2011 Annual Meeting Program Committee

 

Continuing Education

 

ISMRM Staff

 

Sponsors

 

Monday, May 9, 2011

Opening Session

Room Plenary Hall           07:30-08:20                                                                              Chair:  Georg Bongartz, ISMRM President  

07:30         Welcome & Award Presentations.   

2011 Mansfield Lecture

Room Plenary Hall           08:20-09:05                                                                              Chair:  Georg Bongartz, ISMRM President  

08:20                       Challenges in fMRI
Seiji Ogawa, Ph.D.
Tohoku Fukushi University, Sendai, Japan
           

Plenary Lectures                      
Functional Brain Networks at "Rest": Mechanisms, Methods & Clinical Utilization

Room Plenary Hall           09:05-10:20                                                                     Organizers: Peter A. Bandettini & Mark J. Lowe  

09:05         1.           What is the Physiological Basis of Functional Connectivity & What Can It Tell Us?

Maurizio Corbetta

Washington University School of Medicine, St. Louis, MO, USA

Spontaneous or intrinsic, i.e. not stimulus- or task-driven, activity in the brain is not noise, but orderly and organized at the level of large scale systems in a series of functional networks that maintain at all times a high level of coherence. Understanding this distributed spatio-temporal structure is critical for understanding neuronal communication and behavior.

09:30         2.           Resting-State Signals: Identification, Classification & Relation to Brain Connectivity

Stephen M. Smith

Oxford University FMRIB Centre, Oxford, England, UK    

Cardiovascular MRI technology continues to evolve in terms of its ability to rapidly and reliably produce accurate, functional, diagnostic information, and also in its capacity to provide quantitative results.  a number of centers are beginning to explore the use of MRI as a means to triage patients presenting in the emergency room with acute chest pain.  This presentation will explore the latest advances in cardiovascular MRI methods that are especially applicable to the diagnosis of Acute Coronary Syndrome (ACS).

09:55         3.           Resting Functional Connectivity: Potential as a Clinical Marker in Individual Patients

Michael D. Greicius

Stanford University Medical Center, Stanford, CA, USA

Functional MRI currently has few clinical applications. This is due, in part, to the difficulty of using task-activation fMRI in a clinical setting. Resting-state fMRI, which allows for the detection of 15-20 large-scale brain networks, has the potential to overcome some of these clinical limitations. This talk will examine efforts to develop resting-state fMRI biomarkers for several neuropsychiatric disorders including coma, depression and chronic pain. Particular emphasis will be placed on resting-state fMRI as a potential biomarker in Alzheimer’s disease.

Clinical Intensive Course
(Admission limited to Clinical Course registrants only)
Hip Bone & Soft Tissue Pathology: Case-Based Teaching

Room 516A-C                   08:30-09:45                                                                                                       Moderator: Mark Schweitzer  

08:30                       Soft Tissue Pathology About the Hip

Miriam A. Bredella

09:10                       Osseous Pathology About the Hip

Mark Schweitzer

Clinical Intensive Course
(Admission limited to Clinical Course registrants only)
Oncologic Body Imaging

Room 510                           08:30-10:15                                                                                                                                                            

08:30                       Tumor Response Assessment using CT & MRI: Current Clinical Practice

Frank H. Miller

09:00                       Tumor Response Assessment using the Advanced MRI Methods

Dow-Mu Koh

09:30                       Whole Body DWI: Does It Have a Role in Oncology?

Taro Takahara

10:00                       Discussion

Clinical Intensive Course
MR Imaging in Brain Tumors - ISMRM/ASNR Joint Session

Room 510                           11:00-13:00                                                                                  Moderators: Meng Law & Brian D. Ross  

11:00                       Cerebral Blood Flow & Permeability in Brain Tumors

Meng Law

11:25                       Diffusion in Brain Tumors

Danielle van Westen

11:50                       MR Biomakers in Brain Tumor

Thomas L. Chenevert

12:15                       Pseudoprogression, Recurrence & Radiation Necrosis

Pia C. Maly Sundgren

12:45                       Discussion

Clinical Intensive Course
Clinical Protocol Challenges in MSK

Room 516A-C                   11:00-13:00                                                                                                            Moderator: Garry E. Gold  

11:00                       High Field (3T & 7T)

Garry E. Gold

11:40                       Reducing Metallic Susceptibility

Hollis G. Potter

12:20                       Pediatric

Jerry R. Dwek

High Resolution Brain Imaging

Room 511A-C                   11:00-13:00                                                      Moderators: Fernando Calamante & Timothy Q. Duong

11:00         4.           Using In-Vivo MRI to Study Learning Induced Brain Plasticity in Adult Mice Trained on a Spatial Maze

Jurgen Germann1, D. Vousden1, P Steadman1, J. Dazai1, C. Laliberte1, S. Spring1, L. Cahill1, R. M. Henkelman1, Jason P. Lerch1

1The Mouse Imaging Centre, the Hospital for Sick Children, Toronto, Ontario, Canada

Brain shape is influenced by experience. The time course of the changes, however, remains unknown. In our study we longitudinally imaged mice undergoing spatial navigation training. Our results show that learning is associated with definite local brain changes detectable using live-imaging. These changes, found as early as on the second day of training, occur in specific brain regions depending on the experimental setup. The time course of local remodeling varies between regions. Whole brain live MRI is capable of detecting and characterizing these brain changes and is instrumental studying local changes within the brain as a learning system.    

11:12         5.           Can Preexisting Differences in Neuroanatomy Predict Training Performance? An In-Vivo MRI study of Adult Mice Trained on a Spatial Maze

Jurgen Germann1, P. Steadman1, D. Vousden1, J. Dazai1, S. Spring1, C. Laliberte1, L. Cahill1, R. M. Henkelman1, J. P. Lerch1

1The Mouse Imaging Centre, the Hospital for Sick Children, Toronto, Ontario, Canada

The famous London taxi driver study demonstrated that some hippocampal regions are larger in taxi drivers compared to matched controls. These anatomical differences are likely related to extensive experience. What, however, is the influence of preexisting anatomical differences on subsequent learning performance. In our study we imaged mice prior to spatial navigation training. Our results show that local variance in brain shape predicts subsequent learning performance. The relevant regions differ depending on the learning condition. Whole brain live MRI is capable of detecting and characterizing preexisting anatomical differences and instrumental in studying brain behavior relationship.

11:24         6.           Super-Resolution Track-Density Imaging Studies of Mouse Brain: Comparison to Histology

Fernando Calamante1,2, Jacques-Donald Tournier1,2, Nyoman D. Kurniawan3, Zhengyi Yang3, Erika Gyengesi4, Graham J. Galloway3, David C. Reutens3, Alan Connelly1,2

1Brain Research Institute, Florey Neuroscience Institutes, Heidelberg West, Victoria, Australia; 2Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia; 3Centre for Advanced Imaging, the University of Queensland, Brisbane, Queensland, Australia; 4Neuroscience Research Australia, Randwick, New South Wales, Australia

The recently introduced super-resolution track-density imaging (TDI) is able to increase the spatial resolution of the reconstructed images beyond the acquired MRI resolution by incorporating information contained in whole-brain fibre-track modelling results. The TDI technique not only provides a means to achieve super-resolution, but it also provides very high anatomical contrast with a new MRI contrast mechanism. However, the anatomical information-content of this novel contrast mechanism has not been validated yet. We perform such a study using ex vivo mouse brains acquired at 16.4T, and comparing the results of the super-resolution TDI technique to histological staining.

11:36         7.           Ultra-High Resolution Functional MRI & Electrophysiology of the Rat Primary Somatosensory Cortex

Yen-Yu Ian Shih1, You-Yin Chen2, Hsin-Yi Lai2, Timothy Q. Duong1

1Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA; 2Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan

This study employed very high resolution CBV fMRI (40x40 ìm in-plane resolution) and multichannel field potential recording to investigate the neurovascular coupling within cortical laminae. This MRI resolution was achieved by using a small surface coil and an 11.7 T scanner. Graded forepaw electrical stimulation was employed to modulate layer-specific neuronal activities. Our results indicate that CBV responses and field potential changes at laminar resolution are not completely coupled.

11:48         8.           Magnetic Resonance Microscopy of Human α-Motor Neurons & Neural Processes

Jeremy Joseph Flint1,2, Brian Hansen3, Sharon Portnoy1,2, Choong H. Lee2,4, Michael A. King5, Michael Fey6, Franck Vincent6, Peter Vestergaard-Poulsen3, Stephen J. Blackband2,7

1Neuroscience, University of Florida, Gainesville, Fl, USA; 2McKnight Brain Institute, University of Florida, Gainesville, Fl, USA; 3Center for Functionally Integrative Neuroscience, University of Aarhus, Aarhus, Denmark; 4Electrical Engineering, University of Florida, Gainesville, Fl, USA; 5Pharmacology & Therapeutics, University of Florida, Gainesville, Fl, USA; 6Bruker Biospin; 7National High Magnetic Field Laboratory, Talahassee, Fl, USA

The ability to resolve microstructural details of biological tissues has been a long sought-after goal in the field of MR imaging. Magnetic resonance microscopy (MRM) has evolved to reveal ever-finer details of the cellular organization which makes up tissue parenchyma. Such techniques are needed so that we may understand the primary structural origins underlying MR signal changes resultant from pathology. In the current study, we report what we believe to be the first instances of cellular imaging in humans and neural process imaging in humans and pigs using magnetic resonance microscopy techniques.

12:00         9.           Evidence Towards Columnar Organization of Human Area MT with Sub-Millimetric, 3D, T2 weighted BOLD  fMRI at 7 Tesla

Federico De Martino1, Jan Zimmermann1, Gregor Adriany2, Pierre-Francois van de Moortele2, David A. Feinberg3, Kamil Ugurbil2, Rainer Goebel1, Essa Yacoub2

1Cognitive Neuroscience, Maastricht University, Maastricht, Netherlands; 2CMRR, Radiology, University of Minnesota, Minneapolis, MN, USA; 3Advanced MRI Technologies, Sebastopol, CA, USA

We provide direct evidence of columnar organization of direction selective features (DSF) in human area MT using spin echo BOLD based fMRI at ultra high fields (7 tesla). We demonstrate that the functional selectivity and sensitivity of high field high resolution SE BOLD fMRI is sufficient to resolve the fine grained organization of feature representations within higher level folded cortical areas.

12:12         10.         Within Digit Somatotopy of the Human Somatosensory Cortex using fMRI at 7T

Rosa M. Sanchez Panchuelo1, Julien Besle2, Richard Bowtell3, Denis Schluppeck2, Susan Francis3

1Sir Peter Mansfield Magnetic Resonance Centre , University of Nottingham, Nottingham, United Kingdom; 2School of Psychology, University of Nottingham, Nottingham, United Kingdom; 3Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, United Kingdom

The increased BOLD contrast-to-noise ratio at 7T has been exploited to measure fine topographic organisation in individual subjects within the index finger representation (base-to-tip) in human somatosensory cortex (S1) at 1.5mm isotropic resolution using a travelling wave paradigm. Subjects were scanned twice to assess reproducibility, and data displayed on a flattened representation of the cortex. An organized somatotopy within the cortical area corresponding to the index finger was found for two subjects, with phase reversals in the map which are consistent with mirrored representations in adjacent sub-regions 3a/3b/1/2 of S1.  The results were reproducible across sessions for all subjects.

12:24         11.         Fast High Resolution Whole Brain T2* Weighted Imaging using Echo Planar Imaging at 7T

Jaco J. M. Zwanenburg1, 2, Maarten J. Versluis3, Peter R. Luijten1, Natalia Petridou1, 4

1Radiology, Universiy Medical Center Utrecht, Utrecht, Netherlands; 2Image Sciences Institute, Universiy Medical Center Utrecht, Utrecht, Netherlands; 3Radiology, Leiden University Medical Center, Leiden, Netherlands; 4Rudolf Magnus Institute, University Medical Center Utrecht, Utrecht, Netherlands

This work shows that high resolution (0.5 mm isotropic) T2* weighted images of the whole brain can be obtained in less than 6 minutes by utilizing the high SNR efficiency of echo planar imaging (EPI). The image SNR is increased by a factor of 2, and the coverage by a factor of approx. 5, compared to conventional gradient echo imaging (GRE) with the same scan duration. The contrast for both magnitude and phase is equivalent between EPI and GRE imaging.

12:36         12.         Investigation of Magnetic Susceptibility Contrast Across Cortical Grey Matter & White Matter

Masaki Fukunaga1,2, Peter van Gelderen1, Jongho Lee1, Tie-Qiang Li1, Jacco A. de Zwart1, Hellmut Merkle1, Kant M. Matsuda3, Eiji Matsuura4, Jeff H. Duyn1

1Advanced MRI section, LFMI, NINDS, National Institutes of Health, Bethesda, MD, USA; 2Biofunctional Imaging, Immunology Frontier Research Center, Osaka University, Suita, Osaka, Japan; 3Laboratory of Pathology, NCI, National Institutes of Health, Bethesda, MD, USA; 4Laboratory of Neuroimmunology, NINDS, National Institutes of Health, Bethesda, MD, USA

Variations of magnetic susceptibility have been demonstrated in primary visual cortex and shown to relate to tissue iron content. Here we extend this finding to cortical regions in the parietal lobe of human brain. Comparison of 7T MRI data with iron and myelin histology suggests that iron dominates the contrast across many cortical areas including sensory-motor cortex, cingulate and precuneus. Interestingly, myelin and iron differentially contribute to susceptibility contrast in subcortical white matter versus the optic radiation.

12:48         13.         Exploring Orientation Dependence of T2* in White Matter by Extreme Rotation of the Human Head at 7 Tesla

Graham Wiggins1, Chris Wiggins2, Bei Zhang1, Ryan Brown1, Bernd Stoeckel3, Daniel K. Sodickson1

1Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY10016, USA; 2CEA/NeuroSpin, Saclay, France; 3Siemens Medical Solutions USA Inc, New York, NY, USA

At 7T, T2* weighted gradient echo imaging reveals unexpected contrast variation in white matter which appears to be associated with specific fiber bundles. The mechanism behind this variation has been debated, and it has been proposed that it may be caused by intrinsic properties of the fiber bundle such as degree of myelination or iron content, or that it depends on the orientation of the fiber bundles in relation to the main B0 field. With a novel coil system we obtain T2* maps in orientations 90 degrees apart and demonstrate that T2* depends strongly on orientation.

Experimental Myocardial Imaging & Spectroscopy

Room 511D-F                    11:00-13:00                                                                Moderators: David Sosnovik & Gustav J. Strijkers

11:00         14.         Introduction
Frederick H. Epstein

11:12         15.         Regional Quantification of Myocardial Stiffness using MR Elastography

Arunark Kolipaka1, Kiaran McGee1, Shivani Aggarwal1, Qingshan Chen1, Nandan Anavekar1, Armando Manduca1, Richard Ehman1, Philip Araoz1

1Mayo Clinic, Rochester, MN, USA

The mechanical properties of the myocardium are known to be essential for normal cardiac function. Magnetic resonance elastography (MRE) is a noninvasive phase contrast technique to estimate stiffness of soft tissues. The purpose of this study was to regionally quantitate effective stiffness in infarcted and remote, non-infarcted myocardium using MRE. Post 3 weeks of induced infarction on 13 pigs, MRE and mechanical testing was performed. We found significant difference in stiffness estimates between infarcted and remote, non-infarcted myocardium both using MRE and mechanical testing.

11:24         16.         Embryonic Cardiomyocytes Improve Contractility & Viability of Ischemic Myocardium

Leonie E. Paulis1, Alexandra Klein2, Tessa Geelen1, Bernd Fleischmann2, Wilhelm Roell2, Klaas Nicolay1, Gustav J. Strijkers1

1Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands; 2Institute for Physiology, Life & Brain Centre, University of Bonn, Bonn, Germany

Regenerative therapy after myocardial infarction by embryonic cardiomyocyte (eCM) transplantation has potential to increase infarct contractility induced by the electrical coupling of eCM with native myocardium. In this study, it was shown with in vivo (contrast enhanced) cardiac MRI that besides improved global cardiac function (ejection fraction and cardiac output) and reduced infarct volume, eCMs indeed significantly improved infarct wall thickening (WT) in a mouse model of myocardial infarction. These effects were not observed after transplantation of skeletal myoblasts (SMs) or mesenchymal stem cells (MSCs), which lack the intrinsic ability of electrical coupling and also did not differentiate into cardiomyocytes.

11:36         17.         Beyond Qualitative Tractography: A Novel & Reproducible Technique for the Quantitative Analysis of Cardiac Diffusion MR Tractography Datasets In Vivo

Choukri Mekkaoui1, Shuning Huang1, Guangping Dai1, Timothy G. Reese1, Udo Hoffmann2, Marcel P. Jackowski3, David E. Sosnovik1

1Radiology, Harvard Medical School, Massachusetts General Hospital, Martinos Center For Biomedical Imaging, Charlestown, MA, USA; 2Radiology, Massachusetts General Hospital, Harvard Medical School, USA; 3Computer Science, University of São Paulo, Institute of Mathematics & Statistics, São Paulo, Brazil

Diffusion tensor MRI tractography can be used to resolve 3D myofiber architecture in the heart. The analysis of these tractograms, however, has been purely qualitative. Here we present a novel metric to quantify regional variation and measurement noise in diffusion tractography datasets in the heart. The technique is applied in human hearts ex vivo, in infarcted sheep hearts, and in mouse hearts in vivo. The use of this metric revealed that high quality diffusion tractograms of the mouse heart can be acquired in vivo, and that fibers in the remote zone of an infarct undergo a right-handed helix angle rotation.

11:48         18.         Microstructural Signatures of Ischemia & Stem Cell Therapy in the Myocardium Revealed with Serial Diffusion Tensor MRI & Tractography of the Mouse Heart In Vivo.

Shuning Huang1, Choukri Mekkaoui1, Howard H. Chen1, Soeun Ngoy2, Michael Bauer2, Ruopeng Wang1, Van J. Wedeen1, Guangping E. Dai1, Ronglih Liao2, David E. Sosnovik1, 3

1Martinos Center for Biomedical Imaging, Mass General Hospital, Charlestown, MA, USA; 2Cardiology, Brigham & Woman's Hospital, Boston, MA, USA; 3Cardiology, Mass General Hospital, Charlestown, MA, USA

Diffusion tensor MRI (DTI) and tractography of the myocardium has been limited to ex-vivo studies. Here, we show that DTI and tractography of the mouse heart can be performed in-vivo.  We report, for the first time, the serial changes in myocardial microstructure seen in acute ischemia, infarct healing, and following stem cell injection.  Mean diffusivity increased in acute ischemia and returned towards baseline as the infarct healed. The injection of bone marrow derived progenitor cells produced a transient increase in myocardial microstructure. The value of this approach in guiding the development of stem cell therapy is robustly demonstrated.

12:00         19.         Quantitative Assessment of Mitochondrial Metabolic Efficiency by 17O & 31P MR Spectroscopy in Isolated Rat Hearts

Bharath Atthe1, 2, Mary Kemerer1, 2, Ya Chen1, 2, Ming Lu1, 2, Gheorghe Mateescu2, 3, Chris Flask2, 3, Xin Yu1, 2

1Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA; 2Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA; 3Radiology, Case Western Reserve University School of Medicine, Cleveland, OH, USA

In this study, we investigated the potential of combining 17O spectroscopy (17O-MRS) and 31P magnetization transfer (31P-MT) method for evaluating metabolic efficiency in perfused hearts.  ATP synthesis rate was determined from 31P-MT experiments, while mitochondrial oxidation was quantified by the rate of H217O production.  2,4-dinitrophenol (DNP) was used to induce the uncoupling of mitochondrial oxidation and phosphorylation.  Our results suggest that the ratio of ATP synthesis measured by 31P-MT to mitochondrial H217O production quantified by 17O-MRS can be used as an indicator of metabolic efficiency.

12:12         20.         Creatine Kinase Overexpression Increases In Vivo ATP Synthesis in the Failing Mouse Heart

Ashish Gupta1,2, Vadappuram P. Chacko3, Yibin Wang4, Robert G. Weiss2,5

1Department of Medicine, Division of Cardiology, the Johns Hopkins University, School of Medicine, Baltimore, MD, USA; 2Department of Radiology, Division of Magnetic Resonance Research, the Johns Hopkins University , Baltimore, MD, USA; 3Department of Radiology,Division of Magnetic Resonance Research, the Johns Hopkins University School of Medicine, Baltimore, MD, USA; 4Department of Anesthesiology & Medicine, University of California, Los Angeles, CA, USA; 5Department of Medicine, Division of Cardiology, the Johns Hopkins University School of Medicine, Baltimore, MD, USA

Because it was hypothesized that failing heart is energy starved, we used a transgenic approach to augment ATP synthesis in failing hearts. The in vivo rate of ATP synthesis through cardiac creatine kinase (CK Flux) was measured using localized 31P MR triple repetition saturation transfer (TRiST) in healthy mice (n=11), others with heart failure (HF) following thoracic aortic constriction (TAC, n=10), and non-operated (n=8) and TAC (n=7) mice overexpressing the muscle isoform of creatine kinase (CK-M). CK flux was significantly increased in CK-M TAC hearts, indicating that CK-M overexpression offers a means to augment ATP delivery in HF.

12:24         21.         Hyperpolarized 13C Magnetic Resonance Imaging & Spectroscopy Uniquely Reveal Early & Late Onset Metabolic Changes in the Failing Heart

Marie Allen Schroeder1, 2, Angus Z. Lau1, 3, Albert Chen4, Kim Connelly1, 5, Xudong Hu5, Jennifer Barry1, Damian J. Tyler2, Kieran Clarke2, Graham A. Wright1,3, Chuck H. Cunningham1,3

1Schulich Heart Centre, Sunnybrook Health Sciences Centre, Toronto, Ontario , Canada; 2Physiology, Anatomy & Genetics, University of Oxford, Oxford, Oxfordshire, United Kingdom; 3Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; 4GE-Healthcare, Toronto, Ontario, Canada; 5Keenan Research Centre of the Li Ka Shing Knowledge Institute, St Michael's Hospital , Toronto, Ontario, Canada

The aim of this study was to use hyperpolarized 13C MRI and MRS to monitor cardiac substrate utilization alongside structure and function, measured using standard cine-MRI, throughout HF progression. Metabolism of [2-13C]pyruvate to 13C-glutamate was reduced by 59% at an early stage in HF, with no change to PDH flux, indicating that 13C-glutamate relative to H13CO3- production could be an early marker of disease. Carbohydrate oxidation via PDH was maintained until end-stage HF, at which point PDH flux was reduced by 62%. Hyperpolarised 13C MR may be useful to characterize HF progression, and to diagnose disease, in patients.

12:36         22.         Assessment of Chemical Exchange Saturation Transfer Effects in Myocardial Tissue at 7T

Mohammad Haris1, Anup Singh1, Kejia Cai1, Walter R. T. Witschey2, James J. Pilla1, Giovanni Ferrari3, Kevin Koomalsingh3, Robin Hinmon3, Gerald Zsido1, Joseph H. Gorman III3, Robert C. Gorman3, Hari Hariharan1, Ravinder Reddy1

1CMROI, Radiology, University of Pennsylvania, Philadelphia, PA, USA; 2University Hospital Freiburg, Germany; 3Department of Surgery, University of Pennsylvania

We observed the chemical exchange saturation transfer (CEST) effects of water signal in left ventricular infarcted swine heart tissue on 7T clinical scanner. Significantly low CEST contrast was observed in infarcted region compared to non-infarcted region. Low CEST contrast in infarcted region may be due to combined effect from decreased concentration of creatine and low pH. Further characterization of this method on in-vivo animal model of myocardial infarction is in progress.

12:48         23.         High Spatial Resolution Free Breathing 3D T2 Mapping for Edema Detection in Radio Frequency Ablation

Haiyan Ding1,2, Di Xu1, M. Muz Zviman3, Valeria Sena-Weltin3, Luciano Amado3, Saman Nazarian3, Henry Halperin3, Elliot R. McVeigh1, Daniel A. Herzka1

1Department of Biomedical Engineering, Johns Hopkins School of Medicine, Baltimore, MD, USA; 2Department of Biomedical Engineering, Tsinghua University, Beijing, China, People's Republic of; 3Department of Medicine, Division of Cardiology, Johns Hopkins School of Medicine, Baltimore, MD, USA

Differentiating between viable myocardium, scar and injured tissue (edema) in both ventricles and atria can very helpful in predicting the recurrence of arrhythmias after radiofrequency ablation (RFA). We propose a 3D navigator gated imaging sequence designed for high resolution T2 mapping and edema detection. T2 maps pre- and post injection of contrast were generated from an interleaved series of T2-prepared 3D volumes acquired 2hrs post RFA the left atrium of a swine. Enhancement due to edema in pre-contrast T2map was confirmed by T2-STIR and delayed enhancement images. T2 values calculated were comparable to those previously reported.

Fetal & Pediatric Neuro Studies

Room 512A-G                   11:00-13:00                                                          Moderators: Patricia Ellen Grant & Judith Verhoeven

11:00         24.         Radial & Tangential Migrational Pathways Revealed by Diffusion Tractography

Emi Takahashi1, Rebecca D. Folkerth2, Albert M. Galaburda3, P. Ellen Grant1

1Children's Hospital Boston, Boston, MA, USA; 2Brigham & Women's Hospital; 3Beth Israel Deaconess Medical Center

We applied high-angular resolution diffusion imaging (HARDI) tractography to intact whole postmortem fetal human brains to explore the 3-dimensional regression of the radial and tangential migration pathways. Our results show the usefulness of HARDI tractography to image both radial and tangential migrational streams in fetal human brains, and suggest that regional regression of radial organization and regional emergence of fetal brain axonal connectivity proceed in general from postero-dorsal to antero-ventral with local variations related to the later appearance of gyri and sulci.

11:12         25.         In Vivo Fetal Cortical Development

Cedric Clouchoux1,2, Dimitri Kudelski3, Ali Gholipour4, Simon K. Warfield4, Sophie Viseur5, Jean-Luc Mari3, Alan C. Evans2, Adre J. DuPlessis1, Catherine Limperopoulos1, 2

1Children's National Medical Center, Washington, DC, USA; 2Montreal Neurological Institute, Montreal, QC, Canada; 3LSIS, Marseille, France; 4Children’s Hospital Boston, Boston, MA, USA; 5Universite de Provence, Marseille, France

Recent advances in fetal magnetic resonance imaging and post-processing computational methods are providing new insights into fetal brain maturation in vivo. To date, no study has delineated the gyrification process for the in vivo fetal brain.

Herein, we investigate the in vivo fetal cortical folding between 25 and 35 weeks gestational age in healthy fetuses, using 3D reconstructed fetal cortical surfaces. We describe for the first time the in vivo fetal gyrification process using an original feature extraction algorithm applied directly on the cortical surface, providing an explicit delineation of the sulcal pattern during fetal brain development.

11:24         26.         Detection & Mapping of Delays in Early Cortical Folding in Fetuses with Ventriculomegaly from In Utero MRI

Piotr A. Habas1, Julia A. Scott1, Vidya Rajagopalan1, Kio Kim1, A. James Barkovich1, Orit A. Glenn1, Colin Studholme1

1University of California San Francisco, San Francisco, CA, USA

We present the results of spatially unconstrained detection and mapping of folding delays in fetuses with IMVM. MR imaging was performed for 16 IMVM subjects at 22.00-25.43GW and 22 age-matched controls. For each subject, a motion-corrected 3D MRI was reconstructed from multiple stacks of SSFSE T2w slices. Temporal changes in local curvature of the inner cortical surface were represented using a general linear model with a delay term for IMVM subjects. Significant folding delays were detected bilaterally along the parieto-occipital sulcus of IMVM subjects. Analysis with older fetuses will determine whether these differences are transient or persist into later gestation.

11:36         27.         Diminished Regional Brain Growth is Associated with Impaired White Matter Microstructural Development Following Premature Birth

Gareth Ball1, James P. Boardman1, 2, Daniel Rueckert3, Paul Aljabar3, Tomoki Arichi1, 4, Nazakat Merchant1,4, Ioannis S. Gousias1, A. David Edwards1, 4, Serena J. Counsell1

1Imperial College London & MRC Clinical Sciences Centre, London, United Kingdom; 2Simpson Centre for Reproductive Health, Royal Infirmary of Edinburgh, Edinburgh, United Kingdom; 3Department of Computing, Imperial College London, London, United Kingdom; 4Division of Neonatology, Imperial College Healthcare NHS Trust, London, United Kingdom

Preterm birth is a leading cause of cognitive impairment in childhood, and is associated with a spectrum of structural brain abnormalities but the nature and evolution of these developmental processes are poorly understood. Using multi-modal magnetic resonance image analysis we demonstrate a specific pattern of cerebral growth that is related linearly to gestational age at birth, and show that thalamic size is directly related to the integrity of developing white matter tracts. These findings confirm that diminished thalamic growth and alterations in white matter microstructure occur in parallel after premature birth, possibly representing downstream consequences of a common primary insult.

11:48         28.         Initial Experience with Pseudo-Continuous Arterial Spin Labeling (pCASL) in the Infant Brain

Mathieu Dehaes1,2, Rudolph Pienaar2, Janet S. Soul3, P. Ellen Grant1,2

1Division of Newborn Medicine, Department of Medicine, Children’s Hospital Boston, Harvard Medical School, Boston, MA, USA; 2Center for Fetal-Neonatal Neuroimaging & Developmental Science, Boston, MA, USA; 3Department of Neurolory, Children’s Hospital Boston, Harvard Medical School, Boston, MA, USA

Pseudo-continuous Arterial Spin Labeling (pCASL) can improve our understanding of metabolic changes that occur with injury by providing quantitative information on cerebral blood flow (CBF). Here we report our initial experience with pCASL in the first four months of life including two neonates and four young infants. Three subjects were imaged within 24 hours of cardiac arrest and 2 of 3 showed marked whole brain elevated CBF indicating rebound hyperperfusion. pCASL has tremendous potential in improving our understanding of physiological changes with injury. Better characterization of normal subject is needed to determine if there are more subtle increases in CBF.

12:00         29.         Prognostic Value of 1H-MRS & DTI after Hypothermic Treatment in Newborns with Perinatal Asphyxial Encephalopathy

Claudia Testa1, Caterina Tonon1, David Neil Manners1, Emil Malucelli1, Sara Grandi2, Francesca Sbravati2, Giacomo Faldella2, Gina Ancora2, Raffaele Lodi1

1MR Spectroscopy Unit, Department of Internal Medicine, Aging & Nephrology, University of Bologna, Bologna, Italy; 2Neonatology Unit, Department of Woman, Child & Adolescent Health, University of Bologna, Bologna, Italy

1-MRS and DTI were evaluated in 19 neonates with hypoxic-ischemic encephalopathy after brain cooling. MRS was acquired in the basal ganglia, in white and gray matter; DTI was acquired using 15 gradient directions. Metabolites ratios and concentrations, MD and FA maps were calculated. ROIs were semi-automatically drawn onto each FA and MD map using study specific templates.

NAA and mI resulted significantly lower in the basal ganglia and white matter of neonates with pathological outcome and the MD and FA values significantly reduced in ROIs of the supratentorial region suggesting that MR parameters predict the pathological outcome after brain cooling.

12:12         30.         Serial Diffusion Tensor Tractography Studies in Term Neonates with Hypoxic Ischemic Encephalopathy

Richa Trivedi1, Abhishek Yadav2, Gyanendra Kumar Malik3, Archana Yadav3, Ram K. S. Rathore4, Rakesh Kumar Gupta2

1Institute of Nuclear Medicine & Allied Sciences, New Delhi, Uttar Pradesh, India; 2Radiodiagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India, Lucknow, Uttar Pradesh, India; 3Paediatrics, Chhatrapati Sahu ji Maharaj Medical University, Lucknow, Uttar Pradesh, India; 4Mathematics & Statistics, Indian Institute of Technology, Kanpur, Kanpur, Uttar Pradesh, India

Serial diffusion tensor tractography using FACT algorithm was performed on 11 term neonates with moderate hypoxic ischemic encephalopathy (HIE) to look for the change over time of the DTI measures in thalamic radiations in these infants compared to age/sex matched healthy controls through their early infancy. On comparing FA and MD changes over time, we observed altered patterns of age-related FA increase and MD decrease in thalamic radiations in neonates with HIE compared with controls. Our study suggests that abnormal FA and MD values with near normal conventional imaging may allow early and more accurate assessment of injury in neonates with HIE.

12:24         31.         Correlation of Thalamic Volume & Microstructural Abnormalites in Central Visual Pathways in High Risk Preterm Infants

Arabhi C. Nagasunder1, 2, Rafael Ceschin3, Robin L. Haynes4, Jessica Wisnowski1, 5, Jane Tavare6, Marvin D. Nelson1, Stefan Bluml1, 2, Lisa Paquette7, Ashok Panigrahy1,3

1Radiology, Childrens Hospital Los Angeles, Los Angeles, CA, USA; 2Rudi Schulte Research Institute, Santa Barbara, CA, USA; 3Radiology, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA; 4Pathology, Children's Hospital Boston, Boston, MA, USA; 5Brain & Creativity Institute, University of Southern California, Los Angeles, CA, USA; 6Division of Pathology, Childrens Hospital Los Angeles, Los Angeles, CA, USA; 7Division of Neonatology, Childrens Hospital Los Angeles, Los Angeles, CA, USA

Preterm infants are highly vulnerable to a spectrum of cognitive visual disturbances. Here we demonstrate that high risk preterm infants with periventricular leukomalacia (PVL) show significant correlation between thalamic volume and microstructural abnormalities in central visual pathways (optic radiation, splenium). In contrast, preterms infants without PVL demonstrate a milder version of the same injury pattern suggesting that damage to central visual pathways is not always associated with PVL. Thalamic injury may play a pivotal role in the pathogenesis of cognitive visual impairment in survivors of prematurity.

12:36         32.         Corpus Callosum Alterations in Preterm Infants at Term Predict Motor Outcomes at 5 Years

Deanne Kim Thompson1,2, Terrie E. Inder1,3, Gehan Roberts1, Jeremy Lim1, Lex W. Doyle1,4, Peter J. Anderson1, Gary F. Egan2

1Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia; 2Florey Neurosciences Institute, Centre for Neuroscience, University of Melbourne, Parkville, Victoria, Australia; 3Department of Pediatrics, St Louis Children's Hospital, Washington University in St Louis, St Louis, USA; 4Department of Obstetrics & Gynecology, Royal Women's Hospital, Parkville, Victoria, Australia

Motor dysfunction is commonly associated with preterm birth, but its neurological correlates are not well understood. Corpus callosum alterations have been implicated in impaired motor functioning. Structural and diffusion MR imaging at term equivalent age was used to assess differences between very preterm 5 year-olds with (n=20) and without motor impairment (n=69). Corpus callosum area, tract volume, and diffusion measures were obtained. Children with motor impairment demonstrated significantly lower mean, axial and radial diffusivity and higher FA within the callosal tracts, particularly posteriorly. These findings suggest that motor impairment common to very preterm children is partially explained by altered posterior callosal development.

12:48         33.         Prematurity & Prenatal Growth Restriction Differently Affects Brain Connectivity

Elda Fischi-Gomez1, François Lazeyras2, Cristina Borradori-Tolsa3, Jean-Philippe Thiran1, Petra S. Hüppi3

1Signal Processing Laboratory 5 (LTS5), Ecole Politechnique Federale de Lausanne, Lausanne, Vaud, Switzerland; 2Service of Radiology, University Hospital of Geneva, Geneva, Switzerland; 3Division of Development & Growth. Department of Pediatrics, University of Geneva, Geneva, Switzerland

Survival of children born prematurely or with very low birth weight has increased dramatically in the last decades, but the long term developmental outcome remains a concern. The most common cerebral neuro-pathology observed in case of premature birth is a diffuse white matter abnormality. However, many of the children born prematurely present indeed deficits in their cognitive capacities, in particular involving executive domains. The origins of these disabilities are largely unknown but are likely to involve an overriding central nervous system deficit. To understand the neurostructural origin of these disabilities and to investigate the effect of prematurity and intra uterine growth restriction in pre-school children aged 6 years old, we have combined imaging with DWI and TBSS.

Microscopy & Elastography

Room 513A-D                   11:00-13:00                                                          Moderators: Robert R. Edelman & Cornelius J. Faber

11:00         34.         Non-Invasive Visualization of the Complete Cardiac Conduction System using MR Microscopy

Min-Sig Hwang1,2, Katja E. Odening3, Bum-Rak Choi3, Gideon Koren3, Stephen J. Blackband1,2, John R. Forder1,4

1McKnight Brain Institute, Gainesville, FL, USA; 2Neuroscience, University of Florida, Gainesville, FL, USA; 3Cardiovascular Research Center, the Rhode Island Hospital, Alpert Medical School of Brown University, Providence, RI, USA; 4Radiology, University of Florida, Gainesville, FL, USA

In this study, we demonstrate that MRI at microscopic resolutions, i.e. MR microscopy (MRM), combined with high angular resolution diffusion microscopy (HARDM), can describe non-invasively the complete cardiac conduction system and anatomical features in isolated rabbit hearts, as a precurser to developing a mathematical model of depolarizaton in the heart.  The combined investigative technique of MRM and HARDM is observed to be an effective method of monitoring morphological changes occurring in the cardiac conduction system.

11:12         35.         A New Method for Phenotyping the Brain Tumor Microenvironment using MR Microscopy

Eugene Kim1, Jiangyang Zhang2, Karen Hong3, Arvind P. Pathak2,4

1Department of Biomedical Engineering, the Johns Hopkins University School of Medicine, Baltimore, MD, USA; 2Russell H. Morgan Department of Radiology & Radiological Science, the Johns Hopkins University School of Medicine; 3The Johns Hopkins University School of Public Health; 4JHU ICMIC Program

The development of pre-clinical brain tumor models and anti-angiogenic therapies has created a critical need to characterize the brain tumor microenvironment. Here we describe a novel method for whole-brain 3D mapping of the vasculature of a mouse brain tumor model using magnetic resonance microscopy (μMRI). The vascular architecture was characterized by six morphological parameters. Region-of-interest analysis showed significant differences in these parameters between tumor and contralateral brain. In combination with diffusion-weighted MRI, we could characterize the phenotypes of post-inoculation day-12 and day-17 tumors. These results demonstrate the feasibility of using μMRI to characterize microenvironmental changes that accompany brain tumor progression.

11:24         36.         MR Microscopy of Brain Cytoarchitecture by Quantitative Mapping of Magnetic Susceptibility

Chunlei Liu1,2, Wei Li1, G. Allan Johnson2

1Brain Imaging & Analysis Center, Duke University, Durham, NC, USA; 2Radiology, Duke University, Durham, NC, USA

At high field strengths, phase images showed excellent image contrast and revealed anatomic structures that were not visible on the corresponding magnitude images. Here, we demonstrate that phase images and, more importantly, the corresponding susceptibility maps provide a novel contrast mechanism to visualize the microstructure of brain anatomy at the exquisite resolution offered by MR microscopy. In particular, we believe the described technique may provide a powerful tool to visualize brain cytoarchitecture at high speed and with ultra-high spatial resolution. We further anticipate that imaging magnetic susceptibility may provide a powerful tool for studying animal models of white matter diseases.

11:36         37.         Imaging Neural Stem Cell Populations in the Developing Mouse Brain using Magnetic Resonance Micro Histology

Francesca C. Norris1, 2, Jon O. Cleary1, 3, Joanne Henderson4, Benjamin Sinclair1, 5, Karen McCue6, Jack A. Wells1, Sebastien Ourselin7, Paolo Salomoni4, Peter J. Scambler6, Mark F. Lythgoe1

1Centre for Advanced Biomedical Imaging, University College London, London, United Kingdom; 2Centre for Mathematics & Physics in the Life Sciences & Experimental Biology (CoMPLEX), University College London, London, United Kingdom; 3Department of Medical Physics & Bioengineering, University College London, London, United Kingdom; 4Samantha Dickson Brain Cancer Unit, UCL Cancer Institute, London, United Kingdom; 5Centre for Medical Image Computing, University College London, London, United Kingdom; 6Molecular Medicine Unit, UCL Institute of Child Health, London, United Kingdom; 7Centre for Medical Image Computer, University College London, London, United Kingdom

Advanced methods that enable labelling of neural stem cells and progenitor cells are fundamental for investigating brain development under normal and pathological conditions. MR histology is an emergent technique that may be able to provide an array of staining options to highlight distinct cellular structures. We identify previously undetected substructures and delineate regions of neural stem cells and progenitor cells within the intact embryo brain using an MR histological stain. This methodology could enable greater sensitivity for phenotypic characterisation of mutant mouse models by highlighting specific cellular structures for investigation of developmental and disease processes.

11:48         38.         Dual-Mode Optical-MR Microscopy with Uniplanar Gradient Coils

Andrey V. Demyanenko1, Shuyi Nie1, Yun Kee1, Marianne Bronner-Fraser1, Julian Michael Tyszka1

1Biology, California Institute of Technology, Pasadena, CA, USA

Magnetic resonance microscopy offers unique complementary information to optical microscopy in basic biological and clinical applications. The integration of optical microscopes with MR imaging hardware is becoming increasingly popular and we present here a dual-mode MR and visible light optical microscope targeted towards applications in developmental biology and embryology. The instrument consists of a uniplanar three-axis gradient module and planar RF transceiver coil with a MR-compatible CCD optical microscope focused at the center of the gradient target volume via a planar mirror. Simultaneous optical and MR imaging of live Xenopus laevis embryos resulted in images of the dorsal embryonic surface with complementary imaging of internal morphological development over periods longer than 12 hours.

12:00         39.         Investigating Anisotropic Elasticity using MR-Elastography Combined with Diffusion Tensor Imaging: Validation using Anisotropic & Viscoelastic Phantoms

Eric Chuan Qin1, Ralph Sinkus2, Caroline Rae1, Lynne Eckert Bilston1

1Neuroscience Research Australia, Randwick, NSW, Australia; 2Centre de Recherches Biomédicales , Hopital Beaujon, Paris, France

Investigating the anisotropic mechanical properties of tissue can provide additional physical parameters to detect abnormal changes in skeletal muscle diseases such as atrophy. In this study, we combined Diffusion Tensor Imaging (DTI) with MR-Elastography (MRE) to probe the anisotropic elasticity of viscoelastic materials. By assuming a transversely isotropic model, the shear moduli parallel and perpendicular to the local fiber direction (provided by DTI) can be calculated. Results are presented for anisotropic viscoelastic phantoms and ex vivo bovine skeletal muscles. The MRE/DTI mechanical anisotropic ratio was compared with the “gold-standard” rotational rheometry results. No significant difference was observed between the two.   

12:12         40.         Biomechanical Properties Quantified In Vivo By Magnetic Resonance Elastography Correlate wth Myelination & Brain Parenchymal Integrity  – a Combined 7 Tesla MRE & Histopathology Study in a Mouse Model of Multiple Sclerosis

Katharina Schregel1,2, Eva Wuerfel3, Philippe Garteiser4, Timur Prozorovskiy5, Hartmut Merz6, Dirk Petersen1, Jens Wuerfel1,7, Ralph Sinkus4,7

1Institute of  Neuroradiology, University Luebeck, Luebeck, Germany; 2INSERM UMR 773, CRB3, Centre de Recherches Biomédicales Bichat-Beaujon , Paris, France; 3Department of Pediatrics, University Luebeck, Luebeck, Germany; 4INSERM UMR 773, CRB3, Centre de Recherches Biomédicales Bichat-Beaujon, Paris, France; 5Molecular Neurology, Heinrich-Heine-University, Life Science Center, Duesseldorf, Germany; 6Department of Pathology, University Luebeck, Luebeck, Germany; 7authors contributed equally

Magnetic Resonance Elastography (MRE) is a novel technique that directly visualizes and quantitatively measures biomechanical tissue properties in vivo. Already smallest changes of the brain parenchymal viscoelasticity, e.g. occurring during physiological brain maturation in adolescent mice, can be reliably detected. In a longitudinal study, we correlated for the first time biomechanical properties quantified in vivo by MRE with detailed histopathology of brain parenchymal alterations in healthy C57bl/6 mice and in a mouse model of multiple sclerosis. MRE correlated with the degree of myelination as well as with extracellular matrix integrity, but not with cellular infiltration into the brain parenchyma.

12:24         41.         Hydrocephalus Detection using Intrinsically-Activated MRE

Keith D. Paulsen1,2, Adam J. Pattison1, Irina M. Perreard3, John B. Weaver1,3, David W. Roberts3

1Thayer School of Engineering, Dartmouth College, Hanover, NH, USA; 2Norris Cotton Cancer Center, Lebanon, NH, USA; 3Dartmouth-Hitchcock Medical Center, Lebanon, NH, USA

Hydrocephalus is a disease in which cerebrospinal fluid is obstructed causing an increase in ventricular size and, in some cases, an increased intracranial pressure. Current imaging modalities only detect oversized ventricles, which can be confused with cerebral atrophy, a disease where enlargement occurs due to shrinkage of the periventricular parenchyma. Magnetic resonance elastography (MRE) may differentiate between these two categories of disease based on mechanical property differences. A previously described ‘intrinsic activation’ MRE method was applied to a series of normal and hydrocephalic patients. Initial results are promising and show significant differences in stiffness and pore-pressure estimations between the two patient groups.

12:36         42.         Cerebral MR Elastography for Measuring Poroelastic Properties of the Brain

Sebastian Hirsch1, Dieter Klatt1, Sebastian Papazoglou1, Kaspar Josche Streitberger1, Juergen Braun2, Ingolf Sack1

1Department of Radiology, Charité - University Medicine Berlin, Berlin, Germany; 2Institute of Medical Informatics, Charité - University Medicine Berlin, Berlin, Germany

Cerebral MR poroelastography based on multi-slice echo planar imaging is introduced. The method allows for acquisition of full time-resolved 3D-wave fields with 30 slices in 3 min. Gated data acquisition by pulse wave trigger is demonstrated. Two complex mechanical moduli corresponding to Lamé's coefficients are recovered using a direct 3D-harmonic field inversion. While one coefficient corresponds to the shear modulus measured in previous studies of 2D cerebral MRE, the other is related to dilatational deformation occurring in biphasic soft tissue and is thus determined by microscopic fluid filtration.

12:48         43.         Cardiac-Gated Hepatic MR Elastography with Intrinsic Transient Waveforms

David Andrew Olsen1, Pengfei Song1, Kevin J. Glaser1, Richard L. Ehman1

1Mayo Clinic, Rochester, MN, USA

In conventional MR elastography (MRE), an external vibration source generates harmonic waves to characterize tissue. In this study, we developed and evaluated a dynamic MRE method for quantifying liver stiffness using intrinsic transient waveforms imparted on the liver by the beating heart by synchronizing motion-encoding gradients to the cardiac cycle.  Sixteen subjects were imaged with conventional harmonic and cardiac-gated transient MRE. The results show that this method is reproducible and gives quantitative stiffness values that approximate those obtained with conventional MRE and may allow for the eventual screening of patients with liver disease using standard MRI equipment.

Prostate Cancer (Clinical Studies)

Room 518-A-C                  11:00-13:00                                                                   Moderators: Jurgen J. Fütterer & Anwar Padhani

11:00         44.         Introduction
Anwar Padhani

11:12         45.         Diffusion Kurtosis Imaging in Prostate Cancer

Andreas Lemke1, Anja Weidner2, Jörg Döpfert1, Dietmar Dinter2, Lothar Rudi Schad1

1Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany; 2Department of Clinical Radiology & Nuclear Medicine, Heidelberg University, Mannheim, Germany

Diffusion kurtosis parameter maps of six patients with biopsy confirmed prostate cancer (PCa) were obtained using a 3 Tesla Scanner with an endorectal coil and 6 b-values (b=0,100,500,1000,1500,2000 s/mm²). All patients showed an increased value of the kurtosis in the tumor compared to healthy tissue and five of the patients a decreased ADC- and D-value. The mean parameter values in the tumor and the contralateral healthy tissue were: K=1.02±0.25 vs. 0.65±0.06, D=1.33±0.29 µm²/ms vs. 1.78±0.17 µm²/ms, ADC=0.82±0.2 µm²/ms vs. 1.15±0.08 µm²/ms.

11:24         46.         Preoperative Nomograms Incorporating Magnetic Resonance Imaging & Spectroscopy for Prediction of Insignificant Prostate Cancer

Amita Shukla-Dave1, Hedvig Hricak1, Oguz Akin1, Changhong Yu2, Kristen L. Zakian1, Victor Reuter1, Peter T. Scardino1, James Eastham1, Michael W. Kattan2

1Memorial Sloan-Kettering Cancer Center, New York, NY, USA; 2Cleveland Clinic, Cleveland, OH, USA

Many more prostate cancers (PCa) are detected each year. Better methods are needed to predict which patients have insignificant PCa. The aims of the present study were to 1) validate the previously published MR-based nomograms; and 2) design new nomograms incorporating MR Imaging (MRI), MR Spectroscopic Imaging (MRSI) and clinical data without detailed biopsy data for predicting the probability of insignificant PCa. MRI/ MRSI data was examined prospectively in 181 patients studied prior to surgery.  We have successfully validated the previously published MR models. The new BaseMRI and BaseMRI/MRSI models after validation may obviate the need for repeat biopsy.

11:36         47.         Multiparametric 3T MR Imaging of Prostate Cancer: Histopathologic Correlation using Customized MRI-Based Specimen Molds

Baris Turkbey1, Haresh Mani2, Vijay Shah3,4, Marcelino Bernardo3, 4, Ardeshir Rastinehad5, Thomas Pohida6, Yuxi Pang7, Dagane Daar3, Compton Benjamin5, Yolanda McKinney1, Joanna Shih8, Maria J. Merino2, Peter A. Pinto5, Peter L. Choyke1

1Molecular Imaging Program, NCI, NIH, Bethesda, MD, USA; 2Laboratory of Pathology, NCI, NIH, USA; 3Molecular Imaging Program, NCI, NIH, USA; 4Imaging Physics, SAIC Frederick, Inc., NCI-Frederick; 5Urologic Oncology Branch, NCI, NIH, USA; 6Division of Computational Bioscience, Center for Information Technology, NIH, USA; 7Philips Healthcare, USA; 8Biometric Research Branch, NCI, NIH, USA

Multiparametric MRI has better sensitivity for detecting larger (> 5 mm in diameter) and more aggressive (Gleason score of > 7) tumors. The use of the mold enables more exact correlation between each MR parameter and the histopathologic specimen. The customized mold provided tissues blocks that had a one to one correspondence with the in vivo MR.

11:48         48.         Diffusion Weighted Magnetic Resonance Imaging (DW-MRI) for Locally Recurrent Prostate Cancer after External Beam Radiotherapy (EBRT)

Veronica A. Morgan1, Sharon L. Giles1, Sophie F. Riches1, David Dearnaley2, Nandita M. deSouza1

1CRUK & EPSRC Cancer Imaging Centre, Institute of Cancer Research & Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom; 2Academic Urology, Institute of Cancer Research & Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom

This study evaluates the accuracy of T2W plus DW-MRI for detecting recurrent tumor within the prostate following External Beam Radiotherapy (EBRT). Mean ADC measurements of tumor and irradiated non-tumor tissue, confirmed by TRUS biopsy, were documented in 26 patients with evidence of biochemical failure. ADCs of MRI-defined tumor, histology-defined tumor and non-tumor irradiated tissue were compared. Mean ADC for both MRI and histology defined tumor were significantly lower than for non-tumor irradiated tissue. A cut-off ADC of 1337 (x10-6mm2/s) predicted tumor with a 92.9% sensitivity and 100% specificity. DWI MRI can be used for identifying tumor recurrence following EBRT.

12:00         49.         Diagnostic value of ADC in Patients with Prostate Cancer: Influence of the Choice of b-Values

Gregor Thörmer1, Josephin Otto1, Martin Reiss-Zimmermann1, Matthias Seiwerts1, Nikita Garnov1, Michael Moche1, Thomas Kahn1, Harald Busse1

1Department of Diagnostic & Interventional Radiology, Leipzig University Hospital, Leipzig, Saxony, Germany

The differentiation between high (Gleason Score > 6) and low (¡Ü6) grade prostate cancer (PCa) is considered important for therapeutic decision. For that purpose, we investigated the diagnostic potential of the apparent diffusion coefficient (ADC). The influence of the choice of b-values (four methods) was retrospectively studied on 40 patients with known PCa. Although absolute ADC values in PCa and surrounding healthy tissue (SHT) significantly (p<0.001) depended on the b-values, the ADC ratios (PCa/SHT) were nearly independent of the method. Image appearance of ADC maps using b=50 and 800 [mm/s2] was rated most suitable for PCa detection by three readers.

12:12         50.         A Novel Luminal Water Model for DCE MRI of Prostatic Tissues

Susan M. Noworolski1,2, Galen D. Reed1,2, John Kurhanewicz1, 2

1Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; 2Graduate Group in Bioengineering, University of California, San Francisco & Berkeley, San Francisco & Berkeley, CA, USA

It has been suggested that Gd-DTPA does not reach intact prostatic ducts. A novel pharmacokinetic model of the prostate incorporating Gd-inaccessible luminal water is presented. A feature of this Luminal Water model is that it allows for a slower washout, quite common in healthy and benign, glandular prostate tissues. Simulations and an example in vivo case demonstrate that the standard extended Tofts-Kermode model would greatly underestimate Ktrans and Vees in glandular tissues (14% - 44% in cases shown). Incorporation of the Gd-inaccessible luminal water may yield parameters more accurately reflecting underlying tissue and has promise for aiding prostate tissue characterization.

12:24         51.         Validation with DCE-CT Proves that the DCE-MRI Phase Signal Can be Used for Robust Measurement of the Arterial Input Function (AIF) in the Iliac Arteries

Johannes Georg Korporaal1, Cornelis A. T. van den Berg1, Matthias J. P. van Osch2, Greetje Groenendaal1, Marco van Vulpen1, Uulke A. van der Heide1

1Dept. of Radiotherapy, University Medical Center Utrecht, Utrecht, Netherlands; 2Dept. of Radiology, Leiden University Medical Center, Leiden, Netherlands

Arterial input function (AIF) measurements in the iliac arteries from the DCE-MRI phase signal (AIFPHASE) were validated with

DCE-CT (AIFCT) in twelve prostate cancer patients. AIFPHASE and AIFCT were normalized to the injected dose of contrast

agent and compared. For all patients, the shape of AIFPHASE is very similar to the shape of AIFCT. No significant differences

were found between AIFPHASE and AIFCT for the area under the curve of the first pass peak and the signal 180 seconds after

the peak. In conclusion, AIFPHASE shows good agreement in both shape and amplitude with AIFCT.

12:36         52.         Magnetic Resonance Imaging-Transrectal Ultrasound Fusion Improves Biopsy Yield

Daniel Jason Aaron Margolis1, Shyam Natarajan2, Dinesh Kumar3, Ram Narayanan3, Leonard Marks4

1Dept. of Radiology, UCLA David Geffen School of Medicine, Los Angeles, CA, USA; 2Center for Advanced Surgical & Interventional Technology , UCLA David Geffen School of Medicine; 3Eigen; 4Dept. of Urology, UCLA David Geffen School of Medicine, Los Angeles, CA, USA

MRI with diffusion and perfusion imaging was performed in 54 consecutive men referred for prostate biopsy. Target lesions based on diffusion and perfusion parameters were ranked based on level of suspicion and contoured on T2-weighted imaging. Subsequent biopsies were performed with real-time image coregistration with transrectal ultrasound. The number of positive cores was significantly higher for targeted biopsies than for systematic 14-point sextant biopsies, and in some cases, cancer was only found with targeted biopsies.

12:48         53.         3T MRI-Guided Transperineal Targeted Prostate Biopsy: Clinical Feasibility, Safety & Early Results

Kemal Tuncali1, Junichi Tokuda1, Andriy Fedorov1, Iulian Iordachita2, Sam Song1, Sota Oguro1, Andras Lasso3, Fiona M. Fennessy1, Yi Tang1, Nobuhiko Hata1, Clare M. Tempany1

1Radiology, Brigham & Women's Hospital, Boston, MA, USA; 2The Johns Hopkins University, Baltimore, MD, USA; 3School of Computing, Queen’s University, ON, Canada

Nine patients with clinically suspected prostate cancer underwent 3T MRI-guided transperineal targeted prostate biopsy successfully in the lithotomy position without significant compications using local anesthesia and intravenous procedural sedation. Multiparametric diagnostic MRI data were registered to intraprocedural T2 weighted turbo spin echo images to facilitate targeting of index lesions. Needle location was confirmed using real-time 2D FISP. Of eight biopsy results available, two were proved cancer and six showed no malignancy. We have shown this approach to be feasible and safe. It can yield clinically useful results in patients with index lesion on diagnostic MRI.

Cancer Cells

Room 520B-F                    11:00-13:00                                                                   Moderators: E. Jim Delikatny & Kristine Glunde

11:00         54.         Both the Glutaminolytic & Reverse Isocitrate Dehyrdogenase Pathways are Important for De Novo Lipogenesis from Glutamine in Immortilized Hematapoietic Cells

Anthony Mancuso1,2, Kathryn E. Wellen1, Chao Lu1, Weixia Liu, Stephen Pickup, Craig B. Thompson1,3

1Cancer Biology, University of Pennsylvania, Philadelphia, PA, USA; 2Radiology, University of Pennsylvania, Philadelphia, PA, USA Minor Outlying Islands; 3Memorial Sloan Kettering Cancer Center, New York, NY, USA

We have been studying lipogenesis because of its importance in mammalian cell growth and proliferation.  Glucose is normally the primary precursor for this process; however, we have observed that human glioblastoma cells derive much lipogenic carbon from glutamine.  In this work, we report that immortalized hematopoietic cells produce lipid from glutamine via both the glutaminolytic and reverse isocitrate dehydrogenase (IDH) pathways in the presence of glucose.  In the absence of glucose, the more energy efficient glutaminolytic pathway was predominant.  These results are fundamentally different from those observed for glioblastoma cells, which predominantly use the more energy inefficient reverse IDH pathway, perhaps compromising efficiency for the sake of rapid biosynthesis.

11:12         55.         Lactate-Mediated Metabolic Cooperation between Human Stromal & Breast Cancer Cells

Ellen Ackerstaff1, Brijesh B. Patel2, Yanique I. Rattigan2, George Sukenick3, Natalia Kruchevsky1, John W. Glod2, Jason A. Koutcher1, Debabrata Banerjee2

1Memorial Sloan-Kettering Cancer Center, New York, NY, USA; 2The Cancer Institute of New Jersey, RWJMS, UMDNJ, New Brunswick, NJ, USA; 3Sloan-Kettering Institute, New York, NY, USA

We hypothesize that tumor cells recruit stromal cells and that stromal cells metabolize lactate expelled by tumor cells into the microenvironment. Human mesenchymal stem cells (hMSCs) are bone marrow-derived stromal cells which migrate toward hypoxic tumor cells and overexpress functional monocarboxylate transporter 1 in response to lactate exposure. Naive hMSCs and carcinoma-associated fibroblasts (CAFs) exposed to 13C-3-lactate, produced detectable levels of 13C-&#945;-ketoglutarate. Additional 14C-lactate studies showed that lactate uptake in CAFs was higher than in hMSCs. Also, lactate stimulated hMSC migration. Our results suggests the metabolic cooperation between stromal and tumor cells.

11:24         56.         Free Choline Influences Adaptation Mechanisms in Choline Phospholipid Metabolism of Human Breast Cancer Cells

Balaji Krishnamachary1, Noriko Mori1, Mayur Gadiya1, Yelena Mironchik1, Flonne Wildes1, Kristine Glunde1, Zaver M. Bhujwalla1

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

Synopsis:  Increased phosphocholine (PC) and total choline are consistently observed in cancers, especially breast cancer.  Only now are we beginning to uncover the complexity of factors that regulate choline metabolism in cancer, and the compensatory mechanisms that exist in this pathway.  Here we have shown the interdependence between two enzymes in choline metabolism, choline kinase (Chk) the enzyme that forms phosphocholine from free choline, and phosphatidylcholine-specific phospholipase D1 (PLD1), the enzyme that forms choline from phosphatidylcholine.  We have also identified increased free choline as an inhibitor of the increase of PLD1 observed following Chk downregulation.

11:36         57.         Effects of Targeting the Glycerophosphocholine Phosphodiesterase GDPD5 in Breast Cancer Models

Maria Dung Cao1,2, Lu Jiang1, Balaji Krishnamachary1, Mailin Doepkens1,3, Zaver M Bhjuwalla1, Ingrid Gribbestad2, Kristine Glunde1

1Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 2Department of Circulation & Medical Imaging, Norwegian University of Science & Technology (NTNU), Trondheim, Norway; 3Department of Chemistry & Biology, University of Bremen, Bremen, Germany

In our study we investigated the effects of silencing the glycerophosphocholine phosphodiesterase GDPD5 in MCF7 breast cancer cells and tumor xenograft models using both ex vivo high-resolution MRS and in vivo MRSI.  Here we demonstrated for the first time that silencing the specific GPC-PDE enzyme GDPD5 increased the tCho levels in breast cancer cells and tumor models.  Interestingly, the tumor growth rate of the GDPD5-silenced breast tumor xenografts was significantly reduced.  These findings emphasize that GDPD5 may have a potential role as an anticancer target in regulating choline phospholipid metabolism in breast cancer.

11:48         58.         Effect of the HIF Pathway Inhibitor NSC-134754 on Glucose Metabolism

Lauren C. J. Baker1, Yuen-Li Chung1, Jessica K. Boult1, Margaret A. Ashcroft2, Simon P. Robinson1

1CRUK & EPSRC Cancer Imaging Centre, the Institute of Cancer Research & Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom; 2University College London, United Kingdom

Hypoxia-inducible factor (HIF) pathway inhibitors are an emerging class of therapeutics, whose precise mechanism of action is unclear. In this study, we examined the metabolic effects of NSC-134754, a small molecule inhibitor of the HIF pathway. Firstly, we show that NSC-134754 downregulates both the expression and distribution of glucose transporter 1, a downstream target of HIF-1. Secondly, magnetic resonance spectroscopy reveals a unique metabolic profile of the actions of NSC-134754 on cellular metabolism. Finally, we demonstrate that effects on glucose transport in vitro with NSC-134754 are reproduced in vivo in an orthotopic model of prostate cancer.

12:00         59.         Magnetic Resonance Spectroscopy Metabolic Profiling Reveals Different Mechanisms of Action in Response to Signaling Inhibitors in Prostate Cancer

Alessia Lodi1, Sabrina M. Ronen1

1University of California San Francisco, San Francisco, CA, USA

Carcinogenesis often involves signaling pathway deregulation and targeted inhibitors are under investigation as anticancer therapeutics.

Here we used a completely untargeted, MRS-based metabolomics approach to investigate the metabolic consequences of treatment with PI3K or combined PI3K/MAPK inhibitors in human prostate cancer cells. The modulation of phosphocholine and lactate concentrations following treatment with either PI3K or combined PI3K/MAPK inhibitors was similar in different prostate cell lines and recapitulated similar findings in breast cancer cells. Interestingly treatment of prostate cells with 17AAG increased the accumulation of citrate, a key metabolite dramatically decreased upon prostate malignant transformation.

12:12         60.         Comparing the Chemotherapeutic Response of Prostate Cancer Cells using MR-visible Lipids & Fluorescent Fatty Acid Incorporation

Daniel-Joseph Leung1,2, E. James Delikatny2

1Department of Pharmacology, University of Pennsylvania, Philadelphia, PA, USA; 2Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA

Observations of intracellular lipid (particularly triglyceride) accumulation in the form of MR-visible mobile lipids and lipid droplets have been associated with apoptosis and necrosis in a variety of cancer models.  Here we use MRS in combination with fluorescent fatty acids to assess the process of mobile lipid formation in DU145 prostate cancer cells.  This assay is then used to screen DU145 cells against a range of anticancer drugs, resulting in measured fluorescence indicative of a range of lipid response.  This approach, used as a screening tool in conjunction with MRS, will aid in the functional dissection of the contributing pathways involved in lipid formation in cancer cells undergoing chemotherapy.

12:24         61.         Noninvasive Assessment of Renal Tumor Aggressiveness using Hyperpolarized 13C MR

Kayvan R. Keshari1, Bertram Koelsch, Rahwa Iman, Mark Van Criekinge, Daniel B. Vigneron, John Kurhanewicz, Zhen J. Wang

1UCSF, San Francisco, CA, USA

The widespread use of cross-sectional imaging has led to the incidental discovery of many renal tumors. However, triage of therapies is currently difficult due to our inability to reliably differentiate benign from malignant, or indolent from aggressive renal tumors noninvasively by conventional imaging techniques. In this study we use a combination steady-state [3-13C]pyruvate cell labeling and HP [1-13C]pyruvate cell culture bioreactor studies to show that HP13C MR has the potential to noninvasively characterize renal tumor aggressiveness. Specifically, increasing HP [1-13C]lactate may be a useful biomarker for discriminating benign from malignant, and indolent from aggressive renal tumors.

12:36         62.         1H MRS & Hyperpolarised 13C MRS Assays of Pyruvate-Lactate Exchange in SW1222 Cancer Cells In Vitro

Deborah Katherine Hill1, Yann Jamin1, Nicolas Tardif1, Anne-Christine Wong Te Fong1, Simon P. Robinson1, Harold G. Parkes1, Matthew R. Orton1, Martin O. Leach1, Yuen-Li Chung1, Thomas R. Eykyn1,2

1Clinical Magnetic Resonance, CRUK & EPSRC Cancer Imaging Centre, Royal Marsden NHS Trust & the Institute of Cancer Research, Sutton, Surrey, United Kingdom; 2Division of Imaging Sciences, the Rayne Institute, Lambeth Wing, St.Thomas Hospital, London, United Kingdom

Signal enhancements by DNP have facilitated the interrogation of metabolic processes using 13C MRS in real-time. We demonstrate that it is possible to measure in vitro pyruvate-lactate exchange kinetics by utilising scalar couplings of methyl 1H resonances to adjacent [3-13C] labelled nuclei, without the need of hyperpolarisation. The 1H MRS-based assay measured the forward reaction rate with comparable reproducibility to the hyperpolarised 13C assay. The 1H assay has the advantage of also reliably probing the backward reaction, which has large errors in the 13C  assay. Both assays detected a comparable response to treatment with Paclitaxel, a widely used chemotherapy drug.

12:48         63.         Metabolism of Hyperpolarized U-13C-d7-D-Glucose in Living Breast Cancer Cell Cultures

Talia Harris1, Lucio Frydman1, Hadassa Degani2

1Chemical Physics, Weizmann Institute of Science, Rehovot, Israel; 2Biological Regulation, Weizmann Institute of Science, Rehovot, Israel

Elevated glycolytic rates are a known feature of many cancers. The recent development of a method to hyperpolarize nuclear spins more than 10,000x in the liquid states opens up new opportunities to follow metabolic processes non-invasively with high temporal resolution using 13C NMR. In this study we utilize a perfusion-injection system to study the metabolism of hyperpolarized U-13C-d7-D-Glucose in living T47D breast cancer cells. The conversion of Glucose&#61664; Lactate as well as labeling of other metabolites is seen. Further, the conversion of Glucose&#61664;Lactate by T47D cells is shown to have the same concentration dependence as the uptake of radioactively labeled 2-deoxy-D-Glucose.

Compressed Sensing & Sparsity

Room 710A                        11:00-13:00                                                                Moderators: Michael Lustig & Nicole E. Seiberlich

11:00         64.         Introduction

11:12         65.         ESPIRiT (Efficient Eigenvector-Based L1SPIRiT) for Compressed Sensing Parallel Imaging - Theoretical Interpretation & Improved Robustness for Overlapped FOV Prescription

Peng Lai1, Michael Lustig2,3, Shreyas S. Vasanawala4, Anja C. S. Brau1

1Global Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA; 2Electrical Engineering, Stanford University, Stanford, CA, USA; 3Electrical Engineering & Computer Science, University of California, Berkeley, CA, USA; 4Radiology, Stanford University, Stanford, CA, USA

Compressed sensing (CS) parallel imaging (PI) methods, such as L1SPIRiT, provide better image quality than CS or PI alone, but requires highly intensive iterative computation. Efficient L1SPIRiT (ESPIRiT) greatly reduces the computation intensity based on eigenvector computations.  This work provides a theoretical analysis of similarities between these two approaches and demonstrates that they should converge to the same solution. Based on our analysis, we show the existence of multiple dominant eigenvectors for overlapped FOV acquisition, where original ESPIRiT generates significant artifacts like mSENSE and identify a solution. Our results based on invivo datasets showed that the proposed modified ESPIRiT can provide reconstruction very similar to L1SPIRiT regardless of FOV overlap. The modified ESPIRiT algorithm is a robust and computationally efficient solution to CS-PI reconstruction.

11:24         66.         Combination of Compressed Sensing & Parallel Imaging with Respiratory Motion Correction for Highly-Accelerated First-Pass Cardiac Perfusion MRI

Ricardo Otazo1, Daniel Kim1, Leon Axel1, Daniel K. Sodickson1

1Department of Radiology, NYU School of Medicine, New York, NY, USA

First-pass cardiac perfusion MRI studies can be highly accelerated using a combination of compressed sensing and parallel imaging. However, this method is sensitive to respiratory motion, which decreases sparsity in the combined spatial and temporal-frequency domain and produces temporal blurring in the reconstructed images. In this work, we present a rigid respiratory motion correction method for the combination of compressed sensing and parallel imaging, to highly accelerate first-pass cardiac perfusion MRI without the need of strict breath-holding.

11:36         67.         Entropy Aided K-t Group Sparse SENSE Method for Highly Accelerated Dynamic MRI

Muhammad Usman1, Claudia Prieto1, Tobias Schaeffter1, Philip G. Batchelor1

1Division of Imaging Sciences & Biomedical Engineering, King's College London, London, United Kingdom

Over the last few years, the combination of Compressed sensing (CS) and parallel imaging have been of great interest to accelerate MRI. For dynamic MRI, K-t sparse SENSE (K-t SS) has been proposed for combining the CS based K-t Sparse method with SENSE. Recently, K-t group sparse method (K-t GS) has been shown to outperform K-t Sparse for single coil reconstruction, by exploiting the sparsity and the structure within the sparse representation (x-f space) of dynamic MRI. In this work, we propose to extend K-t GS to parallel imaging acquisition in order to achieve higher acceleration factors by exploiting the spatial sensitive encoding from multiple coils. This approach has been called K-t group Sparse SENSE (K-t GSS). In contrast with the previous single-coil based K-t GS method for which a performance parameter is manually optimized for every frequency encode; we propose an entropy based scheme for automatic selection of this parameter. Results from retrospectively undersampled cardiac gated data show that K-t GSS outperformed K-t sparse SENSE at high acceleration factors (up to 16 fold).

11:48         68.         Improving Compressed Sensing Parallel Imaging using Autocalibrating Parallel Imaging Initialization with Variable Density Tiled Random k-Space Sampling

Peng Lai1, Tao Zhang2, Michael Lustig2,3, Shreyas S. Vasanawala4, Anja C. S. Brau1

1Global Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA; 2Electrical Engineering, Stanford University, Stanford, CA, USA; 3Electrical Engineering & Computer Science, University of California, Berkeley, CA, USA; 4Radiology, Stanford University, Stanford, CA, USA

Compressed sensing (CS) parallel imaging (PI) is computationally intensive due to its need for iterative reconstruction.  Autocalibrating PI can improve the initial solution and largely reduce the number of iterations needed. However, random sampling needed for CS generates a huge number of synthesis patterns making PI initialization extremely slow. Also, uniform density k-space sampling currently used for CS-PI is not optimal in terms of reconstruction accuracy. The purpose of this work was to develop a new tiled-random k-space sampling strategy with the desirable features of 1. incoherent k-space sampling with a small number of synthesis patterns and 2. variable density k-space sampling providing more accurate center k-space reconstruction. Based on our evaluations on 4 invivo datasets, the proposed sampling scheme can improve image quality and reconstruction accuracy compared to conventional sampling schemes and meanwhile enables fast PI initialization for CS-PI.

12:00         69.         K-t Group Sparse using Intensity Based Clustering

Claudia Prieto1, Muhammad Usman1, Eike Nagel1, Philip Batchelor1, Tobias Schaeffter1

1Division of Imaging Sciences & Biomedical Engineering, King's College London, London, United Kingdom

K-t Group Sparse (k-t GS) has been recently introduced to achieve high acceleration factors in dynamic-MRI. Kt-GS exploits not just the sparsity of dynamic-MRI but also the spatial group structure of the x-f space. However, it presents two drawbacks: a) an additional training-scan is required for group assignment, and b) the group assignment is based only on the connectivity of neighbouring pixels using a time-consuming hard thresholding scheme. Here we propose to modify k-t GS by using the intensity order, estimated from the same acquired data, for a more robust group assignment. This approach has been tested in cine and perfusion cardiac images with acceleration factors up to 9.

12:12         70.         High-Frequency Subband Compressed Sensing with ARC Parallel Imaging

Kyunghyun Sung1, Anderson N. Nnewihe1,2, Bruce L. Daniel1, Brian A. Hargreaves1

1Radiology, Stanford University, Stanford, CA, USA; 2Bioengineering, Stanford University, Stanford, CA, USA

Compressed sensing (CS) is a technique that allows accurate reconstruction of images from a reduced set of acquired data. Here, we present a new method, which efficiently combines CS and parallel imaging (PI) by separating k-space sampling and reconstruction for high- and low-frequency k-space data. This maximally utilizes the wavelet-domain sparsity and avoids possible CS failure in low frequency region. This work has been demonstrated for high-resolution 3D breast imaging and the reconstructed image successfully recovered low-frequency content and fine structures with a net acceleration of 10.8.

12:24         71.         Joint Bayesian Compressed Sensing for Multi-Contrast Reconstruction

Berkin Bilgic1, Vivek K. Goyal1, Elfar Adalsteinsson1, 2

1EECS, MIT, Cambridge, MA, USA; 2Harvard-MIT Division of Health Sciences & Technology, MIT, Cambridge, MA, USA

Clinical MRI routinely relies on multiple acquisitions of the same region of interest with several different contrasts. We present a reconstruction algorithm based on Bayesian compressed sensing to exploit such multi-contrast acquisitions for accelerated imaging by jointly reconstructing a set of related images from undersampled k-space. Our method offers better performance than when the images are either reconstructed individually with the algorithm by Lustig et al., or jointly with a previously proposed method, M-FOCUSS. 

12:36         72.         Location Constrained Approximate Message Passing (LCAMP) Algorithm for Compressed Sensing

Kyunghyun Sung1, Bruce L. Daniel1, Brian A. Hargreaves1

1Radiology, Stanford University, Stanford, CA, USA

Iterative thresholding methods have been extensively studied as faster alternatives to convex optimization for large-sized problems in compressed sensing (CS). A common large-sized problem is dynamic contrast enhanced (DCE) MRI, and the dynamic measurements possess data redundancies, which can be used to estimate non-zero signal locations. In this work, we present a novel iterative thresholding method called LCAMP (Location Constrained Approximate Message Passing) by adding the non-zero location assumption and an approximate message passing term. The method can reduce computational complexity and improve reconstruction accuracy.

12:48         73.         On the Quality Evaluation for Images Reconstructed by Compressed Sensing

Tobias Wech1, 2, Daniel Stäb1, André Fischer1, Dietbert Hahn1, Herbert Köstler1

1Institute of Radiology, University of Wuerzburg, Wuerzburg, Bavaria, Germany; 2Center for Applied Medical Imaging, Siemens Corporate Research, Baltimore, MD, USA

Compressed Sensing reconstructions are characterized by a non-linear and non-stationary nature of the dedicated algorithms. Therefore image quality estimation as used for regular Fourier Imaging is not feasible. The aim of this work was to develop a workaround that provides a linear PSF-approximation as well as a validity-test to control its quality. The workflow was tested on the example of a sparse temporal difference image of the human heart and showed a positive result for the validity-test.

Brain Microstructure & Diffusion Imaging

Room 710B                        11:00-13:00                                                     Moderators: Valerij G. Kiselev & Eleftheria Panagiotaki

11:00         74.         Axon Diameter Mapping in the Presence of Orientation Dispersion using Diffusion MRI

Hui Zhang1, Penny L. Hubbard2, Geoff J. M. Parker2, Daniel C. Alexander1

1University College London, London, United Kingdom; 2Manchester Academic Health Sciences Centre, Manchester, United Kingdom

Axon diameter mapping using diffusion MRI provides more specific biomarkers than DTI indices.  Earlier works assume a model of strictly parallel axons.  However, such approximation is inadequate for most white matter regions in which axons fan or bend, resulting in significant orientation dispersion.  Such dispersion, if unaccounted for, leads to overestimation of axon diameters.  We ameliorates this problem by proposing a model that captures orientation dispersion explicitly.  We demonstrate that recovery of axon diameters is possible even in the presence of orientation dispersion, supporting accurate axon diameter mapping in a much wider set of white matter than previously possible.

11:12         75.         Magnetic Resonance Characterization of General Compartment Size Distributions

Evren Ozarslan1,2, Noam Shemesh3, Cheng Guan Koay1, 4, Yoram Cohen3, Peter Joel Basser1

1STBB / PPITS / NICHD, National Institutes of Health, Bethesda, MD, USA; 2Center for Neuroscience & Regenerative Medicine, USUHS, Bethesda, MD, USA; 3School of Chemistry, Tel Aviv University, Tel Aviv, Israel; 4Department of Medical Physics, University of Wisconsin, Madison, WI, USA

Previous methods to determine the axon diameter distribution (ADD) from MR data assume a known statistical distribution of compartment sizes. To overcome this limitation, theoretical relationships between the MR signal intensity and the moments of a general distribution of cylindrical compartments are established. A one-dimensional simple harmonic oscillator based reconstruction and estimation (1D-SHORE) framework was used as a numerical tool to estimate these moments. Results on simulated and real MR data obtained from controlled water-filled microcapillaries demonstrate the power of this approach to create contrast based not only on the mean compartment size but also its variance.

11:24         76.         AxCaliber 3D

Daniel Barazany1, Derek Jones2, Yaniv Assaf1

1Neurobiology, Tel Aviv University, Tel Aviv, Israel; 2CUBRIC, School of Psychology, Cardiff University, Wales, UK

So far, the ability to map the axon diameter distribution (ADD) along a given pathway was only possible with AxCaliber if the fiber orientation was known and so this precludes any tract-specific assessment. We extended the AxCaliber framework to 3D, and were able to achieve the ADD in any voxel of the brain and any fiber orientation. In the work, we analyzed the two main fiber fascicles of the porcine spinal cord which are known to have different ADDs. AxCaliber was able to distinguish between them and calculate their ADDs.

11:36         77.         Inferring Micron-scale Tissue Structure using Extreme Value Theory for Cylindrically-restricted Diffusion

Leigh A. Johnston1,2, David Wright2, Rick H. H. M. Philipsen3, Scott C. Kolbe2, James A. Bourne4, Iven M. Y. Mareels1, Gary F. Egan2

1Electrical & Electronic Engineering & NICTA VRL, University of Melbourne, Parkville, VIC, Australia; 2Howard Florey Institute, Florey Neuroscience Institutes, Parkville, VIC, Australia; 3Technical University of Eindhoven, Netherlands; 4Australian Regenerative Medicine Institute, Monash University, Australia

The non-exponential signal decay observed in q-space diffusion acqusitions is derived for restricted diffusion in cylinders, using a probabilistic approach based on extreme value theory and expectation over continuum distributions for geometry-dependent apparent diffusion coefficients.  Simulation and experimental results demonstrate the accuracy of the resultant non-exponential signal decay and the ability to infer axon densities without need for pulse duration or diffusion time approximations.

11:48         78.         Activation Energies for Water Diffusion in ex-vivo White Matter

Bibek Dhital1, Christian Labadie1,2, Harald E. Möller1, Robert Turner1

1Max Planck Institute for Human Cognitive & Brain Sciences, Leipzig, Germany; 2Laboratoire de Spectrométrie Ionique et Moléculaire, Université Claude Bernard Lyon 1, Lyon, France

We made MR measurements of diffusion up to very high b-factor in excised human corpus callosum, over a wide temperature range. Above a freezing phase transition at -20 °C, data showed a robust bi-exponential dependence on b-factor. Below this temperature only half of the slow component remained, suggesting two water pools within this component. An Arrhenius plot revealed significantly different activation energies for the fast and slow components. The lower of these corresponds well to breaking a hydrogen bond in a locally ordered region. This suggests that unfrozen water consists of hydration layers close to the membranes.

12:00         79.         Assessment of Axon Diameter Distribution in Mouse Spinal Cord with q-Space Imaging

Henry H. Ong1, Felix W. Wehrli1

1Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA

Knowledge of axon morphology would provide important insight into neural function, anatomy and pathology. Q-space imaging (QSI) offers potential for indirect assessment of WM architecture and already has been used to measure intra-cellular volume fraction and mean axon diameter. Here, we examine the feasibility of QSI to measure axon diameter distribution (ADD) from white matter tracts in healthy mouse spinal cords using the displacement probability density function. The results show that QSI-derived ADDs semi-quantitatively agree with histologic ADDs and consistently illustrate the relative differences in ADD between WM tracts.

12:12         80.         Surface-to-Volume Ratio with Oscillating Gradients

Dmitry S. Novikov1, Valerij G. Kiselev2

1Radiology, NYU School of Medicine, New York, NY, USA; 2Diagnostic Radiology, University Hospital Freiburg, Freiburg, Germany

Diffusion coefficient is known to reveal the surface-to-volume ratio of restrictions at short diffusion times. Sufficiently short diffusion times are practically achievable with the oscillating gradient technique or with the CPMG refocusing train in the presence of a static gradient. Interpetation of such measurements relies on representing the short-time diffusivity limit in the frequency domain. For both of these oscillating techniques, we derive exact expressions for the high-frequency behavior of the diffusion coefficient, applicable to probe the surface-to-volume ratio of restrictions. We also describe how to calculate the effect of restrictions for arbitrary gradient waveforms.

12:24         81.         Probing Microscopic Cellular Architecture in the Mouse Brain by Oscillating Gradient Diffusion Tensor Imaging

Manisha Aggarwal1, Susumu Mori1, Jiangyang Zhang1

1Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA

Diffusion measurements with conventional pulsed gradient diffusion MRI experiments reflect the combined effects of restriction barriers to water diffusion at multiple spatial scales, but cannot distinguish between different spatial scales. With oscillating diffusion gradients, it is possible to probe diffusion at separate spatial scales by varying the modulation frequency of the oscillating gradients. In this study, three dimensional diffusion tensor imaging (DTI) of perfusion-fixed mouse brains using oscillating diffusion-sensitizing gradients is presented. The resulting diffusion tensor spectrum D(f) revealed, for the first time, unique frequency-dependent tissue contrasts in the mouse cerebellum and hippocampus.

12:36         82.         Double-PFG MR Imaging of the CNS: Probing Underlying Grey Matter Microstructure

Noam Shemesh1, Daniel Barzany2, Ofer Sadan3, Yuval Zur4, Daniel Offen5, Yaniv Assaf2, Yoram Cohen1

1School of Chemistry, Tel Aviv University, Tel Aviv, Israel; 2Department of Neurobiology, Tel Aviv University, Israel; 3Department of Neurology, Tel-Aviv Medical Center, Tel Aviv University, Israel; 4GE Healthcare, Israel; 5Laboratory of Neurosciences, Felsenstein Medical Research Center, Department of Neurology, Rabin Medical Center & Tel Aviv University, Israel

Double-Pulsed-Field-Gradient (d-PFG) MR is emerging as a useful methodology for depicting underlying microstructural information in scenarios where conventional single-PFG (s-PFG) are very limited, such as when anisotropic compartments are randomly oriented. Here, we used d-PFG MRI on phantoms, pig spinal cord and rat brain. The angular variations in the E(ø) data could be easily observed for all specimens even in the raw data; furthermore, the presence of modulated E(ø) plots in grey matter tissues revealed that water is diffusing in randomly oriented anisotropic compartments having different eccentricities, which appeared as different patterns within the cortex of the rat brain.

12:48         83.         A Comparative Study of Axon Diameter Imaging Techniques using Diffusion MRI

Hui Zhang1, Daniel Barazany2, Yaniv Assaf2, Henrik M. Lundell3, Daniel C. Alexander1, Tim B. Dyrby3

1University College London, London, United Kingdom; 2Tel Aviv University, Tel Aviv, Israel; 3Copenhagen University Hospital Hvidovre, Hvidovre, Denmark

Axon diameter and density provide information about the function and performance of white matter pathways.  Direct measurement of such microstructure features offers more specific biomarkers than DTI indices.  Many techniques to measure axon diameter statistics using diffusion MRI have been proposed in the literature, ranging from model-based approaches to Q-space imaging, but little is known of their relative performance and consistency.  This work compares several representative model-based approaches quantitatively to gain insight into how the choices of tissue model and imaging protocol impact the estimation of microstructural features.

Gold Corporate Member Lunchtime Symposium
Siemens

Room Plenary Hall                             12:30-13:30                                                                                                                                         Clinical Intensive Course
MRI of the Foot & Ankle

Room 510                           14:00-16:00                                                                                                  Moderator: Lynne S. Steinbach  

14:00                       Forefoot

Lynne S. Steinbach

14:40                       Ankle Tendons

Kathryn J. Stevens

15:20                       Ankle Excluding Tendon

William B. Morrison

Clinical Intensive Course
Female Pelvis & Bladder: Case-Based Teaching

Room 516A-C                   14:00-16:00                                                                                      Moderators: Patricia Noël & Evis Sala  

14:00                       MRI of the Adnexa: Lesion Characterization

Patricia Noël

14:30                       Bladder Tumors: The Role of MRI in Staging & Treatment Planning

Andrea G. Rockall

15:00                       MRI of the Ovarian Cancer: Staging, Treatment Response & Detection of Recurrence

Evis Sala

15:30                       MRI of Pregnant Patient: Diagnostic & Management Challenges

Fergus Coakley

Clinical Intensive Course
Spine & Spinal Cord Imaging - ISMRM/ASNR Joint Session

Room 520B-F                    14:00-16:00                                                           Moderators: Mauricio Castillo & Majda M. Thurnher  

14:00                       Trauma to the Spine & Spinal Cord

Mauricio Castillo

14:25                       Postoperative Spine Imaging

Mario Muto

14:50                       Tumors to the Spine & Spinal Cord

 

Diana M. Gomez-Hassan

15:15                       Demyelinating Disease + Myelitis

Massimo Gallucci

15:45                       Discussion

ISMRM/SMRT Forum: DTI: is It Ready for the Clinic

Room 511A-C                   14:00-16:00                                                                                                                                                            

14:00                       Technical Considerations for the Clinical Application of DTI: A Physicist's Perspective

Derek K. Jones

14:30                       Technical Considerations for the Clinical Application of DTI: A Radiographer's Perspective

Shawna Farquharson

15:00                       Implementation & Development of Guidelines for using DTI in Routine Clinical Practise: A Radiologist's Perspective

Meng Law

15:30                       Panel Discussion

Non-Contrast & Contrast-Enhanced MRA

Room 511D-F                    14:00-16:00                                                                           Moderators: Tim Leiner & Mitsue Miyazaki

14:00         84.         Introduction: Contrast-Enhanced MRA: Relic of the Past or Alive & Kicking?
Jeffrey H. Maki

14:12         85.         Simultaneous MR Angiography & Perfusion (MRAP): Application in Lower Extremity MRA & Skeletal Muscle Perfusion

Katherine L. Wright1,2, Nicole Seiberlich2,3, John A. Jesberger2, Raymond F. Muzic1,3, Mark A. Griswold1,3, Vikas Gulani2,3

1Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA; 2Case Center for Imaging Research, Case Western Reserve University, Cleveland, OH, USA; 3Department of Radiology, University Hospitals, Cleveland, OH, USA

Complete evaluation of both large and small vessel status would typically require two separate contrast enhanced acquisitions: MR angiography and dynamic contrast enhanced (DCE) perfusion. Both the MRA and quantitative DCE perfusion could be obtained simultaneously if a 3D time-resolved contrast enhanced data set could be acquired in a manner that the contrast and spatial/temporal resolution requirements for both exams could be met. This study demonstrates feasibility and repeatability of simultaneous MRA and perfusion (MRAP) with a time resolved MRA acquisition, and initial application for leg angiography and quantitative skeletal muscle perfusion at rest and following a physiological stimulus (exercise).

14:24         86.         4D PC MR of the portal venous system: Benefits of using a Blood Pool Contrast Agent

Benjamin Landgraf1, Alex Frydrychowicz1, Kevin Johnson2, Alejandro Roldan1, Chris Francois1, Scott Reeder1, 2, Oliver Wieben2

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

This study aims to determine the effects of intravascular contrast agent on radially encoded velocity mapping MRI on the quality of visualization of the portal venous vasculature. While imaging without a contrast agent provides good image quality, examination of vessel signal and diagnostic quality of vasculature in derived angiograms from human volunteer after contrast administration shows greatly improved image quality and visualization of distal branches of the portal vasculature.

14:36         87.         Comparison of CAPR MRA with CT Angiography for Evaluation of Below the Knee Runoff: Preliminary Results of Radiologist Confidence

Phillip Young1, James F. Glockner1, Terri R. Vrtiska, Thanila Macedo, Petrice Mostardi, Stephen J. Riederer

1Radiology, Mayo Clinic, Rochester, MN, USA

We describe initial results of a comparison of radiologist confidence in evaluating CAPR MRA and CTA for below the knee runoff in clinical patients.  CAPR MRA demonstrates significantly higher radiologist confidence for distal vessels than CTA

14:48         88.         ECG-gated First-pass Contrast-Enhanced Magnetic Resonance Angiography of the Thorax - Initial Experience in Healthy Volunteers & Patients

Moritz Wagner1,2, Yutaka Natsuaki2,3, Bernd Hamm4, Gerhard Laub2,3, Paul Finn2

1Radiology, Charite - University Hospital, Berlin, Germany; 2Department of Radiological Sciences, David Geffen School of Medicine, University of California, Los Angeles, CA, USA; 3Siemens Healthcare, USA; 4Radiology, Charite - University Hospital, Berlin, Germany

Our study presents a novel ECG gated first-pass CEMRA sequence which reads out central k-space data during the cardiac resting phase while the overall center of k-space was made to coincide with peak arterial enhancement. The improved data acquisition efficiency of the ECG-gated first-pass CEMRA allowed for high resolution imaging of the entire thorax. We report initial data of ECG-gated first-pass CEMRA in healthy volunteers and patients.

15:00         89.         Incidental Venous Thrombosis as Detected by Magnetic Resonance Thrombus Imaging in 245 Patients with Suspected Peripheral Arterial Disease using a Blood Pool Contrast Agent

Dariusch Reza Hadizadeh1, Guido M. Kukuk1, Ute L. Fahlenkamp1, Jürgen Gieseke1,2, Frank Träber1, Josephine Pressacco3, Christian Schäfer4, Eberhard Rabe5, Arne Koscielny6, Frauke Verrel6, Hans H. Schild1, Winfried A. Willinek1

1Radiology, University of Bonn, Bonn, NRW, Germany; 2Philips Healthcare, Best, Netherlands; 3Radiology, Montreal Heart Institute, Montreal, Quebec, Canada; 4Internal Medicine II, Division of Cardiology, Pneumology & Angiology, University of Bonn, Bonn, NRW, Germany; 5Dermatology, Division of Phlebology, University of Bonn, Bonn, NRW, Germany; 6Vascular Surgery, University of Bonn, Bonn, NRW, Germany

Synopsis: High-spatial resolution contrast-enhanced-MRA of the run-off vessels during the equilibrium phase of blood-pool contrast agents (SSMRA) has been shown to increase sensitivity and specificity in stenosis grading of the arterial vasculature. The simultaneous visualization of veins allows for diagnosis of important additional venous findings that may affect therapeutic regimen. Acute and chronic deep venous thrombosis was diagnosed in 26 of 245 patients of patients with peripheral arterial occlusive disease and was confirmed by duplex ultrasound.

15:12         90.         Acceleration Dependent Vascular Anatomy for Non-Contrast-Enhanced MRA (ADVANCE-MRA)

Andew Nicholas Priest1, Martin J. Graves1, David J. Lomas1

1Department of Radiology, Addenbrookes Hospital & University of Cambridge, Cambridge, United Kingdom

Recently demonstrated methods for non-contrast enhanced MR angiography use velocity-sensitised preparation to suppress the signal from flowing blood. Arterial images are generated by subtraction of bright- and dark-blood images, acquired with and without flow suppression. However, discrimination between arteries and veins is inadequate to allow reliable depiction of arteries without venous contamination. An alternative approach, using acceleration-dependent flow suppression, has been implemented, taking advantage of the pulsatility of arterial flow. It is demonstrated to give good arterial depiction with no venous contamination over a wide range of motion suppression gradient amplitudes, without substantial background signals, fluid contamination and other artifacts.

15:24         91.         Non-Enhanced Extracranial Carotid MR Angiography using Pseudocontinuous ASL: Comparison with Pulsed ASL & Clinical Feasibility at 1.5T

Ioannis Koktzoglou1,2, NavYash Gupta3, Robert R. Edelman1

1Radiology, NorthShore University HealthSystem, Evanston, IL, USA; 2Radiology, the University of Chicago, Chicago, IL, USA; 3Vascular Surgery, NorthShore University HealthSystem, Evanston, IL, USA

Compared with alternate nonenhanced approaches of time-of-flight magnetic resonance angiography (MRA), new nonenhanced techniques such as pulsed arterial spin labeling (PASL) may offer potential benefits. A more recent labeling approach, pseudocontinuous arterial spin labeling (PCASL), has been reported to improve the signal-to-noise ratio (SNR) of cerebral perfusion imaging compared with PASL.  The purpose of this study was to investigate whether PCASL can improve the SNR of nonenhanced carotid MRA compared with pulsed methods.

15:36         92.         3D Angiography with Psuedo Continous Arterial Spin Labeling(PCASL) & Accelerated 3D Radial Acquisition

Huimin Wu1, Walter F. Block2, Patrick A. Turski3, Charles A. Mistretta1, Kevin M. Johnson1

1Medical Physics, University of Wisconsin-Madison, Madison, WI, USA; 2Biomedical engineering, University of Wisconsin-Madison, Madison, WI, USA; 3Radiology, University of Wisconsin-Madison, Madison, WI, USA

3D angiography with pseudo continuous Arterial Spin Labeling (PCASL) tagging scheme and accelerated radial sampling pattern has been implemented. Feasibility studies on intracranial vasculature have been done on healthy volunteer and images show large coverage, transparent background, isotropic resolution, high contrast and SNR. Comparison with standard 3D TOF demonstrate the advantage of 3D PCASL angiography on substantially improved visualization of vessels with slow filling.

15:48         93.         Highly-Accelerated Dynamic Non-Contrast MRA using a Combination of Compressed Sensing & Parallel Imaging

Ricardo Otazo1, Pippa Storey1, Daniel Kim1, Daniel K. Sodickson1, Vivian S. Lee1

1Department of Radiology, NYU School of Medicine, New York, NY, USA

Non-gadolinium MRA with varying flow sensitivities can be performed by acquiring sets of FSE images in systole and diastole with different refocusing flip angles, so that the subtraction of systolic and diastolic images provides angiograms that resemble “time-resolved” MRA. In order to achieve feasible acquisition times and reduce sensitivity to subject motion, accelerated imaging is required. The inherent sparsity of the angiograms and the presence of correlations among the images acquired with different flip angles make the technique a good candidate for compressed sensing. We demonstrate feasibility of 16-fold accelerated dynamic non-contrast MRA using compressed sensing and parallel imaging.

Your Coils & You: A Primer for the Busy Clinician & the Curious Scientist

Room 512A-G                   14:00-16:00                                                                                                                                                            

14:00                       What is an RF Coil?

Cecil E. Hayes

14:30                       A Buyer's & User's Guide to RF Coils

Graham C. Wiggins

15:00                       What Can Coils Do?

Lawrence L. Wald

15:30                       Coils in 2020

Daniel K. Sodickson

Young Investigator Awards, Oral Presentations

Room 710A                        14:00-16:00                                                                                                                                                            

14:00         94.         Magnetic Resonance Elastography of Human Lung Parenchyma:  Technical Development, Theoretical Modeling & In Vivo Validation

Yogesh kannan Mariappan1, Kevin Glaser1, Rolf D. Hubmayr2, Armando Manduca1, Richard L. Ehman1, Kiaran P. McGee1

1Department of Radiology, Mayo Clinic, Rochester, MN, USA; 2Department of Pulmonary & Critical Care medicine, Mayo Clinic, Rochester, MN, USA

The purpose of this work was to develop magnetic resonance elastography (MRE) for in vivo assessment of human lung. A modified 1H spin echo MRE pulse sequence providing a short TE of 9.4 ms was used to acquire human lung MRE data at the residual volume and the total lung capacity in 10 healthy volunteers. MRE-based density corrected stiffness values at TLC were significantly higher than those at the RV. These data indicate that 1H-based MRE can noninvasively measure the shear stiffness of lung parenchyma in vivo and can differentiate shear stiffnesses at differing respiratory states.

14:20         95.         Hyperpolarized Xenon-129 Gas-Exchange Imaging of Lung Microstructure: Preliminary Results in Subjects with Obstructive Lung Disease

Isabel Dregely1, John P. Mugler III2, Iulian Constantin Ruset3, Talissa A. Altes2, Jamie F. Mata2, G. Wilson Miller2, Jeffrey Ketel3, Steve Ketel3, Jan Distelbrinck3, F. William Hersman1,3, Kai Ruppert2

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

The purpose of this study was to develop and test a method, Multiple exchange time Xenon polarization Transfer Contrast (MXTC) MRI, to non-invasively assess lung microstructure. The dynamic encoding of the xenon gas-exchange contrast permits two parameters to be derived regionally which are related to gas-exchange functionality by characterizing the tissue to alveolar-volume ratio and the alveolar wall thickness. By quantifying simultaneously two lung function parameters, MXTC provides a more comprehensive picture of lung microstructure then existing lung imaging techniques and could become an important non-invasive and quantitative tool to characterize pulmonary disease phenotypes.

14:40         96.         3D+T Biventricular Strain from Tagged Magnetic Resonance Images by Phase-Unwrapped HARP

Bharath Ambale Venkatesh1, Himanshu Gupta2, Steven G. Lloyd, Louis Dell' Italia, Thomas S. Denney, Jr.

1Electrical & Computer Engineering, Auburn University, Auburn, AL, USA; 2University of Alabama at Birmingham, USA

Accurate assessment of ventricular function is clinically important. In this abstract, a method for reconstructing three-dimensional biventricular strain over time from unwrapped harmonic phase measurements is validated in normal volunteers and patients. The strain obtained is compared to 3D strain obtained from a feature-based method and 2D strain obtained from harmonic phase strain measurements.

15:00         97.         Multi-Coil Shimming of the Mouse Brain

Christoph Juchem1, Peter B. Brown1, Terence W. Nixon1, Scott McIntyre1, Douglas L. Rothman1, Robin A. de Graaf1

1MR Research Center, Yale University, New Haven, CT, USA

The magnetic homogenization of the mouse brain with dynamically updated multi-coil fields is presented. The novel MC concept enabled the flexible and accurate generation of complex magnetic field shapes that allowed largely improved magnetic field homogenization of the mouse brain at 9.4 Tesla compared to conventional spherical harmonics shimming. The multi-coil shimming technique paves the way for MR applications of the mouse brain as a whole of parts thereof for which excellent magnetic field homogeneity is a prerequisite.

15:20         98.         Double-PFG MR as a Novel Means for Characterizing Microstructures in Grey Matter

Noam Shemesh1, Ofer Sadan2, Daniel Offen3, Yoram Cohen1

1School of Chemistry, the Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, Israel; 2Department of Neurology, Tel-Aviv Medical Center & the Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel; 3Laboratory of Neurosciences, Felsenstein Medical Research Center, Department of Neurology, Rabin Medical center, Israel

Double-Pulsed-Field-Gradient (d-PFG) MR is emerging as a promising methodology for characterizing underlying microstructural features in randomly oriented anisotropic compartments, which are difficult to characterize using conventional diffusion MR methods. Here, d-PFG spectroscopy was performed on isolated pig grey matter (GM). Angular dependencies in the E(ø) plots were observed, indicating the presence of compartment shape and microscopic anisotropies in the grey matter. Angular d-PFG MRI was then performed in the rat brain ex-vivo, showing that different GM regions indeed yield different angular patterns, thus reporting on different underlying microstructures within the GM. Therefore, d-PFG MRI is promising for characterizing GM tissues.

15:40         99.         Low-dimensional-Structure Self-Learning & Thresholding (LOST): Regularization Beyond Compressed Sensing for MRI Reconstruction

Mehmet Akcakaya1, Tamer Basha1, Beth Goddu1, Lois Goepfert1, Kraig V. Kissinger1, Vahid Tarokh2, Warren J. Manning1, Reza Nezafat1

1Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; 2School of Engineering & Applied Sciences, Harvard University, Cambridge, MA, USA

We develop an improved image reconstruction technique for undersampled acquisitions that learns and utilizes the structure of images being reconstructed. The results of our retrospective study with coronary MRI imply that the proposed method achieves higher acceleration rates compared to conventional CS reconstructions. The pilot prospective acquisitions confirm this finding, and additionally show that our method provides superior image quality at higher rates compared to traditional parallel imaging reconstruction.

Clinical Intensive Course
MR Physics & Techniques for Clinicians

Room 516A-C                   16:30-18:30                                                                                                                                                            

16:30                       Spin Gymnastics I

Walter Kucharczyk

17:10                       Spin Gymnastics II

Donald B. Plewes

17:50                       K-space

Kevin M. Koch

Neurophysiological Basis of fMRI

Room 510                           16:30-18:30                                                                                       Moderators: Galit Pelled & Ed X. Wu

16:30         100.       The Laminar Specific Neuronal Responses to Forepaw & Optogenetics Stimulations

John Downey1, Nan Li2,3, Assaf A. Gilad4,5, Piotr Walczak4,5, Nitish V. Thakor3, Galit Pelled1,4

1F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA; 2F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA; 3The Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 4The Russell H. Morgan Department of Radiology & Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 5Cellular Imaging Section, Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA

Changes in the laminar communication associated with cortical plasticity have been difficult to assess in vivo. Recent advances in optogenetics enable immediate and reversible manipulations of neuronal firing rate by using channelrhodopsin (ChR2). Here we determined the laminar specific neuronal responses in the primary somatosensory cortex (S1) of ChR2 engineered rats.  The laminar neuronal responses detected by BOLD fMRI and by local field potentials within S1 were compared between forepaw and ChR2 stimulations. Both forepaw and ChR2 stimulations showed a peak in BOLD and electrophysiology responses in lamina 4, demonstrating the capability of fMRI to resolve optogenetics modulated laminar communication.

16:42         101.       Opto-fMRI in Awake Rodents: Activation & Deactivation fMRI Signals Induced by Excitation & Inhibition of Neurons

Lino Becerra1,2, Gary Brenner2,3, James Bishop1, Pei-Ching Chang1, Hae-Sook Shin3, Aimei Yang4, Michael Baratta4, Patrick Monahan4, Edward Boyden4,5, David Borsook1,2

1A. Martinos Center, Massachusetts General Hospital, Boston, MA, USA; 2Harvard Medical School, Boston, MA, USA; 3Anesthesiology & Critical Care, Massachusetts General Hospital, Boston, MA, USA; 4Media Laboratory, Massachusetts Institute of Technology, Cambridge, MA, USA; 5Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA

In fMRI studies, positive activation is associated with increased neuronal firing.  Negative (deactivation) fMRI BOLD signals have been indirectly associated with inhibition.  Using opto-genetic techniques neurons in rat cingulate and somatosensory cortices were trasfected to be photosensitive.  Specifically, cingulate neurons were inhibited upon optical stimulation while somatosensory neurons were excited when illuminated.  Positive BOLD signal changes were observed in somatosensory cortex while negative ones were observed in cingulate cortex upon illumination.  Furthermore, inhibition of cingulate resulted in fMRI activation of other structures.  This work confirms that neuronal excitation results in positive BOLD signals and neuronal inhibition produces negative BOLD signals.

16:54         102.       Optogenetics-Guided Cortical Plasticity Following Forepaw Denervation

Nan Li1, 2, John Downey3, Amnon Bar-Shir4,5, Assaf A. Gilad4,5, Piotr Walczak4,5, Heechul Kim4,5, Suresh E. Joel3,4, James J. Pekar3, 4, Nitish V. Thakor2, Galit Pelled3, 4

1F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA; 2The Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 3F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA; 4The Russell H. Morgan Department of Radiology & Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 5Cellular Imaging Section, Vascular Biology Program, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA

Ipsilateral neuronal responses originating from the transcallosal pathway following peripheral nerve injury have been suggested to be negatively correlated to rehabilitation. The goal of this study was to decrease the cortical inhibition in a rat forepaw injury model. The neuronal firing rates in the healthy cortex of halorhodopsin engineered rats were optogeneticly manipulated. Electrophysiology, optical imaging and fMRI were used to evaluate the functional responses. The results demonstrate that decreased in the inhibitory activity within the deprived cortex can be achieved using optogenetics manipulations.  This offers novel therapeutic strategies to facilitate rehabilitation.

17:06         103.       Tight Coupling of Resting-State BOLD Fluctuations with Intracortical DC Changes in Rat Somatosensory Cortex during Prolonged Medetomidine Sedation

Wen-ju Pan1, Matthew Magnuson1, Garth Thompson1, Dieter Jaeger2, Shella Keilholz1

1Biomedical Engineering, Emory University/ Georgia Institute of Technology, Atlanta, GA, USA; 2Biology, Emory University, Atlanta, GA, USA

To investigate the neural correspondence of the resting-state BOLD signal fluctuations, simultaneous fMRI and intracortical electrophysiological recording were performed in rat somatosensory cortex under medetomine sedation. During prolonged medetomine administration (1-6 hours), the BOLD signal in the low frequency powers changed from <0.1-Hz to a combination of <0.1 Hz and a localized peak at 0.2-Hz. The intracortical DC/LFPs were correlated to both peaks of the BOLD signal at a time lag of ~2.5 s.

17:18         104.       Strengthening of Thalamocortical Synapses at Layer IV in the Juvenile Whisker Barrel Measured by MRI & Electrophysiology

Xin Yu1, Seungsoo Chung1, Shumin Wang1, Stephen Dodd1, Judith Walters1, John Isaac1, Alan Koretsky1

1NINDS, NIH, Bethesda, MD, USA

In juvenile rats, unilateral infraorbital denervation induces plasticity changes in the whisker-barrel system. Here, we focused on thalamocortical plasticity contralateral to the good whisker pad. Comparison of BOLD-fMRI of cortex and thalamus demonstrated a cortical specific signal increase. Manganese-enhanced MRI was applied to trace thalamocortical connections and estimated an increase of synaptic strength by measuring the transported Mn from thalamus into cortical Layer IV-V.  In vitro slice electrophysiological recordings were applied to confirm this synaptic strengthening of the thalamocortical input.  Therefore, MRI and electrophysiology indicate that plasticity to strengthen the barrel thalmocortical input occurs in the juvenile rodent.

17:30         105.       Layer-Specific Interhemispheric Functional Connectivity in Rat S1fl Revealed by Laminar Electrode Recordings & Resting State fMRI

Kwangyeol Baek1,2, Woo Hyun Shim1,2, Jaeseung Jeong1, Harsha Radhakrishnan2, Bruce R. Rosen2, David A. Boas2, Maria Franceschini2, Young Ro Kim2

1Bio & Brain Engineering, KAIST, Daejeon, Korea, Republic of; 2Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA

Recently, spontaneous BOLD fluctuations in MRI have been reported to be correlated between functionally interconnected brain regions. However, it is not yet clear whether such correlation arises from the synchronized neural activity. In the present study, using laminar electrophysiological recordings, we demonstrated spontaneous neural activities in bilateral primary somatosensory cortices (S1) and layer-specific pattern in interhemispheric functional connectivity. Interestingly, similar pattern was replicated in the resting state BOLD MRI. The fine laminar arrangement in the interhemispheric neural connectivity, e.g. corpus callosum, may mediate the interhemispheric neural communication.

17:42         106.       Caffeine-Induced Reductions in Motor Connectivity: A Comparison of fMRI & MEG Measures

Omer Tal1, Chi Wah Wong2, Valur Olafsson2, Mithun Diwakar1,2, Ming-Xiong Huang2, Thomas T. Liu2

1Department of Bioengineering , University of California - San Diego, La Jolla, CA, USA; 2Department of Radiology, University of California - San Diego, La Jolla, CA, USA

Caffeine has previously been shown to reduce the correlation between resting-state BOLD fluctuations in the motor cortex. However, because of the BOLD signal’s dependence on both neural and vascular factors, it is not known to what extent these reductions reflect caffeine’s effect on neural activity as opposed to its effect on the vasculature. In this preliminary study, we use fMRI and magnetoencephalography (MEG) measures to show that caffeine-related decreases in BOLD correlation partially reflect a decrease in neural connectivity. 

17:54         107.       Simultaneous Intracranial EEG-fMRI in Humans Suggests that High Gamma Frequencies are the Closest Neurophysiological Correlate of BOLD fMRI

David William Carmichael1, Serge Vulliemoz1, 2, Roman Rodionov1, Matthew Walker1, Karin Rosenkranz1, Andrew McEvoy3, Louis Lemieux1, 4

1Clinical & Experimental Epilepsy, UCL Institute of Neurology, London, United Kingdom; 2Epilepsy Unit, University Hospital & University of Geneva, Geneva, Switzerland; 3Victor Horsley Dept. Neurosurgery, National Hospital for Neurology & Neurosurgery, London, United Kingdom; 4MRI Unit , National Society for Epilepsy, Chalfont St Peter, United Kingdom

We investigated EEG-fMRI coupling in a simple motor task and at rest by simultaneously recording intracranial EEG and fMRI in human sensorimotor cortex. One epilepsy patient, implanted for presurgical evaluation with electrodes covering sensorimotor cortex, was scanned following a strict safety protocol. EEG-frequency specific predictors of the BOLD fMRI response were calculated and correlated with fMRI signal changes from the task-activated sensorimotor region. Our results suggest that high gamma frequencies are the most closely correlated to BOLD-fMRI during the task but not during rest and that the peak correlation frequency is highly dependent on measurement location.

18:06         108.       A Simultaneous EEG & High Temporal Resolution fMRI Study of Trial-by-Trial Fluctuations in Visual Evoked Potentials

Pierre LeVan1, Benjamin Zahneisen1, Thimo Grotz1, Jürgen Hennig1

1Medical Physics, University Medical Center Freiburg, Freiburg, Germany

This EEG-fMRI study investigates visual evoked potentials (VEP) using MR-encephalography (MREG), an fMRI technique with a high temporal resolution of 100ms. This allows the accurate estimation of the hemodynamic response function (HRF) to visual stimuli, as well as the removal of physiological artifacts. Trial-by-trial fluctuations of the HRF amplitude were correlated with VEP P1 amplitudes at the center of visual cortex, and with N1 amplitudes at the periphery. Moreover, small HRF delay differences consistent with the VEP were observed between P1- and N1-associated brain regions. MREG is a promising technique to study fast neuronal transients with a high temporal resolution.

18:18         109.       Negative BOLD & CBF Responses are Predicted by Natural Variations in Evoked EEG Response to a Median Nerve Stimulus in Humans.

Karen J. Mullinger1, Stephen D. Mayhew2, Andrew P. Bagshaw2, Richard W. Bowtell1, Susan T. Francis1

1Sir Peter Mansfield Magnetic Resonance Centre, School of Physics & Astronomy, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom; 2Birmingham University Imaging Centre, School of Psychology, University of Birmingham, Birmingham, United Kingdom

The origins of the negative BOLD response (NBR) remain unclear.  Here we use simultaneous EEG-BOLD-ASL recordings during sustained median nerve stimulation to interrogate the NBR. Significant negative correlations of BOLD/CBF with a boxcar model were found in ipsilateral S1.  The magnitude of the negative BOLD/CBF responses in ipsilateral S1 were also correlated with the amplitude of somatosensory evoked potentials (SEP) that originated from contralateral S1. This region was more consistent with the site of the positive BOLD in response to the boxcar model in the opposite hemisphere.  This study provides new evidence for a neural component underlying the NBR.

Vessel Wall Imaging & Coronary MRA

Room 511A-C                   16:30-18:30                                                                       Moderators: René M. Butnar & Kun-cheng Li

16:30         110.       Carotid Plaque Characteristics at MRI & Recurrent Clinical Cerebrovascular Ischemic Events

Robert Kwee1, Robert van Oostenbrugge2, Werner Mess2, Rob van der Geest3, Johannes ter Berg4, Cees Franke5, Arthur Korten6, Bé Meems7, Jos van Engelshoven2, Joachim Wildberger2, Eline Kooi2

1Maastricht University Medical Center, Maastricht, Limburg, Netherlands; 2Maastricht University Medical Center, Netherlands; 3Leiden University Medical Center; 4Orbis Medical Center Sittard, Netherlands; 5Atrium Medical Center Parkstad Heerlen, Netherlands; 6Laurentius Hospital Roermond, Netherlands; 7VieCuri Medical Center Venlo, Netherlands

The results of this first study from mainland Europe suggest that the presence of intraplaque hemorrhage, larger lipid-rich necrotic core volume, and larger maximum vessel wall thickness of carotid plaques are associated with the recurrence of clinical cerebrovascular ischemic events. It confirms previous studies that intraplaque hemorrhage may predict future TIA or stroke. Assessment of carotid plaque characteristics by MRI may help improving patient selection for carotid endarterectomy.

16:42         111.       WITHDRAWN

16:54         112.       Characterization of Carotid Atherosclerotic Plaque Compositions by Single Magnetic Resonance Imaging Sequence: A Comparison Study with Multicontrast Plaque Imaging at 3T

Xihai Zhao1, Niranjan Balu2, Wenbo Liu2, Jinnan Wang3, Huilin Zhao4, Jianrong Xu4, Chun Yuan1,2

We aimed to develop a non-invasive 1H MRS approach that enables in vivo quantification of plaque cholesteryl ester content. We performed in vivo measurements of early and advanced carotid atherosclerotic lesions in 49 subjects, and assessed reproducibility of the 1H MRS protocol. We observed a significant difference in the 2.0:1.2 ppm ratio between vessels without and with plaque, and between fibrous and complex plaque. Furthermore, the 2.0:1.2 ppm ratio showed good interscan reproducibility. Our study shows that plaque liquid cholesteryl ester content can be quantified non-invasively in vivo in human carotid artery plaques on a molecular level, using 1H MRS.

1Department of Biomedical Engineering & Center for Biomedical Imaging Research, School of Medicine, Tsinghua University, Beijing, China, People's Republic of; 2Department of Radiology, University of Washington, Seattle, WA, USA; 3Philips Research North America, Briarcliff Manor, NY, USA; 4Department of Radiology, Renji Hospital, Shanghai Jiao Tong University, Shanghai, China, People's Republic of

17:06         113.       Interpretation of Tissue Contrast in a Rapid Black-Blood Gradient Echo Sequence with Motion-Sensitized Driven Equilibrium (MSDE) Preparation (3D MERGE) for 3D Isotropic High-Resolution Imaging of the Vessel Wall & its Application for Hemorrhage Detection

Niranjan Balu1, Vasily Yarnykh1, William Kerwin1, Jinnan Wang2, Chun Yuan1

1Department of Radiology, University of Washington, Seattle, WA, USA; 2Philips Research North America, Seattle, WA, USA

A new 3D black-blood sequence, 3D-MERGE, has been recently proposed for fast isotropic high-resolution plaque imaging of the vessel wall and validated for the assessment of plaque morphology. However, contrast properties of this 3D technique have not been established limiting its application in studies of plaque composition. 3D-MERGE combines motion-sensitized driven equilibrium (MSDE) preparation with non-steady-state FLASH-type readout, which makes interpretation and management of tissue contrast for this technique a rather complex problem. In this study, we characterize contrast properties of 3D-MERGE and demonstrate its usefulness for in vivo identification of intraplaque hemorrhage.

17:18         114.       Haptoglobin Phenotype Modulates MRIPH Signal

General Leung1,2, Helen Cheung2, Stephanie E. Chiu1, Betty Wong3, David Cole3, Alan R. Moody1,2

1Medical Biophysics, University of Toronto, Toronto, Ontario, Canada; 2Medical Imaging, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; 3Division of Biochemistry & Genetics, Sunnybrook Health Sciences Centre

Intraplaque Haemorrhage (IPH) has been shown to be a predictor of patient outcome. Haptoglobin, a haemoglobin binding protein, appears to modulate the MR signal in vitro. In-vivo, haptoglobin phenotypes appears to be associated with MRIPH status.

17:30         115.       High Resolution 3D Coronary Vessel Wall Imaging with Near 100% Respiratory Efficiency using Epicardial Fat Tracking:  Reproducibility & Comparison with Standard Methods

Andrew David Scott1,2, Jennifer Keegan1,2, David Firmin1,2

1Cardiovascular Magnetic Resonance Unit, Imperial College London, London, United Kingdom; 2Cardiovascular Magnetic Resonance Unit, the Royal Brompton & Harefield NHS Foundation Trust, London, United Kingdom

Coronary wall measurements must be reproducible for longitudinal studies.  Navigator-gated 2D TSE and spiral techniques are commonly used, although respiratory efficiency is low and variable.  Beat-to-beat respiratory motion correction (B2B-RMC) can correct for tidal respiratory motion with ~100% respiratory efficiency, allowing 3D vessel coverage in a reasonable duration.  We compared vessel wall thicknesses using B2B-RMC 3D spiral with navigator-gated 2D TSE and 2D spiral imaging and assessed intra-observer, inter-observer and inter-study reproducibility.  Reproducibility was excellent with B2B-RMC and good with navigator-gated techniques.  B2B-RMC enables reproducible 3D coronary wall assessment within reasonable durations which will permit improved assessment of atherosclerotic disease.

17:42         116.       Left Coronary Artery Imaging at 7T: Initial Results using Multiple B1+ Shimming Algorithms & Targets

Gregory John Metzger1, Lance Delabarre1, Xiaoming Bi2, Saurabh Shah2, Sven Zuehlsdorff2, Tommy Vaughan1, Kamil Ugurbil1, Pierre-Francois van de Moortele1

1Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA; 2Siemens Healthcare, Cardiovascular MR R&D, Chicago, IL, USA

Imaging of the left coronary artery was achieved with high contrast at 7T. The challenges of low peak B1+ and poor transmit homogeneity were overcome by RF pulse and region specific B1+ shimming strategies making us of a 16-channel transceiver TEM stripline array driven by 16, 1 kW amplifiers with independent phase and gain control.

17:54         117.       Water/Fat resolved Whole-Heart Imaging for Coronary MRA

Peter Koken1, Holger Eggers1, Gabrielle Beck2, Peter Börnert1

1Philips Research Laboratories, Hamburg, Germany; 2Philips Healthcare, Best, Netherlands

Fat suppression is essential to improve contrast in coronary MR-angiography (CMRA) but fat also contains diagnostic information. Therefore, in this work whole heart CMRA imaging is proposed that delivers both, the coronary tree and the fat signal distribution at the same spatial resolution without extra scan time. We propose a gradient multi-echo sequence for whole heart CMRA which acquires two or three echoes at both polarities of an alternating readout gradient, allowing an iterative Dixon water/fat separation. This concept was applied and validated in volunteers. Two different magnetization preparation techniques and their influence on the fat signal were investigated.

18:06         118.       Whole-Heart Coronary MRA using 2D Self-Navigation

Markus Henningsson1, Christian Stehning2, Claudia Prieto1, Peter Koken2, Rene M. Botnar1

1Division of Imaging Sciences & Biomedical Engineering, King's College London, London, United Kingdom; 2Philips Research Europe, Hamburg, Germany

Self-navigation techniques have been proposed to improve respiratory motion compensation in CMRA. However static structures within the navigator image can impede self-navigation motion estimation. To overcome this problem we have implemented a 2D Self-navigator by adding phase encoding gradients to the dummy pulses in a bSSFP sequence. With this approach we calculated foot-head and anterior-posterior motion and performed retrospective translational motion correction. We compared this novel method with a “traditional” 1D self-navigator, and a diaphragmatic 1D pencil beam navigator with a tracking factor 0.6. Initial results show improved motion correction with the 2D self-navigator.

18:18         119.       A Joint Prospective-Retrospective Respiratory Navigator for Contrast Enhanced Whole-Heart Coronary MRI

Mehdi Hedjazi Moghari1, Tamer Basha1, Mehmet Akçakaya1, Alan O’Connor1, Lois Goepfert1, Kraig V. Kissinger1, Beth Goddu1, Doug Stanton2, Warren J. Manning1, Reza Nezafat1

1Dept. of Medicine (Cardiovascular Div.), Beth Israel Deaconess Medical Center, Harvard Medical Sch., Boston, MA, USA; 2Philips Research

We have evaluated a joint prospective-retrospective respiratory motion compensation technique for coronary MRI. Studies in respiratory motion phantom and in vivo experiments were used to validate the proposed method.

New Contrast

Room 511D-F                    16:30-18:30                                                   Moderators: Ludovic De Rochefort & Klaas Pruessmann

16:30         120.       SEMI-TWINS: Simultaneous Extraction of Myelin & Iron using a T2*-Weighted Imaging Sequence

Ferdinand Schweser1,2, Andreas Deistung1, Berengar Wendel Lehr3, Karsten Sommer1, 4, Jürgen R. Reichenbach1

1Medical Physics Group, Dept. of Diagnostic & Interventional Radiology 1, Jena University Hospital, Jena, Germany; 2School of Medicine, Friedrich Schiller University of Jena, Jena, Germany; 3Medical Physics Group, Dept. of Diagnostic & Interventional Radiology, Jena University Hospital, Jena, Germany; 4School of Physics & Astronomy, Friedrich Schiller University of Jena, Jena, Germany

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16:42         121.       In Vivo Evidence of Susceptibility Anisotropy & Susceptibility Tensor Imaging of Human Brain

Wei Li1, Bing Wu1, Chunlei Liu1,2

1Brain Imaging & Analysis Center, Duke University, Durham, NC, USA; 2Radiology, Duke University, Durham, NC, USA

Previously, the magnetic susceptibility of brain tissue is generally assumed to be isotopic. Recently, emerging evidences from animal studies and in vitro brain specimens started to show the directionality of susceptibility. In this study, we demonstrated the evidence of magnetic susceptibility anisotropy from in vivo human brain by comparing susceptibility map with the diffusion tensor imaging results and comparing susceptibility obtained from different orientations. Further, the susceptibility tensor is calculated, which shows varied gray and white matter contrast among the three principal eigenvalues. These results provide convincing evidences that the magnetic susceptibility of in vivo human brain is anisotropic.

16:54         122.       Origin of Phase Contrast: Insight from Susceptibility, R2* & Element Imaging by LA-ICP-MS

Ana-Maria Oros-Peusquens1, Andreas Matusch2, Johannes Lindemeyer3, Sabine Johanna Becker4, Nadim Jon Shah1

1Institute of Neuroscience & Medicine (INM-4), Research Centre Juelich, Juelich, NA, Germany; 2INM-2, Research Centre Juelich, Germany; 3INM-4, Research Centre Juelich, Germany; 4ZCH, Research Centre Juelich

MR-based maps of susceptibility, field and R2* distribution were compared to element imaging using Laser Ablation Inductively Coupled Mass Spectrometry (LA-ICP-MS). The distributions of carbon (C) and iron (Fe), elements thought to be the main determinants of susceptibility and phase contrast, show much more detail than the susceptibility and field maps obtained from MRI. A linear dependence between R2* and Fe concentration has been confirmed in a limited, ROI-based analysis. A clustering analysis of the distribution of 15 elements shows features which are unclear  in the phase or susceptibility distributions but can be found in the mixed-contrast T2*-weighted high-resolution images.

17:06         123.       Active Contrast Modulation of Iron Oxide Nanoparticles using Rotary Saturation

Bo Zhu1,2, Thomas Witzel1,2, Shan Jiang3, Daniel G. Anderson3, Robert S. Langer3, Bruce R. Rosen1,2, Lawrence L. Wald1,2

1Harvard-MIT Division of Health Sciences & Technology, Massachusetts Institute of Technology, Cambridge, MA, USA; 2Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA; 3Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA

A novel contrast mechanism for imaging iron oxide contrast agents is described based on the Rotary Saturation effect, whereby the oscillating magnetic fields generated from vibrating iron oxide nanoparticles resonantly couples with the spin system to produce tunable signal changes.  We demonstrate this active contrast modulation with a block-design experiment interleaving vibration of the contrast agent on and off resonance relative to the rotating frame resonance frequency, and observe statistically significant signal changes only for ROIs adjacent to the nanoparticles.  We envision contrast modulation of iron oxide nanoparticles in-vivo using sound waves or endogenous motion to generate the nanoparticle vibration.

17:18         124.       A General T Relaxation Model for Spin-Lock MRI using a Rotary Echo Pulse

Jing Yuan1, Yi-Xiang Wang1

1Department of Imaging & Interventional Radiology, the Chinese University of Hong Kong, Shatin, New Territories, Hong Kong

T1ñ relaxation was conventionally described to follow a purely monoexponential decay as a function of the spin lock time. However, the validity of this monoexponential decay may be violated in the presence of field inhomogeneities, especially at extremely low spin lock frequencies. T1ñ relaxation behavior using a rotary echo spin lock pulse was studied using the Bloch Equation and the rotation matrix transformation. A general analytical expression was derived to describe the T1ñ relaxation at different spin lock frequencies in the presence of B0 inhomogeneity, and verified experimentally by phantom and in vivo imaging from 50Hz to 500Hz. 

17:30         125.       Comparing Electric Properties Tomography at 1.5, 3 & 7 T.

Astrid L. H. M. W. van Lier1, Tobias Voigt2, Ulrich Katscher2, Cornelis A. T. van den Berg1

1Radiotherapy, UMC Utrecht, Utrecht, Netherlands; 2Philips Research Europe, Hamburg, Germany

Recently, the principle feasibility of Electrical Properties Tomography has been shown at different field strengths, 1.5T, 3T, and 7 T. To determine the optimal field strength for EPT, a systematic study was performed comparing phantom measurements and simulations. The influence of SNR and the error induced by using the transceiver phase instead of the transmit phase on the reconstruction are evaluated.

17:42         126.       Imaging Electrical Properties of the Human Brain using a 16-Channel Transceiver Array Coil at 7T

Xiaotong Zhang1, Pierre-Francois Van de Moortele2, Sebastian Schmitter2, Bin He1

1Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN, USA; 2Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA

The electrical properties (EPs, conductivity and permittivity) of brain tissues provide important information for basic brain research and clinical diagnosis of neurological disorders. They also play an important role in SAR calculation. In this study, using a 16-channel transceiver array coil at 7T and based on existing B1-mapping technique, we have developed a novel method to estimate both magnitude and absolute phase distribution of transmit/receive B1 fields, and the electrical conductivity and relative permittivity values. We report our pilot results in a human brain for electrical property imaging using a high field MRI system.

17:54         127.       In Vivo Glioma Characterization using MR Conductivity Imaging

Tobias Voigt1, Ole Väterlein2, Christian Stehning1, Ulrich Katscher1, Jens Fiehler2

1Philips Research Laboratories, Hamburg, Germany; 2Department of Neuroradiology, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany

Conductivity imaging provides a new quantitative contrast for MRI. In the presented study conductivity imaging is applied in a routine clinical environment. First clinical results of glioma patients are reported and compared with healthy volunteers. In vivo conductivity of glioma is found considerably higher than healthy white matter conductivity.

18:06         128.       Real-Time Conductivity Mapping using Balanced SSFP & Phase-Based Reconstruction

Christian Stehning1, Tobias Ratko Voigt2, Ulrich Katscher1

1Philips Research Laboratories, Hamburg, Germany; 2Institute of Biomedical Engineering, University of Karlsruhe, Karlsruhe, Germany

A volumetric, real-time conductivity mapping method based on balanced SSFP and an image phase based reconstruction is presented. It provides sufficient temporal resolution to visualize the dissolving of salt in a water phantom.

18:18         129.       Panel
Richard W. Bowtell, Ludovic De Rochefort, Klaas Pruessmann & Daniel K. Sodickson

Novel Techniques for Image Analysis

Room 512A-G                   16:30-18:30                                                                        Moderators: Jan Scholz & Simon K. Warfield

16:30         130.       Comparison of Cortical Surface Reconstructions from MP2RAGE Data at 3T & 7T

Kyoko Fujimoto1, Jonathan R. Polimeni1, Andre J. van de Kouwe1, Tobias Kober2, Thomas Benner1, Bruce Fischl1,3, Lawrence L. Wald1,4

1Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Charlestown, MA, USA; 2Laboratory for Functional & Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Advanced Clinical Imaging Technology, Siemens Suisse SA - CIBM, Lausanne, Switzerland; 3Computer Science & AI Lab (CSAIL), Massachusetts Institute of Technology, Cambridge, MA, USA; 4Harvard-MIT Division of Health Sciences & Technology, Massachusetts Institute of Technology, Cambridge, MA, USA

Here we demonstrate that accurate surface models can be generated from 7T anatomical data with the recently introduced MP2RAGE pulse sequence with some additional preprocessing steps prior to using the FreeSurfer software package. We compared the surfaces generated from 7T MP2RAGE data with those generated from 3T MP2RAGE data and 3T MEMPRAGE data. We performed a test-retest analysis with the 3T data to quantify the reproducibility of the surface models and to estimate the precision of the surface reconstruction across the two acquisition methods.

16:42         131.       Who Said Fat is Bad? Skull-Stripping Benefits from Additional Fat Image.

Delphine Ribes1,2, Tobias Kober1,2, Giulio Gambarota3, Reto Meuli4, Gunnar Krueger2

1Laboratory for Functional & Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Advanced Clinical Imaging Technology, Siemens Suisse SA - CIBM, Lausanne, Switzerland; 3Clinical Imaging Center, GSK, Imperial College, London, United Kingdom; 4Department of Radiology, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland

Being a preliminary step for many clinical applications and analyses, accurate skull-stripping is a key challenge in MR brain imaging. One of its major difficulties arises from the contrast similarities at brain/non-brain tissue interfaces. Multispectral imaging may help to mitigate this problem. Specifically, the acquisition of multiple echoes in a MP-RAGE sequence as shown in the work of van der Kouwe et al. (2008) can be used for this purpose. We combine their approach with the classical Dixon method to obtain an additional contrast depicting only the fat signal. This work investigates whether the thus generated additional information can improve the outcome of an unsupervised intensity-based skull-stripping algorithm.

16:54         132.       Atlas-Based Online Spatial Normalization

Judd M. Storrs1,2, Jing-Huei Lee1,3

1Center for Imaging Research, University of Cincinnati, Cincinnati, OH, USA; 2Department of Psychiatry & Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH, USA; 3School of Energy, Environmental, Biological & Medical Engineering, University of Cincinnati, Cincinnati, OH, USA

Online spatial normalization to the ICBM452 T1-weighted template was integrated with acquisition of high-resolution 3D anatomic images. The low-spatial frequency components are used for affine spatial normalization during acquisition of the high-spatial frequencies. Online normalization completes prior to the end of scanning and the atlas coordinate system is available immediately for use by the next queued scan.

17:06         133.       Segmentation Priors from Local Image Properties, Not Location-Based Templates

Ziad Serhal Saad1, Andrej Vovk2, Janez Stare3, Dusan Suput2, Robert W. Cox1

1SSCC, NIMH/NIH, Bethesda, MD, USA; 2Institute of Pathophysiology, University of Ljubljana, Ljubljana, Slovenia; 3Institute for Biostatistics & Medical Informatics, University of Ljubljana, Ljubljana, Slovenia

We present a novel approach for generating a voxel's tissue class membership based on its signature; a collection of spatial texture statistics calculated over a set of spherical neighborhoods around that voxel. We produce tissue class priors that can initialize and regularize image segmentation much in the way population-based priors do as a function of spatial location in standard template space. The signature-based approach is a distinct departure from location-based methods by not requiring  population-derived spatial template, registration to template's space, and bias field estimation. It is also suitable where location-based templates are not available or appropriate.

17:18         134.       Improved Segmentation of Mouse MRI Data using Multiple Automatically Generated Templates

Mallar Chakravarty1,2, Matthijs Christiaan van Eede1, Jason P. Lerch1

1Mouse Imaging Centre (MICe), the Hospital for Sick Children, Toronto, Ontario, Canada; 2Rotman Research Institute, Baycrest, Toronto, Ontario, Canada

In human MRI experiments, segmentation of neuroanatomy is often accomplished using a single atlas based nonlinear transformation estimation.  The accuracy of this technique is limited by errors in the nonlinear transformation estimated, differences in the neuroanatomy between the template brain and the subject, or label resampling errors.  Recent work demonstrates improvement of these segmentation techniques through the use of a manually generated template library.  In this methodology, instead of using a single expertly labeled MRI template, a number of different templates are manually labeled, and transformations are estimated to match a single subject to each of these templates.  After the nonlinear transformations are applied to the anatomical labels, a histogram of labels generated at each voxel can be used to inform the final segmentation on a voxel-by-voxel basis.  This template library approach thus improves segmentation accuracy by accounting for varying anatomy through the use of different templates and compensating for registration algorithm inaccuracy by virtue of the multiple registrations needed from each MRI in the template to the target. In the segmentation of MRI data from inbred laboratory mice strains, however, the confounds of variable neuroanatomy are limited, and segmentation errors therefore result from registration inaccuracy and resampling errors. We hypothesize that segmentations can be improved if resampling and nonlinear transformation errors are reduced.   Here, we test this hypothesis by implementing a multi-atlas segmentation scheme using automatically generated atlases (instead of manually labeled ones) and verified the accuracy of the segmentation using manually derived gold standards of the neuroanatomy.

17:30         135.       Creation of a Population-Representative Brain Atlas with Clear Anatomical Definition

Yajing Zhang1, Jiangyang Zhang2, Jun Ma3, Kenichi Oishi2, Andreia V. Faria2, Michael I. Miller1,3, Susumu Mori2,4

1Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 2Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 3Center for Imaging Science, Johns Hopkins University, Baltimore, MD, USA; 4F. M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, USA

An MR based brain atlas is a key component in modern image analysis process. In this study, a population averaged brain atlas was generated from 20 subject MRI/DTI data using a continuous fluid dynamic model based on image metric distance. This estimated atlas presents a group averaged shape that minimize its anatomical bias while preserves sharp image contrast for accurate structure delineation and image mapping.  The characteristics of the estimated atlas were examined with respect to a single subject atlas and two group averaged atlases.

17:42         136.       Computerized Lesion Segmentation on DCE-MRI using Active Contours & Spectral Embedding.

Shannon Agner1, Jun Xu1, Sudha Karthigeyan1, Anant Madabhushi1

1Biomedical Engineering, Rutgers University, Piscataway, NJ, USA

Accurate lesion segmentation is an important component of determining quantitative features for lesions on MRI.  In this study, we develop an automated segmentation method for delineating lesions on DCE-MRI using spectral embedding which serves as alternative image representation upon which to perform an active contour lesion segmentation.  We demonstrate on a cohort of 50 breast DCE-MRI datasets that the automated spectral embedding based active contour (SEAC) provides lesion segmentations that are more comparable to the manual segmentation performed by a radiologist than the popular automated fuzzy c-means segmentation method. While we demonstrate the use of SEAC with breast DCE-MRI data, SEAC could be easily applied to segmenting structures on other high dimensional, time-series imaging data as well. 

17:54         137.       MR Estimation of Longitudinal Relaxation Time (T1) in Spoiled Gradient Echo using an Adaptive Neural Network

Hassan Bagher-Ebadian1,2, Siamak P. Nejad-Davarani1,3, Ramesh Paudyal1, Tom Mikkelsen4, Quan Jiang1,2, James R. Ewing1,2

1Neurology, Henry Ford Hospital, Detroit, MI, USA; 2Physics, Oakland University, Rochester, MI, USA; 3Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; 4Neurosurgery, Henry Ford Hospital, Detroit, MI, USA

Estimating the longitudinal relaxation time, T1, from spoiled-gradient-recalled-echo (SPGR) images is challenging and susceptible to the level of noise-to-signal ratio (SNR) in acquisition. Methods such as Simplex-Optimization, Weighted-Non-Linear-Least-Squares, Linear-Least-Square, and Intensity-based-Linear-Least-Square have been employed to estimate T1. In linear and non-linear methods, the estimated T1 values are dependent on defining the weighting factors, which may result in a biased estimation. Herein, an adaptive neural network is trained and compared with different techniques using an analytical model of the SPGR signal in the presence of different levels of SNR. Receiver-Operator-Characteristic analysis and K-fold-cross-validation were employed for validation, testing, and network optimization.

18:06         138.       Application of the Extended Phase Graph Technique to Improve T2 Quantitation Across Sites

William D. Rooney1, James R. Pollaro1, Sean C. Forbes2, Dah Jyuu Wang3, Krista Vandenborne2, Glenn A. Walter4

1Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, USA; 2Department of Physical Therapy, University of Florida, Gainesville, FL, USA; 3Department of Radiology, the Children's Hospital of Philadelphia, Philadelphia, PA, USA; 4Department of Physiology & Functional Genomics, University of Florida, Gainesville, FL, USA

Quantitative transverse relaxography (qT2) of proton MR signals has shown sensitivity for pathology of tissues such as muscles in patients with DMD.  Standardization across multiple sites, as well as imperfections in multi-echo imaging sequences has led to contamination of the desired primary echo decay.  Crushing gradient schemes have been developed, but these can be difficult to implement, especially in multi-slice acquisitions.  Extended phase graphs applied during post-processing can isolate the primary echo to improve accuracy of qT2 mapping.

18:18         139.       Support Vector Machines can Decode Speech Patterns from High Speed Dynamic Spiral FLASH Images of the Mouth

Stephen LaConte1, Jonathan Lisinski1, Bradley Sutton2

1School of Biomedical Engineering & Sciences, Virginia Tech, Blacksburg, VA, USA; 2Bioengineering, University of Illinois, Urbana-Champaign, Urbana, IL, USA

We imaged the oropharyngeal cavity at 15.8 frames per second using a recently developed multi-shot, field corrected, dynamic spiral FLASH sequence. We explored the extent to which speech-related information is captured by this sequence. During imaging, we asked a subject to perform a visually guided speech task, consisting of alternating 20 sec. blocks of slow and fast counting. Support vector machine analysis used the soft palate, lips, and tongue and resulted in 88% prediction accuracy, demonstrating that it is possible to classify individual frames as either “fast” or “slow” speech. This achievement has potential applications in speech therapy and diagnosis.

Spectroscopy Localization

Room 513A-D                   16:30-18:30                                                         Moderators: Hoby Hetherington & Vladimir Mlynarik

16:30         140.       In-Vivo Proton MR Spectroscopic Imaging of Glycine in Brain Tumors at 3.0 T

Sandeep Kumar Ganji1, Ivan E. Dimitrov1,2, Elizabeth A. Maher3, Changho Choi1

1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; 2Philips Medical Systems, Cleveland, OH, USA; 3Internal Medicine & Neurology, University of Texas Southwestern Medical Center, Dallas, TX, USA

Abnormality of glycine (Gly) concentrations has been reported in several brain disorders using single-voxel localized spectroscopic methods. Spectroscopic imaging of Gly in vivo is challenging due to its low concentrations and the spectral overlap, primarily with myo-inositol. We employed an optimized-TE PRESS-based chemical shift imaging method for glycine imaging. We present phantom validation of the technique and preliminary data from tumor patients together with single-voxel data for comparison. The concentration maps of metabolites are also presented.

16:42         141.       Slice with Non-Parallel Boundaries

Bu S. Park1, M. J. Lizak2, Y. Xiang1, J. Shen1

1National Institute of Mental Health (NIMH), NIH, Bethesda, MD, USA; 2National Institute of Neurological Disorders & Stroke (NINDS), NIH, Bethesda, MD, USA

Adiabatic pulses are widely used for spatial localization in MR spectroscopy because of their high immunity to RF inhomogeneity and excellent slice profiles. Since non-rectangular volume is often preferred in localized spectroscopy, here we optimized and experimentally tested a scheme that uses a time-varying gradient orthogonal to a stationary slice-selection gradient to generate slices with nonparallel boundaries.

16:54         142.       Multi-Slice MRSI of the Human Brain at 7 Tesla using Dynamic B0 & B1 Shimming

Vincent Oltman Boer1, Dennis W. J. Klomp1, Christoph Juchem2, Peter R. Luijten1, Robin A. de Graaf2

1Radiology, UMC Utrecht, Utrecht, Netherlands; 2MR Research Center, Yale University, New Haven, Conneticut, USA

Multi-slice MRSI of the human brain at ultra high field is challenging due to both static field inhomogeneity, spatial B1 variations and SAR limits. In this work it is shown how a low-power water and lipid suppression can be combined with pulse acquire-MRSI localization to generate a high SNR multi-slice MRSI sequence for high field. Steady state water suppression, RF shimmed lipid suppression and dynamic B0 and B1 shim updating were used to improve spectral quality in all slices.

17:06         143.       Diffusion-Weighted Spectroscopic Imaging of Rat Brains After Middle Cerebral Artery Occlusion

Yoshitaka Bito1, Yuko Kawai2, Koji Hirata1, Toshihiko Ebisu3, Toru Shirai1, Satoshi Hirata1, Yoshihisa Soutome1, Hisaaki Ochi1, Masahiro Umeda2, Toshihiro Higuchi4, Chuzo Tanaka4

1Central Research Laboratory, Hitachi, Ltd., Kokubunji-shi, Tokyo, Japan; 2Medical Informatics, Meiji University of Integrative Medicine, Kyoto, Japan; 3Neurosurgery, Nantan General Hospital, Kyoto, Japan; 4Neurosurgery, Meiji University of Integrative Medicine, Kyoto, Japan

A diffusion-weighted echo-planar spectroscopic imaging with a pair of bipolar diffusion gradients (DW-EPSI with BPGs) was applied to acquire apparent diffusion coefficient (ADC) changes of N-acetylaspartate (NAA) after a right middle cerebral artery occlusion (MCAO) in rat brains. Acquired changes in ADC maps of NAA after MCAO were analyzed by using Gaussian mixture distribution, which can handle many spatial pixels acquired simultaneously by diffusion-weighted spectroscopic imaging. It is shown that DW-EPSI with BPGs is effective for investigating spatially varying ADC changes of metabolites and that this technique may be useful for understanding intra-cellular dynamics of neurons by using NAA as a probe.

17:18         144.       High-Resolution Mapping of the Neurochemical Profile after Focal Ischemia in Mice

Malte Frederick Alf1,2, Hongxia Lei1,3, Carole Berthet4, Lorenz Hirt4, Rolf Gruetter1,3, Vladimir Mlynárik1

1Laboratory of Functional & Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Institute of Pharmaceutical Sciences, ETH Zürich, Zürich, Switzerland; 3Department of Radiology, University of Lausanne; 4Department of Clinical Neuroscience, Centre Hospitalier Universitaire Vaudois

We developed a 1H-MRSI protocol on a 14.1T magnet to investigate the localization of changes in the mouse neurochemical profile after 30 minutes of transient ischemia (MCAO model). Maps with 1.4 microliter effective resolution were acquired, including e.g. separate glutamate and glutamine and the, to our knowledge, first in vivo mapping of GABA and glutathione. Metabolite acquisition time was 45 minutes. Lactate and NAA concentration changed in core and penumbra; cholines and glutathione in the entire MCA-territory. Glutamine was elevated in ischemic striatum and cortex until 8h/24h after reperfusion respectively, indicating differences in excitotoxic effects and secondary energy failure.

17:30         145.       Fast 1H Metabolic Imaging of Cancer

Sairam Geethanath1, Hyeon-Man Baek2, Sandeep K. Ganji2,3, Yao Ding3, Robert D. Sims4, Changho Choi2,4, Vikram D. Kodibagkar1,4

1Joint graduate program in biomedical engineering,  UT Arlington & UT Southwestern Medical Center, Dallas, TX, USA; 2Advanced Imaging Research Center, UT Southwestern Medical Center; 3Graduate program in radiological sciences, UT Southwestern Medical Center; 4Radiology, UT Southwestern Medical Center

MRSI has been shown to provide valuable metabolic information critical for cancer prognosis. However, the long acquisition time associated with multidimensional MRSI is a barrier for translation of this technology to the clinic. A novel approach to reduce acquisition time of MRSI has been proposed through the application of compressive sensing. An application of such a reconstruction method has been performed for 1H MRSI of in- vitro brain phantom, in vivo brain (normal, cancer), and prostate cancer MRSI data. The results of reconstruction indicate a significant potential to reduce acquisition times for such studies by 80%.

17:42         146.       Artefact Minimized Spectral Editing at 7T: Quick & Accurate In-Vivo Detection of GABA.

Anna Andreychenko1, Vincent O. Boer1, Jannie P. Wijnen1, Catalina Arteaga1, Peter Luijten1, Dennis W. J. Klomp1

1University Medical Center Utrecht, Utrecht, Netherlands

Spectral editing techniques rely on subtraction of two in vivo MR spectra and, therefore, are prone to artefacts. Here, we implemented and performed an accurate and efficient spectral editing of the 3 ppm GABA resonance in-vivo in the human brain at 7 T, utilizing two editing MEGA pulses in a semi-LASER localization sequence with a minimal chemical shift displacement error. The total scan time was ~4 min. High efficiency of this MEGA-sLASER editing technique preserves 3 ppm GABA resonance in the edited spectrum even obtained with an echo time of 222 ms that allowed us to estimate the T2 relaxation time of GABA.

17:54         147.       Adiabatic Spiral Correlation Chemical Shift Imaging

Ovidiu Cristian Andronesi1, Borjan A. Gagoski2, Elfar Adalsteinsson2, A. Gregory Sorensen1

1Martinos Center for Biomedical Imaging, Radiology Department, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA; 2Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA

The overlap of spectra in magnetic resonance spectroscopy limits the unambiguous identification and quantification of metabolites. Novel correlation chemical shift imaging sequences using optimized low power adiabatic excitation and fast spiral spatial encoding are demonstrated on 3T clinical scanners for two-dimensional COSY (Correlation Spectroscopy) and TOCSY (Total Correlation Spectroscopy) experiments. These methods could reveal metabolites that are otherwise obscured in 1D spectra. To date there has been limited progress reported towards a feasible and robust multivoxel COSY. TOCSY imaging is shown for the first time in this work. Results on phantoms, volunteers and patients with brain tumors are presented.

18:06         148.       Water-Independent Frequency- & Phase-Corrected Spectroscopic Averaging using Cross-Correlation & Singular Value Decomposition

Aaron T. Hess1, André J. W. van der Kouwe2, Ernesta M. Meintjes1

1MRC/UCT Medical Imaging Research Unit, Human Biology, University of Cape Town, Cape Town, South Africa; 2Radiology, Massachusetts General Hospital, Boston, MA, USA

In a single voxel spectroscopy scan voluntary and physiologic movement can induce frequency and phase variations between consecutive FIDs. These variations lead to destructive averaging and line broadening. We present a technique to robustly detect the frequency of each FID by using its spectral cross-correlation with a simulated spectrum. Further we recombined them in a phase-insensitive manner using a set of complex weights calculated from singular value decomposition. We demonstrate the spectral quality improvement using this method from a scan where the subject was particularly restless.

18:18         149.       Short Dual-Band VAPOR-Like Pulse Sequence for Simultaneous Water & Lipid Suppression for In Vivo MR Spectroscopy & Spectroscopic Imaging

Zenon Starcuk Jr.1, Jana Starcukova1, Zenon Starcuk1

1Magnetic Resonance & Bioinformatics, Institute of Scientific Instruments, Academy of Sciences of the Czech Republic, Brno, Czech Republic

Short VAPOR-like water suppression sequences have been shown feasible without sacrificing B1 and T1 insensitivity and exhibiting improved excitation profiles. The same construction principle, i.e. optimization of flip angles and pulse durations of chemical-shift selective pulses interleaved with fixed short delays, is proposed to be applied to fat suppression as well. Independently optimized water- and fat-presaturation sequences are superimposed into a series of customized dual-band presaturation pulses, followed by B1-insensitive inversion and a spin-echo localization module. The reduced length and improved robustness of such a sequence may improve quantifiability and suit the needs of spectroscopic imaging.

Placenta, Fetus & Gynecologic Malignancy

Room 518-A-C                  16:30-18:30                                                               Moderators: Penny Anne Gowland & Patricia Noël

16:30         150.       Introduction: Fetal Development & the Utero-Placental Unit: What Can MRI Tell Us?
Penny Anne Gowland

16:42         151.       The Effect of Maternal Diabetes on Placental Blood Flow Assessed using IVIM

Devasuda Anblagan1, Ruta Deshpande2, Nia W. Jones2, Carolyn Costigan1, Nick Raine Fenning3, Peter Mansell2, George Bugg2, Lopa Leach4, Penny A. Gowland1

1Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom; 2Nottingham University Hospitals NHS Trust, University of Nottingham, Nottingham, United Kingdom; 3School of Clinical Sciences, University of Nottingham, Nottingham, United Kingdom; 4School of Biomedical Sciences, University of Nottingham, Nottingham, United Kingdom

High volume, low resistance blood flow in the placenta is thought to be essential for optimal materno-fetal nutrient exchange. Intrauterine Growth Restriction and maternal diabetes are often related to abnormal placental perfusion. Using IVIM we assessed placental blood flow in diabetic and healthy mothers. We report the difference in distribution of placental blood flow in diabetic placentae: in the normal placenta the flow was fairly uniformly distributed, whilst in the diabetic placenta the flow distribution was generally lower but with small areas of higher flow. This may be related to the abnormal fetal development associated with diabetic pregnancies.

16:54         152.       Changes in Placental & Fetal Organ Perfusion during Chronic Maternal Hypoxia: Assessment by BOLD MRI During Brief Hypercapnic & Hyperoxic Challenge

Rinat Abramovitch1,2, Nathalie Corchia1, Uriel Elchalal3, Yehuda Ginosar4

1The Goldyne Savad Institute of Gene Therapy, Hadassah Hebrew University Medical Center, Jerusalem, Israel; 2MRI lab HBRC, Hadassah Hebrew University Medical Center, Israel; 3Department of Obstetrics & Gynecology, Hadassah Hebrew University Medical Center, Jerusalem, Israel; 4Department of Anesthesiology, Hadassah Hebrew University Medical Center, Jerusalem, Israel

Preeclampsia and intrauterine fetal growth restriction are common disorders of pregnancy frequently associated with reduced uteroplacental blood flow (UPBF) and fetal organ perfusion. In this study we used BOLD-fMRI combined with hypercapnic and hyperoxic challenge to assess uteroplacental and fetal organ perfusion. BOLD-fMRI provided simultaneous assessments of placental and fetal organs (brain, heart, liver) perfusion in pregnant mice. Acute maternal hypercapnia caused reproducible and reversible reductions in UPBF while fetal cerebral perfusion was unchanged; suggestive of the "brain sparing" phenomenon. Moreover, the BOLD-fMRI hypercapnic challenge test was able to differentiate between normal and chronically asphyxiated pregnancies (maternal hypoxia).

17:06         153.       Intra Voxel Incoherent Motion in the Human Placenta using the Akaike Information Criterion

David Mark Morris1,2, Caroline Wright3, Philip A. Baker4, Ian Crocker3, Penny A. Gowland5, Geoff J. M. Parker1,6, Colin P. Sibley3

1Imaging Science & Biomedical Engineering, the University of Manchester, Manchester, United Kingdom; 2Biomedical Imaging Institute, the University of Manchester, Manchester, United Kingdom; 3Maternal & Fetal Helath Research Group, the University of Manchester, Manchester, United Kingdom; 4Faculty of Medicine & Dentistry, University of Alberta, Edmonton, Alberta, Canada; 5Sir Peter Mansfield Magentic Resonance Centre, University of Nottingham, Nottingham, United Kingdom; 6Biomedical Imaging Institute, the University of Manchester, Manchester, United Kingdom

Intra Voxel Incoherent Motion allows for the non-invasive assessment of flow parameters using a bi-exponential model of water diffusion. This MRI technique has been applied to the human placenta where flow changes have been associated with Fetal Growth Retardation resulting in increased perinatal mortality and morbidity. The bi-exponential model will return erroneous results where the data does not support this complex model of diffusion. The Akaike Information Criterion has been used to exclude voxels and this results in a significant increase in the values of the flow parameters.

17:18         154.       Protection of Fetuses from In Utero Inflammation: Can MRI be the Solution?

Sylvie Girard1, Luc Tremblay, Guillaume Sebire, Martin Lepage

1Universite de Sherbrooke, Sherbrooke, QC, Canada

Inflammation during gestation is known to have a major impact on fetuses neurodevelopment leading to increase risk of brain alteration. There are currently no technic that allows a non-invasive detection of in utero inflammation, which is necessary in order to treat and protect both the placenta and fetus.  We used an experimental model of prenatal inflammation, known to lead to alteration of pups cerebral development and behavior. We showed that using MRI we could detect placental inflammation earlier than by histology. This allowed the determination of a therapeutic window during which the administration of anti-inflammatory treatment, even delayed, was protective.

17:30         155.       A Novel Technique for Cardiac MRI of the Fetal Heart: MR Compatible Doppler Ultrasound (CTG) for CardiacTriggering

Ulrike Wedegaertner1, Michael Frisch1, Inga Kopp1, Joachim Graessner2, Kurt Hecher1, Gerhard Adam1, Jin Yamamura1

1University Hospital Hamburg-Eppendorf, Hamburg, Germany; 2Siemens

The novel MR compatible CTG allowed an excellent trigger of the fetal heart rate. An evaluation of anatomical structures and functional information could be obtained from the cMRI. A CTG triggered fetal cardiac MRI might be of great impact in the evaluation of fetuses with complex congenital heart defects.

17:42         156.       Characterising Heterogeneity of Stage 1 Cervical Cancers using Histogram Analysis from Diffusion Weighted Images.

Katherine Downey1,2, S. F. Riches1,2, V. A. Morgan1,2, S. L. Giles1,2, C. Simpkin1,2, D. P. Barton3,4, N. M. deSouza1,2

1Clinical MRI Unit, Institute of Cancer Research, Sutton, United Kingdom; 2Clinical MRI Unit, the Royal Marsden Hospital , Sutton, United Kingdom; 3Gynaecology Unit, the Royal Marsden Hospital, Sutton, United Kingdom; 4Gynaecology Unit, Institute of Cancer Research, Sutton, United Kingdom

This study uses histogram analysis to establish whether ADC values are significantly different in cervical tumours according to their histological characteristics. Patients were scanned with an endovaginal coil to acquire diffusion weighted images. ADC histograms obtained from the entire tumor had 10th, 50th and 90th centile pixel values and skewness of distribution documented. Independent t-test analysis was performed. Increased cellularity of poorly differentiated tumors is reflected in their lower median ADC. ADC distribution does not appear to be associated with lymphovascular space invasion. The increased skewness in the adenocarcinomas is likely to reflect the mixture of glandular and cellular content. 

17:54         157.       Endovaginal Magnetic Resonance Imaging of Stage 1A/1B1 Cervical Cancer with a T2- & Diffusion-Weighted Magnetic Resonance Technique: Effect of Lesion Size & Previous Cone Biopsy on Tumor Detectability

Elizabeth Charles-Edwards1, Veronica Morgan1, Ayoma Attygalle2, Sharon Giles1, Thomas E. Ind3, Michael Davis4, John Shepherd3, Norman McWhinney5, Nandita deSouza1

1CRUK & EPSRC Cancer Imaging Centre, Institute of Cancer Research & Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom; 2Histopathology, Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom; 3Gynaecology, Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom; 4Gynaecology, Kingston Hospital , Kingston, Surrey, United Kingdom; 5Gynaecology, Epsom & St. Helier NHS Trust, Epsom, Surrey, United Kingdom

Diffusion-weighted MRI using an endovaginal coil is a useful adjunct to T2-W imaging for detecting small tumours within the cervix.  Following a cone biopsy/LLETZ procedure where distortion of normal tissue and granulation tissue is present, a tumor volume of 83 mm3 could be detected with 80% sensitivity, 94.7% specificity.  A 5.3 mm maximal histological dimension was detected on MRI with 100% sensitivity, 100% specificity.

18:06         158.       Comparison of Diffusion Weighted Imaging & Dynamic Contrast Enhanced MRI for Assessing the Depth of Myometrial Invasion in Endometrial Cancer

Peter Beddy1, Penelope Moyle1, Masako Kataoka1, Adam K. Yamamoto1, Ilse Joubert1, David J. Lomas1, Robin Crawford2, Evis Sala1

1Radiology, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom; 2Gynaecological Oncology, University of Cambridge, Cambridge, Cambridgeshire, United Kingdom

This study compared DWI and DCE-MRI in assessing the depth of myometrial invasion in endometrial cancer.  50 patients with histologically confirmed endometrial cancer underwent DWI and DCE-MRI as part of their initial preoperative staging MRI.  We demonstrate that DWI is more accurate at assessing the depth of myometrial invasion compared to DCE-MRI and has significantly higher inter-reader agreement.

18:18         159.       Assessment of Ovarian Movement on Consecutive Pelvic MRI Scans for Accurate Radiotherapy Planning in Patients with Gynaecological Malignancies

Nicky HGM Peters1, 2, Gail Horan3, Deborah Gregory3, Li Tee Tan3, Charlotte Coles3, Andrew J. Patterson2, Evis Sala2

1Radiology, University Medical Center Utrecht, Utrecht, Netherlands; 2Radiology, Addenbrooke’s Hospital, Cambridge, Cambridghire, United Kingdom; 3Oncology, Addenbrooke’s Hospital, Cambridge, Cambridghire, United Kingdom

With the technical advances in radiotherapy, treatment can be planned on MRI examinations on which the ovaries can be clearly depicted. We assessed the extent of ovarian movement on consecutive pelvic MRI examinations in patients that underwent pelvic radiotherapy for a gynaecological malignancy to provide a safety volume around the ovaries accounting for ovarian movement. Adding a safety volume around the ovaries of 32 cm3 and 57 cm3 for the left and right ovary respectively could reduce the high radiation dose to the ovaries during pelvic radiotherapy and resulting infertility and premature menopause could possibly be avoided.

Receive Coils & Arrays

Room 520B-F                    16:30-18:30                                                                 Moderators: Hiroyuki Fujita & Tamer S. Ibrahim

16:30         160.       A 64-Channel Array Coil for 3T Head/Neck/C-spine Imaging

Boris Keil1, Stephan Biber2, Robert Rehner2, Veneta Tountcheva1, Kathrin Wohlfarth2, Philipp Hoecht3, Michael Hamm3, Heiko Meyer2, Hubertus Fischer2, Lawrence L. Wald1,4

1A. A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA; 2Siemens Healthcare, Erlangen, Germany; 3Siemens Healthcare, Charlestown, MA, USA; 4Harvard-MIT Division of Health Sciences & Technology, Cambridge, MA, USA

Highly parallel array coils have been applied to the brain to improve sensitivity of accelerated and non-accelerated imaging, but also offer the possibility to extend the coverage to the neck and C-spine. We have developed a new head-neck-Cspine coil with 60 elements (with 4 additional elements used from the spine array) to improve the sensitivity of integrated head, neck and C-spine examinations. We validate the array with SNR and g-factor maps and accelerated imaging up to R=9

16:42         161.       Millimeter Isotropic Resolution Volumetric Pediatric Abdominal MRI with a Dedicated 32-Channel Phased Array Coil

Shreyas S. Vasanawala1, Thomas Grafendorfer2, Paul Calderon3, Greig Scott4, Marcus T. Alley1, Michael Lustig5, Anja C. Brau6, Arvind Sonik1, Peng Lai6, Vijay Alagappan7, Brian A. Hargreaves1

1Radiology, Stanford University, Stanford, CA, USA; 2ATD Coils, GE Healthare, Stanford, CA, USA; 3MR Hardware Engineering, GE Healthcare, Fremont, CA, USA; 4Electrical Engineering, Stanford University, Stanford, CA, USA; 5Electrical Engineering & CS, UC Berkeley, Berkeley, CA, USA; 6Global Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA; 7ATD Coils, GE Healthcare, Aurora, OH, USA

Pediatric abdominal MRI is challenged by small anatomy and limited patient cooperation.  This work investigates the feasibility of utilizing a dedicated high-density pediatric body array to permit high resolution imaging with slices thin enough for adequate multiplanar reformatting.  With IRB approval, 8 pediatric patients underwent abdominal MRI with a high-density coil, including coronal 3D T2, axial 2D T2, coronal 3D T1, and navigated axial 3D T1.   3D acquisitions were assessed for adequacy of SNR and reformat quality and found to be of diagnostic quality.  Thus, a high-density coil may enable a rapid MRI protocol at millimeter resolution for pediatric body imaging.

16:54         162.       A 7T Coil System for Imaging Humans in the Sphinx Position to Evaluate the Effect of Head Orientation Relative to B0 for MR Imaging

Bei Zhang1, Ryan Brown1, Chris Wiggins2, Daniel K. Sodickson1, Bernd Stoeckel3, Graham Wiggins1

1Center for Biomedical Imaging, Department of Radiology, New York University School of Medicine, New York, NY10016, USA; 2CEA/NeuroSpin, Saclay, France; 3Siemens Medical Solutions USA Inc, New York, NY, USA

We present a 7T coil system which allows the head to be rotated by greater than 90 degrees to investigate the effect of orientation upon the T2* contrast and B0 distribution in the brain. A patch antenna is used to create traveling wave excitation. The subject is placed in the ¡°sphinx¡± position with face towards the patch antenna. A six-element U-shaped receive coil was built to wrap over the crown of the head providing high enough SNR for high resolution T2* imaging. Imaging in regular supine position was also done for comparison.

17:06         163.       Multiplexed RF Transmission for Transceiver Arrays at 7T

Hoby Patrick Hetherington1, Nikolai I. Avdievich1, Jullie W. Pan1

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

At 7T single drive volume coils suffer from poor homogeneity and low efficiency. Transceiver arrays using small surface coils provide improved homogeneity and transmission efficiency; however their use is limited by longitudinal coverage. This can be overcome by using multiple rows of coils along the z axis. However this approach requires an increasing number of independent transmit channels (one per coil), which is not available on most clinical platforms and is expensive. The goal of this work was to develop pulse sequence methods that enable small numbers of independent transmit channels to drive transceiver arrays with larger numbers of coils.

17:18         164.       Human Brain Imaging at 9.4 Tesla using a Combination of Traveling Wave Excitation with a 15-Channel Receive-Only Array

Jens Oliver Hoffmann1, Gunamony Shajan1, Rolf Pohmann1

1High-Field Magnetic Resonance Center, Max Planck Institute for Biological Cybernetics, Tuebingen, BW, Germany

Traveling wave imaging using a Tx/Rx patch antenna has the potential to provide a more homogeneous B1+ field over a large field-of-view compared to circularly polarized volume coils. However, the method suffers from poor sensitivity which prevents the application to routine imaging. Therefore, we combined a patch antenna for transmission with a 15-channel receive-only array inside a narrow head gradient for human brain imaging at 9.4 Tesla. The setup can provide spin excitation covering the whole brain for low flip angle applications; high SNR and simple usage. However, anticipated advantages were spoiled by B1+ artifacts in our initial results.

17:30         165.       32-Channel Receive Only Array for Cardiac Imaging at 7T

Carl Jason Snyder1, Lance DelaBarre1, Gregory Metzger1, Kamil Ugurbil1, J. Thomas Vaughan1

1University of Minnesota, Minneapolis, MN, USA

A 32-channel receive-only array was designed and built for cardiac imaging.  The parallel imaging performance, namely g-factors, was evaluated on the male pelvis.  Short axis T-GRAPPA and four-chamber FLASH cines were acquired.

17:42         166.       Highly Accelerated 7T Prostate Imaging using Parallel Imaging

Alexander J. E. Raaijmakers1, Ozlem Ipek1, Wouter Koning2, Hugo Kroeze2, Cecilia Possanzini3, Paul R. Harvey3, Dennis Klomp2, Peter R. Luijten2, Jan J. W. Lagendijk1, Cornelis A. T. van den Berg1

1Radiotherapy, UMC Utrecht, Utrecht, Netherlands; 2Radiology, UMC Utrecht, Utrecht, Netherlands; 3Philips Medical Systems, Best, Netherlands

Prostate imaging at 7 Tesla suffers from high SAR levels and B1 signal attenuation. An array of 8 single-side adapted dipole antennas shows good signal coverage and is able to reduce the SAR levels by a factor of 4. In this work the parallel imaging performance of this array is characterized. The reference image is obtained by travelling wave imaging. GRE images are obtained using SENSE and reduction factors varying from 1 to 8. No folding artefacts are observed up to a reduction factor of 6 and g-factor values in the prostate stay within reasonable bounds for all reduction factors.

17:54         167.       Dual Mouse 8-Element Coil Array & Bed for Sequential Multimodality PET, SPECT, CT & MRI of Multiple Mice

Marcelino Bernardo1,2, Gabriela Kramer-Marek3, Nalini Shenoy4, Jurgen Seidel1, Michael V. Green1, Jacek Capala5, Peter L. Choyke1

1Molecular Imaging Program, NCI, Bethesda, MD, USA; 2SAIC-Frederick, Frederick, MD, USA; 3Radiation Oncology Branch, NCI, USA; 4Image Probe Development Center, NIH, USA; 5Radiation Oncology Branch, NCI, Bethesda, MD, USA

An 8-channel receive-only coil array for imaging two mice simultaneously and a two-mouse bed compatible with PET, SPECT, CT and MRI for use in doubling the throughput of sequential multimodality imaging of mice is described. Results of phantom tests and in vivo PET-MR imaging of a mouse tumor xenograft model are presented.

18:06         168.       A Novel Radiolucent Phased Array Design Suitable for MR Guided Radiation Therapy

Kirk Champagne1, Wayne Schellekens1, Mehran Fallah-Rad1, Hongxiang Yi1, Haoqin Zhu1, Labros Petropoulos1

1IMRIS Inc., Winnipeg, MB, Canada

A novel design of an 8-channel radiolucent phased array for MR guided Radiation Therapy is presented.  The proposed design exhibits superior MR performance characteristics when compared with the equivalent aluminum design.  In addition, the proposed design exhibits a uniform X-ray transparency image with no apparent distinction between the copper and its surrounding substrate.  Volunteer imaging was also performed indicating that the proposed structure can be ideal for abdominal imaging.

18:18         169.       Design Criteria of an MR-PET Array Coil for Highly Parallel MR Brain Imaging

Christin Y. Sander1,2, Boris Keil2, Ciprian Catana2, Bruce R. Rosen2,3, Lawrence L. Wald2,3

1Electrical Engineering & Computer Science, Massachusetts Institute of Technology, Cambridge, MA, USA; 2A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, USA; 3Health Sciences & Technology, Harvard-MIT, Cambridge, MA, USA

The construction of a parallel phased array MR brain coil that is compatible with the state of the art simultaneous MR-PET Brain scanners requires unique material and design specifications. In this study, we evaluate the design criteria of a 32-channel MR-PET coil (including conductor materials, cable thicknesses and component placements with experiment and simulation) to improve SNR and parallel imaging of MR while minimizing the interference with 511 keV γ-ray detection from the PET camera.

Diffusion Acquisition & Pulse Sequences

Room 710A                        16:30-18:30                                         Moderators: Roland Bammer & Claudia A. Wheeler-Kingshott

16:30         170.       Preventing Signal Dropouts in DWI using Continous Prospective Motion Correction

Michael Herbst1, Julian Maclaren1, Matthias Weigel1, Jan Gerrit Korvink2,3, Maxim Zaitsev1

1Medical Physics, University Medical Center Freiburg, Freiburg, Germany; 2Dept. of Microsystems Engineering - IMTEK, University of Freiburg, Freiburg, Germany; 3Freiburg Institute of Advanced Studies (FRIAS), University of Freiburg, Germany

Diffusion weighted imaging (DWI) has become indispensable in clinical routine, especially due to its sensitivity to early stages of brain ischemia. Patient motion during measurements is a major source of artifacts. There are different approaches to correct for rigid body motion depending on the type of motion. However, intrascan motion remains problematic for all of these correction methods. Even for single-shot EPI intrascan motion can lead to severe signal dropouts. This work presents a method to continuously apply prospective motion correction to correct for intra- and interscan motion with six degrees of freedom.

16:42         171.       Benefits of Optical Prospective Motion Correction for Single-Shot DTI

Murat Aksoy1, Christoph Forman2, Daniel Kopeinigg1, Matus Straka1, Rafael O'Halloran1, Samantha Holdsworth1, Stefan Skare1,3, Roland Bammer1

1Radiology, Stanford University, Stanford, CA, USA; 2Computer Science, Friedrich-Alexander-University Erlangen-Nuremberg, Erlangen, Germany; 3Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden

Correction of motion is important in diffusion tensor imaging (DTI) due to long acquisition times and the increased likelihood of involuntary motion. Single-shot echo-planar imaging (sshEPI), which is the most frequently used sequence in DTI, allows retrospective motion correction that includes realigning individual diffusion-weighted volumes. However, this correction method is considerably flawed due to its inability to deal with intra-volume motion or spin history effects. In this study, we used a monovision-based optical tracking system to provide real-time motion correction capabilities for sshEPI-DTI. In-vivo results demonstrate that even for single-shot methods, prospective motion correction yields more accurate and precise FA maps and fiber tracts than retrospective motion correction.

16:54         172.       Prospective Correction of Spatially Non-Linear Phase Patterns for Diffusion-Weighted FSE Imaging using Tailored RF Excitation Pulses

Rita Gouveia Nunes1, 2, Shaihan J. Malik2, Joseph V. Hajnal2

1Institute of Biophysics & Biomedical Engineering, Faculty of Sciences, University of Lisbon, Lisbon, Portugal; 2Robert Steiner MRI Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, United Kingdom

Echo-planar imaging is widely used for diffusion-weighted imaging despite its high sensitivity to field in-homogeneities. Although single-shot fast spin-echo images do not have this limitation, the signal is highly sensitive to the phase of the magnetization prior to the start of the refocusing train (CPMG condition). Brain pulsation and bulk patient motion during diffusion sensitization lead to unpredictable phase patterns, while scanner vibrations produce reproducible non-linear phase modulations. A prospective method for correcting for spatially non-linear phase structures using tailored RF pulses is presented and shown to be effective in phantoms.

17:06         173.       Dynamic & Inherent B0 Correction for DTI using Stimulated Echo Spiral Imaging

Alexandru Vlad Avram1, 2, Trong-Kha Truong2, Arnaud Guidon1, 2, Chunlei Liu2, Allen W. Song2

1Biomedical Engineering Department, Duke University, Durham, NC, USA; 2Brain Imaging & Analysis Center, Duke University Medical Center, Durham, NC, USA

We present a novel stimulated echo (STE) based Diffusion Tensor Imaging (DTI) spiral sequence with inherent capability to correct for off-resonance effects (blurring) due to spatial and temporal variations in the main field B0 (e.g. due to tissue susceptibility, eddy currents, system instabilities, etc). Combined with the self-navigated interleaved spiral acquisition (SNAILS) this technique provides dynamic and non-linear corrections for phase errors (e.g. due to motion) and off-resonance effects, which may find broad applications in diffusion weighted MRI where both of these artifacts are significant.

17:18         174.       Diffusion-Weighted Inner-Field-of-View EPI using 2D-Selective RF Excitations with a Tilted Excitation Plane

Jürgen Finsterbusch1,2

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

Inner-field-of-view EPI based on 2D-selective RF excitations (2DRF) has been shown to be a promising tool for high-resolution diffusion-weighted imaging, e.g. in the spinal cord. In this study, it is shown that tilting the excitation plane to position the side excitations in the dead corner between the slice stack to acquire and the current image section represents a simple and robust method to suppress the unwanted signal contributions. This approach can reduce the 2DRF pulse durations and the echo time considerably and, thus, increase the SNR significantly as is demonstrated in the human spinal cord in vivo.

17:30         175.       3D Submillimeter-Resolution Reduced-Field-of-View Diffusion Tensor Imaging

Anh Tu Van1, Joseph Holtrop2, Bradley P. Sutton2

1Electrical & Computer Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA; 2Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA

The complicated structure of many neuronal regions places an ever-increasing demand on the imaging resolution. By combining 3D encoding with multiecho acquisition on a localized region of interest, the current work targets diffusion tensor imaging with 0.8 x 0.8 x 1 mm3 resolution. Penalized iterative reconstruction is also proposed for minimizing the effects of imperfect realization of localized imaging. In vivo results are shown on the human pons.

17:42         176.       A New Spectro-Spatial RF Pulse Design for High-Resolution Isotropic Diffusion Imaging

Sangwoo Lee1, Gaohong Wu1

1GE Healthcare, Waukesha, WI, USA

Spectro-spatial RF pulses (SPSP RF pulses) for clinical 2D imaging have been widely used for B1-insensitive excitation with excellent lipid suppression compared to the conventional fat saturation methods [1,2]. However, at 3T, pulse design is challenging due to the reduced sub-pulse width, and often results in compromise in the minimum slice thickness and poor slice excitation profile. In this work, we introduce a new spectral-spatial design scheme which allows very thin slice excitation with superior slice profile for single spin echo diffusion imaging.

17:54         177.       Diffusion Weighted vGRASE (DW-vGRASE)

Mathias Engström1, Roland Bammer2, Stefan Skare1

1Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden; 2Radiological Sciences Laboratory, Stanford University, Palo Alto, CA, USA

A Stejskal-Tanner diffusion preparation with a GRAPPA-accelerated vGRASE acquisition is proposed. Compared to conventional ss-EPI, vGRASE is less sensitive to off-resonance effects despite being a single-shot technique and hence also robust to motion. With sequence modifications and phase correction techniques we adress problems induced by the diffusion gradients.

18:06         178.       Bipolar Diffusion Encoding with Implicit Spoiling of Undesired Coherence Pathways

Thorsten Feiweier1

1Siemens AG, Healthcare Sector, Erlangen, Germany

High-resolution DTI requires both high SNR and precise spatial alignment of images acquired with different diffusion encodings. While the bipolar (twice refocused) diffusion-encoding scheme effectively reduces eddy-current-induced distortions as compared to the monopolar Stejskal-Tanner approach, it involves increased TE due to the need for additional spoiler gradients. A new bipolar diffusion-encoding variant is discussed here, omitting the need for explicit spoiling. This approach allows for a markedly reduced TE and correspondingly increased SNR with negligible impact on eddy current suppression efficiency.

18:18         179.       X-PROP: A Fast & Robust Diffusion-Weighted PROPELLER Technique

Zhiqiang Li1, James G. Pipe2, Chu-Yu Lee2,3, Josef P. Debbins2,3, John P. Karis4, Donglai Huo1,2

1MR Engineering, GE Healthcare, Waukesha, WI, USA; 2Neuroimaging Research, Barrow Neurological Institute, Phoenix, AZ, USA; 3Electrical Engineering, Arizona State University, Tempe, AZ, USA; 4Radiology, Barrow Neurological Institute, Phoenix, AZ, USA

DW-PROPELLER techniques have the advantages such as no susceptibility artifacts and the capability for high-resolution imaging. In TurboPROP, gradient and spin echoes are grouped together to form a wider blade, providing robustness to motion but leading to off-resonance artifact. A variant of split-blade TurboPROP was proposed by separating the gradient and spin echoes into individual blades. However, the robustness to motion is lost due to the smaller overlapping area in the center of k-space. To address this issue, X-PROP is proposed by spreading the blades from one TR uniformly in k-space and removing the motion-induced phase error.

Human Brain Tumors: Advances in Diagnosis & Prognosis

Room 710B                        16:30-18:30                                                             Moderators: Sarah J. Nelson & A. Gregory Sorensen

16:30         180.       Feature Analysis in SVM-Based Classification of Gliomas

Frank G. Zoellner1, Kyrre E. Emblem2,3, Lothar R. Schad1

1Computer Assisted Clinical Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany; 2Department of Radiology, MGH-HST A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital & Harvard Medical School, Boston, MA, USA; 3The Interventional Center, Oslo University Hospital, Oslo, Norway

DSC-MRI is a method of choice to differentiate high-grade from low-grade gliomas. Recently, support vector machine (SVM) learning have been introduced as means to prospectively characterize gliomas based on the rCBV histograms. In our study, we have assessed the diagnostic accuracy of the different histogram features used in the SVM analysis (peak height, skewness, etc). By using correlation analysis to reduce 95% of the feature information, a classification accuracy of 88.1% was yielded. Our results suggest that a careful examination of the features in SVM based glioma grading could reduce the number of features substantially, thereby improving the effectiveness of the SVM analysis while maintaining a good classification score.

16:42         181.       In Vivo Detection of IDH Mutations in Gliomas by 1H-MRS

Changho Choi1, Sandeep Ganji1, Ralph De Berardinis1, Zoltan Kovacs1, Robert Bachoo1, Juan Pascual1, Ivan Dimitrov1,2, Bruce Mickey1, Craig Malloy1,3, Elizabeth Maher1

1University of Texas Southwestern Medical Center, Dallas, TX, USA; 2Philips Medical Systems; 3VA North Texas Health Care System

Recent studies indicate that a high fraction of gliomas contain mutations in the metabolic enzymes, isocitrate dehydrogenase-1 and -2, IDH1 and IDH2. As a result, 2-hydroxyglutarate (2HG), which is normally present in vanishingly small quantities, can be elevated by orders of magnitude in gliomas bearing IDH1 or IDH2 mutations. Here, we report for the first time in vivo detection of this oncometabolite in human brain tumors by 1H-MRS at 3T. 2HG was detected with CRLB < 20% in 38 spectra out of 122 spectra from 49 tumor patients (29 GBM, 9 anaplastic astrocytoma, and 11 low-grade glioma), the concentrations being 2 - 8 mM.

16:54         182.       Metabolic Characterization of Glioma Populations with Emphasis on Onco-Metabolite 2-Hydroxyglutarate

Adam Elkhaled1, Llewellyn Jalbert1, Hikari Yoshihara1, Gabriella Bourne1, Joanna Phillips2, Soonmee Cha1, Susan M. Chang3, Radhika Srinivasan1, Sarah J. Nelson1,4

1Department of Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; 2Department of Pathology, University of California, San Francisco; 3Department of Neurological Surgery, University of California, San Francisco; 4Department of Bioengineering & Therapeutic Sciences, University of California, San Francisco

Low grade gliomas with mutations in the  isocitrate dehydrogenase-1 (IDH1) gene carry a significant survival advantage, and have recently been shown to manifest excessive production of 2-hydroxyglutarate (2HG). Given the potential prognostic value of 2HG as an onco-metabolite, we sought to characterize differences in metabolite levels between gliomas of distinct origin and grade using 

proton high-resolution magic-angle-spinning (1H HR-MAS) spectroscopy. Results indicated that:  grade 2 glioma positive for 2HG possess a distinctive metabolic profile; 2HG presence can distinguish between primary and secondary GBM; and transformation to a higher grade can be characterized metabolically

17:06         183.       Presence of 2-Hydroxyglutarate in IDH1 Mutated Low-Grade Glioma using Ex Vivo Proton HR-MAS Spectroscopy

Llewellyn Jalbert1, Adam Elkhaled1, Joanna Phillips2, Hikari Yoshihara1, Radhika Srinivasan1, Gabriela Bourne1, Susan Chang3, Soonmee Cha1, Sarah Nelson1, 4

1Department of Radiology & Biomedical Imaging, University of California - San Francisco, San Francisco, CA, USA; 2Department of Pathology, University of California - San Francisco; 3Department of Neurological Surgery, University of California - San Francisco; 4Department of Bioengineering & Therapeutic Sciences, University of California - San Francisco

Significant survival advantage is conferred to glioma patients harboring mutations in isocitrate dehydrogenase 1 and 2 (IDH1/2), resulting in the excessive production of the onco-metabolite 2-hydroxyglutarate (2HG).  We aimed to determine whether 2HG could be detected in recurrent low-grade glioma samples using proton High-resolution Magic Angle Spinning (1H HR-MAS) spectroscopy, and to correlate the results with IDH1 mutation status assessed by immunohistochemistry.  We have confirmed 2HG presence by 1D and 2D 1H HR-MAS in concordance with IDH1 status; its presence gives rise to a complicated spectral pattern that may be of significant clinical utility as a novel biomarker in glioma.

17:18         184.       Detection of 2-Hydroxyglutarate in Mutant Brain Tumors In Vivo using Proton Magnetic Resonance Spectroscopy

Rajakumar Nagarajan1, Michael Albert Thomas1, Whitney B. Pope1, Robert M. Prins2, Neil Wilson1, Noriko Salamon1, Linda M. Liau2

1Radiological Sciences, University of California Los Angeles, Los Angeles, CA, USA; 2Neurosurgery, University of California Los Angeles

The mutation observed in the isocitrate dehydrogenase1 (IDH1) gene, which occurs in the majority of grade II and grade III gliomas and secondary glioblastomas shows significant elevation of 2-hydroxyglutarate (2HG) in the brain tumors. We have quantified 2HG in the brain tumor patients using proton (1H) MR spectra recorded on a 3T MRI/MRS scanner and post-processed by LC-model algorithm. In this study, we show increased 2HG in the mutant type compared to wild type tumors. 1H MRS enables a non-invasive measure of 2HG in gliomas, which may serve as a potential biomarker for monitoring patients with IDH1 mutant brain tumors.

17:30         185.       Segmentation of Combinations of Mean Diffusivity & DCE Perfusion Derived CBV in Glioblastoma Multiforme

Rishi Awasthi1, Ram Kishan Singh Rathore2, Jitesh Kumar Singh2, Nuzhat Husain3, Priyanka Soni3, Rohit Kumar Singh4, Sanjay Behari4, Rakesh Kumar Gupta1, Shaleen Kumar5

1Radiodiagnosis, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India, Lucknow, Uttar Pradesh, India; 2Mathematics & Statistics, Indian Institute of Technology, Kanpur, Kanpur, Uttar Pradesh, India; 3Pathology, Chatrapati Sahu ji Maharaj Medical University, Lucknow, Uttar Pradesh, India; 4Neurosurgery, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India, Lucknow, Uttar Pradesh, India; 5Radiotherapy, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, India, Lucknow, India

Forty-four untreated patients with a definitive histopathological diagnosis of glioblastoma multiforme were imaged using conventional, DT and DCE MRI. It was possible to segment the tumor tissue by using DCE derived CBV maps and DTI derived MD maps. From these segmented regions, four combinations of CBV and MD values were obtained which represents different tumoral components also evident on immunohistochemistry. We conclude that the combination of DTI and DCE-MRI allows segmentation which classifies different tissue types within the tumor which in turn may prove to be valuable in targeted therapy in future

17:42         186.       Evaluation of Relative CMRO2 from BOLD & CBF Changes in Hyperoxia:  Significant Increase of Oxygen Consumption rate in Glioblastoma
Heisoog Kim1,2, Ciprian Catana1, Kim Mouridsen1, Div Bolar1, Elizabeth R. Gerstner3, Tracy T. Batchelor3, Rakesh K. Jain4, Bruce R. Rosen1,2, A. Gregory Sorensen
1Radiology, A. A. Martinos Center, Charlestown, MA, USA; 2HST/NSE, Massachusetts Institute of Technology, Cambridge, MA, USA; 3Neurology, Massachusetts General Hospital, Boston, MA, USA; 4Radiation Oncology, Massachusetts General Hospital, Boston, MA, USA

 

17:54         187.       A Simultaneous Measurement of Relative CMRO2 with MRI & FMISO Uptake with PET in Glioblastoma

Heisoog Kim1, Ciprian Catana1, Grae Arabasz1, Div Bolar1, Elizabeth R. Gerstner2, Tracy T. Batchelor2, Rakesh K. Jain3, Bruce R. Rosen1, A. Gregory Sorensen1

Cerebral metabolic rate of oxygen (CMRO2) is one of the characteristics utilized to investigate metabolic changes in tumor oxygenation under different baseline physiologies. Based on simultaneous BOLD-ASL measurements, relative CMRO2 in hyperoxia in glioblastoma (GBM) were quantitatively evaluated. Elevated BOLD and reduced CBF signal changes during 100% oxygen breathing were observed in glioblastoma. Our data validated the coupling between BOLD and CBF in Davis’ model in GBM patients. Remarkably, oxygen-induced relative CMRO2 estimated from these measurements showed a significant increase (44%) in tumor and peritumoral regions. It implies that hyperbaric oxygen administration manipulates the oxygenation metabolism in cancer cells.

1Radiology, A. A. Martinos Center, Charlestown, MA, USA; 2Neurology, Massachusetts General Hospital, Boston, MA, USA; 3Radiation Oncology, Massachusetts General Hospital, Boston, MA, USA

18:06         188.       Multicentre Prospective Classification of Childhood Brain Tumours Based on Metabolite Profiles Derived from 1H MRS

Nigel Paul Davies1,2, Simrandip Gill2,3, Theodoros N. Arvanitis3,4, Dorothee Auer5, Richard Grundy6,7, Franklyn A. Howe8, Darren Hargrave9, Tim Jaspan7, Lesley MacPherson3, Kal Natarajan1,3, Geoffrey Payne9,10, Dawn Saunders11, Yu Sun2,3, Martin Wilson2,3, Andrew C. Peet2,3

1Medical Physics, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom; 2Cancer Sciences, University of Birmingham, Birmingham, United Kingdom; 3Birmingham Children's Hospital NHS Foundation Trust, Birmingham, United Kingdom; 4Department of Electrical, Electronic & Computer Engineering, University of Birmingham, Birmingham, United Kingdom; 5Academic Radiology, University of Nottingham, Nottingham, United Kingdom; 6Children's Brain Tumour Research Centre, University of Nottingham, Nottingham, United Kingdom; 7University Hospital Nottingham, Nottingham, United Kingdom; 8St. George's University of London, London, United Kingdom; 9Royal Marsden Hospital, London, United Kingdom; 10Institute of Cancer Research, London, United Kingdom; 11Great Ormond Street Hospital, London, England, United Kingdom

1H MRS provides non-invasive metabolite profiles of brain tumours aiding diagnosis and potentially improving characterisation. In this study we perform a large prospective multicentre evaluation of 1H MRS as a diagnostic tool for grading childhood brain tumours. The classifier was trained on metabolite profiles derived using TARQUIN from 123 single-voxel MRS acquired using a standard protocol on two 1.5T scanners in a single centre. Testing was performed using 110 cases acquired prospectively across 4 different centres with some variations in echo time and field strength. The overall classification accuracy for identifying high grade versus low grade tumours was 86%.

18:18         189.       Segmentation of Tumor Infiltrative & Vasogenic Edema in Brain Tumors using Voxel-Wise Analysis of 11C-Methinonine & FDG PET & its Comparison with Diffusion Tensor Imaging

Manabu Kinoshita1, Testu Goto1, Hideyuki Arita1, Naoki Kagawa1, Yasunori Fujimoto1, Haruhiko Kishima1, Yoichi Saitoh2, Jun Hatazawa3, Naoya Hashimoto1, Toshiki Yoshimine1

1Neurosurgery, Osaka University Graduate School of Medicine, Suita, Osaka, Japan; 2Neuromodulation & Neurosurgery, Center for Advanced Science & Innovation, Osaka University, Suita, Osaka, Japan; 3Nuclear Medicine & Tracer Kinetics, Osaka University Graduate School of Medicine, Suita, Osaka, Japan

Use of DTI has been proposed for the detection of glioma cell invasion. However, other reports have questioned its value. We have been able to segment areas with and without tumor cell invasion in the T2-high intensity area in malignant gliomas using a voxel-wise analysis of 11C-methionine and FDG PET. We also showed the profile of FA and ADC does not differ between these two. Our results suggest the possibility of using voxel-wise analysis of 11C-methionine and FDG PET for tumor cell invasion in the T2-high intensity area in glioma patients and questioning the use of DTI for this purpose.

Study Groups
Dynamic NMR Spectroscopy

Room 510                           18:45-20:45                                                                                                                                                            

Study Groups
Hyperpolarized Media MR

Room 511A-C                   18:45-20:45                                                                                                                                                            

Study Groups
MR Safety

Room 511D-F                    18:45-20:45                                                                                                                                                            

Study Groups
White Matter

Room 512A-G                   18:45-20:45                                                                                                                                                            

Study Groups
Susceptibility Weighted Imaging

Room 513A-D                   18:45-20:45                                                                                                                                                            

Study Groups
Current Issues in Brain Function

Room 516A-C                   18:45-20:45                                                                                                                                                            

Study Groups
Interventional MR

Room 518A-C                   18:45-20:45                                                                                                                                                            

Study Groups
Motion Correction

Room 520 B-F                   18:45-20:45                                                                                                                                                            

Study Groups
Diffusion

Room 710A                        18:45-20:45                                                                                                                                                            

Study Groups
MR Engineering

Room 710B                        18:45-20:45                                                                                                                                                            

Tuesday, May 10, 2011

Clinical Intensive Course
Sunrise Educational Course
Hot Topics in Body MRI 

Room 510                           07:00-08:00                                                                            Moderators: Dow-Mu Koh & Bachir Taouli  

Diffusion Imaging: Body Applications

07:00                       Diffusion Imaging: Physics Applied to Body Applications

Thomas L. Chenevert

07:20                       Liver Lesions: Added Value of Diffusion MRI

Elizabeth M.  Hecht

07:40                       Renal Lesions: Added Value of Diffusion MRI

Hersh Chandarana

Clinical Intensive Course
Sunrise Educational Course
Neuro MRI from Start to Finish

Room 516A-C                   07:00-08:00                                                                                                                                                            

Fetal

07:00                       Conventional MRI

Orit Glenn

07:30                       Non-Conventional MRI

Patricia Ellen Grant

Sunrise Educational Course
Image Analysis

Room 511A-C                   07:00-08:00                                                                                                   Moderator: Simon K. Warfield  

07:00                       Segmentation: Theory
Marleen de Bruijne

07:30                       Segmentation: Practice

Paul A. Yushkevich

Sunrise Educational Course
Translational Imaging: Animal Models in MSK

Room 511D-F                    07:00-08:00                                                                                              Moderator: Bernard J. Dardzinski  

07:00                       Choosing the Best Animal Model

Lisa A. Fortier

07:30                       Live Animal Imaging: Challenges & Longitudinal Analysis

Richard P. Kennan

Sunrise Educational Course
Fast & Furious: The New Era of Rapid Imaging

Room 512A-G                   07:00-08:00                                                                                                                                                            

Fast Cardiovascular Imaging

07:00                       Current Clinical Practices & Needs

Frandics P. Chan

07:30                       Emerging Techniques

Jeffrey Tsao

Sunrise Educational Course
Molecular Imaging & Contrast Agents

Room 513A-D                   07:00-08:00                                                                                                                                                            

07:00                       Conventional Contrast Agents

Val M. Runge

07:30                       Physico Chemical Principles & Applications of Fluorine

Peter M. Jakob

Sunrise Educational Course
Cardiovascular MR Imaging: Bridging the Gap Between Research & Clinical Problems

Room 518A-C                   07:00-08:00                                                                                                                                                            

Stress MRI for Evaluation of CAD

07:00                       Types of Stress MR Imaging

Juerg Schwitter

07:20                       Acquisition Issues

Peter Kellman

07:40                       Postprocessing Issues

Michael Jerosch-Herold

Sunrise Educational Course
MRS - Metabolite Profiling & Metabolism

Room 520B-F                    07:00-08:00                                                                            Moderators: Kevin M. Brindle & Ivan Tkac  

07:00                       Requirements for Reliable Metabolite Profiling

Ivan Tkac

07:30                       Strategies for Probing Metabolism

Robin A. de Graaf

Sunrise Educational Course
Image Reconstruction

Room 710A                        07:00-08:00                                                                                                                                                            

Non-Cartesian Trajectories & Off-Resonance Correction

07:00                       Fast Image Reconstruction from Non-Cartesian Data

Craig H. Meyer

07:30                       Off-Resonance Effects & Correction

Bradley P. Sutton

Sunrise Educational Course
Absolute Beginners' Guide to Anatomical & Functional MRI of the Brain

Room 710B                        07:00-08:00                                                                                              Moderator: Thomas M. Talavage  

07:00                       Functional MRI

Christina Triantafyllou

07:30                       Functional MRI Analysis

Robert W. Cox

Plenary Lectures
Diagnosis & Triage of Acute Coronary Syndromes in the Emergency Room

Plenary Hall                        08:15-09:30                                                                 Organizers: David E. Sosnovik & Matthias Stuber

08:15         190.       Diagnosis of Acute Coronary Syndromes: Scope of the Problem

Warren J. Manning

Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA

 

Acute coronary syndrome (ACS) encompasses a heterogeneous subpopulation of patients presenting with non-traumatic chest pain.  ACS includes the clinical syndromes of STEMI, NSTEMI, and unstable angina.  Despite a careful history, physical examination, and conventional testing with biomarkers, many patients without ACS are unnecessarily admitted to the hospital, while others with ACS are sometimes discharged from the ED to experience high morbidity and mortality. For low and moderate risk ACS patients with inconclusive testing, cardiac imaging often plays a valuable role in the identification of those with ACS and safe discharge for those with non-life threatening conditions

08:25         191.       Cardiac CT: The Imaging Technique of Choice?

Udo Hoffmann

Massachusetts General Hosptial, Boston, MA, USA

 

Cardiac CT provides new insights into cardiac and coronary morphology and function and may be an efficient triage tool for patients presenting with acute chest pain to the Emergency Department.

08:40         192.       Cardiac MRI in the Emergency Room

Andrew E. Arai

National Institutes of Health/NHLBI, Bethesda, MD, USA

 

The diagnosis and triage of acute coronary syndrome (ACS) in the emergency room (ER) is a complex and expensive medical problem that can benefit from incorporation of imaging into clinical practice guidelines and treatment algorithms.  Cardiac MRI can assess many parameters important in the diagnosis and risk stratification of patients with possible ACS. More importantly, several clinical trials have shown that cardiac MRI is feasible, diagnostically accurate, complimentary to conventional clinical tools, and even cost effective in the emergency room setting.

09:05         193.       Faster & Better: Emerging tools for Cardiovascular MRI in the Emergency Room

Orlando P. Simonetti

Ohio State University, Columbus, OH, USA

 

Cardiovascular MRI technology continues to evolve in terms of its ability to rapidly and reliably produce accurate, functional, diagnostic information, and also in its capacity to provide quantitative results.  A number of centers are beginning to explore the use of MRI as a means to triage patients presenting in the emergency room with acute chest pain.  This presentation will explore the latest advances in cardiovascular MRI methods that are especially applicable to the diagnosis of Acute Coronary Syndrome (ACS).

Cardiovascular MRI technology continues to evolve in terms of its ability to rapidly and reliably produce accurate, functional, diagnostic information, and also in its capacity to provide quantitative results.  a number of centers are beginning to explore the use of MRI as a means to triage patients presenting in the emergency room with acute chest pain.  This presentation will explore the latest advances in cardiovascular MRI methods that are especially applicable to the diagnosis of Acute Coronary Syndrome (ACS).

Clinical Intensive Course
(Admission limited to Clinical Course registrants only)
Cortical Cartography: Case-Based Teaching

Room 510                           08:15-09:30                                                                                                   Moderator: Jeffrey Joseph Neil  

08:15                       Development

Petra S. Hüppi

08:45                       Disease

David van Essen

09:15                       Discussion & Meet the Teachers

Clinical Intensive Course
(Admission limited to Clinical Course registrants only)
Liver MRI: How I Do It

Room 516A-C                   08:15-10:15                                                                                                   Moderator: Shahid M. Hussain  

08:15                       Liver MRI: Protocol Optimization

Donald G. Mitchell

08:45                       Contrast Media for Liver MRI: Which One to Choose?

Scott B. Reeder

09:15                       MRI of Focal Liver Lesions: A Step-by-Step Approach

Claude B. Sirlin

09:45                       MRI of Diffuse Liver Disorders

 

Hero K. Hussain

Clinical Intensive Course
MRI of Elbow, Wrist & Hand

Room 510                           10:30-12:30                                                                                                  Moderator: Lynne S. Steinbach  

10:30                       Elbow Tendons

Christine Chung

11:10                       Wrist

Laura W. Bancroft

11:50                       Hand

Ronald C. Shnier

Clinical Intensive Course
MRI in Drug Abuse

Room 512A-G                   10:30-12:30                                                                                                                                                            

10:30                       Drug Exposure in Utero

Claire D. Coles

11:10                       Anatomical & Functional MRI of Cocaine & Nicotine Addiction

Elliot A. Stein

11:50                       MRI of Ecstasy Addiction

Ronald L. Cowan

Clinical Intensive Course
Artifacts in Body MRI: Case-Based Teaching

Room 516A-C                   10:30-12:30                                                           Moderators: Shahid M. Hussain & Caroline Reinhold  

10:30                       Diffusion-Weighted Imaging: Artifacts & Remedies in Body MRI

Thomas G. Perkins

11:00                       Artifacts in Clinical Practice: Physicist's Perspective

Martin J. Graves

11:45                       Artifacts & Pitfalls: Radiologist's Perspective

Donald G. Mitchell

Interventional MRI: Technical Developments & Clinical Applications

Room 511A-C                   10:30-12:30                                                     Moderators: Claudia M. Hillenbrand & Harald H. Quick

10:30         194.       Assessment & Completion of RF Ablation for the Treatment of Atrial Fibrillation using Real-Time MRI Guidance

Sathya Vijayakumar1,2, Eugene G. Kholmovski1,2, Ravi Ranjan2,3, Gaston Vergara2,3, Joshua Blauer2,4, Gene Payne1,2, Nelly Volland1,2, Kamal Vij5, Gregory Gardner2,4, Peter Piferi5, Kimberly Johnson2,3, Li Pan6, Klaus Kirchberg6, Rob MacLeod2,4, Christopher J. McGann2,3, Nassir F. Marrouche2,3

1UCAIR, Department of Radiology, University of Utah, Salt Lake City, UT, USA; 2CARMA Center, University of Utah, Salt Lake City, UT, USA; 3Department of Cardiology, University of Utah, Salt Lake City, UT, USA; 4SCI,, University of Utah, Salt Lake City, UT, USA; 5SurgiVision Inc., Irvine, CA, USA; 6Center for Applied Medical Imaging, Siemens Corporate Research, Princeton, NJ

In this work, we study the feasibility of an EP-MRI workflow for RF ablation procedures for the treatment of atrial fibrillation. This approach consists of the assessment of ablation performed in the EP-suite using MRI, and completing the ablation procedure in the MRI-suite if necessary using real time MRI guidance. This work flow may possibly reduce the number of repeat ablation procedures.

10:42         195.       An Integrated System for Catheter Tracking & Visualization in MR-Guided Cardiovascular Interventions

Li Pan1, Julien Barbot2, Steven M. Shea1, Sunil Patil1, Klaus J. Kirchberg2, Glenn Meredith2, Tongbai Meng1, Eugene G. Kholmovski3,4, Sathya Vijayakumar3,4, Kamal Vij5, Mike Guttman5, Peter G. Piferi5, Kimble L. Jenkins5, Christine H. Lorenz1

1Center for Applied Medical Imaging, Siemens Corporate Research, Baltimore, MD, USA; 2Center for Applied Medical Imaging, Siemens Corporate Research, Princeton, NJ, USA; 3UCAIR, Department of Radiology, University of Utah, Salt Lake City, UT, USA; 4CARMA Center, University of Utah, Salt Lake City, UT, USA; 5SurgiVision, Inc., Irvine, CA, USA

In this work, we present an integrated system that incorporates active device tracking implemented in an interactive real-time sequence as well as a graphical interface for real-time catheter visualization and navigation.  The system supports tracking and visualization of multiple catheters and several options for automatically updating imaging planes. The tracking provided robust catheter location accuracy, and the visualization of the catheters provided the users with an environment similar as with X-ray fluoroscopy guided procedures.  The system is especially suitable for MR guided intravascular interventions in which real-time catheter tracking and visualization for navigation is mandatory.

10:54         196.       Prospective High Resolution Respiratory Resolved Whole-Heart MRI for Image-Guided Cardiovascular Interventions

Christoph Kolbitsch1, Claudia Prieto1, Christian Buerger1, Reza Razavi1, Jouke Smink2, Tobias Schaeffter1

1Division of Imaging Sciences & Biomedical Engineering, King's College London, London, United Kingdom; 2Philips Healthcare, Best, Netherlands

Image-guided catheterisations are an important clinical tool for cardiovascular diseases. In order to increase the accuracy of the procedure with an additional MRI roadmap, a 3D high resolution scan and additional respiratory information are required. Here we present a method that records all the necessary information during a single whole-heart scan with a prospective respiratory resolved acquisition scheme. Moreover, an affine model to describe the breathing motion can be obtained from the same acquired data. Validation on volunteer data yielded a maximum target registration error of less than 3.4mm.

11:06         197.       Evaluation of a Novel MR-RF Ablation Catheter with Full Clinical Functionality

Steffen Weiss1, Bernd David1, Kai-Michael Luedeke1, Oliver Lips1, Daniel Wirtz1, Sascha Krueger1, Peter Koken1, Ronald Holthuizen2, Tobias Schaeffter3, Jas Gill3, Reza Razavi3

1Philips Research Laboratories, Hamburg, Germany; 2Philips Healthcare, Best, Netherlands; 3Division of Imaging Sciences, King's College, London, United Kingdom

Earlier work on an MR-RF ablation catheter has been complemented by adding a sensor to measure the temperature of the ablation electrode as in standard catheters but here connected via highly resistive wires. This provides much increased RF safety and compatibility with clinical RF generators. All wiring in the final prototype either dampens RF resonances by high resistance or avoids RF resonances by segmentation of long cables into short sections using transformers and switches. RF safety of the catheter is demonstrated by RF heating measurements, and all EP functions of the catheter are evaluated by various measurements including MR-guided ablation procedures.

11:18         198.       MRI-Guided Sclerotherapy of Veno-Lymphatic Vascular Malformations:  Evaluation of Procedure Safety & Long-term Efficacy

Sherif G. Nour1, Daniel P. Hsu2, Jamal J. Derakhshan3, Jonathan S. Lewin4

1Radiology, Emory University Hospital, Atlanta, GA, USA; 2Radiology, Case Medical Center, Cleveland, OH; 3Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA; 4Radiology, Johns Hopkins School of Medicine, Baltimore, MA, USA

Veno-lymphatic (slow-flow) vascular malformations typically present in children and young adults with various combinations of pain, localized dysfunction, and disfigurement. They may also bleed or result in fatal coagulopathy. The treatment is often challenging with high recurrence after surgery or traditional x-ray fluoroscopy guided sclerotherapy. This work describes our experience with 46 sclerotherapy procedures performed exclusively within a high-field interventional MRI suite, highlights the necessary technical aspects, demonstrates the safety features related to MRI guidance as compared to traditional x-ray guidance, and reports the long-term efficacy of these procedures as observed on extended follow-up durations of up to 36.1 months. 

11:30         199.       Longitudinal High Resolution MRI to Evaluate a Novel Statin Loaded HDL Nanoparticle Therapy in Experimental Atherosclerosis.

Raphael Duivenvoorden1,2, Jun Tang1, David Izquierdo-Garcia3, David P. Cormode1, Eric S. G. Stroes2, Edward A. Fisher4, Zahi A. Fayad1,3, Willem J. M. Mulder1

1Translational & Molecular Imaging Institute, Mount Sinai School of Medicine, New York, NY, USA; 2Vascular Medicine, Academic Medical Center, Amsterdam, NH, Netherlands; 3Radiology, Mount Sinai School of Medicine, New York, NY, USA; 4Department of Medicine, Division of Cardiology, New York University School of Medicine, New York, NY, USA

We hypothesized that targeted statin delivery to atherosclerotic plaque with a reconstituted high density lipoprotein (rHDL) nanoparticle can inhibit plaque inflammation and development more potently than oral statin therapy or rHDL infusion. We divided 48 apoE-KO mice in 3 equal groups that were either treated with oral simvastatin, rHDL infusion or our rHDL like nanoparticle loaded with simvastatin for 12 weeks. We performed MRI and histology measurements to quantify aortic atherosclerosis. We found that targeted statin delivery to atherosclerotic plaque with rHDL like nanoparticles showed considerably more efficacy in the treatment of atherosclerosis than oral statin therapy or rHDL infusion.

11:42         200.       Quantitative Transcatheter Intraarterial Perfusion MRI to Predict Drug Delivery during Chemoembolization for Hepatocellular Carcinoma

Dingxin Wang1,2, Brian Jin3, Robert Lewandowski3, Robert Ryu3, Kent Sato3, Ann Ragin3, Laura Kulik4, Mary Mulcahy5,6, Frank Miller3, Riad Salem3,6, Andrew Larson3,6, Reed Omary3,6

1Siemens Medical Solutions USA, Inc., Minneapolis, MN, USA; 2Center for Magnetic Resonance Research, University of Minnesota, Minneapolis, MN, USA; 3Department of Radiology, Northwestern University, Chicago, IL, USA; 4Department of Hepatology, Northwestern University, Chicago, IL, USA; 5Department of Medicine, Northwestern University, Chicago, IL, USA; 6Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL, USA

This study accessed the utility of quantitative Transcatheter Intraarterial Perfusion (TRIP)-MRI for predicting chemotherapy-lipiodol delivery during transcatheter arterial chemoembolization (TACE). The volumes of drug distribution in the tumors and liver as well as the selectivity of chemotherapy emulsion delivery to the tumors obtained from pre-TACE TRIP-MRI highly correlated with corresponding parameters seen on CT scans after TACE. These findings suggest that quantitative TRIP-MRI may have the potential to provide important spatial biodistribution information of subsequent drug delivery during liver-directed transarterial locoregional therapies with same catheter positioning.

11:54         201.       Detection & Quantification of Holmium-166 Loaded Microspheres in Patients with Liver Metastases: Initial Experience within the Framework of a Phase I Study

Gerrit Hendrik van de Maat1, Mattijs Elschot2, Peter Roland Seevinck1, Hendrik de Leeuw1, H.W. de Jong3, M. L. Smits3, M. A. van den Bosch3, M. G. Lam3, B. A. Zonnenberg3, A. D. van het Schip3, J. Frank Nijsen3, Chris J. Bakker1

1Image Sciences Institute, University Medical Center, Utrecht, Netherlands; 2Department of Radiology & Nuclear Medicine, University Medical Center, Utrecht , Netherlands; 3Department of Radiology & Nuclear Medicine, University Medical Center, Utrecht, Netherlands

We report the first results of the detection and quantification of Holmium-166 loaded microspheres in patients with liver metastases that were treated within the framework of a clinical phase I study. HoMS concentration maps determined from T2* weighted data acquired using a multi gradient echo sequence show good correspondence with activity maps acquired with Single Photon Emission Computed Tomography (SPECT). The total amount of HoMS in the liver determined from the concentration maps was in good agreement with the total amount that was delivered to the liver. The HoMS were found to mainly accumulate at the tumor site.

12:06         202.       Clinically Usable Tool For Dynamic Scan-Plane Tracking For Real-Time MRI-Guided Needle Interventions in a High-Field-Open MRI System

Uta Wonneberger1, Sascha Krüger2, Daniel Wirtz2, Christoph Leussler2, Steffen Weiss2, Kerstin Jungnickel1, Matthias Ludewig1, Jürgen Bunke3, Jens Ricke1, Frank Fischbach1

1Klinik für Radiologie & Nuklearmedizin, Otto-von-Guericke-Universität Magdeburg, D-39120 Magdeburg, Germany; 2Imaging Systems & Intervention, Philips Research Europe, D-22335 Hamburg, Germany; 3Healthcare, Philips, D-22335 Hamburg, Germany

An actively tracked needle guidance tool, directly connected to the MR system, with respective MR system software modifications to allow for simple-to-use, fast and accurate scan plane controlling with inherent registration to the MRI coordinate system is presented for the use in clinical routine for needle interventions in freehand-technique with the physician practicing from inside the open MR-system. The hand-held device  is equipped with a guide bar to automatically align the needle path with the device and with a thumb switch to perform fast, immediate 90° scan plane rotations around the needle axis without actual rotation of the device while simultaneously toggling between the two viewports of the real-time interactive scanner user interface.

12:18         203.       Pass-Through Piston Driver for MR Elastography Assessment of Percutaneous Laser Ablation

David Arthur Woodrum1, Jun Chen1, Kevin J. Glaser1, Krzysztof Gorny1, Richard L. Ehman1

1Radiology, Mayo Clinic, Rochester, MN, USA

A critical part of the tumor ablation is intra-treatment monitoring to determine whether an adequate treatment is achieved.  Our hypothesis is MR elastography can be used to measure the changing stiffness of the ablation zone during and after the ablation. The purpose of this study is to demonstrate the feasibility of new acoustic path-thru driver at producing mechanical waves through a laser ablation applicator to the ablation zone.  In vivo studies in porcine liver demonstrate that these waves can be produced and measured within the porcine liver.  The stiffness at tip of laser applicator demonstrates increasing stiffness during the ablation.

Parallel Transmission in Three Dimensions

Room 511D-F                    10:30-12:30                                                          Moderators: Kawin Setsompop & V. Andrew Stenger

10:30         204.       Exploiting Phase Encoding Capabilities of Parallel Excitation for Improved Spatial Selectivity in Inner-Volume Imaging

Johannes Thomas Schneider1,2, Martin Haas3, Wolfgang Ruhm1, Juergen Hennig3, Peter Ullmann1

1Bruker BioSpin MRI GmbH, Ettlingen, Germany; 2Dept. of Radiology, Medical Physics, University Medical Center Freiburg , Freiburg, Germany; 3Dept. of Radiology, Medical Physics, University Medical Center Freiburg, Freiburg, Germany

In spatially-selective excitation (SSE) experiments with short repetition times, undesired transverse magnetization outside of specified target volumes, despite being excited with small tip-angles, may be strongly pronounced compared to magnetization generated with larger tip-angles inside the target volumes because of saturation effects and different steady states. This work proposes to apply phase modulation instead of amplitude modulation in SSE, i.e. global excitation with a homogenous tip-angle distribution while achieving spatial selectivity by generating excitation phases, which differ inside and outside the target volumes according to a certain encoding scheme. This approach yields improved selectivity and significant artifact reduction.

10:42         205.       3D Parallel Excitation Pulse Design using Interleaved Sparse Approximation & Local Optimization

William A. Grissom1, Chen Dong1, Laura Sacolick1, Mika W. Vogel1

1GE Global Research, Munich, Germany

Determining optimal phase encoding locations for three dimensional parallel excitation spokes pulses is a non-trivial problem. Current algorithms can be classified as either sparse approximation-based methods, or methods that locally optimize the encoding locations. The two approaches have complementary strengths and weaknesses: sparse approximation-based methods approach global optimality when the target excitation phase is fixed and time-dependent effects (such as off-resonance) are ignored, while local methods can be performed jointly with target phase optimization and can account for time-dependent effects, but are only locally optimal. We introduce a new algorithm similar which interleaves greedy sparse approximation-based phase encoding selection with local gradient and target phase optimization. The new method is demonstrated using multiband pulse designs.

10:54         206.       Application of Kt-Points to Human Brain Imaging At 7 Tesla

Martijn Anton Cloos1,2, Nicolas Boulant1, Guillaume Ferrand2, Michel Luong2, Christopher J. Wiggins1, Denis Le Bihan1, Alexis Amadon1

1LRMN, CEA, DSV, I2BM, NeuroSpin, Gif-Sur-Yvette, ile-de-France, France; 2CEA, DSM, IRFU, Gif-Sur-Yvette, ile-de-France, France

Transmit-SENSE gives the opportunity to implement short excitation pulses with good flip-angle homogeneity at high field.  Recently, a novel non-selective pulse design, referred to as kT-points, was presented which enables sub-millisecond pulses with excellent spatially uniform excitation properties over an extended volume. In this abstract, for the first time, application of this novel pulse design to human brain imaging at 7 Tesla is presented.

11:06         207.       Parallel Transmit using 3D Spokes RF Pulses for Improved B1+ Homogeneity over 3D Volumes

Mohammad Mehdi Khalighi1, Manojkumar Saranathan2, William Grissom3, Adam B. Kerr4, Ron Watkins2, Brian K. Rutt2

1Global Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA; 2Department of Radiology, Stanford University, Stanford, CA, USA; 3Imaging Technologies Lab, General Electric Global Research, Garching B. Munchen, Germany; 4Department of Electrical Engineering, Stanford University, Stanford, CA, USA

B1+ inhomogeneity is a major issue at high field. We introduce a 3D spokes RF pulse designed to improve volumetric B1+ homogeneity; this is achieved by adding z-axis phase encoding to the more conventional 2D spokes pulse design. We show that 2ch pTx using our new 3D spokes pulses improves B1+ uniformity over a complete slab even compared to 2D spokes pulses, and more substantially (factor of 2) compared to conventional quadrature excitation. We have tested experimentally this new 3D spokes pulse concept on a 2-ch pTx-enabled 7T scanner and show the B1+ homogeneity benefits in phantoms and volunteer brain.

11:18         208.       Parallel Transmission Design of Multi-Pulse Sequences using Spatially Resolved Extended Phase Graphs (SREPG)

Shaihan J. Malik1, Hanno Homann2, Peter Börnert3, Joseph V. Hajnal1

1Robert Steiner MRI Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, United Kingdom; 2Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany; 3Philips Research, Hamburg, Germany

The Extended Phase Graph (EPG) formalism is a powerful means for predicting MR signals in sequences involving multiple RF pulses. At high field (3T+) the RF fields (B1) vary strongly in space, so predictions by the EPG algorithm are not valid everywhere.  Parallel transmission enhances control of B1 enabling flip angle distributions to be modulated in both space and time.   The effect of changing fields in this way can be predicted with spatially resolved EPG (SREPG). We demonstrate that pulses may be independently optimised for fast spin echo using SREPG leading to solutions not achievable by RF shimming alone.

11:30         209.       Joint Optimization of Tip-Down & Tip-Up RF Pulses in Small-Tip (Non-Spin-Echo) Fast Recovery Imaging

Jon-Fredrik Nielsen1, Daehyun Yoon2, Neal Anthony Hollingsworth3, Katherine Lynn Moody4, Mary Preston McDougall3,4, Steven M. Wright3,4, Douglas C. Noll1

1Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA; 2Electrical Engineering & Computer Science, University of Michigan; 3Electrical & Computer Engineering, Texas A&M University; 4Biomedical Engineering, Texas A&M University

In “fast-recovery” (FR) or driven-equilibrium steady-state imaging, the magnetization is tipped back toward the longitudinal axis at the end of each repetition interval (TR), with the aim of maximizing the acquired signal. Conventional FR imaging requires one or more spin-echo refocusing pulses, and hence heavy RF deposition.  With the use of parallel RF transmission and 3D RF pulse design, it may be possible to replace the conventional spin-echo pulse train with a small-tip excitation pulse followed by a small-tip recovery (tip-up) pulse. We present a simple and effective approach for jointly optimizing the excitation and recovery pulses such that the residual (unwanted) transverse magnetization after the tip-up pulse is minimized.

11:42         210.       Parallel RF Pulse Design with Subject-Specific Global SAR Supervision

Cem Murat Deniz1,2, Leeor Alon2,3, Ryan Brown3, Hans-Peter Fautz4, Daniel K. Sodickson3, Yudong Zhu3

1Center for Biomedical Imaging , Department of Radiology, NYU School of Medicine, New York, NY, USA; 2Sackler Institute of Graduate Biomedical Sciences, NYU School of Medicine, New York, NY, USA; 3Center for Biomedical Imaging, Department of Radiology, NYU School of Medicine, New York, NY, USA; 4Siemens Medical Solutions, Erlangen, Germany

Specific absorption rate (SAR) management and excitation homogeneity are critical aspects of parallel radio frequency  (RF) transmission pulse design at ultra high magnetic field strength. The design of RF pulses for multiple channels is generally based on the solution of regularized least squares optimization problems, for which the regularization term is selected to control the integrated or peak pulse waveform amplitude. Unlike for single channel transmission systems, the SAR of parallel transmission systems is significantly influenced by interferences between the electric fields of the various transmit elements, which are not taken into account using conventional regularization terms. This work explores the effects upon SAR behavior of incorporating measurable electric field interactions into parallel transmission RF pulse design. The results of phantom experiments show that the global SAR during parallel transmission decreases when electric field interactions are incorporated in pulse design optimization.

11:54         211.       Parallel Spatially Selective Excitation using Nonlinear Non-Bijective PatLoc Encoding Fields: Experimental Realization & First Results

Johannes Thomas Schneider1,2, Martin Haas2, Stéphanie Ohrel1, Heinrich Lehr1, Wolfgang Ruhm1, Hans Post1, Jürgen Hennig2, Peter Ullmann1

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

The PatLoc technique uses non-linear, non-bijective magnetic fields in combination with RF receive sensitivity encoding for spatial encoding in MR image acquisition. Recently, a theoretical study based on simulations has demonstrated that the PatLoc benefits, such as locally increased spatial resolution, faster gradient switching and reduced peripheral nerve stimulation, can also be exploited for Parallel Spatially Selective Excitation (PEX). This work presents the first successful experimental realization of PEX based on PatLoc encoding fields and demonstrates that the ambiguities introduced into the excitation process by the non-bijectivity of these encoding fields can effectively be resolved by using parallel transmission techniques.

12:06         212.       Parallel Transmission with Spectral-Spatial Pulses for Susceptibility Artifact Correction

Cungeng Yang1, Weiran Deng1, Vijayanand Alagappan2, Lawrence L. Wald3, Victor Andrew Stenger1

1University of Hawaii, Honolulu, HI, USA; 2General Electric Medical Systems, Waukesha, WI, USA; 3Athinoula A. Martinos Center for Biomedical Imaging, Charlestown, MA, USA

Susceptibility induced signal loss is a major limitation in high field T2*-weighted MRI applications including BOLD fMRI. Spectral-spatial (SPSP) pulses have been shown to be very effective at reducing through-plane signal loss in axial slices using a single excitation. SPSP pulse design assumes a linear relationship between off-resonance frequency and through-plane susceptibility gradient Gs(f)=&#945;f. This approximation holds well in more superior slice locations, however, inferior slices can have several regions that require different &#945;’s. We propose the use of parallel excitation to apply unique SPSP pulses with each transmitter. The localization introduced by the transmission sensitivities compensates for the spatial distribution of the susceptibility gradients. The method is demonstrated in T2*-weighted human brain imaging at 3T with an eight-channel parallel transmission system.

12:18         213.       Through-Plane Signal Loss Recovery & B1 Inhomogeneity Reduction In Vivo at 7T using Parallel Transmission

Hai Zheng1, Tiejun Zhao2, Yongxian Qian3, Tamer Ibrahim1,3, Fernando Boada1,3

1Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA; 2Siemens Medical Solutions, Pittsburgh, PA, USA; 3Radiology, University of Pittsburgh, Pittsburgh, PA, USA

T2*-weighted functional MRI images at ultra high field (UHF, >3T) is severely affected by through-plane signal loss and B1 inhomogeneity in areas near air/tissue interfaces in the brain. In this study, we demonstrate a parallel transmission technique to simultaneously mitigate signal loss and B1 inhomogenetiy based on the concatenation of multi-slices main magnetic field and B1+ maps during RF pulse design. Our results demonstrate that the approach is a practical means for the reduction of signal loss during in vivo T2*-weighted functional MRI at 7T.

Myocardial Perfusion: Experimental Models & Human Studies

Room 513A-D                   10:30-12:30                                          Moderators: Rohan Dharmakumar & Michael Jerosch-Herold

10:30         214.       Adenosine-Induced Stress Myocardial Perfusion MRI using SW-CG-HYPR with Whole Left Ventricular Coverage: Comparison of Results with X-Ray Angiography in Patients with Suspected Coronary Artery Disease

Heng Ma1, Lan Ge2, Jing An3, David Chen2, Lixin Jin4, Xiaoming Bi5, Renate Jerecic4, Kuncheng Li1, Debiao Li2,6

1Xuanwu Hospital, Capital Medical University, Beijing, China, People's Republic of; 2Northwestern University; 3Siemens Healthcare, MR Collaboration NE Asia, Siemens Mindit Magnetic Resonance; 4Siemens Healthcare, MR Collaboration NE Asia, Siemens Limited China; 5Siemens Healthcare, Cardiovascular MR R&D, USA; 6Cedars-Sinai Medical Center & UCLA

Myocardial perfusion MRI with SW-CG-HYPR allows increased spatial coverage (whole left ventricular coverage), resolution, signal-to-noise ratio and reduced motion artifacts. The accuracy of this technique for detecting CAD has not been determined in a large number of patients. In this work, we have prospectively examined the diagnostic value of adenosine-induced stress myocardial perfusion MRI using SW-CG-HYPR in 50 patients with suspected CAD. Using the SW-CG-HYPR method, perfusion MRI was able to cover the whole left ventricle with an accuracy of 90% and 93% based on per-patient and per-vessel analyses, respectively, using X-ray coronary angiography as a reference standard.

10:42         215.       Cardiac ASL: Optimisation & Validation in the Mouse Heart

Adrienne E. Campbell1,2, Anthony N. Price3, Jack A. Wells1, Roger J. Ordidge2, Mark F. Lythgoe1

1Centre for Advanced Biomedical Imaging, Division of Medicine & Institute of Child Health, University College London, London, United Kingdom; 2Department of Medical Physics & Bioengineering, University College London, London, United Kingdom; 3Robert Steiner MRI Unit, Imaging Science Department, Hammersmith Hostpital, Imperial College London, London, United Kingdom

A time-efficient arterial spin labelling sequence was implemented to measure perfusion in the mouse heart. Data acquisition was improved using a data logger for additional cardiac gating and the generation of objective criteria for rejection of respiration corrupted images. A validation study was performed on 8 CD-1s to analyse the sources of variability in this technique, and to quantify the repeatability of this technique for group comparisons and for longitudinal studies. It was found that between animal variations were larger than technique variations and that achievable changes in perfusion were required for observation of group differences, beyond technique error.

10:54         216.       Quantitative MRI of the Myocardial Microcirculation in Mice using FAIR Look-Locker Arterial Spin Labeling & a Gamma-Variate Model of Blood Transit Time Distribution

Frederick H. Epstein1,2, Nivedita K. Naresh2, Patrick F. Antkowiak2, Moriel H. Vandsburger2, Xiao Chen2

1Radiology, University of Virginia, Charlottesville, VA, USA; 2Biomedical Engineering, University of Virginia, Charlottesville, VA, USA

Experimental therapies for ischemic heart disease are widely investigated in mouse and rat models.  For these investigations, a multi-parametric assessment of the microcirculation would be highly valuable.  We developed a kinetic analysis for arterial spin labeling (ASL) based on a gamma-variate blood transit model that enables the estimation of myocardial blood flow (MBF), myocardial blood volume (MBV), and mean transit time (MTT).  An initial experimental evaluation of this method was performed in mice.  Kinetic ASL with a gamma-variate-based model of the blood transit time distribution shows promise for quantifying multiple parameters of the microcirculation in the mouse heart.

11:06         217.       Detecting Myocardial Ischemia at Rest with Cardiac Phase-Resolved BOLD MRI: Early Findings

Sotirios Athanasios Tsaftaris1,2, Veronica Rundell2, Xiangzhi Zhou2, Ying Liu2, Richard Tang2, Debiao Li2, Rohan Dharmakumar2

1Electrical Engineering & Computer Science, Northwestern University, Evanston, IL, USA; 2Radiology, Northwestern University, Chicago, IL, USA

Vasodilatory stress has been used to probe myocardial oxygenation changes due to coronary artery stenosis on the basis of BOLD MRI. However, since vasodilation is typically achieved with provocative stress, approaches that can identify the presence of stenosis on the basis of microvascular alterations at rest are highly desirable. In this work, using controlled animals studies and theoretical simulations we demonstrate that cardiac phase-resolved BOLD MRI may be used to identify ischemic territories at rest.

11:18         218.       Methods for Quantification of Absolute Myocardial Oxygen Consumption with 17O-CMR

David Muccigrosso1, Xiang He2, Dana Abendschein1, Adil Bashir1, Pradeep Gupte3, Wei Chen4, Robert J. Gropler1, Jie Zheng1

1Washington University School of Medicine, St. Louis, MO, USA; 2University of Pittsburg; 3Rockland Technimed, Ltd.; 4University of Minnesota

A cardiac MR acquisition method and comprehensive model were developed to quantify regional absolute myocardial oxygen consumption using 17O-labeled perfluorocarbon compounds. Experiments were performed in normal and stenotic dogs to evaluate these methods. The calculated oxygen consumption rates agreed well with results in the literature. Mismatched areas between myocardial blood flow and oxygen deficit were observed in severely ischemic regions.

11:30         219.       Rapid CINE Myocardial T2* Mapping at 7T

Fabian Hezel1, Peter Kellman2, Christof Thalhammer1, Wolfgang Renz3, Thoralf Niendorf1,4

1Berlin Ultrahigh Field Facility, Max Delbrueck Center for Molecular Medicine, Berlin, Germany; 2Laboratory of Cardiac Energetics, National Institutes of Health/NHLBI, Bethesda, MD, USA; 3Siemens Medical Systems, Erlangen, Germany; 4Experimental & Clinical Research Center (ECRC), Charité Campus Buch, Humboldt-University, Berlin, Germany

Rapid CINE T2* Mapping of the heart has been demonstrated at 7T using a multi-echo gradient echo technique. Macroscopic B0 inhomogeneities have been reduced by high in-plane spatial resolution and volume selective shimming. Myocardial T2* was found to vary over myocardium and over the cardiac cycle.

11:42         220.       Pyruvate is Superior to Glucose in Supporting Metabolism of Machine Perfused Donor Hearts for Transplantation

Michael Cobert1, Matthias Peltz1, Matthew Merritt2, LaShondra West1, Michael E. Jessen1

1Cardiovascular & Thoracic Surgery, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA; 2Advanced Imaging Research Center, University of Texas Southwestern Medical Center at Dallas, Dallas, TX, USA

Machine perfusion preservation appears to be a useful strategy for donor heart preservation prior to transplantation. An exogenous substrate in the preservation solution may limit depletion of endogenous energy stores and further improve donor heart preservation. We compared carbon-13 labeled glucose and pyruvate as metabolic substrates for the stored heart using 1H and 13C magnetic resonance spectroscopy.  We demonstrated that pyruvate, even at low concentrations, is effective in supporting the metabolic demands of the cold perfused heart.  These findings may have important implications for increasing the cardiac donor pool and improving results of heart transplantation.

11:54         221.       Myocardial ASL Perfusion Reserve Test Detects Angiographic CAD in Initial Cohort of 29 Patients

Zungho Zun1, Terrence Jao1, Padmini Varadarajan2, Ramdas G. Pai3, Eric C. Wong4, Krishna S. Nayak1

1Department of Electrical Engineering, University of Southern California, Los Angeles, CA, USA; 2Division of Cardiology, Loma Linda University Medical Center, Loma Linda, CA, USA; 3Division of Cardiology, Loma Linda University Medical Center, Loma Linda , CA, USA; 4Departments of Radiology & Psychiatry, University of California, San Diego, La Jolla, CA, USA

Rest-stress myocardial arterial spin labeled (ASL) MRI was performed in twenty-nine patients with suspected coronary artery disease (CAD).  Perfusion reserve was estimated in six myocardial segments of a single mid short-axis slice, and compared with X-ray angiography. Receiver operating characteristic (ROC) curves were analyzed for (i) detection of patients with angiographic CAD and (ii) detection of the most ischemic segments. The area under ROC curves were (i) 0.88 and (ii) 0.71.

12:06         222.       Self-Gated Cardiac Perfusion MRI

Edward DiBella1, Ganesh Adluru2, Liyong Chen3, Chris McGann4

1University of Utah, Salt Lake City, UT, USA; 2Radiology, University of Utah; 3Bioengineering, University of Utah; 4Cardiology, University of Utah

Good ECG-gating is essential to obtaining the same cardiac phase of each slice to maximize the value of dynamic contrast enhanced cardiac perfusion scans. However, ECG-gating is often poor, and can be more problematic at higher field strength scanners and in obese patients.  As well, patients with arrhythmias can be problematic for acquiring high quality images due to the R-R interval variations. Here we propose an ungated perfusion acquisition that runs constantly without any gating signals. The images are acquired so rapidly that it is possible to sort the resulting dataset and create effectively self-gated perfusion images.

12:18         223.       Endothelial Progenitor Cells Mediated Improvements in Post-Infarct Left Ventricular Myocardial Blood Flow Estimated by Spin Labeling CMR

Hua-Lei Zhang1,2, Hui Qiao1, Rachel S. Frank1, Stephanie Eucker2, Bin Huang1, William M. Armstead3, Victor A. Ferrari4, Jonathan A. Esptein4, Rong Zhou1

1Laboratories of Molecular Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA; 2Department of Bioengineering, School of Engineering & Applied Science, University of Pennsylvania, Philadelphia, PA, USA; 3Department of Anesthesia, University of Pennsylvania, Philadelphia, PA, USA; 4Department of Medicine (Division of Cardiovascular Medicine), University of Pennsylvania, Philadelphia, PA, USA

Spin Labeling-CMR allowed high resolution mapping of myocardial blood flow (perfusion) in small animals which have rapid heart rates (400-600 bpm). The absolute perfusion values by Spin Labeling-CMR were in excellent agreement with those obtained by standard but invasive fluorescent microsphere method. This noninvasive method enabled serial monitoring of myocardial perfusion improvement in response to stem cell engraftment. Such capability is crucial in the development of cell therapy for myocardial infarction.

Endogenous Contrast Mechanisms: MT & Relaxometry

Room 518-A-C                  10:30-12:30                                                                               Moderators: Karla L. Miller & Bruce Pike

10:30         224.       Fast Bound Pool Fraction Imaging of the In Vivo Rat Brain: Assocation with Myelin Content & Validation in the C6 Glioma Model

Hunter R. Underhill1, Robert C. Rostomily1, Andrei M. Mikheev1, Chun Yuan1, Vasily L. Yarnykh1

1University of Washington, Seattle, WA, USA

Cross-relaxation imaging is a quantitative MRI technique that measures the kinetic parameters of magnetization transfer between protons bound to water and protons bound to macromolecules (i.e. bound pool fraction, f). A new time-efficient approach for solely capturing the in vivo whole-brain parametric map of f was proposed, validated with histology, and used to estimate myelin density in the normal rat brain on a 3.0 T clinical scanner. In both whole-brain f maps and myelin density maps, replacement of normal gray matter and white matter by proliferating and invading tumor cells was readily identified in vivo and confirmed with histology.

10:42         225.       Modeling & Measuring the Myelin G-Ratio

Nikola Stikov1, Lee M. Perry2, Aviv Mezer2, John M. Pauly3, Brian A. Wandell2, Robert F. Dougherty2

1Montreal Neurological Institute, McGill University, Montreal, QC, Canada; 2Psychology, Stanford University, Stanford, CA, USA; 3Electrical Engineering, Stanford University, Stanford, CA, USA

In myelinated axons, the ratio between the axon caliber (diameter) and the total caliber of the axon plus its myelin sheath (i.e., the fiber caliber) is relatively constant and is observed to be near the theoretically optimal value of 0.6. Recently, variations in this axon-to-fiber ratio (the "g-ratio") have been proposed to be associated with differences in brain development. Here we describe a method to estimate the g-ratio in-vivo by combining diffusion imaging and quantitative magnetization transfer.  The methods described here form a novel MR contrast mechanism that may be useful for quantifying the development of white matter and the deterioration of white matter in demyelinating diseases.

10:54         226.       Paradoxical Changes in Magnetization Transfer Ratio & Susceptibility Contrast in the Motor Cortex

Olivier E. Mougin1, Samuel J. Wharton1, Rosa M. Sanchez Panchuelo1, Richard W. Bowtell1, Penny A. Gowland1

1Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom

Myelination and iron storage is variable across the brain, creating specific cortical architecture for different functional areas. We used magnetization transfer imaging as well as susceptibility mapping to look at in-vivo variation across the cortex of healthy volunteers. Variation between areas such as the motor cortex, the visual cortex, the occipital cortex and the frontal lobe shows that contrast in the grey matter is determined not only by iron, but also by myelin.

11:06         227.       Fast Macromolecular Proton Fraction Mapping From a Single Off-Resonance Magnetization Transfer Measurement

Vasily L. Yarnykh1

1Radiology, University of Washington, Seattle, WA, USA

This study demonstrates the feasibility of fast and accurate macromolecular proton fraction (MPF) mapping using only a single-offset MT-weighted image. This approach is the fastest to date quantitative MT (qMT) method, which requires no extra time compared to traditional magnetization transfer ratio (MTR) mapping, if a complementary T1 map is available. Since the proposed method rapidly determines MPF with high accuracy, it provides a viable alternative to both time-consuming multi-parameter qMT techniques and fast but poorly-interpretable MTR measurements.

11:18         228.       Origins of the Ultrashort-T2 1H NMR Signals in Myelinated Nerve: A Direct Measure of Myelin Content?

Robert Adam Horch1,2, John C. Gore2,3, Mark D. Does1,2

1Biomedical Engineering, Vanderbilt University, Nashville, TN, USA; 2Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, USA; 3Radiology & Radiological Sciences, Vanderbilt University, Nashville, TN, USA

Ultra-short echo time (uTE) MRI of the brain has demonstrated white matter-specific signal enhancement from short T2 (<1 ms) signals suspected to arise from myelin. However, the T2 characteristics of these signals, as well as their origins and possible relationship to myelin, remain uncharacterized. Herein, we perform T2 characterizations and isotopic 1H perturbations on myelin phantoms and myelinated central and peripheral nerves to determine the origins of short-lived T2s relevant to uTE MRI. We find sizeable signals in the &#8776; 50 µs – 1 ms T2 domain and provide compelling evidence that they arise from myelin membrane methylene 1H.

11:30         229.       New MRI Contrasts in Experimental Stroke: What Do We Measure with RAFF & ZAPI?

Johanna Närväinen1, Kimmo Jokivarsi2, Timo Liimatainen, Olli Gröhn, Risto A. Kauppinen3

1A. I. Virtanen Institute, University of Eastern Finland, Kuopio, Finland; 2Massachusetts General Hospital; 3Dartmouth College, USA

Recently introduced MRI techniques, RAFF and ZAPI, were used to study acute stroke in a rat model. It is concluded that 1) Relaxation and MT are not coupled in acute cerebral stroke, even when clean on-resonance ZAPI-MT is used. 2) RAFF signal is sensitive to ischemia with sensitivity and temporal behavior comparable to T2, but inferior to T. 3) RAFF signal change in ischemic tissue can be predicted by simulations. 4)  On resonance-MT differs from off-resonance MT, both in magnitude and in temporal evolution during stroke.

11:42         230.       Observation of Myelin Water at Ultra-Short Echo Time by Longitudinal Relaxographic Imaging with Spin-Echo Center-Out EPI (DEPICTING)

Christian Labadie1,2, William D. Rooney3, Charles S. Springer, Jr.3, Jing-Huei Lee4, Monique Aubert-Frécon2, Stefan Hetzer5, Toralf Mildner1, Harald E. Möller1

1Max Planck Institute for Human Cognitive & Brain Sciences, Leipzig, Germany; 2Laboratoire de Spectrométrie Ionique et Moléculaire, Université Claude Bernard Lyon 1, France; 3Oregon Health & Science University, Portland, OR, USA; 4Biomedical Engineering, University of Cincinnati, OH, USA; 5Bernstein Center for Computational Neuroscience, Berlin, Germany

We adapted a spin-echo center-out echo planar imaging with ultra-short echo time [TE] (DEPICTING) pulse sequence with an inversion recovery [IR] preparation.  Two series of 32 pseudo-randomized TIs were acquired with two TEs and analyzed by cross-regularized inverse Laplace transform.  The human white matter water proton T2 value associated with the short component w. small water proton T1 detected by IR relaxographic analysis was determined to be 34.2 ms and supports its the assignment as a myelin water fraction. 

11:54         231.       3D Quantitative Imaging of T1rho & T2

Weitian Chen1, Atsushi Takahashi1, Eric Han1

1Global Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA

T1rho and T2 mapping have potential in a number of clinical applications. 3D acquisition is usually desired for these applications due to the geometry of anatomy. In this abstract, we reported our continous development of a highly SNR efficient 3D T1rho/T2 mapping method based on a pseudo steady state 3D FSE acquisition and demonstrated its accuracy in phantom and in-vivo scans.

12:06         232.       Is Iron the Source of Post Mortem Susceptibility Contrast in the Brain?

Ferdinand Schweser1,2, Christian Langkammer3,4, Andreas Deistung1, Nikolaus Krebs4, Walter Goessler5, E. Scheurer4, K. Yen4, Franz Fazekas3, Jürgen R. Reichenbach1, Stefan Ropele3

1Medical Physics Group, Dept. of Diagnostic & Interventional Radiology 1, Jena University Hospital, Jena, Germany; 2School of Medicine, Friedrich Schiller University of Jena, Jena, Germany; 3Dept. of Neurology, Medical University of Graz, Graz, Austria; 4Ludwig Boltzmann Institute for Clinical-Forensic Imaging, Graz, Austria; 5Institute of Chemistry, Analytical Chemistry, University of Graz, Graz, Austria

Quantitative information of the regional non-heme tissue iron distribution bears clinical potential in the context of various neurological and psychiatric disorders. The goal of the current study was to investigate and compare the relation between tissue iron concentration and tissue magnetic susceptibility of in situ and fixed post mortem brain tissue.

12:18         233.       Three Dimensional T2prep Spiral Imaging with Efficient Brain Coverage For Myelin Water Quantification: Validation At 1.5 Tesla

Thanh D. Nguyen1, Cynthia Wisnieff2, Mitchell Cooper2, Dushyant Kumar1, Ashish Raj1, Martin R. Prince1, Yi Wang1, Tim Vartanian3, Susan A. Gauthier3

1Radiology, Weill Cornell Medical College, New York, NY, USA; 2Biomedical Engineering, Cornell University, Ithaca, NY, USA; 3Neurology, Weill Cornell Medical College, New York, NY, USA

The objective of this study was to develop and optimize an SNR efficient 3D T2prep spiral gradient echo sequence for full brain T2 relaxometry and to validate this sequence using 3D FSE as reference standard at 1.5T. The spiral sequence was found to provide similar T2 on phantom and myelin water fraction for various brain tissues. 28 axial slices and 24 T2prep times can be obtained in 24 min with 2.5-fold higher SNR than conventional 2D FSE approach.

Bridging the Gap between MR & ER

Room 520B-F                    10:30-12:30                                                                          Moderators: Jalal B. Andre & Daniela Prayer  

10:30                       Imaging Requirements in the Emergency Room

James V. Quinn

11:00                       Neurological Emergencies: MR vs CT

Nancy J. Fischbein

11:30                       From the ER to the MR Suite at a Major Academic Hospital: A Body Imager's Perspective

Elmar M. Merkle

12:00                       ER: A Challenge for MR Technology

Steven M. Conolly

Manganese Enhanced MRI - Advances & Applications

Room 710A                        10:30-12:30                                                            Moderators: Nicholas A. Bock & Daniel H. Turnbull

10:30         234.       In Vivo Manganese-Enhanced MRI of Conditioned Fear Response

Iris Yuwen Zhou1,2, Abby Y. Ding1,2, Qi Li3,4, Frank Yik Hin Lee1,2, Shujuan J. Fan1,2, Kevin Chuen Wing Chan1,2, Grainne M. McAlonan3,4, Ed Xuekui Wu1,2

1Laboratory of Biomedical Imaging & Signal Processing, the University of Hong Kong, Hong Kong SAR, China, People's Republic of; 2Department of Electrical & Electronic Engineering, the University of Hong Kong, Hong Kong SAR, China, People's Republic of; 3Department of Psychiatry, the University of Hong Kong; 4Centre for Reproduction Growth & Development, the University of Hong Kong

Fear conditioning is a widely used procedure to study the neural basis of learning and memory. To study the neurocircuits behind this paradigm, in vivo MEMRI was employed to investigate the neural response after subjection to fear-conditioning in mice. Compared to controls, fear-conditioned animals exhibited higher Mn-uptake in amygdala, hippocampus, paraventricular nucleus of hypothalamus and cingulate cortex, which are all highly-involved in the process of fear. The results provide insights to neurocircuits involved in fear-conditioning and consolidate the capability of MEMRI as an in vivo probe for mapping neural activity.

10:42         235.       Mapping CNS Response to Leptin by MEMRI

A-B-M-A Asad1, Serene Y. L. Tong1, Ma Wei2, Weiping Han2, Kai-Hsiang Chuang1

1Magnetic Resonance Imaging Group, Singapore Bioimaging Consortium, A*STAR, Singapore, Singapore; 2Lab of Metabolic Medicine, Singapore Bioimaging Consortium, A*STAR, Singapore, Singapore

Leptin signaling in CNS plays an important role in regulating energy homeostasis which inhibits food intake and increases energy expenditure. To understand the CNS response to leptin, we used manganese enhanced MRI to observe dynamic changes in hypothalamic nuclei by Mn2+ as an Ca2+ activity dependent agent during fasting and peripheral leptin injection. We observed signal changes in arcuate, paraventricular, ventromedial and dorsomedial nuclei in hypothalamus. Injection of leptin suppressed signal significantly in most nuclei in fasted animals. In non-fasted animals, however, leptin injection increased signal in most nuclei but not arcuate. This method can be applied to study hypothalamic function in response to different metabolic signals and hypothalamic dysfunction in animal models of leptin resistance.

10:54         236.       Biocompatible & pH Sensitive PLGA Encapsulated Mno Nanocrystals for Molecular & Cellular MRI

Margaret F. Bennewitz1, Michael K. Nkansah1, Tricia L. Lobo2, Erik M. Shapiro1,2

1Department of Biomedical Engineering, Yale University, New Haven, CT, USA; 2Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, USA

Inorganic manganese particles are attractive for molecular and cellular imaging due to their potential to provide bright contrast on MRI.  We have fabricated pH-sensitive, poly(lactic-co-glycolic-acid) (PLGA) encapsulated manganese oxide (MnO) nanocrystals. Particles were fabricated at 140-nm and 1.7-μm, and incorporated 15 to 20-nm MnO nanocrystals. Intact particles at physiological pH cause little MRI contrast, but following endocytosis into low pH compartments within cells, particles erode, and MnO dissolves to release Mn2+, causing cells to appear bright on MR images. The change in MRI properties is as high as 35-fold, making it the most dynamic ‘smart’ MRI contrast agent yet reported.

11:06         237.       In-Vivo Detection of Cell Cycle Arrest using Manganese-Enhanced MRI (MEMRI)

Shigeyoshi Saito1, Sumitaka Hasegawa1, Takako Furukawa1, Tsuneo Saga1, Ichio Aoki1

1Molecular Imaging Center (MIC), National Institute of Radiological Sciences (NIRS), Chiba, Japan

Recent studies on the utility of manganese have shown that manganese-enhanced MRI (MEMRI) can detect cellular alterations in tumor models. We investigated the relationship between x-ray irradiation and Mn uptake in tumor cells and tested whether MEMRI can detect radiation-induced cell disturbances at an early stage. MEMRI is able to detect cell cycle arrest of tumor cells following radiation exposure. Reductions in Mn accumulation in the irradiated cells were observed both in vitro and in vivo. MEMRI may be suitable for evaluation of not only cell viability but also the acute stage of cell cycle alteration after radiotherapy.

11:18         238.       MEMRI Atlas of Neonatal Mouse Brain Development

Kamila Urszula Szulc1, Brian J. Nieman2, Edward Jospeh Houston1, Alexandra L. Joyner3, Daniel H. Turnbull1,4

1Kimmel Center for Biology & Medicine at the Skirball Institute of Biomolecular Medicine, NYU School of Medicine, New York, NY, USA; 2Mouse Imaging Center, Hospital for Sick Children, Toronto, Canada; 3Developmental Biology Program, Sloan-Kettering Institute, New York, NY, USA; 4Radiology, NYU School of Medicine, New York, NY, USA

MEMRI approach is particularly well suited to visualize brain anatomy and it has been successfully used to do so in mice in vivo at embryonic to adult stages. Here, we have extended MEMRI for longitudinal studies of brain development in individual mice during the critical early postnatal period. Based on these data, a brain atlas was created, consisting of individual and average brains at 11 developmental stages, from postnatal day 1 (P1) to P11. The database generated in this project will serve as an important resource for future phenotypic MEMRI analyses of mutant mice with brain defects.

11:30         239.       Brain Regions Showing Manganese Accumulation in the Human versus the Rat Brain

Ulrike Dydak1,2, Jun Xu1,2, Ashritha Epur2, Xiangrong Li3, Seth Streitmatter1, Li-Ling Long3, Wei Zheng1, Yue-Ming Jiang4

1School of Health Sciences, Purdue University, West Lafayette, IN, USA; 2Department of Radiology & Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; 3Department of Radiology, Guangxi Medical University, Nanning, China, People's Republic of; 4Department of Health Toxicology, Guangxi Medical University, Nanning, China, People's Republic of

A 3D whole-brain T1-weigthed sequence was used to study the human brain structures showing T1 hyperintensities due to occupational Mn exposure in a cohort of smelters and welders. Brain regions showing Mn accumulation were compared to non-exposed controls as well as to a rat model of chronic Mn exposure. While the rat brain predominantly shows Mn accumulation in hippocampus, in humans Mn first accumulates in the globus pallidus. T1 hyperintensities were also found in subthalamic nucleus, pituitary gland, pineal stalk and cerebral peduncle. These differences need to be considered when using animal models to study chronic Mn exposure.

11:42         240.       Mn Distribution in Rat Hippocampus: Correlative use of Synchrotron X-Ray Microprobe & MEMRI

Alexia Daoust1,2, Emmanuel Luc Barbier1,2, Sylvain Bohic1,3

1INSERM U836, Grenoble, France; 2Grenoble Institut des Neurosciences, Université Joseph Fourier, Grenoble, France; 3European Synchrotron Radiation Facility (ESRF), Grenoble, France

In MEMRI protocols, the cellular distribution remains still unclear. To obtain further insights, we imaged rat brains by MRI after IP and IC MnCl2 injections. Then, using synchrotron X-ray microprobe, we mapped the distribution of Mn, Ca, Zn and Fe in rat hippocampus. The hippocampal distributions of Mn obtained by both techniques were in excellent agreement. At a cellular scale, Mn was distributed within the DG/hilus/CA3. After IC injection, Mn was preferentially located in hippocampal fissure, a structure rich in astrocytes. The presence of Mn also modifies the distribution of Fe and Zn.

11:54         241.       Detection of Altered Axonal Transport a Mouse Model of Neurofibromatosis using Manganese Enhanced MRI

Kevin M. Bennett1, Shannon S. Olfers2, Vinodh Narayanan2

1School of Biological & Health Systems Engineering, Arizona State University, Tempe, Az, USA; 2Developmental Neurogenetics Laboratory, Barrow Neurological Institute, Phoenix, Az, USA

Neurofibromatosis 1 (NF1) is a cogenital neurodegenerative disease. The goal of this work is to determine whether fast axonal transport rates in the CNS of mice heterozygous for the neurofibromin 1 (NF1) gene differ from those of WT controls. We used MEMRI to demonstrate that uptake of Mn2+ in the olfactory bulb in NF1 heterozygous mice is significantly lower than in wild-type, implicating RAS deregulation as a potential mechanism for deficits in NF. Animals treated with lovastatin have restored axonal transport, demonstrating that MEMRI may be useful to screen compounds to treat patients with NF1. 

12:06         242.       Aging Impacts Significantly on Neuronal Transport in Normal Mice but Not in an Accelerated Mouse Model of Amyloid Beta Pathology

Umer Abdur Rahim Khan1, Anne Bertrand1,2, Hoang Minh Dung1, Dmitry Novikov1, Lindsay Kathleen Hill1, Benjamin Winthrope Little1, Hameetha B. Rajamohamed Sait3, Mesha Shamsie1, Einar M. Sigurdsson3, Youssef Zaim Wadghiri1

1Radiology, New York University Langone Medical Center, New York, NY, USA; 2URA CEA-CNRS 2210, Mircen, Fontenay-Aux-Roses, France; 3Physiology & Neuroscience, New York University Langone Medical Center, New York, NY, USA

Amyloid Beta (A Beta) and tau play an essential role in the Alzheimer’s disease (AD) pathophysiology. There is in vitro evidence that A Beta oligomers can impair fast axonal transport. Crucially lacking are in vivo non invasive techniques to evaluate neuronal function. Track-Tracing Manganese Enhanced MRI (TT-MEMRI) is currently the only non invasive 4-D volumetric imaging technique to demonstrate neuronal transport perturbations. Applying MEMRI in a transgenic model (Tg2576) of A Beta pathology by expressing human APP mutation confirmed the deleterious effect of A Beta on neuronal transport measured by a decrease in the rate of signal change. We previously investigated a tau model (JNPL3) using a 7 day time-course period where we showed a significant decrease in neuronal transport function in Tg mice. In the present study, we sought to examine with the same approach an accelerated A Beta mouse model (Tg6799 5xFAD) expressing both APP and PS1 human mutations. Surprisingly, our results show significant decrease in neuronal conduction in the (C57/B6xSJL) WT mice with age contrasting with maintained transport function in Tg 5xFAD with age. 

12:18         243.       Paraformaldehyde & Glutaraldehyde Fixations Preserve Manganese Enhancement in Ex Vivo Mouse Brain MRI

Yutong Liu1, Larisa Poluektova2, Balasrinivasa Sajja1, Howard Gendelman2, Boska Michael1

1Radiology, UNMC, Omaha, NE, USA; 2Pharmacology/Exp Neuroscience, UNMC, Omaha, NE, USA

Cross-linking chemicals including paraformaldehyde (PFA) and glutaraldehyde (GA) and focused beam microwave irradiation (FBMI) were evaluated to investigate the fixation methods that preserve in vivo manganese enhancement for ex vivo mouse brain MRI. T1 values were measured and T1-wt MRI was acquired at 24 hours after MnCl2 administration. The mice were then euthanized and brains were fixed for ex vivo MRI. The results demonstrated that the manganese enhancement was preserved by PFA and GA, but lost in FBMI fixed mice.

Human Brain Tumors: Response to Therapy

Room 710B                        10:30-12:30                                                                                 Moderators: Meng Law & Brian D. Ross

10:30         244.       Graded Functional Diffusion Maps (Fdms) Predict Survival in Recurrent Glioblastoma Treated with Bevacizumab

Benjamin M. Ellingson1, Timothy F. Cloughesy2, Albert Lai2, Phioanh L. Nghiemphu2, Whitney B. Pope1

1Radiological Sciences, University of California Los Angeles, Los Angeles, CA, USA; 2Neurology, University of California Los Angeles, Los Angeles, CA, USA

There remains a significant need for sensitive biomarkers that predict response to anti-angiogenic treatment for malignant gliomas. We hypothesize that graded functional diffusion maps (fDMs) are a sensitive biomarker for early prediction of bevacizumab failure in recurrent glioblastoma (GBM).  Eighty-five patients with recurrent GBMs were retrospectively examined. The volume of fDM-classified hypo- and hypercellular tissue in various categories were tested to determine if they were predictive of survival. Using graded fDMs, patients having a large volume of voxels exhibiting a subtle decrease in ADC had a significantly shorter progression-free and overall survival compared to those having a lower volume.

10:42         245.       Combined 31P & 1H MRSI in Recurrent Glioblastomas Prior & Post Antiangiogenetic Therapy

Ulrich Pilatus1, Oliver Bähr2, Joachim Steinbach2, Elke Hattingen1

1Institute of Neuroradiology, Goethe University Frankfurt, Frankfurt/Main, Germany; 2Senckenbergisches Institut für Neuroonkologie, Goethe University Frankfurt, Frankfurt/Main, Germany

31P and 1H MRSI was performed on recurrent glioblastomas prior and following treatment with the antiangiogenic agent Bevazizumab. Untreated tumor tissue revealed decreased glycerophosphocholine (GPE) and increased pH. In patients who were responding to the therapy (RANO criteria), both parameters reverted to normal levels within 8 weeks of treatment.

10:54         246.       MR Spectroscopy as a Biomarker to Predict the Responses of Glioblastoma to an Anti-Angiogenic Treatment

Heisoog Kim1, Ciprian Catana1, Eva-Maria Ratai1, Ovidiu C. Andronesi1, Tracy T. Batchelor2, Rakesh K. Jain3, A. Gregory Sorensen1

1Radiology, A. A. Martinos Center, Charlestown, MA, USA; 2Neurology, Massachusetts General Hospital, Boston, MA, USA; 3Radiation Oncology, Massachusetts General Hospital, Boston, MA, USA

In this study, the changes of predominant metabolites in recurrent glioblastoma (rGBM) were evaluated for predicting tumor responses to an anti-angiogenic treatment. While thirty-one rGBM patients were treated with daily doses of cediranib, chemical shift imaging data were acquired serially at the specific time points of treatment. We measured the concentrations of N-acetyl aspartate (NAA) and choline (Cho) normalized by creatine in normal tissue (norCre) in enhancing tumor by categorizing two different survival groups. Notably, NAA/Cho showed a high prediction to 6-month overall survival in ROC analysis. These observations have important implications for treatment management.

11:06         247.       Increased Blood Flow during Anti-VEGF Induced Vascular Normalization

Kyrre E. Emblem1, Pavlina Polaskova1, Dominique L. Jennings1, Elizabeth R. Gerstner2, Tracy T. Batchelor2, Rakesh K. Jain3, A. Gregory Sorensen1

1A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Boston, MA, USA; 2Pappas Center for Neuro-Oncology, Massachusetts General Hospital, Boston, MA, USA; 3Department of Radiation Oncology, Massachusetts General Hospital, Boston, MA, USA

It is hypothesized that anti-VEGF therapy in combination with radiation and chemotherapy can normalize brain tumor vascularity and restore impaired blood flow characteristics. In this study, we have compared MR-derived flow characteristics in patients treated with an anti-angiogenic agent to that of a patient control group not receiving anti-angiogenic therapy. Our results support the hypothesis of vascular normalization, where the patient group undergoing anti-VEGF treatment showed increased CBF during the vascular normalization window.

11:18         248.       Improved Localization of BOLD Activation in Patients with Brain Tumors using Vasoreactivity Maps

Henning U. Voss1, Kyung K. Peck2, Nicole M. Petrovich Brennan2, Amir Iranmahboob2, Bob L. Hou3, Andrei I. Holodny2

1Dept. of Radiology, Weill Cornell Medical College, New York, NY, USA; 2Dept. of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, USA; 3Dept. of Radiology, West Virginia University, Morgantown, VA, USA

In subjects with brain tumors a global hemodynamic response function may not be sufficient to yield the most accurate maps of eloquent cortical areas in presurgical planning fMRI.

We propose to assess local vasoreactivity by using a breath-holding paradigm and derive a model that takes altered hemodynamics into account.

We obtain altered task response maps as compared to maps obtained without breath-holding information, in particular adjacent to tumors, in half of the studied cases.

Our results suggest that the inclusion of vasoreactivity data could enhance BOLD detection in patients with compromised hemodynamics secondary to pathology.

11:30         249.       Serial Changes in Diffusion Imaging Parameters Vary with Treatment Regimen for Patients with Newly Diagnosed Glioblastoma Multiforme

Laleh Jalilian1, Emma Essock-Burns2, Yan Li1, Soonmee Cha1,3, Susan Chang3, Michael Prados3, Nicholas Butowski3, Sarah J. Nelson1,2

1Radiology & Biomedical Imaging, UCSF, San Francisco, CA, USA; 2Bioengineering, UCSF, San Francisco, CA, USA; 3Neurological Surgery, UCSF, San Francisco, CA, USA

Despite advances in treatment modalities, patients with glioblastoma multiforme have an overall survival of 15 months.  Anti-angiogenic therapies administered with temozolomide have been reported to cause restriction on diffusion-weighted imaging (DWI), which may serve as an adjunct to the assessment of therapy response.  In this study, 100 newly diagnosed GBM patient were administered either a) temozolomide alone, b) temozolomide and a protein kinase C inhibitor, or c) temozolomide and a VEGF antibody.  The results demonstrate that imaging biomarkers used to predict response and prognosis to therapy need to be tailored to take into account the specific treatment regimen being considered.

11:42         250.       How Blood Perfusion Maps are Analyzed Can Greatly Improve the Predictive Potential For Assessing Survival in Patients Treated For Gliomas

Benjamin Lemasson1, Stefanie Galbán2, Christina Tsien2, Charles R. Meyer1,3, Timothy D. Johnson4, Thomas Leonard Chenevert1, Alnawaz Rehemtulla1,2, Brian Dale Ross1, Craig J. Galbán1

1Radiology, University of Michigan, Ann Arbor, MI, USA; 2Radiation Oncology, University of Michigan, Center for Molecular Imaging, Ann Arbor, MI, USA; 3Biomedical, University of Michigan, Center for Molecular Imaging, Ann Arbor, MI, USA; 4Biostatistics, University of Michigan, Ann Arbor, MI, USA

We tested the hypothesis that the method used to analyze the physiological parameter can improve the parameter’s predictive value. As such we compaired the parametric response (PRM) map to several common methods for assessing response. In addition, we evaluated the impact of the volume of interest (VOI) and the time the mid-treatment rCBV map was acquired on the predictive value of one-year and overall survival in a cohort of glioma patients. Only PRM was predictive of response. In addition, PRM is shown to be robust with negligible sensitivity to the VOI or the time the mid-treatment rCBV map was acquired.

11:54         251.       Treatment Effects of Diffuse Intrinsic Pontine Gliomas On Tumor & Normal Appearing Cortical Gray Matter Assessed By Arterial Spin Labeling Perfusion & 3D Volumetric Measurements

Jan Sedlacik1,2, Claudia M. Hillenbrand1, Alberto Broniscer3

1Radiological Sciences, St. Jude Children’s Research Hospital, Memphis, TN, USA; 2Neuroradiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; 3Oncology, St. Jude Children’s Research Hospital, Memphis, TN, USA

In a clinical trial of combined antiangiogenic and local radiation therapy (RT) of brainstem gliomas changes in tumor and cortical grey matter (GM) perfusion were closely monitored by arterial spin labeling and volumetric measurements. Median tumor perfusion was found to be increased and showing a higher variance directly after RT suggesting different tumor responses to treatment compared to tumor volume which decreased in all patients. A temporary drop in cortical GM perfusion and volume was found directly after baseline which may be caused by steroids, given at the beginning of therapy.

12:06         252.       UDP-GlcNAc & UDP-GalNAc, as Detected By 1H MRS, Increase in the Early Phase of Cisplatin –Induced Cell Death in Brain Tumour Cells

Xiaoyan Pan1,2, Martin Wilson1,2, Carmel McConville1, Julian L. Griffin3, Theodoros N. Arvanitis2,4, Andrew C. Peet1,2, Risto A. Kauppinen5

1Cancer Sciences, University of Birmingham, Birmingham, United Kingdom; 2Oncology, Birmingham Children's Hospital NHS Foundation Trust, Birmingham, United Kingdom; 3Biochemistry, University of Cambridge, Cambridge, United Kingdom; 4School of Electronic, Electrical & Computer Engineering, University of Birmingham, Birmingham, United Kingdom; 5Department of Radiology, Dartmouth College, Hanover, NH, USA

In this work, four brain tumour cell lines with different sensitivity to cisplatin were studied. DAPI-stained nuclei of cisplatin treated cells were demonstrated to identify cell death. 1HMRS was performed on the cisplatin treated brain tumour cells to investigate the metabolic change with treatment. The peaks at 7.98, 5.98 and 2.09 ppm assigned to UDP-GlcNAc and UDP-GalNAc were found to increase in the responding cells in the early events of cell death but not in non-responders. They change with similar kinetics to the 1HMRS-detected lipids during cell death.

12:18         253.       Characterization of Microbleed Formation from Normal Brain Microvasculature After Radiation Therapy

Janine M. Lupo1, Susan M. Chang2, Soonmee Cha1,2, Sarah J. Nelson1,3

1Department of Radiology & Biomedical Imaging, University of California, San Francisco, CA, USA; 2Department of Neurological Surgery, University of California, San Francisco, CA, USA; 3Department of Bioengineering & Therapeutic Sciences, University of California, San Francisco, CA, USA

Although a mainstay in the standard-of-care for malignant gliomas, the potential effects of radiation therapy on normal brain tissue and quality-of-life is not well characterized.  This study uses SWI to evaluate the evolution of microbleeds in normal-appearing brain due to radiation therapy in 12 glioma patients, 6 of who received concurrent anti-angiogenic therapy.  Microbleed counts were found to increase linearly as a function of time since receiving radiation, with the rate of microbleed formation escalating after 2 years. The addition of an anti-angiogenic agent appeared to stall this processes.  Microbleed size varied both within and across patients with time.

Gold Corporate Member Lunchtime Symposium
GE Healthcare

Room Plenary Hall                             12:30-13:30                                                                                                                                        

Clinical Intensive Course
Nouvelle Techniques in Current Clinical Use

Room 520B-F                    13:30-15:30                                                         Moderators: Robert C. McKinstry & Kenneth L. Weiss  

13:30                       Clinical Imaging of Short T2/T2* Tissues

Graeme M. Bydder

13:55                       High Field

Keith R. Thulborn

14:20                       New Contrast Agents

Marco Essig

14:45                       Models for Predicting Outcome

Ruth C. Carlos

15:10                       Discussion & Meet the Teachers

Clinical Intensive Course
Commonly Missed Diagnoses in Shoulder & Knee MR

Room 510                           13:30-15:30                                                                                                          Moderator: Hollis G. Potter  

13:30                       Commonly Missed Diagnoses in the Shoulder

Thomas W. Hash

14:20                       Questions

14:30                       Commonly Missed Diagnoses in the Knee

Gustav Andreisek

15:20                       Questions

Clinical Decision Making with Advanced Techniques

Room 516A-C                   13:30-15:30                                                                                                                                                            

13:30                       fMRI

Stefan Sunaert

14:00                       Perfusion MRI (ASL)

Joseph A. Maldjian

14:30                       Diffusion Tensor Imaging

Aaron S. Field

15:00                       Perfusion MRI (DSC-MRI & DCE-MRI)

A. Gregory Sorensen

Cardiovascular MRI - Exploring the Boundaries Part 1: Cardiovascular Molecular Imaging

Room 512A-G                   13:30-15:30                                                                   Moderators: Paula J. Foster & David E. Sosnovik

13:30                       Contrast Agents & Platforms

Peter Caravan

13:50                       Imaging Techniques & Quantification

René M. Botnar

14:10                       Cell Therapy

Dara L. Kraitchman

14:30                       Atherosclerosis

Patrick M. Winter

14:50                       Myocardium

David E. Sosnovik

15:10                       Hybrid Systems

Ciprian Catana

Body Diffusion: Beyond ADC?

Room 518-A-C                  13:30-15:30                                                                     Moderators: Dow-Mu Koh & Thomas C. Kwee

13:30         254.       Introduction
David J. Collins

13:42         255.       Short Term Measurement Reproducibility of Perfusion Fraction (F), Pseudo-Diffusion Coefficient (D*) & Diffusion Coefficient (D) in Colorectal Liver Metastases Derived By Intravoxel Incoherent Motion Analysis of Respiratory-Triggered Diffusion-Weighted MR Imaging

Adrian Andreou1, Matthew Orton2, David J. Collins1,2, Martin O. Leach2, Dow-Mu Koh1

1Department of Radiology, Royal Marsden Hospital, Sutton, Surrey, United Kingdom; 2CRUK-EPSRC Cancer Imaging Centre, Institute of Cancer Research, Sutton, Surrey, United Kingdom

Applying the principles of intravoxel incoherent motion (IVIM) allows quantitative parameters which reflect tissue microcapillary perfusion and tissue diffusivity to be derived. We evaluated the short term measurement reproducibility of the perfusion fraction (f), pseudo-diffusion (D*) and diffusion coefficients (D) of normal appearing liver and colorectal liver metastases in patients. We found that D showed good to moderate measurement reproducibility in liver and metastases. However, the reproducibility of f and D* was relatively poor but using a Bayesian method for analysis significantly improved the reproducibility of f and D* in metastases and D* in the liver. 

13:54         256.       Intravoxel Incoherent Motion (IVIM) Analysis of Liver Fibrosis in an Experimental Mouse Model

April M. Chow1,2, Darwin S. Gao1,3, Shu Juan Fan1,3, Gladys G. Lo4, Siu Ki Yu2, Ed X. Wu1,3

1Laboratory of Biomedical Imaging & Signal Processing, the University of Hong Kong, Pokfulam, Hong Kong SAR, China, People's Republic of; 2Medical Physics & Research Department, Hong Kong Sanatorium & Hospital, Happy Valley, Hong Kong SAR, China, People's Republic of; 3Department of Electrical & Electronic Engineering, the University of Hong Kong, Pokfulam, Hong Kong SAR, China, People's Republic of; 4Department of Diagnostic & Interventional Radiology, Hong Kong Sanatorium & Hospital, Happy Valley, Hong Kong SAR, China, People's Republic of

Early diagnosis of liver fibrosis could facilitate early interventions and treatments, preventing its progression to cirrhosis. Recently, diffusing imaging has been shown to be promising in characterization of liver fibrosis. In this study, using intravoxel incoherent motion (IVIM) analysis and a mouse model of CCl4-induced fibrosis, we showed that both molecular water diffusion and blood microcirculation contribute to the alteration in apparent diffusion changes in liver fibrosis. Among all parameters studied, blood pseudodiffusion coefficient (D*) showed largest percentage change at 2 weeks after CCl4 insult. IVIM analysis can be valuable in characterizing liver fibrosis at early phase and monitoring its progression.

14:06         257.       Assessment of Hepatocellular Carcinoma in Fresh Liver Explants using a Non-Gaussian Diffusion Kurtosis Model.

Andrew B. Rosenkrantz1, Eric E. Sigmund1, Benjamin E. Niver1, Glyn R. Morgan2, Bradley Spieler1, Anthony G. Gilet1, Cristina H. Hajdu3

1Radiology, NYU Langone Medical Center, New York, USA; 2Transplant Surgery, NYU Langone Medical Center, New York, USA; 3Pathology, NYU Langone Medical Center, New York, NY, USA

Eight fresh liver explants in patients with hepatocellular carcinoma (HCC) underwent ex-vivo 1.5T MRI, including diffusion kurtosis imaging (DKI).  ADC using mono-exponential (ADC) and non-Gaussian (D) fit, as well as mean kurtosis (K), were calculated.  There was significant correlation between ADC and D, but not between ADC or D with K.  Relative contrast between liver and HCC was greater for K than for ADC or D.  ADC and D were lowest in non-necrotic HCC, while K was not different between viable and necrotic HCC. Alternate diffusion protocols may have potential for DKI of HCC following chemo-embolization in a clinical setting.

14:18         258.       Histopathological Correlation of IVIM-Derived True Diffusion Constant in Patients with Pancreatic Carcinoma & Chronic Pancreatitis

Miriam Klauss1, Matthias Gaida, Andreas Lemke2, Katharina Grünberg2, Dirk Simon2, Stefan Delorme2, Hans-Ulrich Kauczor, Lars Grenacher, Bram Stieltjes2

1Diagnostic Radiology, University of Heidelberg, Heidelberg, Baden-Württemberg, Germany; 2DKFZ

Fibrosis is the most characteristic histopathological feature of pancreatic carcinoma and chronic pancreatitis. It was shown that the IVIM-derived parameter D (true diffusion constant) did not show differences between these two entities. The aim of this study was to compare differences in D with the histopathological grade of fibrosis in pancreatic diseases.

We compared the histopathological grade of fibrosis with the true diffusion constant D calculated from diffusion data in 24 patients. We found significant differences between the D-values for moderate and severe fibrosis.

The pure diffusion constant could serve as parameter to monitor tumor response in pancreatic carcinoma.

14:30         259.       Association of the Apparent Diffusion Coefficient of Bladder Cancer with Metastatic Disease: Preliminary Results

Thais C. Mussi1, Bradley Spieler1, Andrew B. Rosenkrantz1

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

19 patients with urothelial carcinoma of the bladder who underwent MRI including DWI at 1.5T were included.  Among these, 8 had nodal or distant metastatic disease, and 11 had an absence of metastatic disease (mean follow-up 434 days).  ADC was measured for each lesion and was significantly lower among those cases with metastatic disease (p=0.0012).  Using ADC for prediction of metastatic disease, ROC analysis identified an AUC of 0.920, sensitivity of 87.5%, specificity of 100%, PPV of 100%, and NPV of 91.7%.

14:42         260.       Towards Repeatable ADC Mapping of the Liver: Some Guidance for Clinical Use

Paul Summers1, Antonio Gregoraci2, Giuseppe Petralia1, Anna Caroli3, Roberto Di Filippi1, Luca Antiga3, Massimo Bellomi1

1Department of Radiology, European Institute of Oncology, Milan, Italy; 2Faculty of Medicine & Surgery, University of Milan, Milan, Italy; 3Mario Negri Institute, Bergamo, Italy

We examined the impact of prandial status, choice of b-values in one or three directions, and ROI definition on repeatability of whole liver ADC measurements in 10 healthy subjects. The inclusion of the b=0 image or limiting the b-values used to those greater than 700 s/mm2 significantly increased both the estimated mean ADC and its variability between subjects. Excluding these choices of b-values, intra- and intersubject standard deviations were similar (< 10%, and 15-22% respectively) for both 1 and 3 encoding directions. Prandial status and exclusion of visible vessels from the ROI had little effect on ADC.

14:54         261.       Quantitative Analysis of the Diffusion-Weighted Steady-State Free-Precession Signal in Vertebral Bone-Marrow Lesions

Olaf Dietrich1, Andreas Biffar1, Andrea Baur-Melnyk, Gerwin Schmidt, Maximilian F. Reiser1

1Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, Ludwig Maximilian University of Munich, Munich, Germany

Diffusion-weighted steady-state free-precession (DW-SSFP) sequences are extremely valuable for the differential diagnosis of benign osteoporotic and malignant neoplastic vertebral compression fractures. The purpose of the present study was to provide a detailed theoretical and experimental analysis of the DW-SSFP signal in the spine. It could be demonstrated that the main reasons for the different lesion contrasts are an opposed-phase readout in combination with the differing fat fractions and T2*-values in the fractures as well as in normal-appearing VBM of both entities. The observed signal contrast is therefore rather fat- and T2*-weighted than diffusion-weighted.

15:06         262.       Parallel RF Excitation For Diffusion-Weighted Whole Body MR Imaging with  Background Body Signal Suppression At 3.0 Tesla

G. M. Kukuk1, M. Kaschner1, F. Träber1, D. Skowasch2, J. Gieseke1,3, H. H. Schild1, W. A. Willinek1, P. Mürtz1

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

High field MRI has introduced new challenges for DWIBS body imaging with respect to susceptibility artefacts, fat suppression, dielectric shading, and longer acquisition times. Dual-source parallel RF excitation has been shown to allow for a more homogeneous excitation. Therefore, we evaluated the effect of this technique on DWIBS in 40 patients. Shorter acquisition times by 33%, significantly improved signal homogeneity and fat suppression, and reduced dielectric shading without influencing ADC values was found by using parallel RF excitation in DWIBS at 3.0 T.

15:18         263.       Diffusion-Prepared Fast Imaging with Steady-State Free Precession (DP-FISP): A Rapid Diffusion MRI Technique at 7T

Lan Lu1, Bernadette Erowku1, Gregory R. Lee1, Katherine Dell2,3, Chris A. Flask1,4

1Radiology, Case Western Reserve University, Cleveland, OH, USA; 2Pediatrics, Case Western Reserve University, Cleveland, OH, USA; 3MetroHealth Medical Center, Cleveland, OH, USA; 4Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA

Diffusion MRI applications typically utilize rapid Echo-Planar Imaging (EPI) acquisition techniques.  However, EPI techniques are susceptible to off-resonance distortion and eddy current artifacts, especially for high field MRI applications. We have developed a rapid Diffusion Prepared - Fast Imaging with Steady-State Free Precession (DP-FISP) MRI acquisition for a 7T small animal MRI scanner that combines a diffusion preparation scheme with a rapid FISP imaging readout to provide diffusion-weighted images in less than 500 ms and DTI data (7 directions) in less than 1 minute. Herein, DP-FISP results validated in a water phantom and in vivo polycystic rat kidneys.

Clinical Intensive Course
MR Physics & Techniques for Clinicians

Room 516A-C                   16:00-18:00                                                                                                                                                            

16:00                       Spin Echo Imaging

Bernd A. Jung

16:40                       Gradient Echo Imaging

Brian A. Hargreaves

17:20                       Fast Spin Echo Imaging

Frank R. Korosec

You Are what You Eat

Room 510                           16:00-18:00                                                       Moderators: Bruce M. Damon & Bernard J. Dardzinski

16:00         264.       31P MRS at 7T Shows a Relation Between the Alkaline Ph Compartment Content Compared to Phosphocreatine Recovery Kinetics At 1.5T

Joep van Oorschot1, Hermien Kan2, Andrew Webb2, Klaas Nicolay1, Jeroen Jeneson1

1Biomedical NMR, University of Technology Eindhoven, Eindhoven, Noord-Brabant, Netherlands; 2C. J. Gorter Center for High Field MRI, Dept. of Radiology, Leiden University Medical Center, Leiden, Netherlands

Non-invasive assessment of mitochondrial content in skeletal muscle, during rest, using 31P spectroscopy would be a major improvement over conventional methods, including kinetics of phosphocreatine (PCr) recovery from exercise. Previous research at 7T attributed a peak at 5.2 ppm to the Pi pool inside the mitochondrial matrix (Pi2). In this study we obtained further evidence for this hypothesis, by showing a correlation between Pi2 intensity assessed at 7T to the PCr recovery rate as assessed during in-magnet exercise at 1.5T. Studies were done in both endurance trained athletes and normally active subjects.

16:12         265.       Quantification of Susceptibility-Induced Fat Resonance Shift On Chemical Shift-Based Water/Fat Separation of Skeletal Muscle

Dimitrios C. Karampinos1, Huanzhou Yu2, Ann Shimakawa2, Thomas M. Link1, Sharmila Majumdar1

1Department of Radiology & Biomedical Imaging, University of California, San Francisco, San Francisco, CA, USA; 2Global Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA

Quantitative chemical shift-based water/fat separation approaches rely on a precalibrated multi-peak fat spectrum. However, water-fat susceptibility differences can induce fat spectrum resonance shifts depending on the shape and orientation of the fatty inclusions. The effect is of particular interest in the skeletal muscle due to the anisotropic arrangement of extracellular lipids. In the present work, the effect of susceptibility-induced resonance shift on quantitative chemical shift-based water/fat separation approaches is characterized and a novel algorithm is proposed in order to quantify the resonance shift. The technique is validated in a phantom and preliminary in vivo results are shown in the calf muscle.

16:24         266.       Mitochondrial Dysfunction in Patients with Primary Congenital Insulin Resistance

Alison Sleigh1, Philippa Raymond-Barker2, David Porter3, Kerrie Thackray4, Louise McGrath1, Soren Brage4, Mensud Hatunic4, T. A. Carpenter1, Kevin M. Brindle5,6, Graham J. Kemp7, Steve O'Rahilly4, Rob K. Semple4, David B. Savage4

1Wolfson Brain Imaging Centre, University of Cambridge, Cambridge, United Kingdom; 2Wellcome Trust Clinical Research Facility, Addenbrooke's Hospital, Cambridge, United Kingdom; 3Siemens AG Healthcare Sector, Erlangen, Germany; 4Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom; 5Dept. of Biochemistry, University of Cambridge, Cambridge, United Kingdom; 6Cancer Research UK Cambridge Research Institute, Cambridge, United Kingdom; 7Magnetic Resonance & Image Analysis Research Centre, University of Liverpool, Liverpool, United Kingdom

We use 31P-MRS at rest (saturation transfer technique), and post exercise (PCr recovery rate), in subjects with congenital severe insulin resistance due to loss-of-function mutations in the INSR gene.  PCr recovery post exercise is significantly slowed in the INSR patients suggesting that primary congenital insulin resistance can precede mitochondrial dysfunction. Resting ATP synthesis rate (ST VATP) measured from the saturation transfer method did not differ significantly between groups. This is consistent with recent findings in rats, which support concerns over its validity in accurately measuring ATP synthesis rates. We found no significant correlation between ST VATP and PCr recovery rate.

16:36         267.       Combination of DEPT & PRESS for Detection of UFA in Posterior & Medial Thigh Muscle By 13C MRS At 7T

Xing Chen1, Anke Henning1, Peter Boesiger1

1Institute for Biomedical Engineering, University & ETH Zurich, Zürich, Switzerland

It has been shown that the altered fatty acid contents after supplementation are different according to the specific tissues. However, the low signal sensitivity of natural abundance 13C MRS which is so far the only way to detect unsaturated fatty acids noninvasively limits the measurement in specific positions. In this work, we apply the sequence which combines DEPT and PRESS localization on protons to in vivo detection of UFA. Theoretical calculation by the product operator formalism, phantom measurements and in vivo results from human thigh muscle at 7T showed that the sequence achieved sufficient SNR enhancement as well as precise localization. The UFA detected from posterior and medial thigh muscle on two healthy volunteers indicates that the sequence based on DEPT and PRESS is capable of assessing the fatty acids characterization in specific tissues non-invasively in vivo.

16:48         268.       Diffusion Measurements Reveal a Difference in Apparent Diffusion Coefficients of Intra- & Extramyocellular Lipids

Vaclav Brandejsky1, Roland Kreis1, Christine Sandra Bolliger2, Chris Boesch1

1Dept. of Clinical Research, University of Bern , Bern, Switzerland; 2Dept. of Clinical Research, University of Bern, Bern, Switzerland

Intra- (IMCL) and extramyocellular (EMCL) lipids have been studied by diffusion weighted MRS, which is optimized to avoid motion- and vibration-related artifacts at large b-values. Results show differences between the diffusion properties of the EMCL/IMCL lipid pools in human muscle. The low apparent diffusion coefficient of IMCL can only be explained by restricted diffusion while EMCL seems to diffuse freely. The results indicate that in vivo droplet size measurements of IMCL using MRS might be possible.

17:00         269.       Quantitative Assessment of the Inter- & Intra-Muscle Fat Fraction Variability in Duchenne Muscular Dystrophy Patients

Beatrijs Wokke1, Janneke van den Bergen1, Annemieke Aartsma-Rus2, Andrew Webb3, Jan Verschuuren1, Hermien Kan3

1Neurology, Leiden University Medical Centre, Leiden, Netherlands; 2Human genetics, Leiden University Medical Centre; 3Radiology, Leiden University Medical Centre

Quantitative assessment of fatty infiltration in 18 muscles in the upper and lower leg of Duchenne Muscular Dystrophy (DMD) patients showed large variation in fat fractions between the analyzed muscles as well as variation between distal and proximal regions in several muscles in the lower leg. In a potential longitudinal study of DMD patients, analyzing only the most and least affected muscle could provide adequate information for monitoring. However, for the analysis of some muscles multiple slices should be acquired to prevent an under- or overestimation of the fat fraction. 

17:12         270.       Lipid Accumulation & Mitochondrial Function in Skeletal Muscle of ATGL Knockout Mice: A 31P MRS Study

Patricia M. Nunes1, Andor Veltien1, Henk Arnts2, Tineke van de Weijer3, Patrick Shrauwen3, Cees J. Tack4, Arend Heerschap1

1Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 2Central Animal Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 3Human Biology, NUTRIM, School of Nutrition, Toxicology & Metabolism,  Maastricht University Medical Centre, Maastricht, Netherlands; 4Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands

Absence of adipose-triglyceride-lipase(ATGL), mainly expressed in muscle and adipose tissue, leads to triglyceride accumulation and decreased free-fatty-acid availability, boosting glucose metabolism. Here, we tested muscle mitochondrial oxidative capacity of ATGL-KO mice, in vivo, with dynamic 31PMRS, simultaneously with force measurements.

ATGL-KO electro-stimulated muscles presented lower force and fast relaxation compared to WT. 31PMRS showed that resting muscles of WT and ATGL-KO did not differ in phosphor-metabolites or in pH. After contraction ATGL-KO and WT muscles had comparable PCr depletions and Pi formations, as well as pH. The mono-exponential-curve-fitting of PCr recovery showed similar recovery times, suggesting analogous mitochondrial oxidative capacities.

17:24         271.       Quantification of Adipose Tissue Depots in the Thigh with Two-Point Dixon Imaging: Effect of Fitness Level on Adiposity in Elderly Women

Danchin Daniel Chen1, Diego Hernando2, Curtis Laurence Johnson1, Armen Alex Gharibans1, Dolores D. Guest3, Christie Ward4, Bhibha Das3, Ellen M. Evans4, John G. Georgiadis1

1Mechanical Science & Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA; 2Department of Radiology, University of Wisconsin, Madison, WI, USA; 3Department of Kinesiology & Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, USA; 4Department of Kinesiology, University of Georgia, Athens, GA, USA

A two-point Dixon MRI technique was used to quantify the adipose tissue depots in the thigh of elderly women.  Women were divided into obese (n=24) and lean (n=17) groups based on BMI, and the lean group was further divided into active (n=9) and sedentary (n=8) based on physical activity level.  Thigh composition in lean, sedentary women was found to be similar to that of obese women, while relative adipose tissue depots were elevated relative to active women.

17:36         272.       Diffusion Weighted Spectroscopy: A Novel Approach to Investigate Intramyocellular Lipids

Li Xiao1,2, Ed X. Wu1,2

1Laboratory of Biomedical Imaging & Signal Processing, the University of Hong Kong, Hong Kong, Hong Kong SAR, China, People's Republic of; 2Department of Electrical & Electronic Engineering, the University of Hong Kong, Hong Kong, Hong Kong SAR, China, People's Republic of

Recognizing the correlation between insulin sensitivity and intramyocellular lipid (IMCL) level, non-invasive 1H MRS assessment of IMCLs has been extensively pursued. One major technical challenge in such IMCL quantitation is the spectral overlap and contamination by the large, broad and muscle orientation dependent extramyocellular lipid (EMCL) spectrum. Motivated by their difference in microscopic diffusion environment, we characterized the diffusion properties of IMCLs and EMCLs both ex vivo and in vivo. Our results demonstrated that EMCLs have significantly higher diffusivity, and they can be reliably suppressed via diffusion weighting while IMCLs remain visible. The proposed approach can be readily employed in study of human skeletal muscles in vivo, providing more reliable IMCL quantitation in MRS/MRI investigation of obesity and diabetes.

17:48         273.       Using DTI to Assess the Effect of Obesity & Physical Activity on Muscle Quality in Elderly Women

Armen Alex Gharibans1, Danchin Daniel Chen1, Curtis Laurence Johnson1, Dolores D. Guest2, Christie Ward3, Bhibha Das2, Ellen M. Evans3, John G. Georgiadis1

1Mechanical Science & Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA; 2Department of Kinesiology & Community Health, University of Illinois at Urbana-Champaign, Urbana, IL, USA; 3Department of Kinesiology, University of Georgia, Athens, GA, USA

Seeking to assess skeletal muscle quality, the primary and secondary eigenvector tracts were reconstructed from DTI in the vastus medialis of elderly women (n=41) blocked on adiposity (obese vs. lean), with the lean group (n = 17) further blocked on physical fitness (sedentary vs. physically active).  Three parameters related to the asymmetry of the diffusion tensor in the direction perpendicular to the muscle fiber are used as structural metrics of muscle quality. Statistical analysis of the cross-sectional study outcome shows that physical activity and obesity influence muscle quality such that: slender/active group > slender/sedentary group > obese group.

Myocardial Function: Experimental Models & Human Studies

Room 511A-C                   16:00-18:00                                                                       Moderators: Thoralf Niendorf & Mihaela Pop

16:00         274.       A Feasibility Study: MR Elastography as a Method to Compare Stiffness Estimates in Hypertrophic Obstructive Cardiomyopathy & in Normal Volunteers

Arunark Kolipaka1, Kiaran McGee1, Shivani Aggarwal1, Nandan Anavekar1, Armando Manduca1, Richard Ehman1, Philip Araoz1

1Mayo Clinic, Rochester, MN, USA

Hypertrophic cardiomyopathy (HOCM) is a genetic cardiac disease and is thought to increase myocardial stiffness. Recently, MR elastography (MRE) has been adapted to measure stiffness in the myocardium. The purpose of this study was to demonstrate the feasibility of using MRE to identify changes in the stiffness of LV in HOCM’s when compared to normals. MRE was performed on 18 normal volunteers and 2 HOCM patients. During end-systole an increased stiffness with a mean value of 14.5 kPa was found as compared to normals with a mean value of 5.6 kPa.

16:12         275.       Direct Elastography of In Vivo Human Heart

Heiko Tzschätzsch1, Thomas Elgeti1, Sebastian Hirsch1, Thoralf Niendorf2, Jürgen Braun3, Ingolf Sack1

1Department of Radiology, Charité University Medicine, Berlin, Germany; 2Berlin Ultrahigh Field Facility, Charité University Medicine, Berlin, Germany; 3Institute of Medical Informatics, Charité University Medicine, Berlin, Germany

The variation of myocardial elasticity enables the heart to circulate blood through the cardiovascular system. Thus, measurement of heart elasticity by elastography techniques may play a key role in the diagnosis of cardiac dysfunction. This paper presents a novel approach in cardiac MR elastography. The method relies on shear waves with amplitudes in the order of the in-plane resolution of vibration-synchronized MRI. Wall oscillations in the heart can directly be monitored in magnitude images without the need of specialized motion encoding gradients and phase unwrapping algorithms.

16:24         276.       Anatomic & Functional Cardiac MR at 7T: A Comparison of 4, 8 & 16-Element Transceive RF Coil Designs

Lukas Winter1, Christof Thalhammer1, Matthias Dieringer1,2, Celal Özerdem1, Jan Rieger1, Fabian Hezel1, Wolfgang Renz3, Thoralf Niendorf1,2

1Berlin Ultrahigh-Field Facility, Max Delbrueck Center for Molecular Medicine, Berlin, Germany; 2Experimental & Clinical Research Center (ECRC), Charité Campus Buch, Humboldt-University, Berlin, Germany; 3Siemens AG, Erlangen, Germany

Multichannel transmit and receive coil arrays give promising results to overcome the challenges towards clinical cardiac imaging at ultrahigh field strengths. The comparison of 4-, 8- and 16-channel cardiac coils shows a higher SNR, CNR as well as image homogeneity while moving towards a higher number of TX/RX elements. Clinically relevant short axis and four chamber view cardiac 2D CINE FLASH, tag band prepared 2D CINE FLASH and 2D CINE SSFP images were acquired and compared.

16:36         277.       Free-Breathing 3D Whole Heart Black Blood Imaging with Motion Sensitized Driven Equilibrium

Subashini Srinivasan1,2, Peng Hu2, Kraig V. Kissinger2, Beth Goddu2, Lois Geopfert2, Ehud J. Schmidt3, Sebastian Kozerke1, Reza Nezafat2

1Institute of Biomedical Engineering, ETH, Zurich, Switzerland; 2Department of Medicine (Cardiovascular Division), Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; 3Department of Radiology, Brigham & Women’s Hospital, Harvard Medical School, Boston, MA, USA

2D black blood imaging of the heart is commonly used in the assessment of myocardial wall anatomy, cardiac masses and other pathologic conditions. In this study, we describe a free-breathing whole heart 3D black-blood imaging using MSDE preparation pulse. Images with T1 weighted turbo spin echo, spoiled gradient echo, and balanced steady state free precession in axial and short axis planes were acquired from 7 healthy adult subjects. Excellent suppression of blood and clear delineation of the cardiac chamber walls and papillary muscle was observed with all the imaging sequences but with additional undesired signal loss in the myocardium (14%-27%).

16:48         278.       Temporal Evolution of Cardiac Function in Mice with Myocardial Hypertrophy & Heart Failure

Bastiaan J. van Nierop1, Elza D. van Deel2, Dirk J. Duncker2, Gustav J. Strijkers1, Klaas Nicolay1

1Biomedical NMR, Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, Netherlands; 2Department of Cardiology, Thoraxcenter, Erasmus MC, University Medical Center Rotterdam, Rotterdam, Netherlands

In this study the temporal evolution of cardiac function was studied in C57BL/6 mice with a mild constriction of the aorta, resulting in compensated hypertrophy, and in mice with a severe constriction of the aorta. Only the mice with a severe constriction showed a progressive increase in left ventricular mass accompanied by a progressive decline of left and right ventricular ejection fraction, as well as lung edema. The different disease progression between both animal models opens unique opportunities to study interventions, and to study different aspects of myocardial hypertrophy during the transition from compensated hypertrophy towards overt HF.

17:00         279.       Molecular & Microstructural Changes Accompanying Left Ventricular Hypertrophy Revealed with In-Vivo Diffusion Tensor MRI (DTI) & Molecular Imaging of the Mouse Heart

Shuning Huang1, Choukri Mekkaoui1, Miloslav Polasek1, Howard H. Chen1, Ruopeng Wang1, Soeun Ngoy2, Ronglih Liao2, Van J. Wedeen1, Guangping Dai1, Peter Caravan1, David E. Sosnovik1,3

1Martinos Center for Biomedical Imaging, Mass General Hospital, Charlestown, MA, USA; 2Cardiology, Brigham & Woman's Hospital, Boston, MA, USA; 3Cardiology, Mass General Hospital, Boston, MA, USA

The transition from adaptive hypertrophy to heart failure is poorly understood. Here, we use molecular MRI of a collagen-binding gadolinium chelate and in-vivo diffusion tensor MRI (DTI) of the mouse heart to characterize the response of the left ventricle to pressure overload. We show that pressure overload results in significant amounts of fibrosis and circumferential realignment of myofibers well before the overt transition to diastolic heart failure.

17:12         280.       Human Statistical Atlas of Cardiac Fiber Architecture from DT-MRI

Herve Lombaert1,2, Jean-Marc Peyrat3, Stanislas Rapacchi4, Laurent Fanton5, Herve Delingette2, Nicholas Ayache2, Pierre Croisille4

1Ecole Polytechnique, Montreal, QC, Canada; 2Asclepios, INRIA, Sophia-Antipolis, France; 3Siemens Molecular Imaging, Oxford, United Kingdom; 4Creatis-LRMN, HCL, Lyon, France; 5Institut Universitaire de Médecine Légale, Lyon, France

A human statistical atlas of the cardiac fiber architecture is constructed from ex-vivo diffusion tensor images and is based on a set of 10 normal human hearts. To the best of our knowledge, this is the first time that such study has been conducted with human data. We have developed a semi-automated method where only minimal interactions are required for the segmentation of the myocardium, and where the registrations are fully automated via symmetric log domain diffeomorphic demons. The results on the variability of human cardiac fibers concur with studies on other mammals. The cardiac fiber orientation is indeed much more consistent across our population than the orientation of the cardiac laminar sheets.

17:24         281.       In Vivo Characterization of Myocardial Microstructure in Normal & Infarcted Hearts using the Supertoroidal Model

Choukri Mekkaoui1, Shuning Huang1, Guangping Dai1, Timothy G. Reese1, Marcel P. Jackowski2, David Sosnovik3

1Radiology, Harvard Medical School, Massachusetts General Hospital, Martinos Center For Biomedical Imaging, Charlestown, MA, USA; 2Computer Science, University of São Paulo, Institute of Mathematics & Statistics, São Paulo, Brazil; 3Cardiology, Harvard Medical School, Massachusetts General Hospital, Martinos Center For Biomedical Imaging, Charlestown, MA, USA

The supertoroid-based representation of cardiac diffusion tensor MRI (DT-MRI) has previously been shown to enhance the three-dimensional perception of myocardial tissue structure and organization. In this work, the quantification of DT-MRI data using the supertoroidal model is performed in vivo for the first time. The toroidal indices TV and TC revealed that diffusivity and anisotropy values are homogeneous and highly reproducible in the myocardium in vivo. Changes in diffusivity in infarcted myocardium are detected with greater sensitivity with TV than MD. The supertoroidal formalism thus holds significant promise for the analysis of myocardial microstructure with DT-MRI.

17:36         282.       Sequence Timing Optimization in Multi-Slice Diffusion Tensor Imaging of the Beating Heart

Christian Torben Stoeck1, Nicolas Toussaint2, Peter Boesiger1, Philip G. Batchelor2, Sebastian Kozerke1,2

1Institute for Biomedical Engineering, University & ETH Zurich, Zurich, Switzerland; 2Imaging Sciences, King's College London, London, United Kingdom

Cardiac DTI faces major challenges due to underlying physiological motion such as breathing and the heart beat. Therefore the timing of diffusion encoding is essential for the success of diffusion weighted imaging in the heart. In this Study we introduce a dynamic timing scout sequence and investigate time windows during the cardiac cycle usable for DTI. Imaging is possible during the upslope of circumferential contraction and symmetry point of rotational motion. It appears that the optimal timing window is independent of the subject’s heart rate.

17:48         283.       Imaging Three-Dimensional Myocardial Mechanics in Mice using Volumetric Spiral Cine DENSE

Xiaodong Zhong1, Lauren B. Gibberman2, Andrew D. Gilliam3, Craig H. Meyer2,4, Brent A. French4, Frederick H. Epstein2,4

1MR R&D Collaborations, Siemens Healthcare, Atlanta, GA, USA; 2Radiology Department, University of Virginia, Charlottesville, VA, USA; 3Andrew D. Gilliam Consulting, Providence, RI, USA; 4Biomedical Engineering Department, University of Virginia, Charlottesville, VA, USA

MRI of myocardial mechanics in mice enables the investigation of the roles of individual genes and experimental therapies in cardiac function. While two-dimensional tagging, HARP, and DENSE have previously been demonstrated in the mouse heart, myocardial mechanics are more comprehensively assessed using three-dimensional (3D) methods. In this study, 3D cine DENSE acquisition and analysis methods for mice imaging were developed, and were evaluated in normal mice. A comprehensive assessment of 3D myocardial mechanics in mice can be performed with a scan time of less than 25 minutes and a segmentation time of about an hour, followed by automatic post-processing.

Static & Dynamic Bo

Room 511D-F                    16:00-18:00                                                                Moderators: Christoph Juchem & Kevin M. Koch

16:00         284.       Correction of Breathing-Induced Artefacts in High-Field Brain MRI using Concurrent Field Monitoring

Johanna Vannesjö1, David Brunner1, Christoph Barmet1, Klaas Paul Pruessmann1

1Institute for Biomedical Technology, University & ETH Zurich, Zurich, Switzerland

Artefacts in anatomical brain images stemming from field fluctuations caused by breathing have previously been reported, and a navigator-based correction scheme has been shown. In this work, concurrent field monitoring was used to observe field shifts correlated with breathing, and to correct for breathing-related artefacts by including the monitored field evolutions in the image reconstruction. One advantage of the field monitoring approach, is that no alteration or extension of the imaging sequence is required.

16:12         285.       Theoretical Basis of Projection Based Shim Estimation

Daniel Nicolas Splitthoff1, Maxim Zaitsev1

1Dept. of Radiology, Medical Physics, Unversity Medical Center Freiburg, Freiburg, Germany

Projections have been suggested for estimating B0 inhomogeneities. A detailed analysis of the phase difference of projections is given and put into the framework of linear algebra. The insights gained from this analysis lead to the conclusion that for proper detection of inhomogeneities the cross talk of the different orders need to be taken into account. We here present a solution of how to measure the cross talk when no further a priori information is available and show the benefit in a phantom measurement.

16:24         286.       Instant Measurement of Point Spread Functions using an NMR Field Probe

Lars Kasper1,2, Bertram Jakob Wilm1, Christoph Barmet1, Klaas Paul Prüssmann1

1University & ETH Zurich, Institute for Biomedical Engineering, Zurich, Switzerland; 2University of Zurich, Laboratory for Social  & Neural Systems Research, Zurich, Switzerland

The point spread function (PSF) is a comprehensive concept to describe the imaging and reconstruction process in MRI. Its analysis gives insight into the signal model of MR sequences as well as their imperfections, thus revealing true resolution and typical artifacts. By definition, the PSF describes the mapping of a point source of MR signal onto pixels of an image reconstruction matrix. We take this definition literally and use a miniaturized water-filled NMR field probe to determine the PSF experimentally. Hereby, we treat the MR scanner as a black box and infer information about the reconstruction characteristics solely from probing.

16:36         287.       Accelerated Point Spread Function Mapping using Signal Modelling for Accurate EPI Geometric Distortion Correction

Iulius Dragonu1, Thomas Lange1, Nicoleta Baxan1, Jürgen Hennig1, Maxim Zaitsev1

1Dept. of Radiology, Medical Physics, University Medical Center Freiburg, Freibug, Baden-Wuerttemberg, Germany

Single-shot EPI is a fast technique allowing the acquisition of an image following a single RF excitation. However, EPI is prone to geometric distortions in presence of magnetic field inhomogeneities. We propose here a new method based on the modelling of the PSF data signal to allow accelerated acquisition for accurate geometric distortion corrections.

Fully sampled PSF data of healthy volunteers were acquired. Undersampling factors up to 12.8 in the PSF-encoding direction were subsequently simulated. The pixel shift map obtained with the undersampled data and fully sampled data were compared. For each experiment the maximum error was below 0.15 pixels.

16:48         288.       Comprehensive Correction of Artifacts due to Eddy Current-Induced Echo Shifts in Partial Fourier DTI

Trong-Kha Truong1, Nan-kuei Chen1, Allen W. Song1

1Brain Imaging & Analysis Center, Duke University, Durham, NC, USA

Partial Fourier imaging is typically used in DTI to increase the SNR. However, eddy currents induced by the diffusion gradients lead to: 1) signal loss if the echo is shifted outside the acquired k-space, 2) partial Fourier reconstruction errors if the echo is shifted outside the central k-space, and 3) variation of the effective TE, resulting in additional T2*-weighting. All three types of artifact vary with location and diffusion direction, causing errors in the diffusion tensor. Here, we propose a novel acquisition and post-processing method that can effectively correct for all three types of artifact while maintaining a high SNR.

17:00         289.       Magnetic Resonance Imaging of Arthroplasty: Comparison of  MAVRIC & Conventional Fast Spin Echo Techniques

Matthew F. Koff1, Catherine Lee Hayter1, Parina Shah1, Kevin M. Koch2, Theodore T. Miller1,3, Hollis G. Potter1,3

1Department of Radiology & Imaging, Hospital for Special Surgery, New York, NY, USA; 2Applied Science Laboratory, General Electric Healthcare, Waukesha, WI, USA; 3Weill Cornell Medical College of Cornell University, New York, NY, USA

Significant susceptibility artifacts occur when performing MRI around orthopedic hardware. This study evaluated standard of care 2D FSE imaging with the multi-acquisition variable-resonance image combination (MAVRIC) technique. Patients with joint replacements (hip or shoulder) were scanned using optimized 2D FSE and MAVRIC sequences. MAVRIC scans improved the visualization of the synovium, bone and supraspinatus tendon in the shoulder. MAVRIC scans resulted in increased detection of synovitis, peri-prosthetic osteolysis and supraspinatus tendon tears, resulting in a change in diagnosis almost 50% of the cases. This study further supports the use of MAVRIC for clinical implementation.

17:12         290.       MRI Assessment of Wear-induced Synovitis

Catherine Lee Hayter1, Hollis G. Potter1,2, Douglas E. Padgett3, Giorgio Perino4, Bryan J. Nestor3

1Department of Radiology & Imaging, Hospital for Special Surgery, New York, NY, USA; 2Weill Cornell Medical College of Cornell University, New York, NY, USA; 3Department of Orthopedic Surgery, Hospital for Special Surgery, New York, NY, USA; 4Department of Pathology, Hospital for Special Surgery, New York, NY, USA

This study assessed the ability of MRI to detect different qualitative patterns of synovitis in symptomatic patients with hip arthroplasty compared to asymptomatic controls. We hypothesized a distinct, qualitative synovial MRI pattern would exist for metal on metal wear, metal on polymeric debris and aseptic lymphocytic vasculitis-associated lesions (ALVAL), that would be concordant with histologic findings. MRI could distinguish between tissue containing particulate debris and tissue without debris. MRI was sensitive in detecting polymeric debris, but did not detect the presence of metal in all samples. ALVAL elicited a specific synovial pattern on MRI that was highly concordant with histology.

17:24         291.       New MR Imaging Methods for Metallic Implants in the Knee: Artifact Correction & Clinical Impact

Christina A. Chen1, Weitian Chen2, Stuart B. Goodman, Brian A. Hargreaves, Kevin M. Koch2, Wenmiao Lu3, Anja C. Brau2, Hillary J. Braun, Garry E. Gold

1Radiology, Stanford University, Stanford, CA, USA; 2GE Healthcare Applied Science Lab; 3Nanyang Technological University

Slice Encoding for Metal Artifact Correction (SEMAC) is a recently developed MRI method that corrects for the metal-induced artifact that has previously limited the diagnostic value of postoperative images.  This study found SEMAC to accurately measure metallic implant rotation in the knee, as implant misalignment is an important cause of implant pain and revision surgery.  In addition, SEMAC significantly reduces artifact compared to fast spin echo in subjects, allowing for visualization of knee pathology that was able to guide patient management.

17:36         292.       Metal Artifact Reduction using Slice Encoding with Shear Correction

Pauline Wong Worters1, Kim Butts Pauly1, Brian A. Hargreaves1

1Stanford University, Stanford, CA, USA

Slice Encoding for Metal Artifact Correction (SEMAC) is a robust method for resolving spatial distortion of tissue around metal in MRI.  This method, as well as an alternative hybrid MAVRIC sequence, uses View-Angle Tilting (VAT) to correct for distortion in the readout direction.  However, VAT imposes timing limitations in order to reduce blurring due to the RF profile.  In this work, a shear post-processing method is proposed to replace VAT to correct for readout distortions.  Shear correction allows for longer readout acquisitions (e.g., by using a lower readout bandwidth) and avoids the timing limitations imposed by VAT, while maintaining effective artifact correction. 

17:48         293.       Frequency Encoding in the Presence of Extreme Static Field Gradients

Kevin M. Koch1, Kevin F. King1, Weitian Chen2, Garry E. Gold3, Brian A. Hargreaves3

1Global Applied Science Laboratory, GE Healthcare, Waukesha, WI, USA; 2Global Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA; 3Department of Radiology, Stanford University, Stanford, CA, USA

MR capabilities when imaging in the direct vicinity of metallic devices have been substantially improved with the development of 3D-MSI methods.  The MAVRIC, SEMAC, and VS-MSI techniques have shown promising clinical capabilities in diagnosing soft-tissue pathology in previously inaccessible regions.  Here, we discuss some limitations on how close 3D-MSI, or any technique relying on frequency-encoding, can image near metal in the presence of substantial local induction gradients.   The presented analysis and results can aid in explaining residual artifacts in 3D-MSI and in predicting the effective spectral coverage required by the techniques. 

Arterial Spin Labeling

Room 512A-G                   16:00-18:00                                                                       Moderators: David C. Alsop & Wen-Chau Wu

16:00         294.       Blind Detection of Source Vessel Locations & Resonance Offsets using Randomly Encoded VEASL

Eric Wong1, Jia Guo2

1Radiology/Psychiatry, UC San Diego, La Jolla, CA, USA; 2Bioengineering, UC San Diego, La Jolla, CA, USA

In Vessel Encoded ASL (VEASL), arteries in the tagging plane are encoded in a pseudo-continuous ASL tagging scheme to allow for the identification of vascular territories.  Resonance offsets in the tagging plane reduce tagging efficiency and can be alleviated using multiphase approaches.  In this work, we introduce the use of random encoding to simultaneously encode and identify both the vessel locations and resonance offsets with high efficiency and without any prior knowledge.  We expect that this approach will be useful when collateral or variant circulation may be present, and resonance offsets significant.

16:12         295.       Mapping Cerebral Blood Flow Territories using Harmonic Encoding Pseudocontinuous Arterial Spin Labeling, Fuzzy Clustering & Independent Component Analysis

Wen-Chau Wu1,2

1Graduate Institute of Oncology, National Taiwan University, Taipei, Taiwan; 2Graduate Institute of Clinical Medicine, National Taiwan University, Taipei, Taiwan

Vessel-encoded pseudocontinuous arterial spin labeling (VEPCASL) is a novel MRI technique with capability of differentiating flow territories of the primary arteries passing through a predefined tagging plane. We implemented VEPCASL with harmonic encoding to expand feature dimension and employed ICA and FCM clustering for territory separation. Results have shown that ICA and FCM substantially improve the robustness of K-means clustering. Feature dimension can be efficiently expanded using harmonic encoding, especially along the direction where vascular branches are more complex. FCM may depict the borderline of two or more flow territories and provide useful information for clinical evaluation of watershed infarction.

16:24         296.       Increased Tagging Efficiency in Velocity Selective ASL using Multiple Velocity Selective Saturation Modules

Jia Guo1, Eric C. Wong2

1Bioengineering, University of California San Diego, La Jolla, CA, USA; 2Department of Radiology & Psychiatry, University of California San Diego, La Jolla, CA, USA

In VSASL, arterial blood is tagged by velocity selective saturation (VSS).  This method is inherently insensitive to transit delays and may be useful in applications where transit delay can be long, such as white matter and in stroke. In this work, we note that by using two or more VSS modules, T1 decay of the tag can be reduced, increasing the overall tagging efficiency and hence the SNR of VSASL.   Dual VSS VSASL was implemented and tested in human volunteers, and the measured signal was approximately 40% higher using 2 VSS modules, in good agreement with theory.

16:36         297.       Arrival Time Changes Demonstrate Active Cerebral Autoregulation in Normal Subjects using Lower Body Negative Pressure & Arterial Spin Labeling MRI

John Robert Cain1, Gerard Thompson1, Laura M. Parkes1, Alan Jackson1

1Imaging Science, University of Manchester, Manchester, United Kingdom

Cerebral autoregulation maintains cerebral perfusion during varying cardiac outputs. We present MRI perfusion data demonstrating active cerebral autoregulation.

We constructed an MRI compatible lower body negative pressure (LBNP) chamber and investigated its effects on cerebral perfusion and bolus arrival time (BAT) using arterial spin labeling.

Ten volunteers (24-31years) underwent MRI during the control state and -20mmHg LBNP.

-20mmHg LBNP reduced cardiac output by 0.5l/min. No difference between grey matter (GM) perfusion was found between control and -20mmHg LBNP. GM BAT was delayed during -20mmHg LBNP. The BAT delay suggests -20mmHg LBNP causes autoregulatory mechanisms to dilate vessels maintaining GM perfusion.

16:48         298.       Modelling Dispersion in Arterial Spin Labelling with Validation from ASL Dynamic Angiography

Michael A. Chappell1,2, Bradley J. MacIntosh2,3, Mark W. Woolrich2, Peter Jezzard2, Stephen J. Payne1

1Institute of Biomedical Engineering, University of Oxford, Oxford, United Kingdom; 2FMRIB Centre, University of Oxford, Oxford, United Kingdom; 3Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada

The dispersion of the labelled bolus in Arterial Spin Labeling (ASL) has a substantial effect on the quantification of cerebral blood flow. A number of models exist to account for dispersion effects. However, the comparison and validation of these models is difficult using the conventional perfusion signal. Here data from an ASL preparation coupled with a dynamic angiographic readout is used to capture signal whilst blood is still within the arteries. A ‘Goodness-of-fit’ metric for the different models is compared and models based on a vascular transport function with an asymmetric kernel appear to be most accurate.

17:00         299.       Cardiac Triggering & Label-Control Transition Profiles in Hadamard Encoded Pseudo-Continuous Arterial Spin Labeling

Wouter Teeuwisse1, Michael Helle2, Susanne Rüfer2, Matthias J. P. van Osch1

1Radiology, C. J. Gorter Center for High Field MRI, Leiden University Medical Center, Leiden, Netherlands; 2Institute for Neuroradiology, Christian-Albrechts-Universität, UK-SH, Kiel, Germany

Hadamard encoded continuous ASL is a promising technique to obtain dynamic ASL angiography images and temporal information such as transport delay time in a short scan time. However blurring of the encoding pattern by the cardiac cycle and non instantaneous switching between label and control can hamper the efficacy. By means of simulations and in vivo experiments, the necessity of cardiac triggering is shown and a minimum switching time of 50 ms for pCASL is demonstrated.

17:12         300.       Impact of Equilibrium Magnetization of Blood On ASL Quantification

Yufen Chen1, Ze Wang1,2, John A. Detre1

1Center for Functional Neuroimaging, University of Pennsylvania, Philadelphia, PA, USA; 2Department of Psychiatry, University of Pennsylvania, Philadelphia, PA, USA

The equilibrium magnetization of blood (M0b) is an important factor for ASL quantification that is difficult to measure due to the low image resolution. In this study, we compared the quantification results of map-based and ratio-based M0b estimates. Although the gray matter cerebral blood flow (CBF) estimates were similar, map-based M0b reduced the gray to white matter contrast of the CBF maps unless tissue-specific partition coefficients are used. Ratio-based M0b methods are preferred but require accurate T2* and coil sensitivity correction for accurate CBF quantification.

17:24         301.       Quantification of Cerebellar Blood Flow using Arterial Spin Labeling

Alan Jerry Huang1,2, Jun Hua1, Jonathan Farrell1, Qin Qin1, James J. Pekar1, Matthias van Osch3, John E. Desmond4, Peter van Zijl

1FM Kirby Research Center, Johns Hopkins University, Baltimore, MD, USA; 2Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, USA; 3Department of Radiology, Leiden University Medical Center, Leiden, Netherlands; 4Department of Neurology, Johns Hopkins University, Baltimore, MD, USA

The cerebellum is an important part of the brain responsible for motor functions, sensory control, and cognitive function. Arterial spin labeling (ASL) is a non-invasive, non-ionizing technique that allows for repetitive measurements of perfusion. The location of the cerebellum allows for access of labeled spins to reach the cerebellum quickly allowing for higher temporal resolution of ASL scans. We report an average cerebellar gray matter perfusion value of 63.6±5.0 mL/100 g parenchyma/min for three healthy subjects.

17:36         302.       Comparison of Pseudocontinuous & Velocity Selective Arterial Spin Labeling with Gold Standard Xenon CT: A Study in Patients with Moyamoya Disease

Deqiang Qiu1, Michael E. Moseley1, Greg Zaharchuk1

1Lucas Imaging Center, Stanford University, Stanford, CA, USA

In this study, we compared the performance of 3D-FSE pseudocontinuous arterial spin labeling (pcASL) acquired at multiple post-label delay times and velocity-selective ASL (VSASL) in Moyamoya disease patients, who have known arterial transit arrival delay due to collateral networks. Stable xenon CT perfusion served as a CBF gold standard. Mean CBF differences and correlations were determined and compared.  VSASL was shown to provide relatively more accurate absolute measurement of CBF values, though its correlation with xeCT measurement is not as strong as for pcASL due to overall lower SNR.

17:48         303.       SPECT Validation of Pseudo-Continuous Arterial Spin Labeling MRI

Peiying Liu1, Jinsoo Uh1, Michael D. Devous2, Bryon Adinoff3,4, Hanzhang Lu1

1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, USA; 2Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, USA; 3Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, USA; 4VA North Texas Health Care System, Dallas, TX, USA

Pseudo-continuous Arterial Spin Labeling (PCASL) as a new arterial spin labeling (ASL) technique has shown great promises in terms of sensitivity and practicality. Validation of this technique with a gold-standard method would provide a critical step toward wider applications in neurological and brain mapping studies. Here we first determined the arterial transit times which are important in the quantification of CBF from ASL signals by measuring the time difference between the appearance of Gd-DTPA bolus in the labeling and imaging slices, respectively. We then conducted a validation study of PCASL using a radiotracer-based single photon emission computer tomography (SPECT) method.

Spectroscopy Quantification & Metabolism

Room 513A-D                   16:00-18:00                                                                     Moderators: Ulrike Dydak & Richard A. Edden

16:00         304.       Measurement of Elevated 2-Hydroxyglutaric Acid in Brain Tumors By Difference Editing At 3T In Vivo

Changho Choi1, Sandeep Ganji1, Zoltan Kovacs1, Ralph DeBerardinis1, Elizabeth Maher1

1University of Texas Southwestern Medical Center, Dallas, TX, USA

Recent mass spectroscopy studies in-vitro and ex-vivo indicated that a fraction of gliomas contain mutations of isocitrate dehydrogenase-1 and -2, causing accumulations of 2-hydroxyglutaric acid (2HG). Here, we present in vivo detection of 2HG in human brain tumors by means of difference editing at 3T. The C2-proton resonance of 2HG at 4.02 ppm was edited using a 20 ms Gaussian radio-frequency (RF) pulse for selective 180„a rotation of the its coupling partners at ~1.9 ppm. In vivo measurement was conducted in various tumors. The results indicated that 2HG is elevated to 2 - 8 mM in low-grade gliomas and secondary glioblastomas.

16:12         305.       Elucidating Brain Metabolism by Dynamic 13C Isotopomer Analysis

Alexander A. Shestov1, Dinesh K. Deelchand1, Kamil Ugurbil1, Pierre-Gilles Henry1

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

Information from 13C isotopomers, which appear as multiplets in 13C NMR spectra can be measured and quantified in vivo. We show here that using this additional information on isotopomers along with an extended brain bionetwork model allows accurate fitting of the experimental dynamic 13C isotopomer turnover curves.

16:24         306.       Increased Brain Monocarboxylic Acid Transport & Metabolism in T1DM Patients with Hypoglycemia Unawareness

Henk M. De Feyter1, Barbara I. Gulanski2, Kathleen A. Page3, Anne Howard O'Connor, Ellen V. Hintz, Susan M. Harman, Renata Belfort De Aguiar, Graeme F. Mason, Douglas L. Rothman, Robert S. Sherwin

1Diagnostic Radiology, Yale University, New Haven, CT, USA; 2VA Connecticut Healthcare System, West Haven; 3USC Keck School of Medicine, Los Angeles, USA

Previously we showed in well-controlled type 1 diabetes patients increased brain metabolism of acetate, a monocarboxylic acid (MCA) transported over the blood-brain barrier via MCT1. However, it is unclear whether these adaptations are related to frequency and severity of hypoglycemic episodes or type 1 diabetes per se. We therefore investigated the relationship between cortical metabolic adaptations and i) severity of antecedent hypoglycemia unawareness and ii) counterregulatory response to acute hypoglycemia using 13C MRS and infusion of [2-13C]-acetate and show how the severity of hypoglycemia unawareness and lack of counterregulatory response is independent of diabetes and correlates with the degree of MCA transport and metabolism.

16:36         307.       Brain Glycogen Content & Metabolism in Type 1 Diabetes

Gulin Oz1, Nolawit Tesfaye1, Anjali Kumar1, Dinesh K. Deelchand1, Elizabeth R. Seaquist1

1University of Minnesota, Minneapolis, MN, USA

Supercompensated brain glycogen levels may contribute to the development of hypoglycaemia unawareness in patients with type 1 diabetes (T1D) by providing energy for the brain during periods of hypoglycaemia. To determine if brain glycogen content is higher in patients with T1D and hypoglycaemia unawareness, brain glycogen content and turnover was measured in 5 patients and 5 age/gender/BMI matched healthy controls using 13C MRS and IV infusion of [1-13C]glucose followed by [1-12C]glucose for a total of 50h. A strong trend for lower glycogen levels in patients than controls (p=0.05) was observed, refuting supercompensated glycogen levels in T1D and hypoglycaemia unawareness.

16:48         308.       Definition of the Macromolecular Baseline Based On T1 As Well As T2 Properties

Daniel Guo Quae Chong1, Christine S. Bolliger2, Johannes Slotboom3, Chris Boesch2, Roland Kreis2

1Dept. of Diagnostic, Interventional & Pediatric Radiology (DIPR), Inselspital, Bern, Switzerland; 2Dept. of Clinical Research, University of Bern, Bern, Switzerland; 3Institute for Diagnostic & Interventional Neuroradiology, Inselspital, Bern, Switzerland

Macromolecule baseline (MMBl) determination have usually been done with inversion recovery or saturation recovery techniques. This abstract presents an alternative using both T1 and T2 information by combining inversion recovery and 2D JPRESS spectra iteratively. Part of the study involves ensuring repeatability and the result suggests that MMBl has inter-individual variability.

17:00         309.       Metabolite Concentration Changes during Visual Stimulation using Functional Magnetic Resonance Spectroscopy (Fmrs) on a Clinical 7T Scanner

Benoit Michel Schaller1, Ralf Mekle2, Lijing Xin3, Rolf Gruetter1,4

1Laboratory of Functional & Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Vaud, Switzerland; 2Physikalisch-Technische Bundesanstalt, Berlin, Germany; 3Department of Radiology, University of Lausanne, Lausanne, Switzerland; 4Department of Radiology, Universities of Lausanne and Geneva, Switzerland

Functional MR Spectroscopy allows direct measurement of low concentrated metabolites with small concentration changes (<0.2µmol/g) during neuronal activation providing insight into brain metabolism. In this study, the inter-subject analysis revealed an increase of [Lac] of 20±3%, [Glu] of 10±5% and a decrease of [Asp] of 5±4% in the visual cortex during the activation. The use of SPECIAL sequence at 7T yielded increased SNR compared to STEAM providing a twofold time resolution for the time courses of different metabolites concentration (Lac and Glu). Fewer scans had to be averaged to enable reliable metabolite quantification.

17:12         310.       Classification of Single Voxel 1H Spectra of Brain Tumours using Lcmodel

Felix Raschke1, Elies Fuster-Garcia2,3, Kirstie Suzanne Opstad1, Franklyn Arron Howe1

1Division of Clinical Science, St George’s University of London, London, United Kingdom; 2IBIME & ITACA, Universidad Politécnica de Valencia, Valencia, Spain; 3Universitat Internacional Valenciana, Valencia, Spain

This study presents a novel method for the direct classification of single voxel 1H MR spectra of brain tumours using the widespread analysis tool LCModel. LCModel is designed to estimate individual metabolite proportions by fitting a linear combination of metabolite spectra to an in vivo MR spectrum, but here is used to fit representations of complete tumour spectra. Classification according to the highest estimated tumour proportion in a test set of 46 spectra comprising high grade gliomas, low grade gliomas and meningiomas, LCModel gives a classification accuracy of 93% compared to 95% by the INTERPRET Decision Support System.

17:24         311.       Investigating the Metabolic Changes Due to Visual Stimulation using Functional Proton Magnetic Resonance Spectroscopy At 7T

Yan Lin1,2, Mary C. Stephenson1, Samuel J. Wharton1, Lijing Xin3, Olivier E. Mougin1, Antonio Napolitano4, Peter G. Morris1

1Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom; 2Medical Imaging Department, Second Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong, China, People's Republic of; 3Laboratory of Functional & Metabolic Imaging, Ecole Poly technique Federale de Lausanne, Lausanne, Switzerland; 4Academic Radiology, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom

Previous functional proton MRS studies of the activated human brain at 7T investigated the changes in the levels of Lac, Glu, Asp and Glc, these related mainly to oxidative energy metabolism. Our results demonstrate the changes in Glu (increased by 2%¡À1%), Gln (decreased by 5%¡À3%), Asp(decreased by 9%¡À6%), Lac(increased by 9%¡À6%), Glc (decreased by 30%¡À14%), GSH (increased by 7%¡À2%), and Gly (decreased by 19%¡À5%), in response to visual stimulation. On the basis of these results from the visual cortex, we propose an increase in oxidative metabolism, excitatory neurotransmitter cycling and GSH synthesis, possibly related to Glu clearance and ROS detoxification.   

17:36         312.       Quantitative MRS of Ovaries & Ovarian Masses at 3T: Methodology & Initial Findings

Patrick J. Bolan1, Jori S. Carter2, Navneeth Lakkadi1, Levi S. Downs Jr. 2

1Radiology/CMRR, University of Minnesota, Minneapolis, MN, USA; 2Obstetrics, Gynecology & Women’s Health, University of Minnesota, Minneapolis, MN, USA

This work describes the development of a methodology for performing quantitative 1H MRS in ovarian masses and normal ovaries at 3T and reports the initial findings in 68 spectra. MRS performance varied depending on the structure measured: healthy ovaries had low SNR due to small size, cystic regions had low metabolic content, and solid regions regularly showed a total choline (tCho) resonance and occasionally other metabolites including creatine, glycine, and an unidentified 2.05ppm resonance. The new quantification method, which uses T2-corrected water as an internal reference, found tCho ranging from 0.2-3.4 mmol/kg in solid regions.

17:48         313.       Hepatic Glycogen Metabolism in Mice by In Vivo 13C MRS at 14T

Christine Nabuurs1, Frederic Preitner2, Bernard Thorens2, Rolf Gruetter3

1CIBM, Hôpitaux Universitaires de Genève (HUG), Lausanne, Switzerland; 2Mouse Metabolic Facility, Center for Integrative Genomics, UNIL, Lausanne, Switzerland; 3Laboratory of Functional & Metabolic Imaging (LIFMET), l'Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland

Contributions of direct and indirect glycogen synthesis in liver tissue can be determined by 13C MRS upon labeled glucose infusion. We optimized a protocol for in vivo MRS at 14T in mouse liver to study the incorporation of 13C into different positions of glycogen by overcoming the large bandwidth needed for simultaneous detection of signals with a chemical shift difference of 6kHz by applying interleaved transmitter frequencies. This allowed for sufficient time resolut