

We present MRI temperature imaging using a 3-D gradient echo sequence that undersamples k-space and is reconstructed using a model predictive filtering (MPF) algorithm. The MPF algorithm combines information from an identified thermal model of the tissue with undersampled k-space data. The 3-D imaging was chosen for its superior spatial resolution and coverage. The technique provides temperature maps with 2mm3 isotropic spatial resolution and 6 second temporal resolution. The 3-D MPF technique was compared to the traditional 2-D PRF technique over 8 HIFU heating experiments. The standard deviation of the temperature difference between the 2 methods was 0.57 degrees C.

11:54         446.       Transcranial MRI-Guided Focused Ultrasound Surgery of Brain Tumors: Initial Findings in Patients

Nathan McDannold1, Greg Clement1, Eyal Zadicario2, Peter Black1, Ferenc Jolesz1, Kullervo Hynynen1,3

1Brigham & Women's Hospital, Boston, MA, USA; 2InSightec, Haifa, Israel; 3University of Toronto, Sunnybrook Health Sciences Centre, Toronto, ON, Canada

In initial trials in three glioblastoma patients, we found that it was possible to focus an ultrasound beam transcranially into the brain and to visualize the heating with MR temperature imaging. While we were limited by the power available at the time with the device and thus appeared to not achieve thermal coagulation, analysis of the temperature measurements suggests that thermal ablation will be possible with this device without overheating the brain surface, with some possible limitation on the treatment envelope. These findings are a major step forward in producing a completely noninvasive alternative to surgical resection for brain disorders.

12:06         447.       Determination of Pulse Sequence and Timing of Contrast-Enhanced MRI for Assessing Blood-Brain Barrier Disruption Following Transcranial Focused Ultrasound

Jun-Cheng Weng1, Sheng-Kai Wu2, Feng-Yi Yang3,4, Win-Li Lin2,5, Wen-Yih I. Tseng1,6

1Center for Optoelectronic Biomedicine, National Taiwan University College of Medicine, Taipei, Taiwan; 2Institute of Biomedical Engineering, College of Medicine and College of Engineering, National Taiwan University, Taipei, Taiwan; 3Institute of Biomedical Engineering, College of Medicine and College of Engineering,, National Taiwan University, Taipei, Taiwan; 4Department of Biomedical Imaging and Radiological Science, National Yang-Ming University, Taipei, Taiwan; 5Medical Engineering Research Division, National Health Research Institutes, Miaoli, Taiwan; 6Department of Medical Imaging, National Taiwan University Hospital, Taipei, Taiwan

The purpose of this study was to find the optimum pulse sequence and timing of contrast-enhanced MRI that best indicate the BBB disruption in the presence of hemorrhage. Twelve rat brains were sonicated with center frequency of 1 MHz at four different doses of ultrasound contrast agent (0, 150, 300, and 450 μl/kg, three rats for each dose). T1WI spin echo and T1WI gradient echo sequences were performed at three time points, baseline, 10 min and 45 min after Gd-chelate T1-shortening administration. The degree of enhancement was quantified and correlated with the Evans blue staining. Our results showed that contrast-enhanced T1W spin echo sequence acquired at 10 min post contrast enhancement can reliably indicate the degree and location of the BBB disruption despite in the presence of hemorrhage.

12:18         448.       PRF Shift in Frozen Tissue at 3T.

Elena Kaye1,2, Aiming Lu3, Marcus Alley2, Kim Butts Pauly2

1Electrical Engineering, Stanford University, Palo Alto, CA, USA; 2Radiology, Stanford University, Palo Alto, CA, USA; 3University of Chicago

In clinical cryoablation temperature monitoring is typically done with temperature sensors built into cryoprobes or inserted in addition to cryoprobes. Placement of temperature sensors is invasive, time consuming, and doesn’t provide continuous temperature feedback throughout the region of treatment. The following MRI parameters have been shown to be sensitivity to temperature: signal intensity, R2*, and phase shift. The phase shift is a parameter that is usually used for MRI-based thermometry in tissue at T>0 C. In frozen tissue, there is still little known about the phase and proton resonance frequency (PRF) shift dependence on temperature. In a previous 7T spectroscopy study, PRF shift as a function of temperature was found to go from a linear temperature dependence at T>0 C to an exponential dependence at T<0 C. In this work, for the first time, we measure frequency shift in frozen tissue on a clinical 3T MRI scanner.

Diffusion: Biophysical Foundations, Accuracy & Reproducibility

Room 316BC                       10:30-12:30                                                                             Moderators: Yaniv Assaf and Sharon S. Peled

10:30         449.       Experimentally Measured Intracellular Water at Very Short Diffusion Times

Kevin D. Harkins1, Jean-Phillipe Galons2, Joe L. Divijak1, Theodore P. Trouard1

1Biomedical Engineering, University of Arizona, Tucson, AZ, USA; 2Radiology, University of Arizona, Tucson, AZ, USA

The apparent diffusion coefficient is a measure of water diffusion in tissue, and is sensitive to cellular properties and tissue integrity. In this work, we present estimates of the intrinsic intracellular diffusivity derived from hollow-fiber bioreactor cell culture measurements using oscillating gradient diffusion measurements at very short diffusion times. The ADC of intracellular approaches 2.0 to 2.4 mm2 /ms as the diffusion time approaches 0 ms.

10:42         450.       Permeability and Surface Area of Cell Membranes from the DWI Signal

Dmitry S. Novikov1, Jens H. Jensen1, Joseph A. Helpern1

1Radiology, NYU Medical Center, New York, NY, USA

Diffusion of water in tissues is strongly restricted on the cellular length scale. The consequence of such a restriction is a ubiquitous non-Gaussian shape of the diffusion-weighted imaging (DWI) signal. We demonstrate how a non-Gaussian shape of the DWI signal can originate solely due to the presence of cell membranes, with no diffusivity difference between the intra- and extra-cellular compartments. We find that the effective diffusivity acquires frequency dependence. We relate the cell membrane permeability and surface-to-volume ratio to experimentally relevant parameters, such as dispersive diffusivity and time-dependent kurtosis.

10:54         451.       Fast Monte Carlo Simulations Replace Analytical Tissue Models in Diffusion MRI

Markus Nilsson1, Erik Alerstam2, Sara Brockstedt3, Ronnie Wirestam1, Freddy Ståhlberg1,4, Jimmy Lätt3

1Department of Medical Radiation Physics, Lund University, Lund, Sweden; 2Department of Physics, Lund University, Lund, Sweden; 3MR Department, Center for Medical Imaging and Physiology, Lund University Hospital, Lund, Sweden; 4Department of Diagnostic Radiology, Lund University, Lund, Sweden

Evaluation of diffusion MRI data obtained with different diffusion times currently involves non-linear fitting of analytical models. These models rely on assumptions about the tissue as well as on mathematical approximations in the derivation of the signal expression. Replacing the non-linear fitting by a lookup database, constructed from fast Monte Carlo simulations, improves and speeds up the evaluations. This novel approach was demonstrated by investigating the estimated posterior distributions for four tissue parameters, i.e. the intracellular volume fraction, the cell diameter, the intracellular exchange time and the apparent diffusion coefficient, given simulated signal-versus-b curves with added noise.

11:06         452.       MR Characterization of Compartment Shape Anisotropy (CSA)

Evren Ozarslan1

1STBB / LIMB / NICHD, National Institutes of Health, Bethesda, MD, USA

Anisotropy observed in diffusion-weighted acquisitions is influenced by the shape of the cells (compartment shape anisotropy, CSA) and any coherence in the alignment of the population of cells (ensemble anisotropy, EA). We show that CSA and EA can be probed simultaneously and differentiated if double pulsed field gradient (double-PFG) sequences are employed. To this end, expressions for the MR signal intensity from capped cylinders with completely arbitrary parameters of the double-PFG sequence are derived. Our findings suggest that simultaneous noninvasive measurements of cell size, eccentricity and orientation distributions may be possible using relatively small gradient strengths.

11:18         453.       Feasibility of in Vivo Metabolites Diffusion Tensor Assessment

Nicolas Kunz1,2, Stéphane Sizonenko2, Rolf Gruetter1,3

1Laboratory of functional and metabolic imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Division of Child Growth & Development, Dept. of Pediatrics, University of Geneva, Geneva, Switzerland; 3Department of Radiology, University of Lausanne and Geneva, Switzerland

DTI is based on water molecules’ diffusion motion, which is present in both intra- and extra-cellular spaces. On the other hand, DW-MRS uses metabolites as diffusion markers by combining MRS with diffusion weighting technique and provides information limited to the intra-cellular compartment. In this study, DW-MRS shows that the principal diffusion directions of the metabolites were aligned to the water along the corpus callosum fibers, and is likely to shed light on the nature of the diffusion signal.

11:30         454.       On the Effects of Dephasing Due to Local Gradients in DTI Experiments: Relevance for DTI Fiber Phantoms

Frederik Bernd Laun1, Sandra Huff1, Bram Stieltjes

1Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Baden-Württemberg, Germany

Former versions of DTI phantoms could not be oriented arbitrarily towards B0 due to susceptibility induced local gradients. We countered this limitation by matching susceptibilities of restricting structure and fluid. This is achieved by solving sodium chloride. Thus, T2 becomes independent of orientation and diffusion measurements become reliable.

11:42         455.       Comparison of DTI Fiber Tracks with Light Microscopy of Myelinated Fibers

Ann Sunah Choe1,2, Xin Hong1,2, Daniel Christopher Colvin1,2, Iwona Stepniewska3, Zhaohua Ding1,2, Adam W. Anderson1,2

1Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; 2Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; 3Department of Psychology, Vanderbilt University, Nashville, TN, USA

Fibers tracked using Diffusion Tensor Imaging (DTI) are directly compared with myelin stained fibers on a microscopic level. Gold standard measurements of fiber orientation and spread from micrographs enabled us to investigate the challenges of DTI fiber tracking in brain tissue. Limitations due to partial volume averaging and image noise are readily observed.

11:54         456.       Correlation Between R2* and FA in Human Brain White Matter

Tie-Qiang Li1, Masaki Fukunaga2, Peter van Gelderen2, Jeff H. Duyn2

1Medical Physics, Karolinska Huddinge, Stockholm, Sweden; 2NINDS, NIH, Bethesda, MD, USA

High resolution MRI at 7T suggests that T2* contrast may be sensitive to white matter composition and microstructure. In this study, the quantitative correlation between T2* relaxation rate (R2*=1/ T2*) and diffusion fractional anisotropy (FA) in white matter was investigated in a dozen of normal volunteers at 3T and 7T.

12:06         457.       Evaluation of Within-Site and Cross-Site Accuracy and Precision of DTI Measurements Through a Multi-Center Human Volunteer Study

Tong Zhu1, Michelle Gaugh2, Xiaoxu Liu3, Michael Taylor4, Yuen Tso5, Giovanni Schifitto2, Constantin Yiannoutsos6, Bradford Navia7, Jianhui Zhong8

1Biomedical Engineering, University of Rochester, Rochester, NY, USA; 2Neurology, University of Rochester, Rochester, NY, USA; 3Electrical Engineeering, University of Rochester, Rochester, NY, USA; 44University of California San Diego, San Diego, CA, USA; 5Stanford University, Stanford, CA, USA; 6Indiana University, Indianapolis, IN, USA; 7Tufts University, Medford, MA, USA; 8Imaging Sciences, University of Rochester, Rochester, NY, USA

In a typical neuroimaging multicenter DTI study, biases and variations in data due to differences in scanners among sites prevent pooling of data for conventional statistical inferences. This is one of unsolved critical issues we are facing for multi-center DTI studies. In this study, multiple DTI data of a healthy volunteer were acquired at three imaging centers. Precision of DTI measurement of each center was quantified by the bootstrap analysis of measurement uncertainty while the accuracy (bias) of measurement was evaluated by comparing DTI parameters from each site to those from a “super” data set with all data combined. Our study suggests that, while precision level of DTI data from different sites is not significantly affected by the short-term variations of scanners at a site, the bias of DTI data from each site will vary and reduce the statistical power when data from multiple sites are combined together. In order to facilitate the multiple-center DTI study, a routine calibration process to regularly measure the bias level is necessary.

12:18         458.       Statistical Assessment of the Effects of Physiological Noise and Artifacts in a Population Analysis of Diffusion Tensor MRI Data

Lindsay Walker1, Lin-Ching Chang1,2, Efstathios Kanterakis3, Luke Bloy3, Kristina Simonyan4, Ragini Verma3, Carlo Pierpaoli1

1NICHD, NIH, Bethesda, MD, USA; 2Dept of EE & CS, Catholic University of America, Washington, DC, USA; 3Dept of Radiology, University of Pennsylvania, Philadelphia, PA, USA; 4NINDS, NIH, Bethesda, MD, USA

Corrupted DWI data has an effect on DTI derived quantities. An analysis of the effect of physiological noise on statistical analysis of a population is presented. Comparison of non-robust and RESTORE robust tensor fitting shows significant differences in the mean and variance of anisotropy and mean diffusivity. The effects are regionally varying across the brain, and not the same for different tensor derived metrics. When considering a statistical analysis of a population, the effect of outliers may not be the same for both patient and control groups. Statistically significant results may originate from the presence of outliers instead of pathology.

Mapping Fat, Susceptibility & Fields

Room 313BC                       10:30-12:30                                                                   Moderators: Richard W. Bowtell and Nadim J. Shah

10:30         459.       Young Investigator Award Finalist: Robust Water/Fat Separation in the Presence of Large Field Inhomogeneities Using a Graph Cut Algorithm

Diego Hernando1, Peter Kellman2, Justin Haldar1, Zhi-Pei Liang1

1Electrical and Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA; 2NHLBI, National Institutes of Health, Bethesda, MD, USA

Water/fat separation is a classical problem for in vivo MRI. Although many methods have been proposed, robust water/fat separation is still challenging, especially in the presence of large field inhomogeneities. This work tackles the problem using a statistically-motivated formulation which jointly estimates the complete field map and water/fat images. This formulation results in a difficult (high-dimensional and non-convex) minimization problem, which is solved using a novel graph cut algorithm. The proposed method has good theoretical properties and an efficient implementation. It has proven effective for characterizing intramyocardial fat, producing robust water/fat separation in cases containing large field inhomogeneities due to susceptibility effects and magnet imperfections.

10:50         460.       Fast Dynamic Fat-Water Separation Using Shorter Spatial-Spectral Excitation and Novel Temporal Acquisition

Jing Yuan1, Tzu-Cheng Chao2, Riad S. Ababneh3, Yi Tang1, Lawrence P. Panych1, Bruno Madore1

1Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA; 2National Taiwan University, Taipei; 3Department of Physics, Yarmouk University, Irbid, Jordan

We present a novel fat-water separation strategy that combines a short spatial-spectral (SPSP) excitation with a TE-modulation acquisition scheme. The hybrid strategy effectively combines their strengths, and mitigates each other’s weaknesses. A SPSP pulse as short as 2ms suppresses most fat signals, and residual fat signals are identified by a varying TE acquisition in each time frame. Such modulations essentially label the phase of fat signals, by which fat is identified and removed through temporal processing in reconstruction. Higher temporal resolution could be achieved than with a normal SPSP excitation or a multi-echo Dixon’s separation.

11:02         461.       Magnitude Fitting Following Phase Sensitive Water-Fat Separation to Remove Effects of Phase Errors

Huanzhou Yu1, Ann Shimakawa1, Scott B. Reeder2, Charles A. McKenzie3, Jean H. Brittain4

1Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA; 2Departments of Radiology, Medical Physics, Biomedical Engineering and Medicine, University of Wisconsin, Madison, WI, USA; 3Department of Medical Biophysics, University of Western Ontario, London, ON, Canada; 4Applied Science Laboratory, GE Healthcare, Madison, WI, USA

Multi-point water-fat separation techniques rely on different water-fat phase shifts at multiple echo times to estimate the Bo fieldmap, water and fat. By utilizing the fieldmap smoothness, water-fat ambiguity can be resolved. However, these methods may be sensitive to eddy currents induced phase errors. In this work, the conventional phase-sensitive water-fat separation (first step) is followed by a fitting algorithm based on magnitude images (second step) for “fine-tuning”. The second step relies on the results from the first step for initial conditioning. The two-step approach is effective at removing phase errors for applications in both qualitative and quantitative water-fat separation.

11:14         462.       A Weighted Gradient Regularization Solution to the Inverse Problem from Magnetic Field to Susceptibility Maps (Magnetic Source MRI): Validation and Application to Iron Quantification in the Human Brain

Ludovic de Rochefort1,2, Tian Liu1, Bryan Kressler1, Jian Liu1, Pascal Spincemaille1, Jianlin Wu3, Yi Wang1

1Radiology, Weill Medical College of Cornell University, New York, NY, USA; 2LMN, MIRCen, I2BM, DSV, CEA, Fontenay-aux-roses, France; 3Radiology, The 1st Hospital of Dalian Medical University, Dalian, Liaoning Province, China

A reconstruction technique is presented to extract susceptibility maps from phase and magnitude MR data. The linear problem is solved using least-square regularization based on two terms to define boundary conditions and preserve edges. The technique is validated on phantom and applied in human to quantify iron in cerebral hemorrhage.

11:26         463.       Susceptibility Mapping in the Human Brain at 3 and 7T

Samuel James Wharton1, Andreas Schäfer2, Richard Bowtell1

1Sir Peter Mansfield Magnetic Resonance Centre, School of Physics and Astronomy, University of Nottingham, Nottingham, UK; 2Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

Phase images generated using gradient echo techniques at high field strengths show excellent contrast related to the different magnetic susceptibilities of various brain tissues. However, extraction of accurate anatomical information from these images is made difficult by the non-local relationship between the field perturbation and associated susceptibility distribution. Here, we validate a Fourier-based method for calculating 3D susceptibility maps from phase data using a specially-constructed agar phantom containing doped inclusions of known susceptibility. Results produced by applying the method to measuring the susceptibility of the substantia nigra and red nuclei from data acquired at 3 and 7T are also discussed.

11:38         464.       Improvements in Quantitative Magnetic Susceptibility Mapping at Using Additional Low Resolution Scans

Maarten J. Versluis1,2, Matthias J.P. van Osch1,2, Mark A. van Buchem1,2, Andrew G. Webb1,2

1Radiology, Leiden University Medical Center, Leiden, Netherlands; 2C.J. Gorter Center for high field MRI, Leiden University Medical Center, Leiden, Netherlands

Phase images measured with gradient echo sequences are sensitive to changes in the local magnetic field and can be used to identify regions with different magnetic susceptibilities. We have used the Fourier based relation between phase and susceptibility to calculate susceptibility maps. Simulations of phase maps showed improvements of susceptibility maps by combining high and low resolution data with different orientations to the magnetic field. Preliminary results of in-vivo data showed that artifacts in magnetic susceptibility maps can be reduced considerably using this approach.

11:50         465.       Quantitative Susceptibility Mapping of Human Brain by Inverting Local Magnetic Fields Measured at Multiple Small Angles

Tian Liu1,2, Pascal Spincemaille2, Ludovic de Rochefort2, Martin Prince2, Yi Wang1,2

1Biomedical Engineering, Cornell University, Ithaca, NY, USA; 2Radiology, Weill Cornell Medical College, New York, NY, USA

Quantitative susceptibility mapping of the brain would be valuable for assessing iron or calcium deposits associated with neurodegenerative and ischemic diseases, and for quantifying deoxygenated venous blood in fMRI. In this study, Calculation of Susceptibility through Multiple Orientation Sampling (COSMOS) was adapted to quantitatively map susceptibility of the cerebral venous blood. Veins were well-distinguished from the surrounding tissues and oxygen saturation level was assessed.

12:02         466.       The Dependence of Tissue Phase Contrast on Orientation Can Be Overcome by Quantitative Susceptibility Mapping

Karin Shmueli1, Peter van Gelderen1, Brian Yao1, Jacco A. de Zwart1, Masaki Fukunaga1, Jeff H. Duyn1

1Advanced MRI Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA

Interpretation of phase images is confounded by the dependence of the contrast on the tissue orientation relative to the main magnetic field (B0). To mitigate this, inverse Fourier methods have been proposed to reconstruct the underlying tissue magnetic susceptibility from the phase data. To evaluate this approach, we assessed the similarity of susceptibility maps calculated from phase images of human brain sections acquired at 0° and 90° relative to B0. The phase contrast was often reversed by rotation whereas the susceptibility maps were mostly unaffected. This demonstrates that the susceptibility calculation overcomes the strong orientation dependence of the phase contrast.

12:14         467.       Removing Background Phase Variations in Susceptibility Weighted Imaging Using a Fast, Forward-Field Calculation

Jaladhar Neelavalli1, Yu-Chung Norman Cheng2, Jing Jiang3, Ewart Mark Haacke2

1Biomedical Engineering, Wayne State University, Detroit, MI, USA; 2Academic Radiology, Wayne State University, Detroit, MI, USA; 3The MRI Institute for Biomedical Engineering, Detroit, MI, USA

We present here a novel method for removing background field effects from SWI phase images. The method involves predicting the air-tissue interface geometry induced field deviation and, from it the phase, and removing its contribution form the collected SWI phase data. The resultant images are referred to as Geometry Dependent Artifact Corrected phase images (GDAC phase) which lead to significant improvement in the processed susceptibility weighted magnitude images.

 

EDUCATIONAL COURSE
Imaging the Fetus & Newborns

Room 314                             10:30 – 12:30                                                                          Moderators:  Petra Hüppi and Pek Lan Khong

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Describe novel developments in techniques and applications of fetal and neonatal MR imaging;

·   Explain technical challenges in fetal and neonatal MR imaging, in particular motion, and the methods that have been applied to circumvent them;

·   Describe clinical applications and implement techniques in cardiovascular MR in neonates and infants;

·   Explain the role and contribution of MRI in the evaluation of ventriculomegaly in the fetus;

·   Evaluate the timing of perinatal asphyxia and the complementary roles of MRI and MRS, especially with regard to potential intervention; and

·   Assess the role of MRI and MRCP in the diagnosis of biliary atresia and ductal anomalies.

 

10:30       Advanced MR Imaging in Perinatal Brain Injury:  Timing of Injury-Potential for Intervention
Terri E. Inder


10:50      
Advanced MR Methods for Evaluating the Fetus; MRS, DTI, and ASL:  Feasibility and Application

Robert V. Mulkern

11:20       MRI of Moving Subjects

Joseph V. Hajnal

11:40       Cardiovascular MR in Neonates and Infants - No syllabus contribution at time of publication.

Taylor Chung

12:00       MRCP in the Neonate
               
Myeong-Jin Kim

 

12:20       Panel Discussion

HANDS-ON WORKSHOP 1
Neuro and Musculoskeletal Protocol Optimization
Siemens

Room 324                             10:30 – 12:30                                                                                                                                                           


GOLD CORPORATE MEMBER LUNCHTIME SYMPOSIUM
GE Healthcare

Ballroom                              12:30 – 13:30                                                                                                                                                           

CLINICAL INTENSIVE COURSE
Case-Based Teaching III:  MRI of the Lower Extremity

Room 310                             13:30 – 15:30                                                                                                   Moderator:  Lynne S. Steinbach

13:30         Hip

                  Hollis G. Potter

                                                     

14:10         Knee

                  Russell C. Fritz

                                                     

14:50         Ankle and Foot

                  James M. Linklater

Hepato-Pancreatic Metabolism

Room 316A                         13:30-15:30                                                                               Moderators: Daniel T. Boll and Joachim Lotz

13:30         468.       The Effect of Galactose and Fructose Intake on Synthesis of Liver Glycogen: A 13C-MRS Study

Roy Jentjens1, Michael Ith2, Eva Scheurer2, Jacques Décombaz3, Asker Jeukendrup4, Chris Boesch2

1Nestlé Research Center, Lausanne, Switzerland; 2Dept.Clinical Research, University Bern, Bern, Switzerland; 3Nestlé Research Center,, Lausanne, Switzerland; 4School of Sport and Exercise Science,, University of Birmingham, Birmingham, UK

Prolonged, strenuous exercise is associated with liver glycogen depletion (hence hypoglycemia) as well as muscle glycogen depletion. This study investigates the hypothesis that ingestion of large amounts of maltodextrin-based drinks containing added fructose or added galactose results in faster post-exercise liver glycogen synthesis than an iso-osmolar drink with added glucose. In a double blind, randomized cross-over study including 10 well-trained male cyclists, liver glycogen was measured by 13C-MRS. Consumption of the maltodextrin-fructose or -galactose drinks during post-exercise recovery led to significantly higher rates of liver glycogen replenishment over 6 hours than when the iso-osmolar glucose drink was consumed.

13:42         469.       13C MRS Shows Altered Cerebral Glucose Metabolism During Acute Mild Hypoglycemia in Humans

Kim van de Ven1, Marinette van der Graaf1, Bastiaan de Galan2, Cees Tack2, Arend Heerschap1

1Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 2General Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands

Cerebral glucose metabolism was assessed by 13C-MRS under euglycemic (5.16 mmol/l) or hypoglycemic (2.95 mmol/l) conditions in 8 human volunteers during 2-hour hyperinsulinemic glucose clamps. Using 13C-1-glucose 20% solutions a stable plasma glucose 13C-enrichment was achieved, resulting in high SNR spectra. MRS-measurements were conducted with a 13C/1H volume head coil, and an ISIS-DEPT pulse sequence at 3T. Under hypoglycemic conditions, 13C signals of Asp3 and Glu2 reached a higher level, while Asp2 and Glu3 (and also Glu4) reached a lower level compared to euglycemic conditions This indicates altered cerebral glucose metabolism during mild hypoglycemia, possibly reflecting upregulated anaplerosis.

13:54         470.       Effect of Suppression of Free Fatty Acids on ATP Turnover and Inorganic Phosphate Uptake in Type 2 Diabetes Studied by 31P-MRS During an Isoglycaemic-Hyperinsulinaemic Clamp

Kieren Grant Hollingsworth1, Ee Lin Lim1, Mei Jun Chen1, Jean Gerrard1, Roy Taylor1

1Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle, Tyne and Wear, UK

7 patients (age 56.7±4.3) with well-controlled Type 2 diabetes were brought in fasted on two separate study days and given (i) acipimox and (ii) a placebo tablet. Saturation transfer between ATP and Pi was used to measure ATP turnover 3 hours and just before a 120 minute isoglycaemic-hyperinsulinaemic clamp. Further measurements were made 20 minutes and 90 minutes into the clamp. Acipimox suppressed free fatty acids rapidly. The ATP flux at 90 minutes on the acipimox study day was significantly greater than with placebo. The percentage increase in inorganic phosphate was significantly greater at 90 minutes with acipimox.

14:06         471.       Endogenous Gluconeogenic Sources Account for the Majority of Hepatic Glycogen Synthesis After an Oral Glucose Load in 24-Hour Fasted Rats

Ana Francisca Soares1,2, John Griffith Jones1, Francisco Veiga2, Rui Albuquerque Carvalho1

1Biochemistry and Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal; 2Pharmaceutical Technology, University of Coimbra, Coimbra, Portugal

Hepatic glycogen fluxes were characterized in 24-hour fasted rats following an oral tracer-enriched load. Combination of 13C isotopomer analysis with 2H-enrichment from 2H2O, resolved load contribution from that of endogenous gluconeogenesis to hepatic glycogen. The latter accounted for 66 ± 13 % of the glycogen synthesized during the experiment whereas less than one third originated in the oral load following direct and indirect pathways at similar extents: 18 ± 3 % and 16 ± 2 %, respectively. Thus hepatic glycogen synthesis contributes to normoglygemia mostly by diverting gluconeogenic carbons from hepatic glucose production rather than through net uptake of glucose.

14:18         472.       Localized MRS of Human Pancreas

Ildiko Lingvay1, Angela L. Price1, Jaime Legendre1, Sarmistha Sen1, Lidia S. Szczepaniak2

1Internal Medicine, University of Texas, Southwestern Medical Center, Dallas, TX, USA; 2Internal Medicine & Radiology, University of Texas, southwestern Medical Center, Dallas, TX, USA

Obesity is known to influence insulin sensitivity, but its direct effect on insulin secretion is still debated. The lipotoxicity hypothesis provides a unifying link between chronic positive energy balance and metabolic syndrome abnormalities. Accumulation of fat in the human liver, skeletal muscle, and the heart, along with associated decline in the function of these organs, has been confirmed by previous clinical studies, yet data on fat accumulation in the human pancreas is limited to autopsy reports, and there is very limited information regarding the relationship between insulin secretion and pancreatic fat accumulation. We performed studies in humans to determine whether proton-localized magnetic resonance spectroscopy can be used to noninvasively assess pancreatic steatosis. We performed a series of studies in healthy human volunteers to document the reproducibility of the pancreatic triglyceride measurement in vivo and examined the cross-sectional relationship between pancreatic triglyceride content, body mass index, and glycemic status.

14:30         473.       The Effect of Nutritional Early-Life Programming on Adult Body Composition and Appetite Regulation

Jelena Anastasovska1, Nachiket Abhay Nadkarni1, Po-Wah So2, Neena Modi3, Elizabeth Louise Thomas1, Gary Frost4, Jimmy D. Bell1

1Metabolic and Molecular Imaging Group, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, UK; 2Biological Imaging Centre, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, UK; 3Section of Neonatal Medicine, Chelsea and Westminster Campus, Imperial College London, London, UK; 4Nutrition and Dietetics Research Group, Metabolic Medicine, Hammersmith Hospital, Imperial College London, London, UK

The effect of nutrition at specific stages of development has been investigated using different diets during fetal and neonatal growth. In this study, we investigate the effects of low protein diet during either pregnancy or lactation in combination with a hypercaloric post-lactation diet, on lipid content and distribution and appetite regulation, in the adult offspring using MRI and MRS. We show that the stage of early life at which undernutrition occurs has significant effects in determining the adult phenotype. Low protein in the early post-natal period leads to an improvement in adiposity and lipid metabolism, despite an increased appetite.

14:42         474.       Phosphorous and Carbon Spectroscopy of Porcine Islet Extracts : Comparison of Effects of Normoxic and Hypoxic Culture Conditions

Chardonay Julia Vance1,2, Hitoshi Kubo3, Kristen Stewart Maynard1, Klearchos K. Papas1, Gulin Oz2

1Diabetes Institute, U of MN, Minneapolis, MN, USA; 2CMRR, U of MN, Minneapolis, MN, USA; 3Medical Imaging, University of Tokushima Graduate School, Tokushima, Japan

Pancreatic islet transplantation is a promising treatment for restoring normoglycemia in some patients with Type-1 diabetes. Islet death induced by hypoxia limits viable islet yield and the success rate of transplantations. To address the metabolic consequences of islet exposure to anoxia, we compared anaerobic and oxidative carbohydrate metabolism (as measured by 13C label incorporation from 13C-glucose to metabolites in exchange with TCA cycle intermediates) and energy status (as measured by ATP-to-ADP ratio via 31P NMR) of highly purified porcine islets. The ATP/ADP ratio fell during anoxia. GABA, lactate and alanine synthesis from glucose increased, and glutamate synthesis decreased during anoxia.

14:54         475.       Liver 31P MRSI Using an 8-Channel Dual-Tuned 31P/1H Coil at 3T

Anshuman Panda1,2, Judy Rose James1,2, Uwe Boettcher3, Rahul Srinivasa Raghavan1, Kumar Sandrasegaran2, Alex Aisen2, Helmut Stark4, Navin Bansal1,2, Ulrike Dydak1,2

1School of Health Sciences, Purdue University, West Lafayette, IN, USA; 2Department of Radiology, Indiana University School of Medicine, Indianapolis, IN, USA; 3Siemens Healthcare, Erlangen, Germany; 4Stark Contrast MRI Coils Research, Erlangen, Germany

In-vivo results of 31P MR Spectroscopic Imaging (MRSI) of a whole axial slice through the liver obtained from a novel eight-channel phased-array dual-tuned 31P/1H coil at 3T are presented in this work. Data was acquired using a slice-selective MRSI sequence, showing that this coil allows MRSI of a whole slice of the abdomen and provides good sensitivity throughout the liver. The signal to noise ratio of the spectra allows for relative phase correction before signal combination from each channel. A nominal resolution of 25x25x30 mm3 over a field-of-view of 400x250x30 mm3 can be achieved within a scantime of ~20 min.

15:06         476.       Toward Quantitation of Pancreatic β Cell Mass Using a Two-Site Exchange Analysis of Manganese-Enhanced MR Images

Patrick F. Antkowiak1, Moriel H. Vandsburger1, Sarah Tersey2, Raghavendra G. Mirmira2, Frederick H. Epstein1,3

1Biomedical Engineering, University of Virginia, Charlottesville, VA, USA; 2Medicine, Indiana University; 3Radiology, University of Virginia

In normal individuals, pancreatic beta cells release insulin into the bloodstream after an increase in blood glucose level. In Type 1 diabetes, beta cell mass and function are impaired. Manganese (Mn) enhanced MRI has been used to probe beta cell function; we aimed to extract parameters related to beta cell mass using a two site exchange analysis of Mn-enhanced MR images. Two site exchange analysis revealed that diabetic mice had increased intra- and extracellular compartment T1 values and had a decreased intracellular fraction, consistent with the loss of beta cell mess, as compared to non-diabetic mice.

15:18         477.       MR-Guided Engraftment of Human Pancreatic Islet Cells in a Diabetic Swine Using Immunoprotection with Clinically Applicable Magnetocapsules.

Dian Respati Arifin1,2, Aravind Arepally1, Thomas W. Link2,3, Wesley D. Gilson1,4, Victor A. Ferrari5, Robert L. Wilensky5, Dara L. Kraitchman1, Jeff W.M. Bulte1,2

1Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 2Cellular Imaging Section, Institute for Cell Engineering, Johns Hopkins University School of Medicine; 3Biomedical Engineering, Johns Hopkins University School of Medicine; 4Siemens Corporate Research, Inc., Baltimore, MD, USA; 5Cardiovascular Division, Hospital of University of Pennsylvania, Philadelphia, PA, USA

Transplantation of pancreatic cells is a promising treatment of type 1 diabetes. Pancreatic cells were immunoprotected inside novel alginate/protamine sulfate/alginate magnetocapsules. Magneto-encapsulated human pancreatic cells transplanted in a streptozotocin-induced diabetic swine were viable and functional for at least 14 days post-transplantation. The swine was vetsulin-independent and showed healthy blood glucose levels 2 days and one day post-transplantation, respectively. Magnetocapsules were clearly visualized as hypointensities in vivo using a 1.5T clinical MR-scanner. Magneto-encapsulated pancreatic cells show potential for treatment of type 1 diabetes in a large animal model, providing a means to non-invasively monitor cell transplantation in real-time using MR-imaging.

Characterizing Myocardial Injury & Predicting Risk

Room 313A                         13:30-15:30                                               Moderators: W. Patricia Bandettini and Christopher M. Kramer

13:30         478.       Cardiac Magnetic Resonance (CMR) Evaluation of Patients with ST-Elevated Acute Myocardial Infarction (STEMI): Influence of Time-To-Reperfusion on the Extent of the Area at Risk, Infarct Size and Microvascular Damage

Iacopo Carbone1, Marco Francone2, Emanuela Algeri2, Ilaria Iacucci2, David Cannata2, Luciano Agati2, Carlo Catalano2, Roberto Passariello2

1La Sapienza University of Rome, Rome, Italy, Italy; 2La Sapienza University of Rome, Italy

Seventy STEMI patients treated with primary PCI within 12 hours from symptom onset underwent CMR in the first week after hospital admission to assess the influence of time to reperfusion on infarct size, microvascular damage and salvaged myocardium. A progressive increase of infarct size and microvascular damage over time has been observed. However, the new finding of the present study is that salvaged myocardium suddenly decreases after 60 minutes of coronary occlusion confirming the importance to shorten the delay in STEMI treatment.

13:42         479.       Quantitative Tissue Characterization of Infarct Heterogeneity in Patients with Ischemic Cardiomyopathy by Magnetic Resonance Predicts Future Cardiovascular Events

Harendra Patel, MD1, Shahriar Heidary, MD2, Hajime Yokota, MD2, Chandra Katikireddy, MD2, Patricia Nguyen, MD2, John M. Pauly, PhD3, Masahiro Terashima, MD, PhD2, Michael V. McConnell, MD, MSEE2, Phillip C. Yang, MD2

1Medicine, Stanford University, Stanford, CA, USA; 2Cardiovascular Medicine, Stanford University, Stanford, CA, USA; 3Electrical Engineering, Stanford University, Stanford, CA, USA

77 patients with ischemic cardiomyopathy (LVEF < 50%, mean LVEF: 28 ± 15%) considered for revascularization or medications ± ICD were enrolled. Using a 1.5T MRI scanner, the core and border zones of infarcted myocardium were analyzed. Patients were followed for cardiovascular events: VT, VFIB, ICD firing, CHF, hospitalization, MI, repeat revascularization, syncope and death. 39 patients (39%) had events (mean follow-up: 20 ± 16 months). The mass of the border zone rather than the core infarct was associated significantly with events (16.6 ± 13.2 g vs. 10.7 ± 10.1 g, p = 0.017 and 19.2 ± 11.7 g vs. 15.0 ± 11.6 g, p= 0.061, respectively). LVEDV, LVESV, and LVEF were not significantly different in patients with or without events. Quantitative tissue characterization of the border zone mass of infarcts is superior to core infarct mass, LVEDV, LVESV, and LVEF in prognosticating the likelihood of future cardiovascular events in patients with ICM. This CMR-guided technique may assist in clinical management of patients with ICM.

13:54         480.       Clinical Validation of Multi-Contrast Delayed Enhancement (MCDE) for Wall Motion and Viability Imaging

Jay Stephen Detsky1,2, Kim A. Connelly1,3, Gideon A. Paul1,4, John J. Graham3, Alexander J. Dick4, Graham A. Wright1,2

1Imaging Research, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; 2Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; 3Cardiology, St. Michael's Hospital, Toronto, Ontario, Canada; 4Schulich Heart Program, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada

The clinical accuracy and reproducibility of a new multi-contrast delayed enhancement (MCDE) sequence was tested in 41 patients. MCDE can be used to simultaneously visualize cardiac wall motion and viability; MCDE showed excellent agreement with the conventional wall motion and delayed enhancement sequences in this study. MCDE provides improved visualization of small infarcts and halves the number of breath-holds required wall motion and viability imaging.

14:06         481.       Papillary Muscle Infarction by Delayed-Enhancement Magnetic Resonance Imaging: Reproducibility and Potential as an Independent Predictor of Ischemic Mitral Regurgitation

Thananya Boonyasirinant1, Ronan Curtin2, Randolph M. Setser1, Michael L. Lieber3, Scott D. Flamm1

1Radiology, Cleveland Clinic, Cleveland, OH, USA; 2Cardiology, Cleveland Clinic, Cleveland, OH, USA; 3Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH, USA

Delayed-enhancement MRI (DE-MRI) has been accepted as the high resolution, non-invasive infarction specific imaging for evaluation of myocardial viability. However the prevalence, feasibility, and reproducibility of papillary muscle infarction identification and the relationship between IMR severity and papillary muscle viability have not been established. This study demonstrated the feasibility of papillary muscle infarction identification using DE-MRI with excellent intra-observer and inter-observer reproducibility. The presence of posterior papillary muscle infarction and impaired EF are independent predictors of MR severity in ICM patients. The identification of papillary muscle infarction may provide novel insights into improved surgical strategies for IMR.

14:18         482.       Elite Olympic Calibre High-Endurance Athletes Have Evidence for Myocardial Fibrosis : A Cardiovascular Magnetic Resonance Study

Myra Sabene Cocker1, Oliver Strohm1, David J. Smith2, Craig Butler1, Israel Belenkie3, Willem Meeuwisse4, Matthias G. Friedrich1

1Stephenson CMR Centre at the Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada; 2Human Performance Lab, Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada; 3Cardiac Sciences, University of Calgary, Calgary, Alberta, Canada; 4Sports Medicine Centre, University of Calgary, Calgary, Alberta, Canada

Background: Athletes have a greater risk of sudden cardiac death then the rest of the population. Autopsy findings show evidence for myocardial fibrosis in athletes. We speculate that a large proportion of athletes have evidence for myocardial fibrosis.  Methods: 48 elite high-endurance athletes and 8 healthy controls were recruited. Following LV function assessment, contrast enhanced cardiovascular magnetic resonance (CMR) was performed to assess for the presence of myocardial fibrosis.  Results: 77% of athletes had myocardial fibrosis in late enhancement image, compared to 13% of healthy control subjects.

Conclusion: The incidence of myocardial fibrosis in elite athletes is very high, and can be visualized with contrast enhanced CMR.

14:30         483.       Cardiac T1 Mapping: A Comparison of Methodologies for Quantifying Cardiac T1 Values

Ting Song1, Maureen N. Hood2, Vincent B. Ho3, Sandeep N. Gupta4, Jeffrey A. Stainsby5

1Applied Science Laboratory, GE Healthcare, Bethesda, MD, USA; 2Radiology, Uniformed Services University of the Health Sciences and National Naval Medical Center, Bethesda, MD, USA; 3Radiology, Uniformed Services University of the Health Sciences and National Naval Medical Center, Bethesda, Bethesda, MD; 4GE Global Research, Niskayuna, NY, USA; 5Applied Science Laboratory, GE Healthcare, Toronto, ON, Canada

Cardiac T1 mapping provides a quantitative way to characterize tissue abnormalities, such as myocardial infarction and amyloidosis. IR prepared SSFP, CINE-IR, and the modified look-locker saturation-recovery (MLLSR) were evaluated on both phantoms and human studies in this paper. The sensitivity of these techniques to variations in heart rate and flip angle were compared. The MLLSR sequence gave consistent, reliable results across the widest range of T1 values, flip angles and heart rates.

14:42         484.       Myocardial T2* Mapping Free of Distortion Using Susceptibility Weighted Spin-Echo Based Imaging: A Feasibility Study at 1.5 T and 3.0T

Uwe Heinrichs1, Jane Francis Utting2, Tobias Frauenrath2, Fabian Hezel2, Gabriele A. Krombach2, Michael AJ Hodenius3, Sebastian Kozerke4, Thoralf Niendorf2,5

1Department of Diagnostic Radiology, RWTH Aachen University , Aachen, Germany; 2Department of Diagnostic Radiology, RWTH Aachen University, Aachen, Germany; 32Department of Applied Medical Engineering, Helmholtz-Institute, RWTH Aachen University, Aachen, Germany; 43Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 5Faculty of Mathematics, Computerscience and Natural Science, RWTH Aachen University , Aachen, Germany

This study is designed to demonstrate the promise of navigator gated, susceptibility weighted fast spin-echo imaging in conjunction with ventricular blood suppression for anatomically accurate T2*-mapping of the heart. First results of phantom and volunteer studies demonstrate the geometrical integrity and high image quality obtained with UFLARE - even for strong T2*-weighting at 1.5T and 3.0T. T2*-mapping using UFLARE yielded mean T2* values for the inferoseptal myocardium of 29.9±6.6 ms at 1.5T and 22.3±4.8 ms at 3.0T. The results derived with susceptibility weighted UFLARE promise to extend the capabilities of CVMR including mapping and quantification of myocardial iron content.

14:54         485.       Navigator-Gated T2 and T2*-Weighted Imaging of Myocardial Edema and Hemorrhage Following Primary Coronary Intervention

Declan Patrick O'Regan1, Rizwan Ahmed2, Giuliana Durighel1, Amy McGuinness1, Jo V. Hajnal1, Stuart A. Cook2

1Robert Steiner MRI Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, UK; 2Molecular Cardiology Group, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, UK

We assessed the feasibility of using T2* mapping to quantify regions of myocardial hemorrhage following percutaneous primary coronary intervention (PPCI) for acute myocardial infarction. We also assessed myocardial edema imaging using a T2-weighted asymmetric turbo spin echo with spectrally-selective inversion recovery (SPIR) fat suppression. To reduce respiratory motion artifact and ghosting from the blood pool we used navigator gating and a black blood prepulse in both sequences. Our findings show that hemorrhage is frequently observed following PPCI and is an indicator of poor myocardial salvage.

15:06         486.       Navigated DENSE Strain Imaging for Post RF-Ablation Lesion Assessment in Swine Left Atria: A Comparison with Delayed Enhancement

Ehud Jeruham Schmidt1, Maggie M. Fung2, Pelin Aksit3, GodtFred Holmvang4, Ting Song5, Sandeep M. Gupta6, Andre D'Avila7, Vivek Y. Reddy7, Stephan B. Danik8

1Radiology, Brigham and Womens Hospital, Boston, MA, USA; 2MRI, GE Healthcare, Waukesha, WI, USA; 3Radiology, Yale University, New Haven, CT, USA; 4Cardiology, Massachusetts General Hospital, Boston, MA, USA; 5Applied Science Laboratory, GE Healthcare, Bethesda, MD, USA; 6GE Global Research, Niskayuna, NY, USA; 7Cardiology, University of Miami, Miami, FL, USA; 8Heart Center, Massachusetts General Hospital, Boston, MA, USA

High-resolution navigated strain imaging is compared to high-resolution Myocardium Delayed Enhancement in the assessment of the completeness of RF ablation of the pulmonary-vein/left-atrial junction in swine models. It is shown that DENSE strain detects ablation as regions of low and disorganized strain, and ablation gaps as regions of organized strain. Strain imaging is a possible method for non-contrast visualization of ablation injury in the thin atrial wall.

15:18         487.       Simultaneous Three-Dimensional Visualisation of Delayed Enhancement and T2 Weighted MRI for the Characterisation of RF Ablation Lesions

Benjamin R. Knowles1, Dennis Caulfield1, Aldo Rivaldi2, Michael Cooklin2, Jaswinder S. Gill2, Julian Bostock2, Reza Razavi1, Kawal S. Rhode1, Tobias Schaeffter1

1Division of Imaging Sciences, King's College London, London, UK; 2Department of Cardiology, Guy's and St Thomas' NHS Foundation Trust, London, UK

Radiofrequency ablation of the pulmonary veins is a common treatment for atrial fibrillation. The endpoint of the procedure is usually determined by measuring signals within each PV to ensure electrical isolation. Electrical isolation however, may be caused permanently by necrosis of the myocardium, or temporally by oedema formation. In this study we image acute post ablation patients using a combination of delayed enhancement and T2 weighted MRI. We visualise the patterns of enhancement and oedema to characterise the ablation lesions and assess wherever pulmonary veins are permanently isolated by necrosis, or have areas of temporary isolation by oedema.

The Fetus &  Developing Brain

Room 311                             13:30-15:30                                                                 Moderators: Nadine J. Girard and Jeffrey Joseph Neil

13:30         488.       Optimisation of a Balanced Fast Field Echo Cine Sequence for the Assessment of Human Fetal Motor Function

Tayyib Hayat1,2, Joanna Allsop1, Amy McGuinness1, Fabrizio Ferrari3, Mary Rutherford1,2, Joseph V. Hajnal1

1Robert Steiner MRI Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, UK; 2Perinatal Imaging Group, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, UK; 3Department of Pediatrics and Neonatology, Modena University Hospital, Italy

The analysis of motor function is an important element of the neurological assessment of human neonates, with General Movements (GM) being a recognised pattern that is clinically useful in diagnosing abnormal infants. To assess GM, the whole infant must be observed. Attempts to study fetal GM in utero by ultrasound have been hindered by limitations in the field-of-view, particularly later in pregnancy. We have optimised a MR cine sequence for imaging the whole fetus throughout gestation and performed a pilot study that shows differences in movement quality with age and a neurological condition.

13:42         489.       The Evolution of Brain Functional Architecture from the Age of 2 Weeks to 2 Years

Wei Gao1, Hongtu Zhu2, Kelly Giovanello3, Keith Smith4, Dinggang Shen5, John Gilmore6, Weili Lin5

1Department of Biomedical Engineering, University of North Carolina-Chapel Hill, Chapel Hill, NC, USA; 2Department of Biostatistics and BRIC, University of North Carolina-Chapel Hill; 3Department of Psychology and BRIC, University of North Carolina-Chapel Hill; 4Department of Radiology, University of North Carolina-Chapel Hill; 5Department of Radiology and BRIC; 6Department of Psychiatry, University of North Carolina-Chapel Hill

Human brain is intrinsically organized as a functionally connected network, facilitating efficient information integration, processing and decision making. This study shows the evolution of this network from the age of 2 weeks to 2 years.

13:54         490.       Differences in Blood Perfusion Between Extremely Low Birth Weight (ELBW) Pre-Term Infants and Control Term Infants

Arvind Caprihan1, U Sakoglu1, J Pfeuffer2, J Rael3, J Stephen1, J Lowe3, S Duvall1, C Gasparovic1, R K. Ohls3, J P. Phillips1,3

1The Mind Research Network, Albuquerque, NM, USA; 2Siemens Medical Solutions USA, Inc, Charlestown, MA, USA; 3University of New Mexico, Albuquerque, NM, USA

Reduced blood perfusion is one of the causes of ischemic brain injury in extremely low birth weight (ELBW) infants. One potential new therapy to reduce or prevent brain injury is the use of human recombinant erythropoietin (Epo). We compare neurodevelopmental outcomes with brain blood perfusion distribution in preterm infants who received Epo during their hospitalization, compared to preterm infants who did not, and compared with healthy term controls. This is an ongoing blind study and at present we report on blood perfusion measurements by pulsed arterial spin labeling (PASL) in ELBW infants and healthy term controls.

14:06         491.       Development of Major White Matter Tracts in Fetal Brains Revealed by DTI

Hao Huang1, Linda J. Richards2, Paul Yarowsky3, Susumu Mori4,5

1Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, USA; 2Queensland Brain Institute, The University of Queensland, St Lucia, QLD, Australia; 3Pharmacology and Experimental Therapeutics, University of Maryland, Baltimore, MD, USA; 4Radiology, Johns Hopkins University, Baltimore, MD, USA; 5F.M. Kirby Functional MRI Center, Kennedy Krieger Institute, Baltimore, MD, USA

The human fetal brain development is characterized with dramatic structural changes. Specifically during the second trimester, some important white matter tracts begin to form and the existing tracts undergo significantly morphological changes. DTI colormap and tractography are capable of revealing the white matter changes. In this study, DTI data of postmortem human fetal brains from 13 to 22 gestational weeks were acquired for structural annotation and tractography. Tracts in brain stem and limbic tracts develop early and before second trimester. During second trimester, corpus callosum, uncinate, inferior fronto-occipital and inferior longitudinal fasciculus begin to form.

14:18         492.       Following the Development of Corpus Callosum (CC) in the Prenatal Period in Humans Through Diffusion Tensor Tractography (DTT)

Richa Trivedi1, Sona Saksena1, Shruti Agarwal2, Nuzhat Husain3, Ram K  S Rathore2, Rakesh K. Gupta1

1Department of Radiodiagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India; 2Department of Mathematics and Statistics, Indian Institute of Technology, Kanpur, India; 3Neuropathology, Chhatrapati Sahuji Maharaj Medical University, Lucknow, India

DTT using FACT Algorithm was performed on 20 normal human fetal brains with age ranging from 16 to 40 weeks of gestational age (GA) to study the normal appearance and development of CC. Quadratic model was considered to examine the trends in callosal FA with increasing GA. A significant positive correlation was observed between callosal bundle FA values and GA. Beyond 19 weeks of GA, CC formed a shape like adult form only in terms of superficial appearance that further showed increment in both fiber length and thickness with age. The ability to noninvasive monitoring of CC development in vivo should greatly improve our understanding of the normal developmental pattern of CC in human fetal brain that may be used as a reference for the diagnosis of developmental defects of the CC.

14:30         493.       Quantitative Diffusion Tensor Tractography (DTT) of Motor and Sensory White Matter Pathways in Cerebral Palsy

Richa Trivedi1, Shruti Agarwal2, Vipul Shah3, Vimal K. Paliwal4, Ram K  S Rathore2, Rakesh K. Gupta1

1Department of Radiodiagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India; 2Department of Mathematics and Statistics, Indian Institute of Technology, Kanpur, India; 3Pediatric Orthopedic Surgery unit, Bhargava Nursing Home, Lucknow, India; 4Department of Neurology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India

DTT using FACT Algorithm was performed on 39 children with cerebral palsy (CP) (8 years mean age) as well as 14 age/ sex matched healthy controls. Free hand ROIs for FA and MD quantitation were drawn on axial T2 image near the brain’s vertex on the precentral and postcentral gyri, and were defined as motor or sensory tracts, respectively. Based on the present study, it appears that patients with CP with normal imaging on conventional MRI have microstructural damage predominately in the sensory pathway. In conclusion, this quantitative DTT characterizes the trends in spatially averaged diffusivity and FA for the CP patients with normal as well as abnormal imaging in motor and sensory tracts.

14:42         494.       Early White Matter Maturation: A Longitudinal Study of Normal Pediatric Subjects from the Age of 2 Weeks to 4 Years

Yasheng Chen1, Hongtu Zhu2, Dinggang Shen1, Hongyu An1, John Gilmore3, Weili Lin1

1Radiology, UNC-CH, Chapel Hill, NC, USA; 2Biostatistics, UNC-CH, Chapel Hill, NC, USA; 3Psychiatry, UNC-CH, Chapel Hill, NC, USA

This is a longitudinal study to quantify early white matter maturation patterns via diffusion tensor imaging (DTI). Twenty nine full-term, healthy babies were longitudinally scanned for a total of 71 data sets spanning from 2wks after birth to four-year-old. The changing patterns in four DTI parameters including fractional anisotropy, mean, radial and axial diffusivities were quantified through a generalized estimating equation based longitudinal analysis framework. We found that the genu of the corpus callosum has a more rapid myelination process when compared to the internal capsule and the splenium and body of the corpus callosum. The external capsule has a slower maturation pace compared to the corpus callosum and internal capsule.

14:54         495.       White Matter Maturation in Healthy Children and Patients Treated with Brain Radiation: A Longitudinal DTI Study

Firouzeh Tannazi1, Todd R. McNutt2, Siamak Ardekani3, Moody D. Wharam2, Alena Horska1

1The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 2Radiation Oncology & Molecular Radiation Sciences, Johns Hopkins University, Baltimore, MD, USA; 3Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA

A longitudinal DTI study with 3 follow-up examinations (over a 27 month period) was conducted to examine brain maturation of selected white matter regions in healthy children and adolescents, and pediatric patients who received radiation therapy for brain malignancies. Healthy children demonstrated regional age-related decrease in ADC and increase in FA. In children who received radiation therapy, regional increase in ADC, decline in FA, and increase in radial diffusivity was detected consistent with radiation-induced demyelination.

15:06         496.       Voxel Based Analysis of Diffusion Indices and Deformation Based Volumetric Alterations in Late Childhood and Adolescence

Siamak Ardekani1, Firouzeh Tannazi2, Alena Horska2

1Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD, USA; 2The Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA

Changes in white matter microstructure and brain tissue volume during late childhood and early adolescence were studied using voxel-based analysis of diffusion parameters and deformation-based volumetric measures, utilizing a non-linear registration algorithm. Fifteen healthy children were examined longitudinally, at baseline and a 15 month follow-up. Statistical analyses revealed significant ADC decrease and FA increase, and axial and radial diffusivity decline in several regions (internal and external capsule, forceps minor, and corona radiata). A trend to increased tissue volume was also detected in several regions. These results suggest continuation of regional brain maturation and increase in fiber density during late childhood.

15:18         497.       Multimodality Neuroimaging to Study Tourette Syndrome: Correlating AMT-PET and DT-MRI.

Anita SD Saporta1, Malek I. Makki2, Benjamin J. Wilson1, Michael E. Behen1, Otto Muzik1, Csaba Juhasz1, Harry T. Chugani1

1Pediatrics, Wayne State University, Detroit, MI, USA; 2Radiology, Wayne State University, Detroit, MI, USA

To study serotonin-metabolism and microstructure associations in caudate nucleus (CN) and thalamus (TH), components of cortico-striato-thalamic-circuit affected in Tourette-Syndrome (TS), 15 children with TS underwent AMT-PET and DT-MRI scans. Eigenvalues, FA, ADC, linear, planar, and spherical (Cs) indices were obtained. Coregistration of both scans was performed to delineate those structures. Pearson-correlation analyses of the asymmetry index (AI) of AMT and DTI showed negative correlation between AMT and FA (r= -0.744;p=0.001) and positive correlation between AMT and Cs (r=0.594;p=0.019) in CN, but none in TH. Our findings will help to track neuronal/axonal/dendritical changes and to obtain a better understanding of TS.

EDUCATIONAL COURSE
Introduction to Biomarkers

Room 315                             13:30 – 15:30                                                            Moderators:  H. Cecil Charles and Jeffrey L. Evelhoch

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Describe what a biomarker is and how magnetic resonance can be used as a biomarker;

·   Explain how biomarkers are qualified to be fit for their intended purpose;

·   Review what is required to use MR biomarkers in both preclinical studies and clinical trials; and

·   Give examples of how imaging biomarkers are being used in at least two of the following areas:  multiple sclerosis, oncology, cardiovascular diseases, and neurodegenerative diseases.


Introduction to Imaging Biomarkers

 

13:30       What Imaging Biomarkers Are and How They Are Used
John C. Waterton


14:00      
Non-Imaging Biomarkers and Regulatory Aspects of Imaging Biomarkers

Jeffrey L. Evelhoch

14:30       Preclinical Applications of Imaging Biomarkers

Markus von Kienlin

15:00       Imaging Biomarkers in Neurodegenerative Diseases

Clifford R. Jack, Jr.

EDUCATIONAL COURSE
Use of Intravenous Contrast in MRI

Room 314                             13:30 – 15:30                                                             Moderators:  Marco Essig and Pia C. Maly Sundgren

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Explain NSF and its consequences in relation to contrast media;

·   Describe overall current and future use contrast media;

·   Describe the differences in use of contrast media at high field;

·   Recognize the limited need for contrast media in neuro MR imaging of infants;

·   Recognize the challenges, limitations, and pitfalls of current imaging techniques with respect to the use of contrast media; and

·   Discuss present and future potential MR imaging techniques that can be used as alternatives when contrast media cannot be used.

 

13:30       What is New in Contrast-Enhanced MRI?
Marco Essig


13:55      
Contrast at High Field - No syllabus contribution at time of publication.

Michael V. Knopp

14:20       The Use of High-Dosage Contrast in the Era of NSF - No syllabus contribution at time of publication.

Ruth C. Carlos

14:45       Is There a Need for Use of Contrast in the Pregnant Mother and in Small Children?

Pia C. Maly Sundgren

15:10       Use of Contrast Agents in Functional Imaging Techniques: Perfusion or Dynamic Contrast-Enhanced MRI vs.

Non-Enhanced Techniques

Xavier G. Golay

HANDS-ON WORKSHOP 2
Body and Cardiovascular Protocol Optimization
Siemens

Room 324                             13:30 – 15:30                                                                                                                                                           

CLINICAL INTENSIVE COURSE
Case-Based Teaching IV: fMRI & DTI in Clinical Practice

Room 310                             16:00 – 18:00                                                         Moderators:  Nicola De Stefano and Micheal D. Phillips

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Describe the main applications of fMRI and DTI on clinical grounds;

·   Describe the technical requirements necessary for implementing robust, accurate, and repeatable clinical advanced fMRI/DTI studies in patients with neurological diseases;

·   Implement appropriate fMRI/DTI protocols for clinical assessment of single cases;

·   Recognize challenges, limitations and pitfalls of performing advanced fMRI/DTI protocols to answer clinical questions in neurological patients; and

·   Implement quality assurance procedures necessary to run reliable and successful fMRI/DTI protocols in clinic.


16:00        
What to Know to Do It Well - No syllabus contribution at time of publication.

                  John L. Ulmer

                                                     

16:45         Questions

 

17:00         Limitations

                  Andreas Bartsch

 

17:45         Questions

CLINICAL INTENSIVE COURSE
MR Physics & Techniques for Clinicians

Room 313A                         16:00 – 18:00                                                                   Moderators:  Marcus Alley and Frank R. Korosec               

Educational Objectives:
Upon completion of this session, participants should be able to:

·   Define and describe the fundamental principles of MR imaging, including the definition of spin magnetization, the Larmor relationship, relaxation phenomena, and the process of using the spin magnetization to produce an image;

·   Explain imaging pulse sequences based upon spin and gradient echoes, including fast spin-echo and echo planar techniques;

·   Design MR imaging protocols for diagnostic applications considering image contrast, spatial resolution, acquisition time, signal-to-noise ratio, and artifacts; and

·   Describe the principles of parallel imaging, high-field imaging, perfusion imaging, diffusion imaging, and functional MR imaging.



16:00       Ultrafast Imaging

Jeffrey Tsao

16:40       Parallel Imaging

                Mark A. Griswold

 

17:20       High Field Imaging

                Klaus Scheffler

Emerging RF Methods

Room 316A                         16:00-18:00                                                                  Moderators: Arne Reykowski and Andrew G. Webb

16:00         498.       Whole-Body Traveling-Wave Imaging at 7 Tesla: Simulations and Early In-Vivo Experience

Bei Zhang1, Graham Wiggins1, Qi Duan1, Riccardo Lattanzi1, Daniel K. Sodickson1

1Radiology, Center for Biomedical Imaging, NYU School of Medicine, New York, NY, USA

Using full-wave electrodynamic simulations with a human body model as well as in-vivo human imaging, we explore basic principles of signal distribution and energy deposition for whole-body traveling wave MR driven by a patch antenna at 7T. Both simulations and experimental results demonstrate preferential excitation and energy deposition proximal to the patch antenna, with increasing attenuation at increasing distance. This phenomenon can be explained using simple models of dielectric-filled waveguides. Reflections from dielectric boundaries can result in local field focusing. Incomplete containment of fields from the patch antenna within the scanner bore reduces transmit and receive efficiency.

16:12         499.       Travelling-Wave MRI: Initial Results of In-Vivo Head Imaging at 7T

David Otto Brunner1, Jan Paska2, Juerg Froehlich2, Klaas Paul Pruessmann1

1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 2Laboratory for Electromagnetic Fields and Microwave Electronics, ETH Zurich, Zurich, Switzerland

Travelling wave MRI has been tested for safety aspects for its application to human head imaging by means of full wave simulations including anatomical tissue models. It could be shown, that such a setup can be safely used within the same power limitations as volume head coils. Based on that, initial experiments revealing the RF coverage achieved by travelling wave MRI have been performed. The scans showed, that covering the head including the shoulders is feasible. In order to cope with present non-uniformities, an initial approach to match dielectric interfaces reducing reflections has been evaluated.

16:24         500.       Effective Delivery of the Traveling Wave to Distant Locations in the Body at 7T

Anna Andreychenko1, Dennis W.J. Klomp1, Bob van den Bergen1, Bart L. van de Bank1, Hugo Kroeze1, Jan J.W. Lagendijk1, Peter Luijten1, Cornelis A.T. van den Berg1

1Dept. of Radiotherapy and Radiology, University Medical Center Utrecht, Utrecht, Netherlands

A strong attenuation of the traveling wave occurs during the passage through the body. In this study we propose a new concept to deliver a maximum B1+ to distant locations in the body using the waveguide with a coaxial conductive inset. A 2 to 6 times higher SNR ratios in 7T MR images of the male pelvis comparing to the standard traveling wave excitation were achieved with this concept. On top of that, the use of the coaxial conductive inset results in significantly lower SAR levels in the body.

16:36         501.       An Optically Detunable Coil for Improved Self Gating in Small Animals

Matthias Korn1, Reiner Umathum1, Jessica Schulz1,2, Axel Joachim Krafft1, Wolfhard Semmler1, Michael Bock1

1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; 2Siemens Healthcare, Erlangen, Germany

Physiological motion correction using MR-signals (self gating) has become a widely used method. However in small animal MRI the acquisition of motion dependent signals can be challenging. In this work a hardware-device, consisting of an inductively coupled coil that can be dynamically detuned by an optical trigger signal, is presented. Only during acquisition of the gating signal the coil is tuned and therefore enhances the gating signal while the over all image remains homogeneous. Experiments on mice are shown where the self gating signal was amplified by a factor of 1.7 to 2.8.

16:48         502.       Calcium Titanate Based Ceramic Resonators for High Field Magnetic Resonance

Kristina Haines1, Thomas Neuberger2, Michael Lanagan3, Elena Semouchkina3, Andrew Webb4

1Electrical Engineering, Penn State University, USA; 2Huck Institute, Penn State University, USA; 3Materials Research Laboratory, Penn State University; 4Radiology, Leiden University Medical Center, Leiden, Netherlands

A high sensitivity resonator was constructed from CaTiO3, relative permittivity 156, Q value of 2081, for magnetic resonance experiments at 600 MHz. This design is simple to construct, avoids wavelength effects, is highly mechanically stable and is low loss. The sample is placed in a volume of strong, homogeneous B field and very low E field. High resolution images of zebrafish have been acquired using this probe.

17:00         503.       Beyond Copper: MR Imaging with Carbon Nanotube Receiver Coils

Raju Viswanathan1, Bradley Goldstein1, Kevan Anderson2, Michael Bronskill2, Ray Baughman3, Mei Zhang4, Shaoli Fang3, Anvar Zakhidov3, Ali Aliev3

1Tursiop Technologies, LLC, Cleveland, OH, USA; 2University of Toronto, Toronto, Ontario, Canada; 3University of Texas at Dallas, Richardson, TX, USA; 4Florida State University, Tallahassee, FL, USA

Fabrication advances in nanotechnology have recently enabled construction of nanostructured materials with macroscopic dimensions and interesting electrical properties. A macroscopic sheet composed of carbon nanotubes was used to construct an MR receiver coil. The electrically conducting nanomaterial is made by a solid-state process akin to textile drawing. It displays negligible electrical skin effects over the range of frequencies relevant to MR imaging. The receiver coil was used to image a mouse head at 3T at 0.25 mm in-plane resolution and resulted in excellent image quality. The material offers the possibility of significant enhancements in SNR in clinical MR imaging applications.

17:12         504.       Operational Inkjet-Printed Metal-On-Kapton MRI Receiver Coil

Dario Mager1, Ute Loeffelman1, Andreas Peter1, Laura Del Tin1, Elmar Fischer2, Patrick James Smith1, Juergen Hennig2, Jan Gerrit Korvink1

1Dept. of Microsystems Engineering – IMTEK, University of Freiburg, Freiburg, Germany; 2Dept. of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany

We present for the first time the results of a self-resonant MR receiver coil, manufactured on a flexible Kapton foil, with the metal lines pattern by inkjet printing. An MRI image sequence was taken using a Bruker BioSpec scanner at 9.4 T. The results of the measurement were comparable to a standard receiver coil. Inkjet printing can therefore be considered as a feasible approach in the rapid and low cost production of receiver coils. Inkjet printing is

not limited to planar substrates, since it can be easily adapted to produce non-planar structures.

17:24         505.       A Mechanically Rotating RF Transceive System and Method  for Applications in Magnetic Resonance

Adnan Trakic1, Bing Keong Li1, Ewald Weber1, Feng Liu1, Stephen Wilson1, Stuart Crozier1

1The School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Queensland, Australia

This study introduces a new MRI approach using a rapidly rotating RF (RRF) transceive coil. RF coil rotation offers an additional degree of freedom for MR imaging in that it emulates a large conventional RF coil array. To test its feasibility, a small RRF transceive coil system was constructed and operated at about 1200 revolutions per minute in a 2 Tesla field. The MR images obtained were uniform and of good quality. The RRF approach may obviate the need for multiple channels and tedious RF coil decoupling.

17:36         506.       Real-Time Full-Wave Simulations of RF Coils by Fast Integral Equation Methods

shumin wang1, Jacco de Zwart1, Jeff Duyn1

1NIH, Bethesda, MD, USA

A fast integral equation method is proposed for real-time patient-dependent simulations of high-field RF coils. This topology-based multi-level Crout method starts by partitioning a model into sub-domains and organizing them in a multi-level fashion. Based on the rank-deficient nature of the interactions between distant sub-domains, the Crout algorithm was applied to compress the corresponding matrix blocks. Numerical results were used to verify this method and to demonstrate its efficiency in real-time coil simulations. A promising application is per-patient specific absorption ratio (SAR) estimation.

17:48         507.       Improving SNR by Generalizing Noise Matching for Array Coils

Christian Findeklee1

1Philips Research Europe, Hamburg, Germany

The theory of noise matching is well known for single elements or well decoupled coils. However, in practical applications, residual mutual coupling leads to noise coupling, which decreases the final SNR. As shown in this paper, this can be avoided by generalizing the scalar noise matching for array coils. Simulations and Experiments have been performed to prove the new concept.

fMRI: Spatial & Temporal Signal Characteristics

Room 323ABC                    16:00-18:00                                                                          Moderators: Laura M. Parkes and Kamil Uludag

16:00         508.       From Two-Photon Microscopy to BOLD-FMRI: Association of an Undershoot of Arteriolar Diameter with the BOLD Post-Stimulus Undershoot

Anna Devor1,2, Richard Buxton3, Peifang Tian1, Ivan Teng1, Kun Lu1, Larry May1, Ron Kurz1, Anders Dale1

1University of California, San Diego; 2Martinos Center for Biomedical Imaging, Harvard; 3University of California, San Diego, La Jolla, CA, USA

Although the origins of the BOLD post-stimulus undershoot have been debated since the early days of fMRI, there is still no consensus on whether it is a neural, metabolic or vascular effect, and experimental evidence has been presented for each interpretation. To test directly whether vascular dynamics are evident during the post-stimulus undershoot, we performed BOLD-fMRI and 2-photon microscopic dynamic vascular diameter measurements under the same conditions in rat primary somatosensory cortex (SI). Although there was no evidence of a venous balloon effect, arteriolar diameter exhibited a post-stimulus undershoot with a similar time scale to the BOLD post-stimulus undershoot, suggesting a vascular rather than metabolic origin for the undershoot.

16:12         509.       Revisit Nonlinearity in Blood-Oxygenation-Level-Dependent Signal

Nanyin Zhang1, Essa Yacoub1, Xiao-Hong Zhu1, Kamil Ugurbil1, Wei Chen1

1Radiology, University of Minnesota, Minneapolis, MN, USA

Literature studies suggest that there are significant nonlinear characteristics in the BOLD signal in response to evoked neuronal activity. We demonstrated previously that when eliminating contributions from large vessels, the nonlinearity in the BOLD signal becomes much less significant. In this study we have investigated (non)linear characteristics of the BOLD signal from the microvasculature using a combination of SE fMRI and a paired-stimulus paradigm. We found that that SE BOLD signal acquired at high magnetic fields, which is sensitive mainly to the microvasculature, is primarily a linear system.

16:24         510.       Neural and Vascular Response Nonlinearity in Human Visual Cortex

Zhongming Liu1, Cristina Rios1, Lin Yang1, Nanyin Zhang2,3, Wei Chen2,3, Bin He1

1Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA; 2Center for Magnetic Resonance Research, University of Minnesota Medical School, Minneapolis, MN, USA; 3Department of Radiology, University of Minnesota Medical School, Minneapolis, MN, USA

The BOLD nonlinearity may reflect a nonlinear neural response to stimuli and/or a nonlinear vascular response to neural activity. To pinpoint the origin of the BOLD nonlinearity, we investigated the nonlinear effects of neural and vascular responses to sustained visual stimuli with variable temporal frequency ranging from 1/6 to 25 Hz. Using scalp EEG, we found the neural response nonlinearity existed only at very short ISI (<200 ms). Using fMRI, we observed the BOLD nonlinearity for ISI between 0.25 and 4 sec. Such nonlinearity has an exclusively vascular origin and is attributed to the vascular refractory effect instead of the vascular saturation effect.

16:36         511.       Measurement of Parenchymal T2* Changes During Visual Stimulation Using Grey Matter Nulled and VASO FMRI

Yuji Shen1, Ida Mengyi Pu2, Risto A. Kauppinen3

1School of Medicine, University of Birmingham, Birmingham, UK; 2Department of Computing, Goldsmiths, University of London, London, UK; 3Biomedical NMR Research Center, Dartmouth Medical School, Hanover, NH 03755, USA

It is feasible to use MRI for quantification of blood oxygen saturation (Y) and oxygen extraction fraction (OEF) in vivo from transverse relaxation data. In this study we used grey matter nulled (GMN) and vascular space occupancy (VASO) fMRI techniques to measure T2* in brain parenchyma at baseline and during visual stimulation at 3T. The change in T2* obtained by GMN fMRI was 1.8±0.8 ms, which was much greater than that detected by VASO fMRI (0.6±0.3 ms). The venous oxygen saturation (Yv) during activation and OEF derived from VASO data were found to be 0.77±0.02 and 0.22±0.02, respectively.

16:48         512.       BOLD Imaging of Inhibition and Facilitation Induced by Paired-Pulse Transcranial Magnetic Stimulation:  Feasibility and Reproducibility

Juergen Baudewig1, Carsten Schmidt-Samoa1, Peter Dechent1

1MR-Research in Neurology and Psychiatry, University of Goettingen, Goettingen, Germany

It is still a matter of controversy whether local hemodynamic changes detected with BOLD-fMRI are equally correlated to inhibitory and excitatory processes. Paired-pulse TMS is a well established method to induce inhibition or facilitation by varying the interstimulus intervals. We applied paired TMS pulses during simultaneous fMRI recordings at 3T in order to visualize the TMS-induced modulation of cortical excitability. EMG data acquired directly prior to the fMRI experiment proved the excitatory or inhibitory effect of long or short interstimulus intervals. Excitatory TMS pulse pairs resulted in increased BOLD responses in comparision to inhibitory stimulus intervals.

17:00         513.       Cerebral Blood Flow (CBF) and Cerebral Blood Volume (CBV) Coupling Differs During Neuronal and Vascular Tasks

Manus Joseph Donahue1,2, Robert D. Stevens3, Jun Hua1,2, Alan Huang1,2, James J. Pekar1,2, Peter CM van Zijl1,2

1Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA; 2FM Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA; 3Anesthesiology and Critical Care Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, USA

A common BOLD quantification approach employs a hypercapnic stimulus to evaluate CBF contributions. This method assumes that the neuronal hemodynamic response is due to increased metabolism causing release of vasodilatory CO2/H+ and that CBV/CBF coupling is equal for neuronal and vascular stimuli. Using breath hold as vascular stimulus and visual activation as neuronal stimulus, we found (n = 9) a similar CBF response and a doubling of the CBV response for breath hold versus visual stimulation. These results challenge the assumption of invariance in CBF/CBV coupling and suggest BOLD calibration should account for both CBF and CBV changes.

17:12         514.       Transcortical BOLD Impulse Response Functions: Implications for Layer-Specific CMRO2 Calculation

Peter Herman1,2, Basavaraju G. Sanganahalli1, Hal Blumenfeld3,4, Fahmeed Hyder1,5

1Diagnostic Radiology, Yale University, New Haven, CT, USA; 2Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Budapest, Hungary; 3Neurology, Yale University, New Haven, CT, USA; 4Neurobiology, Yale University, New Haven, CT, USA; 5Biomedical Engineering, Yale University, New Haven, CT, USA

Oxidative neuroenergetics with calibrated fMRI has become a popular technique. Measurements of BOLD, CBV, CBF and/or neural activity are needed to calculate CMRO2. Transcortical selection of signals can be an important factor as these parameters may vary across cortical layers. We calculated transfer functions in three cortical layers to explore transcortical differences in BOLD and LFP signals. The amplitude of the BOLD and LFP signals decreases toward the deeper layers, but the normalized signals show very high correlation between layers. The transfer function analysis revealed, while the upper and middle layers interchangeable, the lower layer is needed for calibration separately.

17:24         515.       Layer Specific BOLD Activation in Human V1 at 3 Tesla

Peter Jan Koopmans1, Markus Barth1,2, David Gordon Norris1,2

1Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands; 2Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, Germany

This study shows cortical layer specific activation measured in human visual cortex using gradient echo acquisition at 3 Tesla. The BOLD point-spread function reported in literature is too broad for such measurements. Based upon the known laminar blood-vessel distribution we conclude that the PSF is much smaller in the through-cortex direction and that the intrinsic spatial resolution of the GE-BOLD-fMRI signal is in the sub-millimeter range.

17:36         516.       BOLD FMRI of Forepaw Stimulation at Different Amplitudes in Mice

Simone Claudia Bosshard1, Christof Baltes1, Thomas Mueggler1, Markus Rudin1,2

1Institute for Biomedical Engineering, ETH Zurich, Zurich, Switzerland; 2Institute of Pharmacology and Toxicology, University of Zurich, Zurich, Switzerland

fMRI in mice is challenging due to high demands in sensitivity. Using a cryogenic RF transceiver probe, BOLD fMRI of electrical forepaw stimulation was performed in mice under isoflurane anesthesia. The BOLD signal comprised a slow and a fast component, which may reflect different processing pathways. The two signal contributions were analyzed separately in the S1 somatosensory cortex and the thalamus and were shown to correlate well with the current amplitude of the stimulus. The segregation of the signal into two components might help to understand the underlying physiological processes.

17:48         517.       Predicting Human Decisions in a Social Interaction-Scenario Using Real-Time Functional Magnetic Resonance Imaging (Rt-FMRI)

Maurice Hollmann1, Sebastian Baecke1, Charles Mueller1, Johannes Bernarding1

1Institute for Biometry and Medical Informatic, University Magdeburg, Magdeburg, Sachsen-Anhalt, Germany

Making decisions in a social context is fundamental in our daily life. Is it possible to predict decisions by investigating activation patterns of the brain? We used a paradigm from economic behavioral research: the Ultimatum Game (UG). In the UG, two players split a sum of money. One player decides how the money should be split. The responder can accept or reject this offer. If rejected, neither player receives anything. In our study an rtfMRI-system was used to predict the decision of the responder 1-2 seconds before the subject conveys the decision. Classification accuracy reached 70% averaged over seven subjects.

MR Tracking of Capsules & Cells

Room 316BC                       16:00-18:00                                                                       Moderators: Anna V. Moore and Michal Neeman

16:00         518.       Development of a Magnetosonoporation-Enhanced Stem Cell Labeling Technique

Bensheng Qiu1, Daohai Xie, Piotr Walczak2, Jesus Ruiz-Cabello3, Satoshi Minoshima, Jeff W.M. Bulte2, Xiaoming Yang

1Radiology, University of Washington, Seattle, WA, USA; 2Johns Hopkins University; 3Universidad Complutense de Madrid

Monitoring of stem cells migrating or homing to the targets is essential for the success of stem cell-based therapies. For non-invasive magnetic resonance imaging (MRI) to serially track cell migration, recent efforts have focused on labeling cells with MR contrast agents, such as superparamagnetic iron oxide (SPIO) particles1. The currently-available MR cell labeling techniques include simple incubation and magnetoelectroporation. We attempted to develop an alternative instant cell labeling technique, using ultrasound to facilitate MR-labeling of cells, called magneto-sonoporation (MSP), which is based on the fact that ultrasound can increase cell membrane permeability to external molecules.

16:12         519.       Enhanced Cerebral Targeting of Magnetically Labeled Glial Precursor Cells Using the VLA-4/VCAM-1 Adhesion Pathway

Piotr Walczak1,2, Michael Levy2,3, Michael Gorelik2,3, Douglas A. Kerr2,3, Jeff W.M Bulte1,2

1Radiology, Johns Hopkins University, Baltimore, MD, USA; 2Institute for Cell Engineering, Johns Hopkins University, Baltimore, MD, USA; 3Neurology, Johns Hopkins University, Baltimore, MD, USA

Global cerebral targeting and homing of therapeutic stem cells is of key importance for neurodegenerative disorders having multiple lesions. For cell therapy using intra-arterial injections, it is critical to achieve a high level of initial cellular adhesion to cerebral endothelium before cells can enter the brain parenchyma. We have exploited the use of the VLA-4/VCAM-1 endothelial adhesion pathway to enhance initial endothelial binding by means of transfecting glial restricted precursors (GRPs) with VLA-4. In an LPS-induced inflammatory brain model, Feridex-labeled and VLA-4 over-expressing GRPs showed a dramatically enhanced global cerebral retention as compared to those injected in normal brain.

16:24         520.       Development of an in Vivo Functional Assay to Monitor the Effect of SPIO Labeling on Murine Dendritic Cells Used for Cell Therapy in MRI

Richard Tavaré1, Gopal Varma1, Pervinder Sagoo2, Yakup Tanriver2, Tobias Schaeffter1, Robert Lechler2, Giovanna Lombardi2, Greg Mullen1

1Division of Imaging Sciences, King's College London, London, UK; 2Department of Nephrology and Transplantation, King's College London, London, UK

Dendritic cells are currently being studied as a therapy for both cancer and transplant tolerance. Non-invasive imaging of dendritic cells labeled with superparamagnetic iron oxides (SPIOs) migrating to lymph nodes allows for the monitoring of an efficient cellular therapy. Here, to test the funtion of labeled versus unlabeled cells, the development of an in vivo funtional assay is described, as well as serial imaging of SPIO labeled dendritic cells migrating to the popliteal lymph node.

16:36         521.       Using a 19F MRI Tracer Agent for in Vivo Tracking of Human Dendritic Cell Vaccines<

Brooke M. Helfer1, Aaron D. Nelson1, Jelena M. Janjic2, Eric T. Ahrens2,3, Roberto R. Gil4, Pawel Kalinski5, Jolanda de Vries6, Robbie B. Mailliard1

1Research and Development, Celsense, Inc, Pittsburgh, PA, USA; 2Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA; 3Pittsburgh NMR Center for Biomedical Sciences, Carnegie Mellon University, Pittsburgh, PA, USA; 4Department of Chemistry, Carnegie Mellon University, Pittsburgh, PA, USA; 5Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA; 6Department of Pediatric Hemato-Oncology, Nijmegen Center for Molecular Life Sciences, Radboud University, Nijmegen, Netherlands

Dendritic cells (DCs), the central antigen presenting cells of the immune system, have been widely used in clinical trials as anti-cancer vaccines with mixed success. This is partially due to inabilities to non-invasively track adoptively transferred cells after administration. In this study, we show for the first time that clinically relevant human DCs can be effectively labeled in vitro with commercially 19F-tracers without impact to cell health, phenotype, or function, allowing these cells to be visualized post-injection in vivo by 19F-MRI. This study demonstrates the utility and possible clinical application of this method for monitoring patients in cell therapy trials.

 

16:48         522.       Tracking Enhanced Green Fluorescence Protein (EGFP) and Micrometer-Sized Particles of Iron Oxide (MPIO) Labeled Mesenchymal Stem Cells (MSCs) in a Myocardial Infarction Model with Granulocyte-Colony Stimulating Factor (GCSF) Modulation

Yidong Yang1,2, Yuhui Yang2, Brianna Klein2, Nathan Yanasak2, Xingming Shi3, William Dave Hill4,5, Tom C.-C. Hu1,2

1Medical Physics Program, Georgia Institute of Technology, Atlanta, GA, USA; 2Department of Radiology, Medical College of Georgia, Augusta, GA, USA; 3Department of Pathology, Medical College of Georgia, Augusta, GA, USA; 4Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, GA, USA; 5Veterans Affairs Medical Center, Medical College of Georgia, Augusta, GA, USA

Synopsis: Stem cells play an important role in tissue repair and regeneration. In this study, MSCs labeled with EGFP and MPIO were transplanted into the mouse bone marrow. It was observed using MRI that the labeled cells infiltrated and engrafted into the myocardial injury and adjacent site and lead to gradual signal attenuation. Furthermore, the GCSF potentially modulated the infiltration rate of labeled MSCs and enhanced the signal attenuation. Results from this study suggest a useful method for the development of drugs designed to modulate the stem cell mobilization process.

17:00         523.       Ferritin Overexpression for Molecular Imaging of Transplanted Cells

Anna Naumova1, Hans Reinecke2,3, Vasily Yarnykh1, Chun Yuan1, Charles Murry2,3

1Radiology, University of Washington, Seattle, WA, USA; 2Pathology, University of Washington, Seattle, WA, USA; 3Center for Cardiovascular Biology, Seattle, WA, USA

We are developing genetically-based technique for molecular imaging of the MRI gene reporter ferritin to enable noninvasive assessment of cell survival and biodistribution after transplantation into infarcted rodent heart. pcDNA3-HAFerr transduction vector encoding ferritin was successfully constructed. Mouse skeletal myoblasts transduced by the vector increased intracellular iron stores, confirmed by Prussian blue staining and yielding a robust detectable effect on T2 and T1 relaxation times in vitro. Ferritin overexpression did not affect cell viability, proliferation and differentiation into multinucleated myotubes. Our pilot studies are encouraging for further in vivo studies of transplanted cells in a beating heart.

17:12         524.       MR-Visible and Immunoprotective Alginate Microcapsules for Treatment of Fulminant Liver Failure

Thomas W. Link1,2, Dian Arifin2,3, Chris M. Long1,2, Piotr Walczak2,3, Naser Muja2,3, Jeff W.M Bulte2,3

1Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; 2Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 3Cellular Imaging Section, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA

20-30% of patients with fulminant liver failure die waiting for a transplant due to shortage of donors. Microencapsulated human hepatocytes have the potential to provide a bridge to transplantation. Feridex was incorporated into novel protamine sulfate cross-linked alginate microcapsules to create MR-visible magnetocapsules. Magneto-encapsulated bioluminescent human hepatocytes were characterized in vitro, and injected into the peritoneal cavity of normal mice. Bioluminescent imaging and detection of human albumin by ELISA demonstrated that hepatocytes remained viable and functional for at least 2 weeks. Magnetocapsules were clearly visible as hypointensities throughout the peritoneal cavity.

17:24         525.       Facilitated Detection and Quantification of Theragnostic Magnetocapsules by Analyzing MRI Susceptibility Perturbations

Parker H. Mills1,2, Thomas Link3, Aravind Arepally3, Joseph D. Thompson4, Jeff W.M. Bulte3, Eric T. Ahrens1,2

1Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA, USA; 2Pittsburgh NMR Center for Biomedical Research, Pittsburgh, PA, USA; 3Institute for Cell Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA; 4Division of Materials Science & Technology, Group 10, Los Alamos National Laboratory, Los Alamos, NM, USA

Non-invasive studies have monitored the delivery and engraftment of pancreatic islets encapsulated in alginate shells containing Feridex, an FDA-approved superparamagnetic iron-oxide (SPIO). These magnetocapsules are permeable to metabolites, but not native antibodies, thus reducing or avoiding immunosuppressive therapy. Here we apply a newly developed post-processing method, Phase map cross-correlation Detection and Quantification (PDQ), to gel phantoms containing ~103, 450 μm diameter magnetocapsules. PDQ automatically identified and counted magnetocapsules, accurately measuring their magnetic moment (within 1-21% of SQUID-measured values). PDQ can potentially search tissue volumes for absolute magnetocapsule numbers, providing insight on overall islet immunoprotection and survival. PDQ requires no special pulse sequences and works on previously-acquired data.

17:36         526.       Novel Trimodal Gadolinium-Gold Microcapsules for Simultaneous Immunoprotection and Positive Contrast MRI, X-Ray, and Ultrasound Imaging of Human Pancreatic Islet Cells.

Dian Respati Arifin1,2, Christopher Long1,2, Assaf A. Gilad1,2, Sameer Manek2,3, Emma Call2, Christophe Alric4, Stephane Roux4, Olivier Tillement4, Thomas W. Link2,3, Aravind Arepally1, Jeff W.M. Bulte1,2

1Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 2Cellular Imaging Section, Institute for Cell Engineering, Johns Hopkins University School of Medicine; 3Biomedical Engineering, Johns Hopkins University School of Medicine; 4Laboratoire de Physico-Chimie des Materiaux Luminescents, Universite Claude Bernard Lyon 1, Lyon, France

Transplantation of pancreatic islet cells is a potential treatment for type I diabetes. Pancreatic islet cells and novel gold nanoparticles functionalized with DTDTPA:gadolinium chelates (GadoGold) were encapsulated inside immunoprotective microcapsules. The viability and functionality of cells encapsulated in GadoGold microcapsules was demonstrated in vitro and in vivo in diabetic mice. The capsules were readily imaged with 9.4 Tesla MRI, micro-CT, and a 40 MHz ultrasound imager. GadoGold microcapsules have potential for cell engraftment providing a means to monitor transplanted cells in vivo using MRI , X-ray and/or ultrasound imaging.

17:48         527.       Multifunctional Perfluorinated Microcapsules for Mesenchymal Stem Cell Delivery and Engraftment Tracking Using 19F MRI, X-Ray, and Ultrasound

Yingli Fu1, Dorota A. Kedziorek1, Ronald Ouwerkerk1, Steven M. Shea2, Nicole Azene1, Aravind Arepally1, Jeff WM Bulte1,3, Robert Krieg4, Frank Wacker1, Dara L. Kraitchman1

1Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, USA; 2Imaging and Visualization, Siemens Research Corporate, Inc., Baltimore, MD, USA; 3Institute of Cell Engineering, Johns Hopkins University, Baltimore, MD, USA; 4Siemens AG Healthcare Sector, Erlangen, Germany

Mesenchymal stem cell (MSC) transplantation is a promising angiogenesis induction therapy for peripheral arterial disease. To immunoprotect MSC after transplantation and monitor MSC delivery and track engraftment noninvasively in vivo, we have developed novel multifunctional perfluoroctylbromide microcapsules (PFOB Caps). Our strategy couples microencapsulation techniques with multi-modality imaging, and converts direct cell labeling and tracking task into microcapsule labeling and tracking task. In vitro, MSC viability within PFOB Caps was enhanced as compared to that in unlabeled capsules. The visibility of PFOB Caps was demonstrated in vitro and in vivo using clinical X-ray, c-arm CT, ultrasound, and 19F MR imaging systems.

Multinuclear MRS Studies of Metabolism

Room 315                             16:00-18:00                                                                  Moderators: Sebastián Cerdán and Matthew Merritt

16:00         528.       Sources of Hepatic Glycogen Synthesis During an Oral Glucose Tolerance Test: Effect of Transaldolase Exchange on Flux Estimates

Teresa Cardoso Delgado1, Claúdia Silva1, Isabel Fernandes2, Madalena Caldeira2, Margarida Bastos3, Carla Baptista3, Manuela Carvalheiro3, Carlos F.G.C. Geraldes1, John Griffith Jones1

1NMR Laboratory, Center for Neurosciences and Cell Biology of Coimbra, Coimbra, Portugal; 22Chemistry Department, Faculty of Sciences and Technology, Coimbra University, Coimbra, Portugal; 3Department of Endocrinology, Diabetes and Metabolism, University Hospital of Coimbra, Coimbra, Portugal

Sources of hepatic glycogen synthesis during a glucose tolerance test were evaluated in healthy subjects by enrichment of a glucose load with 6.67% [U-13C]glucose and 3.33% [U-2H7]glucose and 2H/13C NMR analysis of plasma glucose and hepatic UDP-glucose enrichments (sampled as urinary menthol glucuronide).The direct pathway contribution, as estimated from the dilution of [U-13C]glucose between plasma glucose and hepatic UDP-glucose, was unexpectedly low (36±5%).With [U-2H7]glucose, direct pathway estimates based on the dilution of position 3 2H-enrichment between plasma glucose and glucuronide were significantly higher (50±6%).These differences reflect the exchange of the carbon 456 moiety of fructose-6-phosphate and glyceraldehyde-3-phosphate catalyzed by transaldolase.

16:12         529.       A Novel 13C MRS-Based Marker of Pyruvate Cycling in Perfused Mouse Liver Using [2-13C] Pyruvate and 13C MRS<

Corin O'Dell Miller1, Haiying Liu1, Leslie Balogh2, Jin Cao1, Mike R. Tota3, Reshma Patel3

1Imaging, Merck, Rahway, NJ, USA; 2Laboratory Animal Research, Merck, Rahway, NJ, USA; 3Metabolic Disorders, Merck, Rahway, NJ, USA

A 13C MRS approach was employed in perfused mouse livers metabolizing substrate levels of [2-13C] pyruvate to develop a novel ex-vivo marker of pyruvate recycling based on the 13C-enrichment in lactate. Inhibition of each of the pyruvate recycling pathways (PEPCK via 3-mercapto-picolinic acid, and Malic enzyme via tartronic acid) reduced this marker in liver extracts while simultaneous inhibition of each pathway further reduced this marker to levels near the LOQ. Real time data from whole perfused livers agreed with data from extracts of freeze-clamped livers indicating that this approach may be translatable to whole tissues and possibly in vivo.

16:24         530.       Liver Tissue Repair in a Mouse Model of Toxicant-Induced Liver Injury Is Associated with Increased Hepatic Energy Metabolism:    a Multinuclear Magnetic Resonance Study

Sven Gottschalk1, Tom S. Chan1, Valérie-Ann Raymond1, Dieter Leibfritz2, Claudia Zwingmann1,2, Marc Bilodeau1

1Département de sciences biomédicales, Université de Montréal, Montréal, Québec, Canada; 2Department of Organic Chemistry, University of Bremen, Bremen, Germany

Due to its ability regenerate, the liver is an ideal model for studying tissue repair mechanisms. Only little is known about the repair-associated changes in cellular metabolic pathways. Energy-intensive repair processes should be reflected in alterations in energy metabolism. An in vivo liver-injury model was used to generate an onset of liver tissue-repair. We assessed the extent of liver-injury and NMR-spectroscopy was used to characterize changes in energy metabolism and metabolites. Our results showed that induction of liver-regeneration was consistent with an up-regulation of the cells overall energy metabolism and a higher demand for TCA-cycle intermediates (eg. for amino-acids synthesis).

16:36         531.       Detection of Altered Hepatic Gluconeogenesis by Nuclear Magnetic Resonance (NMR) and Hyperpolarized 13C Pyruvate

Matthew E. Merritt1, Crystal Harrison1, Craig R. Malloy1, A Dean Sherry1, Shawn C. Burgess1,2

1Advanced Imaging Research, UT Southwestern Medical Center, Dallas, TX, USA; 2Pharmacology, UT Southwestern Medical Center, Dallas, TX, USA

Abnormal hepatic gluconeogenesis is a hallmark feature of obesity, insulin resistance and diabetes, but its measurement requires sophisticated tracer approaches and/or serial MRS measurements over several hours. We used the DNP process to hyperpolarize [1-13C]pyruvate and followed its incorporation into hepatic metabolites over 60 seconds by 13C NMR in isolated perfused mouse liver. In addition to lactate and alanine, several resonances consistent with mitochondrial intermediates of the TCA cycle were observed. The appearance of these metabolites was diminished in livers with impaired gluconeogenesis. The data demonstrate that HP-pyruvate will be useful to observe a number of hepatic pathways, including gluconeogenesis.

16:48         532.       Real Time Assessment of Krebs Cycle Metabolism with Hyperpolarized [2-13C]Pyruvate

Damian John Tyler1, Marie Allen Schroeder1, Helen Jennifer Atherton1, Daniel R. Ball1, Mark Aaron Cole1, Lisa Claire Heather1, Julian L. Griffin2, Kieran Clarke1, George K. Radda1

1Physiology, Anatomy & Genetics, University of Oxford, Oxford, Oxfordshire, UK; 2Biochemistry, University of Cambridge, Cambridge, Cambridgeshire, UK

The Krebs cycle plays a fundamental role in cardiac energy production and is often implicated in energetic imbalances characteristic of heart disease. This study presents a novel magnetic resonance spectroscopy technique that enables real-time monitoring of Krebs cycle metabolism in whole hearts. Hyperpolarized [2-13C]pyruvate was infused into isolated perfused hearts, in both healthy and ischaemic states. The conversion of pyruvate to lactate, acetyl-carnitine, citrate and glutamate was observed. Following ischaemia, the appearance of 13C-labelled citrate and glutamate was decreased relative to the healthy state, indicating that hyperpolarized [2-13C]pyruvate may be useful when studying impaired Krebs cycle metabolism in heart disease.

17:00         533.       A 13C Isotopomer Model for Accurate NMR Quantification of Substrate Selection and Anaplerosis

Wei Li1, Fang Bian1, Priyanajana Chaudhuri1, Xin Yu1

1Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA

Pyruvate carboxylation is important in energy metabolism. However, accurate quantification of pyruvate carboxylation with NMR remains to be demonstrated. In this study, a 13C isotopomer model for citrate acid cycle was developed and applied to the quantification of pyruvate carboxylation and the comparison of NMR and GC-MS. Two groups of rat hearts were perfused with buffer containing 5.5 mM glucose and 0.6 mM palmitate with either glucose or palmitate being uniformly labeled with 13C. Pyruvate carboxylation was determined from NMR analysis of experiments. NMR and GCMS were equally good in quantifying substrate utilization, but different in quantifying anaplerosis.

17:12         534.       Novel Application of Deuterium MRS: In Vivo Monitoring of Glucose Consumption

Allen Ye1, Jeffrey L. Duerk1,2, Chris A. Flask1,2, Gheorghe D. Mateescu3

1Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA; 2Radiology, Case Western Reserve University, Cleveland, OH, USA; 3Chemistry, Case Western Reserve University, Cleveland, OH, USA

Multinuclear MRS provides a powerful platform for studying metabolism in many diseases. We have developed a novel application of Deuterium MRS to measure mitochondrial function in vivo. This straightforward method consists of the administration of deuteriated glucose to live organisms (mice, larvae) resulting in the formation of detectable levels of deuteriated metabolic water (D2O/HDO). Preliminary glucose consumption data are reported at 9.4T. A particularly important aspect of this novel approach is the simultaneous determination of glucose and oxygen consumption. Potential translation into the clinic will be useful in the diagnosis and treatment of mitochondrial diseases.

17:24         535.       Resolution of H3proS and H3proR Deuterations in [2-13C]glutamate

Tiago Brandao Rodrigues1, Inês Ribeiro Violante1, Sebastián Cerdán1

1LISMAR, Instituto de Investigaciones Biomédicas CSIC, Madrid, Spain

We provide a protocol to discriminate the 2H substitution of the H3proR or H3proS hydrogens of [2-13C]glutamate. Using 13C MRS at 18.8T, we detected the existence of two different isotopically shifted singlets in the glutamate C2 resonance of brain extracts of deuterated animals as derived from the deuterium substitutions in 3R or 3S, respectively. We show that the H3S depicted a lower value of vicinal isotopic shift (δ 1=-0.058ppm) while the H3R originated the higher-field resonance (δ 1=-0.071ppm), measured relatively to the [2-13C]glutamate C2 resonance.

17:36         536.       Hyperpolarized  13C Magnetic Resonance Detection of Carboxypeptidase G2 Activity

Yann Jamin1, Cristina Gabellieri1, Lynette Smyth1, Steve Reynolds2, Simon P. Robinson1, Caroline J. Springer1, Martin O. Leach1, Geoffrey S. Payne1, Thomas R. Eykyn1

1Institute of Cancer Research and Royal Marsden NHS trust, Sutton, UK; 2Oxford Instruments Molecular Biotools Ltd, Abingdon, UK

Carboxypeptidase G2 (CPG2) is used in cancer chemotherapy to activate selectively non toxic prodrugs into potent cytoxics in tumors. Employing Dynamic nuclear polarisation (DNP) and natural abundance 13C MRS, we demonstrate the dynamic detection of CPG2 activity in vitro, using the reporter molecule 3,5-difluorobenzoyl-L-glutamic acid (3,5-DFBGlu). This strategy could be translated in vivo to monitor CPG2-based therapy.

17:48         537.       Generation of Hyperpolarized Substrates by Secondary Labelling with [1,1- 13C] Acetic Anhydride

David M. Wilson1, Ralph E. Hurd2, Albert P. Chen2, Mark Van Criekinge1, Kayvan Keshari1, Sarah J. Nelson1, Daniel B. Vigneron1, John Kurhanewicz1

1Department of Radiology, University of California, San Francisco, San Francisco, CA, USA; 2GE Healthcare

Hyperpolarized [1,1-13C] acetic anhydride was used to achieve rapid, high SNR analysis of amino acid mixtures and to perform secondary polarization of other biomolecules in solution. This electrophile can be well polarized (6%), has a relatively long T1 relaxation time (33.9s at 11.7T), and preferentially reacts with amine nucleophiles in aqueous solution. This approach was used to reproducibly and near-quantitatively (mean yield – 89.8%) resolve a mixture of amino acids Gly, Ser, Val, Leu, and Ala, with a signal enhancement of up to 1400 fold. The method can also be used to create a hyperpolarized low molecular weight drug like acetylcysteine.

Animal Models of Neurodegeneration

Room 311                             16:00-18:00                                                                   Moderators: Louise van der Weerd and Ruth Vreys

16:00         538.       Young Investigator Award Finalist:  Magnetic Resonance Imaging and Histological Analysis of Beta-Amyloid Plaques in Both Human Alzheimer’s Disease and APP/PS1 Transgenic Mice

Mark David Meadowcroft1,2, James R. Connor3, Michael B. Smith1, Qing X. Yang1,3

1Radiology, Pennsylvania State University - College of Medicine, Hershey, PA, USA; 2Neural and Behavioral Sciences, Pennsylvania State University - College of Medicine, Hershey, PA, USA; 3Neurosurgery, Pennsylvania State University - College of Medicine, Hershey, PA, USA

The histo-pathological basis of image contrast associated with Aβ plaques and the connected relaxation mechanism has not been well-understood. T2*-weighted images and R2* parametric maps were compared to histology stains from the same set of AD and APP/PS1 tissue slices. The electronic microscopy and histology images revealed differences in plaque morphology and associated iron concentration between APP/PS1 mice and AD tissue. T2* contrast of Aβ-plaques was associated with the gradation of iron concentration and plaque morphology. These data suggested a duality in the relaxation mechanism where both focal iron concentration and highly compact fibrillar Aβ masses cause rapid proton transverse magnetization decay.

16:20         539.       Imaging Biophysics of Axonal Transport with MEMRI: Optic Tract Transport Is Altered in Mouse Model of Alzheimer's Disease

Elaine L. Bearer1, Xiaowei Zhang2, Octavian Biris1, Russell E. Jacobs2

1Pathology and Laboratory Medicine, Brown University, Providence, RI, USA; 2Biology, California Institute of Technology, Pasadena, CA, USA

Alterations in transport dynamics are implicated in neurodegenerative diseases. We are using MEMRI to image the biophysics of intra-neuronal axonal transport and correlate rates of MR intensity changes with genetic/molecular differences in transport mechanics. Here we compare Mn++ transport dynamics observed by capturing 6-min time-lapse MR images in the polarized neural processes of the optic track between aged mice expressing an APP mutant correlated with Alzheimer' disease in humans (swAPP) and their wild-type age-matched counterparts. Our findings show that transport dynamics in the optic track are altered in the swAPP mouse, an Alzheimer's disease model.

16:32         540.       Early Impaired Axonal Transport in a Triple Transgenic Mouse Model of Alzheimer’s Disease

Jieun Kim1, In-Young Choi1,2, Mary L. Michaelis3, Sang-Pil Lee1,4

1Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS, USA; 2Department of Neurology, Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA; 3Department of Pharmacology and Toxocology, University of Kansas, Lawrence, KS, USA; 4Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS, USA

Axonal transport deficit has been implicated as a common mechanism of Alzheimer’s disease (AD) pathology. We used MEMRI to measure fast axonal transport rates in olfactory bulbs and olfactory cortex of a triple transgenic mouse model of AD (3xTg). Our results indicate that axonal transport deficit starts as early as 3 months of age and precedes Aβ plaque and neuro-fibrillary tangle pathology.

16:44         541.       Longitudinal Assessment of Neurodegeneration in a Spinocerebellar Ataxia Type 1 (SCA1) Mouse Model by 1H MRS at 9.4 Tesla: Correlation with Histopathology

Gulin Oz1, H. Brent Clark1, Christopher D. Nelson1, Dee M. Koski1, Pierre-Gilles Henry1, Malgorzata Marjanska1, Dinesh K. Deelchand1, Harry T. Orr1

1University of Minnesota, Minneapolis, MN, USA

To assess the sensitivity of high field 1H MRS to disease onset and progression in neurodegenerative diseases, we measured cerebellar neurochemical profiles of a mouse model of spinocerebellar ataxia 1 (SCA1) and controls at 3 different ages at 9.4T using short-echo LASER. Multiple biomarkers clearly distinguished the mutant animals from controls at all ages. Multiple MRS measures were significantly different in the mutant animals already at 6 weeks, prior to significant pathological and neurological changes. These data demonstrate the ability of MRS to non-invasively detect pre-clinical disease, as well as its sensitivity to disease progression.

16:56         542.       Assessment of Neurodegeneration Reversal in a Spinocerebellar Ataxia Type 1 (SCA1) Mouse Model by 1H MRS at 9.4 Tesla

Gulin Oz1, H. Brent Clark1, Christopher D. Nelson1, Dee M. Koski1, Manda L. Vollmers1, Harry T. Orr1

1University of Minnesota, Minneapolis, MN, USA

To assess the sensitivity of high field 1H MRS to reversal of neurodegeneration, we utilized a conditional mouse model of SCA1. We turned off the mutated gene from 12-24 weeks and measured cerebellar neurochemical profiles of treated and untreated conditional mice and controls at 9.4T using short echo LASER and LCModel. The altered levels of multiple biomarkers partially reversed to control values at 24 weeks in the treated mice, in agreement with partial reversal of Purkinje cell pathology. These data demonstrate the ability of MRS to non-invasively detect disease reversal and its potential utility in future pre-clinical and clinical trials.

17:08         543.       Increased VEGF Expression Correlates with Severely Reduced Cerebral Perfusion in Glutaric Acidemia Type I (GA-1) Mouse Model of Diet Induced Encephalopathy

Jelena Lazovic1, William J. Zinnanti1,2, Ellen Wolpert3, David A. Antonetti3, Russell E. Jacobs1

1Biology, California Institute of Technology, Pasadena, CA, USA; 2Biochemistry, Pennsylvania State University, Hershey, PA, USA; 3Physiology, Pennsylvania State University, Hershey, PA, USA

The neuroprotective role of vascular endothelial factor (VEGF) following cerebral ischemia remains highly controversial. The inborn error of metabolism glutaric acidemia type-1 (GA-1) is frequently associated with cerebral and retinal hemorrhages, and affected individuals often experience ischemic injury involving basal ganglia. To investigate the relationship between VEGF expression and ischemic injury we measured cerebral blood flow using arterial spin labeling method, and VEGF protein levels in mouse model of GA-1. Significantly increased levels of VEGF correlated with severely reduced perfusion, and were found in encephalopathic mice.

17:20         544.       Deformation-Based Morphometry in the R6/2 Huntington's Disease Mouse Brain

Stephen J. Sawiak1, Nigel I. Wood2, G B. Williams1, A J. Morton3, T A. Carpenter1

1Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, UK; 2Department of Pharmacology, University of Cambridge; 3Department of Pharmacology, University of Cambridge, UK

With the relative ease of creating transgenic mouse models of disease, mice are increasingly used for studying pathology. Automated analysis techniques are of increasing importance to deal with overwhelming amounts of data. Having previously examined the phenotype of the R6/2 Huntington's model with voxel-based morphometry (VBM) here we present our findings with an increased dataset of 116 images, using deformation-based morphometry (DBM), showing it to be more sensitive in finding differences within the same tissue classes.

17:32         545.       Tract Based Spatial Statistics in Mouse Model of Neurodegerative Unverricht-Lundborg (EPM1) Disease

Otto Heikki Henrikki Manninen1, Kimmo K. Lehtimäki2, Teemu Laitinen3, Tarja Joensuu1, Outi Kopra1, Anna-Elina Lehesjoki1, Olli Gröhn3

1Folkhälsan Inst. of Genetics and Neuroscience Center, University of Helsinki, Helsinki, Finland; 2Department of Biotechnology and Molecular Medicine, University of Kuopio, Kuopio, Finland; 3Dept. of Neurobiology, A.I.Virtanen Institute for Molecular Sciences, University of Kuopio, Kuopio, Finland

We implemented a recently introduced whole brain voxelwise statistical analysis method, tract based spatial statistics (TBSS), into a mouse model of neurodegenerative disease, introducing TBSS in mice. Doing black box statistical comparison of diffusion tensor imaging (DTI) parameters between controls and affected animals, TBSS revealed areas of significantly redused FA compared to controls in both brain regions known to be associated with mouse model of Unverricht-Lundborg disease as well as regions not earlier connected with the disease, promising great potential to serve as a robust screening method to guide histological analysis to novel target areas in the brain.

17:44         546.       In Vivo Brain Phenotypes of the Reeler Mutant Mouse by Using DT-MRI and MEMRI

Laura-Adela Harsan1, Csaba David2, Dominik Paul1, Susanne Schnell1, Jürgen Hennig1, Jochen F. Staiger2, Dominik von Elverfeldt1

1Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany; 2Department of Neuroanatomy, Institute for Anatomy and Cell Biology, Center for Neuroscience, Freiburg, Germany

In the present study, the brain cytoarchitecture of the Reeler mutant mouse was visualized by using MEMRI while the neural connectivity was depicted in-vivo and non-invasively by DT-MRI. Disorganization of the neuronal layers was clearly visible in cortical structures of the Reeler brain. In-vivo DT-MRI and fiber tracking showed distorted axonal pathways when compared to wild type brain. Particularly, Reeler mice have poorly compacted thalamic axonal bundles that project abnormally into the cortical structures. Furthermore, color-coded maps evidenced abnormalities at the level of the cingulum structure in Reeler mice and depicted the failure in the cerebellar cortex lamination.

SPECIAL INTEREST SESSION
Biomechanics

Room 312                             16:00-18:00                                                             Moderators: Kimberly K. Amrami and Bruce M. Damon

16:00         547.       Quantitative Analysis of the Post-Contractile BOLD Effect in Human Skeletal Muscle

Theodore F. Towse1, Jill M. Slade2,3, Jeffrey A. Ambrose1, Mark C. DeLano2, Ronald A. Meyer1,2

1Physiology, Michigan State University, East Lansing, MI, USA; 2Radiology, Michigan State University, East Lansing, MI, USA; 3Manipulative Medicine, Michigan State University, East Lansing, MI, USA

Brief single contractions of muscle are followed by increases in blood flow and oxygenation, resulting in a post-contractile BOLD response. This study shows that the magnitude and time course of muscle post-contractile BOLD responses are quantitatively explained from changes in muscle blood volume and hemoglobin saturation measured by near-infrared spectroscopy (NIRS). Furthermore, using a simple one-compartment vascular model the NIRS and MRI changes can be accurately predicted from changes in muscle blood flow and oxygen consumption.

16:12         548.       Twisting Motion as a Confound to Skeletal Muscle BOLD

Andrew D. Davis1,2, Greg D. Wells3,4, Bereket Falk5, Michael D. Noseworthy6,7

1Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario, Canada; 2Medical Physics and Applied Radiation Sciences, St. Joseph's Healthcare, Hamilton, Ontario, Canada; 3Department of Anesthesia, University of Toronto, Toronto, Ontario, Canada; 4Physiology and Experimental Medicine, The Hospital for Sick Children, Toronto, Ontario, Canada; 5Department of Physical Education and Kinesiology, Brock University, St. Catharines, Ontario, Canada; 6Electrical and Computer Engineering, School of Biomedical Engineering, McMaster University, Hamilton, Ontario, Canada; 7Brain-Body Institute, St. Joseph's Healthcare, Hamilton, Ontario, Canada

BOLD data was acquired at 3T in skeletal muscle of the lower leg during an on/off isometric exercise paradigm. This was compared to data taken by substituting a twisting motion for the exercise. Both data sets were analysed using a square wave based GLM. The twisting data was found to mimic the exercise data, confounding the analysis. In-plane twists must therefore be eliminated from during-exercise BOLD scans, since the motion effects may be mistaken for true changes in perfusion and oxygenation.

16:24         549.       Development of a Spin Tag Sequence with Spiral Acquisition for Elucidating Shear at the Deep Gastrocnemius Aponeurosis and Other Dynamics of the Musculoskeletal Elements of the Lower Leg.

Gajanan Nagarsekar1, John Hodgson1, David Shin1, Shantanu Sinha1

1Radiology, University of California at San Diego, San Diego, CA, USA

In order to visualize dynamics of the active and passive components of the musculoskeletal system at 100% maximum voluntary contractions, a rapid method using gated spin tagging with spiral acquisition was developed that allowed acquisition of high resolution images in 16~21 contractions. Movement of soleus and gastrocnemius during isometric and passive plantar-flexion was imaged in 6 subjects using a home-built computer controlled foot pedal device. Significant differences in displacement between the two muscles were observed. These surprising findings suggest minimal mechanical interactions between the soleus and gastrocnemius aponeuroses and significant functional disparity between adjacent regions of soleus and gastrocnemius muscles.

16:36         550.       Dependence of the Ratio of Fiber Length Strain to Aponeurosis Strain (Gear Ratio) of the Human Medical Gastrocnemius on Anatomical Position and Loading Conditions

David Dongsuk Shin1, John A. Hodgson2, Gajanan Nagarsekar3, V Reggie Edgerton2, Shantanu Sinha3

1Biomedical Engieering, University of California, Los Angeles, CA, USA; 2Physiological Science, University of California, Los Angeles, CA, USA; 3Radiology, University of California, San Diego, CA, USA

Velocity encoded phase contrast MRI and a computer-controlled hydraulic ankle rotation apparatus were used to measure the in vivo gear ratio of the medial gastrocnemius (MG) in 6 healthy human subjects. The gear ratio changed significantly in three regions of MG, increasing from distal to proximal (distal: 1.00 ± 0.03, mid: 1.10 ± 0.02, proximal: 1.22 ± 0.03). Slightly less gain was observed in passive (1.13 ± 0.02) compared to active mode (1.08 ± 0.03). For the first time, the architectural parameter of gear ratio and its variation with anatomical position under different loading and movement conditions were measured.

16:48         551.       Hamstrings and Quadriceps Muscle Displacements During Knee Joint Flexion as Determined by 3D DENSE

Niccolo Fiorentino1, Xiadong Zhong2, Michael Rehorn2, Fred Epstein2,3, Silvia Blemker1,2

1Mechanical & Aerospace Engineering, University of Virginia, Charlottesville, VA, USA; 2Biomedical Engineering, University of Virginia, Charlottesville, VA, USA; 3Radiology, University of Virginia, Charlottesville, VA, USA

A 3D DENSE sequence was used to image a volume of tissue in the mid-to-distal thigh during knee joint flexion. Three-dimensional displacements for the quadriceps and hamstrings muscle groups were determined in 20 transverse 5-mm slices and over 80% of the flexion motion. The mean reconstructed displacements of the hamstrings and quadriceps muscle groups were found to be 2.9 +/- 1.2 mm and -1.4 +/- 0.7 mm, respectively, which is expected from a protagonist-antagonist pair. This study demonstrates that 3D cine DENSE MRI is a feasible method for capturing the 3D deformation of skeletal muscle tissue volumes.

17:00         552.       Vibration Imaging for Functional Analysis of Flexor Muscle Compartments

Yogesh Kannan Mariappan1, Kevin J. Glaser1, Armando Manduca2, Richard L. Ehman1

1Department of Radiology, Mayo clinic, Rochester, MN, USA; 2Biomathematics resource, Mayo clinic, Rochester, MN, USA

We investigated a novel technique for the analysis of the functional compartments of the forearm flexor muscles. The fingers were vibrated individually with pressure-activated drivers and the resultant motions within these muscles were imaged with a modified phase-contrast MR imaging technique that is highly sensitive to cyclic motion. The results show that this technique provides detailed mapping of the regions of the complex flexor muscle compartment that correspond to each digit for both the flexor digitorum profundus and the flexor digitorum superficialis. The results also demonstrate the extent of mechanical interdependence between flexors, offering potential methods for studying normal and abnormal hand and wrist biomechanics.

17:12         553.       Dynamic 31P MRS of Exercising Human Muscle in a 7T Whole Body System, with STEAM and Semi-LASER Localisation

Martin Meyerspeer1,2, Thomas Mandl1,2, Tom Scheenen3, Ewald Moser1,2

1Center for Biomedical Technology and Physics, Vienna Medical University, Vienna, Austria; 2High Field MR Centre of Excellence, Vienna Medical University, Vienna, Austria; 3Radiology (667), Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands

We demonstrate that localised 31P MRS can be used to follow metabolic changes with high temporal resolution and, by selecting a single muscle, high specificity in a 7T whole body scanner. The SNR benefit of the high field strength can be exploited, as localised high order shimming yielded line widths comparable to previous results at 3T, even during and after tissue motion under exercise. In consequence, PCr recovery curves were successfully fitted to non-averaged single acquisitions (TR=8s) of spectra localised in a single exercising muscle, yielding consistent results. Application of adiabatic 31P-semi-LASER further increased SNR in comparison with 31P-STEAM.

17:24         554.       Dual Gradient Echo MRI Method for the Evaluation of Muscle Microvascular Function

Otto Alexander Sanchez1, Elizabeth Anne Copenhaver1, Marti Ann Chance1, Michael James Fowler2, Jane Kent-Braun3, Bruce Murray Damon1,4

1Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN, USA; 2Diabetes, Endocrinology, & Metabolic Division, Vanderbilt University, Nashville, TN, USA; 3Kinesiology, University of Massachusetts-Amherst, Amherst, MA, USA; 4Biomedical Engineering, Vanderbilt University, Nashville, TN, USA

To test the ability of a dual GRE MRI method to detect microvascular dysfunction, the time course of SI6 and SI46 , reflecting blood volume and %HbO2, respectively were compared between healthy subjects and individuals at high risk of microvascular disease (type 2 diabetics). Changes in SI between baseline and peak (δSI) and time to peak TTP following isometric contractions of 50%MVC and MVC were compared between groups. Subjects with type 2 diabetes had a higher BMI and HbA1c values than healthy individuals. δSI6 and δSI46 were significantly lower in diabetic subjects following 50%MVC. This method can potentially detect microvascular dysfunction.

17:36         555.       23Na-MRI Contrasts for Application in Muscular Sodium Channel Diseases

Armin Michael Nagel1, Marc-André Weber2, Christian Matthies1, Julien Dinkel, Karin Jurkatt-Rott3, Frank Lehmann-Horn3, Lothar Rudi Schad4

1Medical Physics in Radiology, German Cancer Research Center, Heidelberg, Germany; 2Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany; 3Applied Physiology, University Ulm, Ulm, Germany; 4Computer Assisted Clinical Medicine, Faculty of Medicine Mannheim, University Heidelberg, Mannheim, Germany

Three different 23Na-MRI contrasts were applied and compared with regard to the information they provide about the compartments from which the 23Na signal originates. In particular, a T1-weighted, a concentration-weighted contrast, and an inversion recovery sequence, the latter of which suppresses the 23Na fluid signal were used. It was shown that the 23Na-IR sequence is well suitable to visualize an intracellular sodium accumulation, caused by provocation of the lower leg muscles in patients with hypokalemic periodic paralysis, a muscular sodium channelopathy. This is substantiated by the fact, that the total sodium concentration stays constant after provocation.

17:48         556.       Effects of a 3-Month Training Program on Muscular Lipid Metabolism and Physical Health in Sedentary Non-Insulin-Dependant Diabetes Mellitus Patients

Michael Ith1, Monika Mattes-Schaub1, Roland Kreis1, Kim-Anne Lê2, Luc Tappy2, Jean-Paul Schmid3, Emanuel Christ4, Chris Boesch1

1Department Clinical Research, University Bern, Bern, Switzerland; 2Physiology Department, University Lausanne, Lausanne, Switzerland; 3Cardiology Department, University Bern, Bern, Switzerland; 4Diabetology Department, University Bern, Bern, Switzerland

For patients with impaired insulin sensitivity there is a clear consensus that weight loss improves their metabolic state, however, the effect of increased physical activity is less clear. This study therefore aimed to investigate the effects of a 3-month structured training program on physical performance, clinical parameters as well as levels and utilization of intramyocellular lipids (IMCL) in patients with non-insulin dependent diabetes mellitus type 2. The presented results will demonstrate a significant improvement of metabolic state and physical performance together with reduced levels of IMCL thereby approaching values of a simultaneously investigated control group.

Image Reconstruction: Dynamic Imaging & Phase Mapping

Room 313BC                       16:00-18:00                                                                                  Moderators: Ricardo Otazo and John Pauly

16:00         557.       Reconstruction Strategies for MRI with Simultaneous Excitation and Acquisition

Markus Weiger1, Klaas Paul Pruessmann2, Franek Hennel3

1Bruker BioSpin AG, Faellanden, Switzerland; 2Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 3Bruker BioSpin MRI GmbH, Ettlingen, Germany

The concept of simultaneous excitation and acquisition (SEA) introduced with the SWIFT technique enables MRI of samples with very short T2 also under B1 constraints. Here, new reconstruction strategies are reported that address the specific encoding scheme of SEA in a general way, providing an exact and flexible reconstruction procedure. Artefact-free SEA images acquired with 50 kHz bandwidth and 10 µs echo time are presented.

16:12         558.       k-T PCA: Temporally Constrained k-T BLAST Reconstruction Using Principal Component Analysis

Henrik Pedersen1, Sebastian Kozerke2

1Functional Imaging Unit, Glostrup Hospital, Glostrup, Denmark; 2Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland

The k-t BLAST technique has become widespread for achieving faster dynamic MRI. In its basic form k-t BLAST speeds up the data acquisition by undersampling k-t space and resolves the resulting aliasing in the reciprocal x-f space using an adaptive filter derived from low-resolution training images. However, this filtering process tends to increase the reconstruction error or lower the achievable acceleration factor. We show that temporal basis functions calculated by subjecting the training data to principal component analysis (PCA) can be used to constrain the reconstruction such that the temporal resolution is improved. The presented method is called k-t PCA.

16:24         559.       Technique for Reconstruction Based on Intensity Order (TRIO) Applied as a Second Stage for Dynamic MRI Reconstruction.

Leonardo Ramírez1,2, Claudia Prieto3, Cristian Tejos1,2, Marcelo Guarini1,2, Pablo Irarrazaval1,2

1Departamento de Ingeniería Eléctrica, Pontificia Universidad Católica de Chile, Santiago, Chile; 2Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile; 3Division of Imaging Sciences, King's College London, London, UK

Recently, a Technique for Reconstruction based on Intensity Order (TRIO) has been proposed which uses the intensity order of the pixels of an image to reconstruct undersampled data. This work introduces the use of TRIO as a second stage reconstruction to improve the results obtained from traditional undersampled reconstruction algorithms. The effects of incorrect estimation of the intensity order on the results are also discussed, showing that TRIO reconstruction is dependant on the quality of the intensity order information but always achieving improvements in the reconstruction.

16:36         560.       Accelerating Dynamic MRI Via Spatially Varying Causal Windows

Uygar Sümbül1, Juan Manuel Santos, John Mark Pauly1

1Electrical Engineering, Stanford University, Stanford, CA, USA

A causal, pixel-dependent exponential decay window is suggested to improve time series reconstruction. The study is motivated by the observation that many image pixels change slowly over time, while a few pixels experience rapid changes. The window interpretation is realized via a Kalman filter based algorithm. This fast statistical algorithm decreases the temporal blur of the sliding window reconstruction. Moreover, the algorithm handles arbitrary readout trajectories and multiple coils naturally.

16:48         561.       Motion Adaptive HYPR: An Algorithm for Dynamic Imaging Applications

Lauren Keith1, Alexei Samsonov1, Orhan Unal1, Dana Peters2, Charles Mistretta1,3, Julia Velikina1

1Medical Physics, University of Wisconsin-Madison, Madison, WI, USA; 2Harvard University, Boston, MA, USA; 3Radiology, University of Wisconsin-Madison, Madison, WI, USA

HYPR and HYPR LR algorithms provide means for reconstructing images with high SNR and high spatial resolution from undersampled datasets. However, the conventional formation of the composite image makes applications to dynamic imaging difficult. HYPR MA circumvents the problem of blurring due to object motion by computing a composite image in an alternate fashion. Using this technique, dynamic images can be reconstructed with high SNR, high spatial resolution, and high temporal resolution. Applications to cardiac imaging and catheter tracking are shown.

17:00         562.       Integration of Higher-Order Dynamic Fields Into MR Image Reconstruction

Bertram Jakob Wilm1, Christoph Barmet1, Matteo Pavan1, Peter Boesiger1, Klaas Paul Pruessmann1

1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland

Recent improvements in magnetic field monitoring opened up the possibility of capturing higher-order dynamic field evolution, providing the necessary information to correct for the image distortions they cause. In the present work a technique for higher order field reconstruction is introduced and demonstrated for diffusion weighted EPI. It has been found that eddy currents of diffusion gradients can induce considerable higher-order field perturbations, causing residual error in conventional first-order reconstruction. Higher-order reconstruction largely eliminated these errors in phantom and in-vivo experiments.

17:12         563.       Effects of Discrete and Finite Sampling in PatLoc Imaging

Gerrit Schultz1, Maxim Zaitsev1, Jürgen Hennig1

1Dept. of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany

Discrete and finite sampling leads to the well known truncation artifacts, which include ringing and possibly aliasing. In PatLoc imaging the gradients are replaced by nonlinear, non-bijective encoding fields. In this case no trivial mapping from frequency space to image space exists. It turns out that the truncation artifacts appear in frequency space in principle in the usual way. The shape of the encoding fields then determines how these artifacts translate into image space. The purpose of this work is to examine these properties and illustrate them with simulation data. One application of this finding is accelerated imaging using PatLoc and SENSE imaging in combination.

17:24         564.       Low-Resolution Spectral Cost Function for Field Map Estimation

Kristin L. Granlund1,2, Bruce L. Daniel1, Brian A. Hargreaves1

1Radiology, Stanford University, Stanford, CA, USA; 2Electrical Engineering, Stanford University, Stanford, CA, USA

Spiral imaging is very sensitive to field inhomogeneity and, therefore, is significantly improved by off-resonance correction. Generating an accurate field map is essential to correcting for B0 field variations. In this work, we use low-resolution spectra to estimate off-resonance, which is then used to perform multi-frequency water/fat separation for spiral breast imaging.

17:36         565.       Rapid Fieldmap Estimation for Cardiac Shimming

Saurabh Shah1, Peter Kellman2, Andreas Greiser3, Peter J. Weale1, Sven Zuehlsdorff1, Renate Jerecic1

1Siemens Medical Solutions USA, Inc., Chicago, IL, USA; 2National Institutes of Health, Bethesda, MD, USA; 3Siemens AG Healthcare Sector, Erlangen, Germany

Accurate field map estimation is the first step towards an improved cardiac shimming. Field map estimation in the heart is challenging due to the presence of cardiac and respiratory motion, and blood flow effects. In this study, the effects of cardiac and respiratory motion on field map acquisition were investigated using multi-echo GRE sequence. High resolution field maps acquired at different cardiac phases were analyzed to study the effects of cardiac motion. Different field map acquisition schemes were compared to derive a rapid non-ECG triggered method with parallel imaging support, which provides volumetric coverage around the heart in 5-6 seconds.

17:48         566.       JIGSAW: Joint Inhomogeneity Estimation Via Global Segment Assembly for Water-Fat Separation

Yi Lu1, Wenmiao Lu2, Brian Andrew Hargreaves3

1Electrical Engineering, Stanford University, Stanford, CA, USA; 2Electrical & Electronic Engr., Nanyang Technological University, Singapore, Singapore; 3Radiology, Stanford University, Stanford, CA, USA

Key to the success of three-point water-fat separation is reliable estimation of field inhomogeneities, which remains difficult in many clinical applications. The difficulty arises when the spectral field-of-view is not sufficient to accommodate the field inhomogeneities, causing aliasing. This work describes a novel field map estimation technique called JIGSAW, which is based on belief propagation (BP) to produce large segments of pixels with smooth field map values. The field map estimation problem is then reduced to the assembly of a few large segments. In vivo results show that JIGSAW correctly resolves field inhomogeneities in the presence of spectral aliasing.

Sorting Out Some Artifacts

Room 314                             16:00-18:00                                                                        Moderators: Brian A. Hargreaves and X. J. Zhou

16:00         567.       Embedded PLACE Correction for Geometric Distortion and N/2 Ghosting in Single-Shot EPI

Qing-San Xiang1, Frank Q. Ye2

1Radiology, University of British Columbia, Vancouver, BC, Canada; 2Neurophysiology Imaging Facility, National Institute of Mental Health, NIH, Bethesda, MD, USA

Geometric distortion and N/2 ghosting are two major artifacts in EPI. They can be simultaneously and instantaneously suppressed by a new method based upon Phase Labeling for Additional Coordinate Encoding (PLACE). Since all data are acquired within a single RF excitation, the correction is instant and thus the new method is termed iPLACE. A few central k-space lines are collected 3 times. This allows an effective N/2 ghost suppression, as well as further distortion correction. iPLACE has been demonstrated to be effective by phantom experiments performed on a 4.7 T scanner.

16:12         568.       Understanding the Origin of Image Intensity Displacement in Spiral-In Versus Spiral-Out Acquisitions

Kimberly D. Brewer1,2, Chris V. Bowen2,3, Steven D. Beyea2,3

1Department of Physics, Dalhousie University, Halifax, Nova Scotia, Canada; 2Institute for Biodiagnostics (Atlantic), National Research Council of Canada, Halifax, Nova Scotia, Canada; 3Departments of Physics, Radiology and Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada

Pulse sequences using reverse spiral trajectories (i.e. Spiral-In) are commonly used to avoid signal loss and distortion in regions with susceptibility field gradients (SFGs). Although there have been theories postulated as to why Spiral-In is superior to Spiral-Out, none of them explain why Spiral-In continues to recover more signal in SFG regions, even when acquired with an acquisition window that begins after that of Spiral-Out. We explored this phenomenon further through use of a phantom that produces well-known field patterns as well as computer simulations.

16:24         569.       Simple Robust Estimation of Gradient Delays for Spiral MRI

Ryan Keith Robison1, James Grant Pipe1

1Keller Center for Imaging Innovation, Barrow Neurological Institute, Phoenix, AZ, USA

Timing delays between gradient transmission and data sampling are a major source of artifact in spiral MRI. These delays result most often from eddy currents, among other things. Many of the common methods used to measure these delays require specialized hardware, advanced pulse sequences, or very small phantoms. A simple technique is proposed to measure gradient delays associated with a spiral sequence on all three gradient axes in six excitations.

16:36         570.       Eliminating Metal Artifact Distortion Using 3D-PLACE

Michael Nicholas Hoff1, Qing-San Xiang1,2

1Department of Physics, University of British Columbia, Vancouver, BC, Canada; 2Department of Radiology, University of British Columbia, Vancouver, BC, Canada

A method is presented which removes in-plane and through-plane distortion stemming from MRI of a metallic hip prosthesis. Two images are acquired using 3D turbo spin-echo sequences differing only by added gradient lobes along the frequency encoding (FE) direction, which yield a relative phase ramp across the field-of-view. The undistorted FE coordinate for each voxel is encoded into the additional phase information contained in the phase difference image. Distortion correction of a Lego structure surrounding the prosthesis is demonstrated. The sequence modification is straightforward, the required scan time is minimal, and phase unwrapping is unnecessary for this technique.

16:48         571.       A Method to Remove Nyquist Ghosts from Echo Planar Images (EPI) Using UNFOLD

W Scott Hoge1, Huan Tan2, Robert A. Kraft2

1Radiology, Brigham and Women's Hospital, Boston, MA, USA; 2Wake Forest University School of Medicine, Winston-Salem, NC, USA

Nyquist ghosts are a persistent artifact in echo planar imaging (EPI), and occur when data sampled along positive and negative read-out gradients is inconsistent. Previous methods to correct these effects include double-sampled EPI, which doubles the echo train length leading to greater magnetic susceptibility artifacts, and echo interleave strategies that carry a cost of reduced temporal resolution. Here, we present an approach using the slightly modified trajectory common to interleave strategies, but utilizing UNFOLD in place of interleaving to combine the data. This has the advantage of greatly reducing visible Nyquist ghosts while maintaining 90% of the original temporal sampling bandwidth.

17:00         572.       B1 Correction Using Dual Tau Look-Locker (DτLL)

Trevor Wade1,2, Brian Rutt1

1Robarts Research Institute, London, Ontario, Canada; 2Biomedical Engineering, University of Western Ontario, London, Ontario, Canada

A new method of mapping the transmit B1 field is introduced that is capable of rapidly producing 3D B1 maps at low flip angles without relying on the double angle assumption. It is based on the accelerated 3D Look-Locker sequence and has been compared to both the standard double angle method as well as a double angle implementation of the 3D Look-Locker sequence.

17:12         573.       Sense Shimming (SSH), First In-Vivo Results

Daniel Nicolas Splitthoff1, Maxim Zaitsev1

1Dept. of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, BW, Germany

Recently, a new shimming method has been introduced, named Sense Shimming, or SSH. Due to expected complication regarding chemical shift artefacts and physiological noise, up to now only phantom measurements have been shown. We here present the first in-vivo measurements.

17:24         574.       Simultaneous Fat Suppression and Band Reduction with Large-Angle Multiple-Acquisition BSSFP

Neal Kepler Bangerter1,2, Garry E. Gold 3, Glen R. Morrell2, Brian Andrew Hargreaves3

1Electrical & Computer Engineering, Brigham Young University, Provo, UT, USA; 2Radiology, University of Utah, Salt Lake City, UT, USA; 3Radiology, Stanford University, Stanford, CA, USA

Balanced SSFP (bSSFP) is a fast and highly SNR-efficient imaging technique, but can suffer from characteristic bands of signal loss in the presence of field inhomogeneity. Effective fat suppression with bSSFP is also challenging in regions with large field inhomogeneities. While techniques exist for both banding artifact reduction and fat suppression with bSSFP, they are sometimes incompatible and typically require a significant increase in scan time. In this work, we present a novel approach to simultaneous fat suppression and banding artifact reduction in bSSFP.

17:36         575.       Oscillating Radial Trajectories for Reduced Undersampling Artifacts

Rizwan Ahmad1, Lee C. Potter2, Periannan Kuppusamy1

1Davis Heart and Lung Research Institute, Department of Internal Medicine,, The Ohio State University, Columbus, OH, USA; 2Department of Electrical and Computer Engineering, The Ohio State University, Columbus, OH, USA

We have proposed an oscillating radial trajectory of k-space which significantly improves the reconstruction quality as compared to the traditional radial sampling. Adding oscillations reduces the coherency of the radial trajectory and hence minimizes the aliasing artifacts. In contrast to the other methods for generating randomized trajectories, the proposed k-space trajectories are smooth and hence easy to implement on a conventional MRI gradient coil system. We present a systematic way of generating oscillating radial trajectories and show an improvement over the traditional radial sampling using simulations.

17:48         576.       Effects of Concomitant Fields on Short-Time-Scale Noble Gas Diffusion Measurements

Michael Carl1,2, John P. Mugler III3, Gordon D. Cates2, Wilson Miller3

1GE Healthcare, Applied Science Lab, Milwaukee, WI, USA; 2Physics, University of Virginia, Charlottesville, VA, USA; 3Radiology, University of Virginia, Charlottesville, VA, USA

In previous work we described a specialized pulse sequence designed to access very short diffusion times using noble-gas NMR. In the present work we study the quantitative effects that concomitant fields have on the resulting diffusion measurements, and develop strategies for minimizing or correcting for these effects. We derived an approximate threshold criterion to determine under what circumstances concomitant field distortions remain insignificant compared to the desired diffusion attenuation. Phantom diffusion experiments were performed to confirm our results.

 

Study Group
Musculoskeletal MR

Room 313BC                       19:30 - 21:30                                                                                                                                                            

Study Group
Current Issues in Brain Function

Room 316BC                       19:30 - 21:30                                                                                                                                                            

Study Group
Hyperpolarized Media MR

Room 311                             19:30 - 21:30                                                                                                                                                            

Study Group
Psychiatric MR Spectroscopy & Imaging

Room 313A                         19:30 - 21:30                                                                                                                                                            

Study Group
MR Engineering

Room 316A                         19:30 - 21:30                                                                                                                                                            

Study Group
White Matter

Room 312                             19:30 - 21:30                                                                                                                                                            

Study Group
Susceptibility Weighted Imaging

Room 315                             19:30 - 21:30                                                                                                                                                            


SUNRISE EDUCATIONAL COURSE
Image Reconstruction

Room 314                             07:00 – 08:00                                         Moderators:  Peter Börnert, Klaas Pruessmann, and Jeffrey Tsao

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Describe the main steps involved in efficient non-Cartesian image reconstruction;

·          Formulate a generalized signal model incorporating gradient encoding, coil sensitivity and B0 inhomogeneity;

·          List the pros and cons of Cartesian and non-Cartesian parallel MRI;

·          Compare compressed sensing, HYPR, and k-t BLAST with respect to their use of prior knowledge;

·          Describe the principles of separating water and fat signals; and

·          Name three differentn approaches for motion correction and appraise their potential to become routine methods.

 

Sparse Data

07:00        
Compressed Sensing and HYPR

                  Oliver Wieben

                                                     

07:30         Exploiting Spatiotemporal Correlations for Dynamic Imaging

                  Jeffrey Tsao

SUNRISE EDUCATIONAL COURSE
Safety Update

Room 320                             07:00 – 08:00                                                          Moderators:  Penny A. Gowland and Roger Luechinger

Educational Objectives:
Upon completion of this session, participants should be able to:

·          Explain the issues involved in setting the SAR limit for a pulse sequence;

·          List the causes of PINS and how coils are designed to prevent it;

·          Describe standards related to medical implants in the MR environment;

·          Describe causes of accidents and preventative measures in the MR environment; and

·          Explain risks and minimization of acoustic noice in the MR environment.

 

07:00         Implants and ASTM Labelling Standards

                  Wolfgang Kainz

 

07:30         The New ISO/IEC Standard for Active Implants

                  Hans M. L. Engels

SUNRISE EDUCATIONAL COURSE
Quantitative Neuroanatomic & Functional Image Assessment

Room 316A                         07:00 – 08:00                                                               Moderators:  Peter A. Bandettini and Carlo Pierpaoli

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Assess the challenges and obstacles involved with quantitative assessment of anatomic and functional MRI data;

·          Describe the necessary steps to perform group comparisons of anatomic data;

·          List the neuronal, scanner-related, and physiological factors that influence the fluctuations in fMRI data;

·          Explain the neuronal, scanner-related, and physiological factors that influence the magnitude of the activation-induced fMRI signal change;

·          Describe the methods by which fMRI activation-related signal may be calibrated; and

·          List the methods by which fMRI resting state data can be filtered such that only neuronally related signal changes remain.

 

07:00         Image Registration

                  Daniel Rueckert

07:30         Atlas Building and Statistical Group Analysis
                 
Guido Gerig

SUNRISE EDUCATIONAL COURSE
Mobile Lipids in Disease

Room 313A                         07:00 – 08:00                                                                  Moderators:  Carles Arús and Edward J. Delikatny

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Recognize the various ML resonances detectable in the 1H NMR spectral pattern of a tissue or organ;

·          Select optimal acquisition conditions to detect ML resonances and appreciate their possible variation in biological samples;

·          Describe the possible biochemical origins of ML;

·          List possible causes for qualitative and quantitative changes in ML pattern;

·          Interpret qualitative and quantitative changes in the ML pattern of cells and tissues; and

·          List possible clinical applications of in vivo ML detection for disease diagnosis, staging and response to therapy.

Cancer, Brain, and Other

07:00         Animal Studies

                  Risto A. Kauppinen

 

07:30         Clinical Studies

                  Martin O. Leach

SUNRISE EDUCATIONAL COURSE
MRI Applications for Tissue Engineering

Room 311                             07:00 – 08:00                                                                                               Moderator:  Richard G. S. Spencer

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Define what is meant by tissue engineering;

·          Appreciate the current status of the field of tissue engineering, including several of the products currently on the market;

·          Recognize some of the current approaches to development of tissue-engineered constructs;

·          Describe the role of MR in certain current tissue engineering studies; and

·          Identify further opportunities for application of MR to problems in tissue engineering.

07:00         Urinary Bladder: Imaging the Regeneration of a Dynamic Organ

                  Hai-Ling Margaret Cheng

 

07:30         Cartilage Development in an MRI-Compatible Hollow-Fiber Bioreactor

                  Richard G. S. Spencer

 

07:45         What Can MRI Tell Us About Early Bone Growth?  What Does It Not Say?
                 
Richard L. Magin, Ph.D.

SUNRISE EDUCATIONAL COURSE
Clinical Science for Physicists & Engineers

Room 313BC                       07:00 – 08:00                                                      Moderators:  Vivian S. Lee, Tim Leiner, and Bachir Taouli

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Identify basic anatomy and physiology of the central nervous system, kidney, liver, cardiac, vascular and musculoskeletal systems;

·          Describe the process and diagnosis of stroke and white matter formation and damage;

·          Explain kidney and liver anatomy and function and how MRI can be used to evaluate these organs;

·          Describe basic cardiac physiology and the consequences of coronary artery disease and heart failure;

·          Describe the process of bone and cartilage formation and degeneration; and

·          Appraise unmet clinical needs that could potentially be solved by physicists and engineers.

 

07:00         Coronary Arteries: What You Need to Know

                  Tim Leiner

 

07:30         Heart Failure:  What You Need to Know

                  Bernd J. Wintersperger

SUNRISE EDUCATIONAL COURSE
Cardiovascular Disease or Problem-Based Teaching & Practical Protocols

Room 316BC                       07:00 – 08:00                                                                 Moderators:  Victor A. Ferrari and Stefan G. Ruehm

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Critique the strengths and limitations of current cardiovascular MRI techniques when applied to clinical diagnostic testing;

·          Compare coronary MR and CT angiography at 1.5 and 3T field strengths and how practical these approaches currently are;

·          Describe the etiologies of right heart failure, and the clinical applications of MR techniques to evaluate these disorders, especially the assessment of right heart function;

·          Compare the current clinical techniques for assessment of ischemic heart disease and the use of MR methods for assessment of ischemia, perfusion reserve, and viability;

·          Appraise the potential clinical applications of 7T cardiovascular MRI and the technical challenges that will need to be resolved for wider application of the technique; and

·          Evaluate how the attendee’s current approaches to these diseases may need to be modified based on expert advise.

Ischemic Disease

07:00        
Nuclear Medicine

                  Thomas Schindler

 

07:20         Evaluation of Ischemia/Perfusion Reserve

                  Michael Jerosch-Herold

 

07:40         Prediction of Functional Recovery (Viability and Perfusion)

                  Christopher M. Kramer

SUNRISE EDUCATIONAL COURSE
MRI & MRS of the Mouse Brain: Techniques & Applications

Room 312                             07:00 – 08:00                                                                     Moderators:  Jeffry R. Alger and Afonso C. Silva

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Identify hardware/software configurations that are needed to perform anatomical imaging, diffusion tensor imaging, functional imaging, and magnetic resonance spectroscopy in the mouse brain;

·          Recognize the constraints associated with the small size of the mouse body and brain and how to achieve stable physiology of the animals during the MRI/MRS experiments;

·          Define how to perform anatomical imaging, diffusion tensor imaging, functional imaging, and magnetic resonance spectroscopy in the mouse brain;

·          Describe the anatomical or physiological properties that can be measured with MRI in mouse brain; and

·          Identify significant biomedical findings that have been obtained through mouse brain neuroimaging using anatomical imaging, diffusion tensor imaging, functional imaging, and magnetic resonance spectroscopy.

Functional Brain Imaging

07:00         How to Image CBF in the Mouse Brain

                  Frank Kober

07:30         Functional Magnetic Resonance Imaging of the Mouse
                 
Kai-Hsiang Chang

SUNRISE EDUCATIONAL COURSE
Unsolved Problems in MSK MRI:  What Do We Know and What Don’t We Know?

Room 310                             07:00 – 08:00                                                                       Moderators:  Christine Chung and Juerg Hodler

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Avoid over-diagnosis and over-treatment when performing MR imaging of the lumbar spine, rotator cuff, wrist, and knee;

·          Describe the current developments potentially leading to more precise diagnosis of abnormalities in the lubar spine, rotator cuff, wrist, and knee; and

·          List six (6) pitfalls which lead to over- or under-diagnosis in the lumbar spine, rotator cuff, wrist, and knee.

Wrist Instability

07:00         MR Findings without Clinical Significance

                  Hiroshi Yoshioka

                                                     

07:30         Clinical Abnormalities not Detectable on MR Images

                  Kimberly K. Amrami

SUNRISE EDUCATIONAL COURSE
Hot Topics in Body MRI

Room 315                             07:00 – 08:00                                                          Moderators:  Claudia Hillenbrand and Elmar M. Merkle  

Educational Objectives:
Upon completion of this course, participants should be able to:

·          Compare the potential utility of the various methods for pulmonary MRI including proton-based techniques and hyperpolarized gas MRI;

·          Protocol and interpret MRI examinations for the evaluation of rectal cancer and non-neuro fetal abnormalities;

·          Describe the techniques for MRI guided interventions including vascular and non-vascular interventions;

·          Identify patients and clinical situations in which whole body MRI for cancer evaluation and lymph node detection would be appropriate, and protocol and interpret the examinations.

 

07:00         MR Guided Non-Vascular Interventions

                  Jonathan S. Lewin

                                                     

07:30         MR Guided Vascular Interventions - No syllabus contribution at time of publication.

                  Deniz Bilecen

OPENING SESSION

Ballroom                              08:15 – 08:30                                                                                 Chair:  David G. Norris, ISMRM President

08:15                       YIA and Poster Award Presentations

2009 LAUTERBUR LECTURE

Ballroom                              08:30 – 09:10                                                                                 Chair:  David G. Norris, ISMRM President

 

 
08:30                       MRI:  A Charmed Past & an Exciting Future

Albert Macovski, Ph.D.

Stanford University, Palo Alto, California, USA



PLENARY LECTURES
MR Scanners in 2025

Ballroom                              09:10-10:00                                                                          Moderators: Oliver Heid and Lawrence L. Wald

09:10         577.       MR-PET, the Potential for Combined Imaging Modalities

Simon R. Cherry 1

1University of California Davis, Davis, CA, USA

No single imaging modality provides the optimal combination of high spatial and temporal resolution, and high sensitivity for imaging functionally-relevant targets.  However, combinations of modalities may approach this ideal, allowing the strengths of more than one technique to be integrated in a single   imaging system. The combination of positron emission tomography (PET) and MR techniques is particularly attractive, allowing for high spatial resolution and sensitivity, with accurate spatial and temporal registration of data between the two datasets. This talk with trace the development of PET/MR systems, demonstrate the success of early prototypes and speculate on the uses for PET/MR technology.

09:35         578.       MR-HIFU: The Potential for Combined Imaging and Therapy

Kullervo Hynynen 1

1Sunnybrook Health Sciences Centre, Toronto, ON, Canada

High Intensity Focused Ultrasound (HIFU) is a noninvasive method to concentrate energy deep in the body. MRI‘s excellent soft tissue contrast, and temperature sensitivity make it well suited for the guidance of HIFU. The treatment of uterine fibroids with MRI-HIFU is on its way to becoming clinical routine. In addition there are several clinical reports demonstrating the feasibility of MR-HIFU for the treatment of other tumors. Animal experiments have also shown that HIFU exposures can increase blood vessel wall permeability. This may allow local delivery of large molecules into image defined locations and has especially high potential in brain.

Case-Based Teaching V: Physics & Engineering: Guess That Artifact!

Room 310                             10:30 – 12:30                                                           Moderators:  Mark A. Griswold and Lawrence L. Wald

Educational Objectives:
Upon completion of this session, participants should be able to:

·   List and evaluate principle categories of artifacts;

·   Explain sources of commonly encountered artifacts and methods to avoid them; and

·   Recommend further tests for problem solving and troubleshooting artifacts.


In our “Guess That Artifact” game show, contestants will compete in the evaluation of MR artifacts from the mundane to the esoteric.  Emphasis will be placed on the physical origin and methods for mitigating the artifact.  Winners will receive valuable prizes!  Each round will be followed by a brief (five-minute) explanation by one of the hosts.  There will be no lovely assistant.

Breast MR Gets Better!

Room 312                             10:30-12:30                                                                Moderators: Eva C. Gombos and Ingrid S. Gribbestad

10:30         579.       Fat Suppression with Independent Shims for Bilateral Breast MRI

Misung Han1,2, Sandra Rodriguez1, Anne M. Sawyer1, Bruce L. Daniel1, Charles Cunningham3, John M. Pauly2, Brian A. Hargreaves1

1Radiology, Stanford University, Stanford, CA, USA; 2Electrical Engineering, Stanford University, Stanford, CA, USA; 3Medical Biophysics, University of Toronto, Toronoto, ON, Canada

There exists a significant static field inhomogeneity for breast MRI related to the shape of the breast and the susceptibility difference at air/tissue interfaces. Field inhomogeneity can cause imaging artifacts or failure in fat suppression, especially when spectral-selective fat suppression methods are used. For bilateral breast MRI, the large field variation over the two breast volumes makes robust fat suppression more difficult. We compared fat suppression by using standard shims and independent shims of each breast, incorporated with a dual-band spectral-spatial pulse. Our experiments show that independent shims provide improved fat suppression compared to standard shims.

10:42         580.       Preoperative Breast MRI in Patients with Invasive Lobular Carcinoma Reduces the Rate of Surgical Re-Excision

Ritse Maarten Mann1, Claudette E. Loo2, Jelle O. Barentsz1, Kenneth G.A. Gilhuijs2, Theo Wobbes3, Carla Boetes1,4

1Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 2Radiology, The Netherlands Cancer Institute \ Antoni van Leeuwenhoek Hospital, Amsterdam, Netherlands; 3Surgery, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 4Radiology, Maastricht University Medical Centre, Maastricht, Netherlands

In invasive lobular carcinoma of the breast (ILC), conventional imaging is unable to assess tumor size. Though preoperative MRI has been shown more reliable, the use of preoperative MRI is disputed. We assessed the need for surgical re-excision and the rate of mastectomies in patients treated for ILC with or without preoperative breast MRI. Our results clearly show that preoperative MRI reduces the rate of re-excisions without increasing the rate of mastectomies and should thus be performed in all patients.

10:54         581.       MRI Characterization of Ex Vivo Healthy Human Lymph Nodes at 7T

Mies Andrea Korteweg1, Jaco J.M. Zwanenburg1, Paul van Diest2, I. H. Borel Rinkes3, Willem P. Mali1, Peter R. Luijten1, Wouter B. Veldhuis1

1Radiology, University Medical Center Utrecht, Utrecht, Netherlands; 2Pathology, University Medical Center Utrecht, Utrecht, Netherlands; 3Surgery, University Medical Center Utrecht, Utrecht, Netherlands

Nodal status strongly determines prognosis in breast cancer patients. We analyzed morphology and relaxation times of healthy human axillary nodes at 7T, with pathologic examination as the gold standard. Of two axillary lymph node dissection specimens the mean nodal T1, T2*, and T2 relaxation times, as well as the apparent diffusion coefficients (ADC) were determined. Results: Mean T1; 1387.22±114.81ms, mean T2*; 18.38±7.33ms, mean T2; 72.05±14.55ms, mean ADC; 0.40±0.11•10-3 s/mm2. MRI allowed detailed identification of B-cell follicles as well as blood- and lymph vessels. MRI correlated well with pathology.

11:06         582.       Quantitative DWI for Differentiation of Benign and Malignant Breast Lesions: The Influence of the Choice of B-Values

Nicky HGM Peters1, Koen L. Vincken2, Maurice A.A.J. van den Bosch1, Peter R. Luijten2, Willem PThM Mali1, Lambertum W. Bartels2

1Radiology, University Medical Center Utrecht, Utrecht, Netherlands; 2Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands

The ADC varies with the choice of different b-values. However, the diagnostic performance is not affected by the choice of b-values. The results imply that to differentiate benign from malignant breast lesions, the choice of b-values is not important. However, when the ADC value is compared to reported ADC threshold values in literature, the b-values should be taken into account.

11:18         583.       Comparison of Different Diffusion Parameters in DWI for Differentiation of Breast Lesions at 3.0 Tesla – Effects of Perfusion and Diffusion Compartments on ADC

Wolfgang Bogner1,2, Stephan Gruber1,2, Katja Pinker1,2, Günther Grabner1,2, Andreas Stadlbauer3, Ewald Moser2, Thomas Helbich1, Siegfried Trattnig1,2

1Department of Radiology, Medical University Vienna, Vienna, Austria; 2MR Center of Excellence, Medical University Vienna, Vienna, Austria; 3Landesklinikum St.Pölten, St.Pölten, Austria

Seventy-four patients suspect for breast cancer were examined on a 3T MR system with an additional DWI protocol. The impact of different diffusion schemes on diagnostically relevant parameters such as CNR and ADC precision/accuracy was investigated. The influence of perfusion and compartment effects on the ADC were studied in the breast. The diagnostic accuracy of an optimized diffusion scheme were determined. The application of such an optimized DWI protocol at 3T provided a diagnostic sensitivity of 96% and specificity of 94% in our patient group of 69 women.

11:30         584.       Statistical Modeling of Longitudinal Total Choline Measurements During Chemotherapy

Ann M. Brearley1, Lynn E. Eberly1, Naomi R. Mraz2, Michael T. Nelson2, Douglas Yee3, Michael Garwood4, Patrick J. Bolan5

1Biostatistics, University of Minnesota, Minneapolis, MN, USA; 2Radiology, University of Minnesota, Minneapolis, MN, USA; 3Masonic Cancer Center, University of Minnesota, Minneapolis, MN, USA; 4Center for MR Research / Radiology,, University of Minnesota, Minneapolis, MN, USA; 5Center for MR Research / Radiology, University of Minnesota, Minneapolis, MN, USA

In this work we describe a retrospective analysis of choline measurements acquired in breast cancer subjects undergoing neoadjuvant chemotherapy. We proposed a series of models to describe the time-course of the choline response during therapy, and selected an optimal model based on Akaike and Bayesian information criteria. The model fits, and the relative suitability of the various models, were then used to infer important characteristics of the total choline response that are useful for designing future clinical trials.

11:42         585.       The Association Between Choline Concentration Measured by 1H MR Spectroscopy with Clinical Characteristics and Biomarkers of Breast Cancer

Hui Liu1, Jeon-Hor Chen1,2, Hyeon-Man Baek1, Ke Nie1, Hon J. Yu1, Orhan Nalcioglu1, Min-Ying Lydia Su1

1Tu & Yuen Center for Functional Onco-Imaging, University of California, Irvine, CA, USA; 2Department of Radiology, China Medical University, Taichung, Taiwan

We investigated the association between tCho measured by single-voxel MRS (using the internal reference method) and other clinical characteristics in different breast lesions. A total of 63 patients were included. A higher choline concentration was significantly correlated with younger age (p<0.05), and was associated with DCE washout pattern (higher angiogenesis), higher tumor grade, and in patients with triple negative breast cancer, but not reaching significance level (p<0.1). We also found other well-known relationships such as a high correlation between ER and PR (p < 0.001), and that mass lesions are more likely to show washout DCE pattern (p<0.017).

11:54         586.       Diagnostic Value of Breast Proton Magnetic Resonance Spectroscopy at 1.5T in Different Histological Types

Hyeon-Man Baek1,2, Jeon-Hor Chen3,4, Orhan Nalcioglu3, Min-Ying Su3

1Department of Radiology, UT Southwestern Medical Center, Dallas, TX, USA; 2Center for Function Onco-Imaging , University of California-Irvine, Irvine, CA, USA; 3Center for Function Onco-Imaging, University of California-Irvine, Irvine, CA, USA; 4Department of Radiology, China Medical University Hospital, Taichung 404, Taiwan

The impact of tumor size and histological types on the diagnostic performance of in vivo 1H MR spectroscopy was investigated in 105 biopsy-confirmed breast tumors. The sensitivity was only 46% in tumors of 1.0-1.9 cm, then increased to 70% in 2.0-2.9 cm group, and 82% in 3.0 cm & above group. The detection sensitivity was higher for invasive cancer (71%) than for DCIS (27%), and higher for invasive ductal cancer (74%) or mixed type (67%) than for invasive lobular cancer (50%). Further improvement in the signal-to-noise ratio (SNR) may enhance the detection of tCho and improve the diagnostic sensitivity. One approach is to use the scanner at higher magnetic fields (3.0T and 7.0T).

12:06         587.       Dynamic Imaging of Dual Contrast-Enhancement Using a Combined MR-Optical Imaging System

Mehmet Burcin Unlu1, Yuting Lin1, Orhan Nalcioglu1, Gultekin Gulsen1

1John Tu & Thomas Yuen Center for Functional Onco-Imaging, University of California, Irvine, CA, USA

We measure the enhancement kinetics of an optical and an MR contrast agent in a small animal breast tumor model (R3230 ac) simultaneously using a combined magnetic resonance-diffuse optical tomographic imaging system. A mixture of a small molecular-weight MR contrast agent Gd-DTPA and a large molecular-weight optical contrast agent indocyanine green was administered intravenously for multimodal dynamic imaging.

12:18         588.       Image-Guided Combined SiRNA and Enzyme/Prodrug Cancer Therapy

Cong Li1, Marie-France Penet1, Flonné Wildes1, Tomoyo Takagi1, Paul Winnard Jr. 1, Dmitri Artemov1, Zaver M. Bhujwalla1

1Radiology, Medical School of Johns Hopkins Univ., Baltimore, MD, USA

The ability to downregulate specific pathways that are overexpressed and critically important in cancer using small interfering RNA (siRNA) technology provides unprecedented opportunities to develop novel cancer-cell specific treatments. The ability to detect the delivery of the siRNA and combine it with the delivery of a chemotherapeutic agent primarily localized within the tumor would be of significant advantage in this quest. Here we have developed a prototype agent to image the delivery of a prodrug enzyme, bacterial cytosine deaminase, that converts a nontoxic prodrug 5-fluorocytosine to 5-fluorouracil, in combination with siRNA targeting of choline kinase, an enzyme critically important in breast cancer.

Hybrid & Unconventional Systems

Room 316A                         10:30-12:30                                                              Moderators: Steven M. Conolly and Timothy J. Scholl

10:30         589.       Evaluation of a Clinical PET/MR System

Hans F. Wehrl1, Armin Kolb1, Martin S. Judenhofer1, Matthias P. Lichy, Claus D. Claussen, Bernd J. Pichler1

1Laboratory for Preclinical Imaging of the Werner Siemens-Foundation, Department of Radiology, University of Tuebingen, Tuebingen, BW, Germany

Clinical PET/MR is a new, emerging imaging approach. An evaluation of the MR and PET image performance without and with the PET-Insert installed in a 3 T MR scanner was conducted. MR and PET imaging quality are not fundamentally influenced in this hybrid imaging device. Patient studies show the potential of simultaneous PET/MR imaging.

10:42         590.       First Hybrid Images from a Combined PET and Field-Cycled MRI System

Geron Andre Bindseil1, William B. Handler1, Timothy J. Scholl1, Kyle M. Gilbert2, Blaine A. Chronik1

1Department of Physics and Astronomy, The University of Western Ontario, London, Ontario, Canada; 2Robarts Research Institute, The University of Western Ontario, London, Ontario, Canada

The first fully interleaved hybrid images from a combined positron emission tomography (PET) and field-cycled MRI (FCMRI) system are presented. In FCMRI, it is possible to rapidly turn all magnetic fields off, enabling the use of conventional photomultiplier-tube-based PET detectors. PET data were acquired during MRI sequences in an interleaved manner with a period of several seconds.

10:54         591.       Simultaneous MRI/PET Image Acquisition from an MRI Compatible Positron Emission Tomography System

Sri Harsha Maramraju1, Bosky Ravindranath1, Sachin Junnarkar2, Dardo Tomasi2, S. David Smith2, Sudeepti Southekal1, Sean Stoll2, Sergio Rescia2, Jean-Francois Pratte2, Martin Purschke2, Xiaole Hong3, David Bennett3, Ken Cheng3, Aiping Jiang3, William Lenz2, Srilalan Krishnamoorthy2, Craig Woody2, Paul Vaska2, David Schlyer2

1Biomedical Engineering, Stony Brook University, Stony Brook, NY, USA; 2Brookhaven National Laboratory, Upton, NY, USA; 3Aurora Imaging Technology, North Andover, MA, USA

We have developed MRI compatible PET scanners based on RatCAP for truly simultaneous acquisition of MRI and PET images by integrating PET in 1.5T, 4T and 9.4T MRI facilities, respectively. The main objective is to obtain structural and functional information simultaneously, retaining MRI and PET functionalities. Simultaneous rat brain and striatum phantom MRI/PET images were acquired with RatCAP in 4T and 9.4T MRI facilities, respectively. MR image quality tests were performed in 1.5T MRI, with our prototype breast MRI/PET scanner based on RatCAP. Our initial results demonstrate the feasibility of performing quantitative MRI/PET studies, with minimal interference between both modalities.

11:06         592.       Is Accurate Bone Segmentation Required for MR-Based PET Attenuation Correction?

Ciprian Catana1, Andre van der Kouwe1, Thomas Benner1, Michael Hamm2, Christian Michel3, Bruce Fischl1, Matthias Schmand3, Bruce R. Rosen1, A. Gregory Sorensen1

1MGH, Radiology, A.A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA; 2Siemens Medical Solutions USA Inc., Charlestown, MA, USA; 3Siemens Medical Solutions USA Inc., Knoxville, TN, USA

Combined PET and MRI systems have recently been developed. Attenuation correction is one of the most important and difficult correction that have to be applied to the PET data. In an integrated scanner, we have to rely on the MR data for obtaining attenuation correction maps. The challenge is that the MR images are not typically directly related to tissue linear attenuation and tissues with very different attenuation properties cannot be easily distinguished using conventional MR sequences. In this work, we studied the effects of misclassifying the bone on PET data quantification in structures of interest using segmented MR images.

11:18         593.       System for MRI Guided Radiotherapy

Johan Overweg1, Bas Raaymakers2, Jan Lagendijk2, Kevin Brown3

1Philips Research Europe, Hamburg, Germany; 2University Medical Center Utrecht, Utrecht, Netherlands; 3Elekta, Crawley, UK

The abstract presents key features of an MRI system for MRI guided radiotherapy. The Linac-based radiation source is located on the outside of a cylindrical high-field MR scanner, radiating through the magnet's cryostat. The coil designs of main magnet and gradient coil provide a gap in the midplane of sufficient width to allow the beam to pass through. Magnetic interaction with the Linac is minimized by modification of the magnet’s active shielding configuration so that a ring-shaped low field ring is obtained at the location of the field-sensitive parts of the accelerator.

11:30         594.       The Application of MRI Pulse Sequences in the Verification of Proton Beam Radiotherapy

Joao Seco1, Ravi Teja Seethamraju2, George Phil Broussard3, Hanne Kooy1, Mukesh Harisinghani4

1Radiation Oncology, Harvard Medical School and Massachusetts General Hospital, Boston, MA, USA; 2Siemens Medical Solutions, USA Inc., Charlestown, MA, USA; 3Francis H Burr Proton Center, Massachusetts General Hospital, Boston, MA, USA; 4Radiology, Harvard Medical School and Massachusetts General Hospital, Boston, MA, USA

The purpose of this study is to assess the clinical feasibility and effectiveness of magnetic resonance imaging (MRI) for quality assurance in proton beam therapy. The hypothesis is that as MRI relies on the relaxation times of protons within the patient and proton beam therapy delivers protons to the tumor volume, the extra protons delivered to the cancer tumor volume will produce an additional magnetic signal that can be observed by MRI. Therefore, MRI is assessed as a tool to give functional information of proton beam therapy of cancerous tumor volume.

11:42         595.       Lorentz Force Effects in Multimodality MR-SPECT Imaging

Mark Jason Hamamura1, Seung-Hoon Ha1, Werner W. Roeck1, Orhan Nalcioglu1, Douglas J. Wagenaar2, Dirk Meier2, Bradley E. Patt2

1Tu & Yuen Center for Functional Onco-Imaging, University of California, Irvine, CA, USA; 2Gamma Medica-Ideas Inc., Northridge, CA, USA

In a multimodality MR-SPECT system, a SPECT detector system is placed within the high magnetic field of an MRI system. In this study, we investigated the effects of the Lorentz force on the SPECT measurements. The results revealed a shift in the position of the SPECT projection data that must be taken into account for more accurate image reconstruction. Proper acquisition of the flood field image for sensitivity correction was also found to be critical for accurate image reconstruction.

11:54         596.       Direct Imaging of SPIOs in Mice Using Magnetic Particle Imaging:  Instrument Construction and 3D Imaging

Patrick Goodwill1, Greig Scott2, Pascal Stang2, Gary Chiray Lee1, Doug Morris3, Steve Conolly4

1Joint Graduate Group in Bioengineering, UC Berkeley / UCSF, Berkeley, CA, USA; 2Electrical Engineering, Stanford University; 3National Institutes of Health, Bethesda, MD, USA; 4Bioengineering, University of California, Berkeley, Berkeley, CA, USA

We have developed the first Magnetic Particle Imaging (MPI) scanner capable of imaging a whole mouse. The system directly detects the magnetization of Super-Paramagnetic Iron Oxide (SPIO) particles commonly used as MRI contrast agents with remarkable sensitivity and resolution over a 3cm field of view without requiring sample movement. Our system incorporates technical advances that enable small receive bandwidths at high frequencies, with a clear path towards body noise dominance.

12:06         597.       A Novel Single-Sided Imaging Device for MR Elastography

Daniel V. Litwiller1, Eric A. Borisch1, Roger C. Grimm1, Joel P. Felmlee1, Richard L. Ehman1

1Radiology, Mayo Clinic, Rochester, MN, USA

Recent years have seen the development of small, single-sided NMR systems suitable for a variety of applications in biomedicine. These novel imaging systems are typified by their small size, single-sided nature and nonuniform polarizing fields. Another emerging field of research is non-invasive imaging of material properties of tissues and biomaterials with the clinical application of techniques like MR elastography. The goal of this work was to develop a low cost single-sided NMR device, capable of MR elastography, which would be potentially useful for applications such as evaluation of normal and pathological skin, benchtop pathology, and evaluating engineered tissue constructs.

12:18         598.       Development of Cryogen-Free Ultra-Low Field MRI Instrument

Byeong Ho Eom1, Konstantin Penanen1, Peter K. Day1, Inseob Hahn1, Mark S. Cohen2

1Jet Propulsion Lab/Caltech, Pasadena, CA, USA; 2Center for Cognitive Neuroscience, UCLA School of Medicine, Los Angeles, CA, USA

In-vivo MR imaging at very low fields using superconducting quantum interference device (SQUID) magnetometry and pre-polarizing field cycling technique has been demonstrated recently and many advantages have been noted. Although the expensive superconducting magnet can be essentially eliminated in a pre-polarizing low field SQUID MRI system, expendable cryogens and its maintenance service, required to cool the low temperature detector, are still placing increasing burden on the operational cost. We have built a prototype cryogen-free SQUID MRI system. Here we present its design, noise characterizations and the first phantom image.

Vessel Wall Imaging

Room 316BC                       10:30-12:30                                                                        Moderators: Jianming Cai and J. Kevin DeMarco

10:30         599.       High-Resolution 3D Coronary Vessel Wall Imaging Using Spiral Image Acquisition at 3T

Miriam Wilhelmina Lagemaat1, Markus Henningsson2, Matthias Stuber3, Andrea J. Wiethoff2,4, Rene M. Botnar2

1Dep. of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands; 2NIHR Biomedical Research Centre at Guy's & St Thomas' Hospital and King's College London, London, UK; 3Dep. of Radiology, Johns Hopkins University, Baltimore, MD, USA; 4Philips Healthcare, Reigate, UK

A non-invasive approach for coronary plaque imaging would be desirable in addition to X-ray coronary angiography. MR coronary vessel wall and plaque imaging techniques at 1.5T have been reported previously and were successful in imaging the RCA and LAD vessel walls. With the wider spread availability of high field 3T clinical scanners and the advent of commercially available 32-channel coils, higher resolution coronary vessel wall imaging has become feasible. In this study we sought to implement and optimize the local inversion pre-pulse technique on a 3T system and to obtain higher-resolution (0.5mm) 3D black blood cross-sectional coronary vessel wall images.

10:42         600.       Increasing Lipid Core Size in Carotid Plaque Is Predictive of Cardiovascular Events in Elder Asymptomatic Individuals Using Contrast-Enhanced High-Resolution MRI

Jianming Cai1, Qingjun Wang1, Lin Ma1, Youquan Cai1, Qian Zhao1

1Radiology, Chinese PLA General Hospital, Beijing, China

By using contrast-enhanced high-resolution MRI, we studied prospectively whether increasing lipid core predicts future new cardiovascular events in elder asymptomatic individuals. Each subject in the present study was given consecutive pre and post contrast-enhanced MRI examinations every 6-9 months and followed up for new cardiovascular events. Our findings show that the increasing size of lipid core is significantly associated with the risk of the new vascular events. Being a noninvasive and accurate measure tool for lipid core, contrast-enhanced high-resolution MRI may be helpful to predict future cardiovascular events and improve the effectiveness of therapeutic strategies.

10:54         601.       Quantification of Arterial Wall Inflammation in Patients with Arteriits Using High Resolution DCE-MRI: A Correlation Study with 18F-FDG PET-CT

Clemens C. Cyran1, Tobias Saam1, Steven Soubron1, José G. Raya1, Katja Bochmann1, Markus Hacker2, Axel Rominger2, Peter Bartenstein2, Thomas Pfefferkorn3, Michael Dichgans3, Maximilian F. Reiser1, Konstantin Nikolaou1

1Department of Clinical Radiology, University Hospitals Munich - Grosshadern, Munich, Germany; 2Department of Nuclear Medicine, University Hospitals Munich - Grosshadern, Munich, Germany; 3Department of Neurology, University Hospitals Munich - Grosshadern, Munich, Germany

DCE-MRI was compared to the gold standard 18F-FDG-PET-CT for its applicability in the non-invasive quantification and measurement of arterial wall inflammation in patients with arteriitis in carotid and vertebral arteries. DCE-MRI of the carotid/vertebral arteries of 12 patients with suspected arteriitis was acquired at 3T (2D-SR-SGRE) using a dedicated 4-channel surface coil. Patients underwent 18F-FDG-PET-CT within one week of the MRI scan. Results showed a good correlation of DCE-MRI with 18F-FDG-PET-CT. This method might be useful in the diagnosis of arteriitis and in monitoring anti-inflammatory therapy.

11:06         602.       Minimization of MR Contrast Weightings for the Comprehensive Evaluation of Carotid Atherosclerotic Disease

Xihai Zhao1, Jianming Cai2, Hunter Underhill1, Minako Oikawa1, Li Dong1, Hideki Ota1, Thomas Hatsukami3, Chun Yuan1

1Department of Radiology, University of Washington, Seattle, WA, USA; 2Department of Radiology, PLA General Hospital, Beijing, China; 3Department of Surgery, University of Washington, Seattle, WA, USA

Multi-sequence MR imaging (TOF, T1W, PDW, and T2W) has been shown noninvasively characterizing carotid atherosclerosis. Although the use of these multiple contrast weightings can evaluate a spectrum of plaque features, each contrast weighting requires additional scan time and adds to the time required for image analysis. To minimize MR contrast weightings for the comprehensive evaluation of carotid atherosclerosis is potentially capable of reduce the scan time and cost. This study compared three MR contrast weighting combinations in evaluating carotid plaque features. The results showed that comprehensive carotid plaque interpretation can be performed with T1W, CE-T1W, and TOF sequences.

11:18         603.       Multi-Spectral MRI Shows Unorganized Thrombus One Year After Endovascular Abdominal Aortic Aneurysm Repair.

Sandra Adriana Cornelissen1,2, Maarten J. van der Laan3, Koen L. Vincken4, Frans L. Moll3, Willem P. Mali1, Max A. Viergever2, Lambertus W. Bartels2

1Radiology, UMC Utrecht, Utrecht, Netherlands; 2Image Sciences Institute, UMC Utrecht, Utrecht, Netherlands; 3Vascular Surgery, UMC Utrecht, Utrecht, Netherlands; 4Image Sciences Institute, UMC Utrecht, Netherlands

Not all aneurysms without endoleak after endovascular abdominal aortic aneurysm repair (EVAR) shrink. In such cases it is unclear whether EVAR has been successful. Therefore it is important to further investigate this phenomenon. Apparently, more parameters are needed to evaluate treatment success. We present the first results of longitudinal monitoring of thrombus organization in patients after EVAR using multispectral MRI. Surprisingly, one year after EVAR unorganized thrombus is still present in the non-luminal aneurysm sac. Its etiology and significance is currently investigated in a larger population.

11:30         604.       Thrombus Development and Fragmentation in Rats Using Non-Enhanced MRI

Abdel Bidar1, Frank Risse1, Anna Ravnefjord2, Susanna Pehrsson2, Arno Nauerth3, Margareta Elg2, Paul D. Hockings1

1DECS Imaging, AstraZeneca, Molndal, Sweden; 2BioScience, AstraZeneca, Molndal, Sweden; 3Bruker BioSpin, Ettlingen, Germany

To our knowledge this is the first study to show the time course of thrombus formation over the first 4 days. Maximal average thrombus size was obtained 50 minutes after thrombus induction with no marked decrease over the following 4 days. Thrombus fragmentation was seen in several rats which potentially explains some of the variability seen in thrombosis models. An excellent correlation was found for MRI volume measurement and wet weight. MRI can follow thrombus formation, growth, fragmentation and dissolution in the same animal and thus drastically reduce the number of animals needed.

11:42         605.       Comparison Between Three T1-Weighted Sequences for Detection and Area Measurement of Intraplaque Hemorrhage in Carotid Atherosclerotic Plaque Imaging at 3 Tesla.

Hideki Ota1, Vasily L. Yarnykh2, Marina S. Ferguson2, Hunter R. Underhill2, J Kevin DeMarco1, Minako Oikawa2, Li Dong2, Xihai Zhao2, David C. Zhu1, Thomas S. Hatsukami3, Chun Yuan2

1Department of Radiology, Michigan State University, East Lansing, MI, USA; 2Department of Radiology, University of Washington, Seattle, WA, USA; 3Department of Surgery, University of Washington, Seattle, WA, USA

In this study using a 3.0T scanner, the detection and area measurement of carotid intraplaque hemorrhage were compared amongst three T1W sequences: 2D-FSE, 3D-SPGR, and 3D-MPRAGE. For each T1W sequence, an experienced radiologist identified hemorrhage blinded to histology and the images and results from the other sequences. A total of 198 slices in 18 arteries were matched to histology. MPRAGE demonstrated the highest agreement for detection and quantification of hemorrhage with histology and the highest %-contrast of hemorrhage among 3 weightings. T