2010 Annual Meeting Program Committee

 

Local Organizing Committee

 

Reviewer List

 

2009 Teacher Awards

 

Continuing Education

 

Declaration of Financial Interest and Relationships for Invited Speakers & Organizers

 

Declaration of Financial Interest and Relationships for Authors of Proffered Papers

 

Sponsors

 

ISMRM/ESMRMB Staff

OPENING SESSION

Room A1        07:15 – 8:25      Chairs: David G. Norris, ISMRM President  & Isabel Berry, M.D., Ph.D., ESMRMB President

 

 
07:15                                       Welcome and Awards Presentations

2010 LAUTERBUR LECTURE

Room A1        08:25 – 9:05      Chair:  David G. Norris, ISMRM President

 

 
08:25                       Lauterbur Lecture: MRI Over the Next Decade: Quo Vadis?

William G. Bradley, M.D., Ph.D.

University of California, San Diego, CA, USA

Clinical Needs & Technological Solutions: Alzheimer's & Dementia

A1       09:05-10:15         Organizers & Moderators: Stefan Sunaert and Mark A. van Buchem

09:05                       1.             Clinical Needs for Dementia and AD: Revising the Criteria

Bruno Dubois1

1Hôpital La Salpêtrière, Paris, France

New diagnostic criteria for Alzheimer disease have been recently proposed that are centered around a clinical core of early and significant episodic memory impairment. They stipulate that in addition there must also be at least one or more abnormal biomarkers amongst structural neuroimaging with MRI, molecular neuroimaging with PET and CSF analysis of amyloid β/tau proteins. The timeliness of these criteria is underscored by the myriad of drugs currently under development that are directed at altering the disease pathogenesis, particularly at the production and clearance of amyloid β as well as at the hyperphosphorylation state of tau.

09:25                       2.             Imaging Solutions I: Structural and Functional Imaging

Wiesje M. van der Flier1

1Lieden University, Leiden, Netherlands

MRI has an increasingly large role in the clinical work-up of dementia. In the new research criteria, atrophy of the medial temporal lobe is mentioned as one of the diagnostic criteria for AD, but norm values are still awaited. Mixed disease (i.e. combination with vascular disease) remains a challenge, as there are no diagnostic guidelines available. MRI measures hold promise as markers of disease progression and can potentially be used as outcome measures in trials. The heterogeneity of AD is increasingly acknowledged. MRI may prove valuable to describe endophenotypes of AD, both in terms of structural and functional brain changes

09:50                       3.             Imaging Solutions II: Molecular Imaging

Louise van der Weerd1

1Leiden University Medical Centre, Leiden, Netherlands

The development of molecular imaging techniques for in vivo assessment of beta-amyloid accumulation in the ageing brain is an important and active area of research in AD. Numerous ligands have been developed with affinity for beta-amyloid, based on beta-amyloid peptide, monoclonal antibody fragments, or small peptides, which were functionalized with iron oxide particles or gadolium chelates. Alternatively, amyloid plaques have been labeled with small molecules containing a 19F atom and visualized using 19F MRI. Up to now, the only compounds that are in use for clinical imaging are nuclear medicine–based amyloid labeling tracers.

CLINICAL INTENSIVE COURSE
(Admission limited to Clinical Intensive Course registrants only)
Shoulder & Elbow Imaging: Case-Based Teaching

K1       08:15-10:15                Organizer & Moderator:  Juerg Hodler

08:15                       Elbow: Case-based
Russell C. Fritz, M.D.

09:15                       Shoulder: Case-based
Lynne S. Steinbach, M.D.

10:15                       Adjournment          

 

CLINICAL INTENSIVE COURSE
Women’s Imaging: Case-Based Teaching

K1          11:00 -13:00                   Moderators:  Talissa Altes, Elmar Max Merkle, and Bachir Taouli

EDUCATIONAL OBJECTIVES
Upon completion of this course participants should be able to:

  • Describe the impact of functional MR methods in body imaging;
  • Apply new body MR techniques in their practice;
  • Use multiparametric MRI for improved diagnosis of abdominal diseases; and
  • Design new female pelvic and prostate MR protocols tailored to new therapeutic methods, introduce these methods and compare them to more conventional approaches.

11:00                       Benign Breast Lesions
                               
Elizabeth A. Morris, M.D.

 

11:30                       Breast MRI: Easy and Difficult Cases
                               
Bonnie N. Joe, M.D., Ph.D.

 

12:00                       Benign Diseases of  the Uterus
                               
Andrea G. Rockall, M.R.C.P., F.R.C.R.

 

12:30                       Ovarian Masses
                               
Evis Sala, M.D., Ph.D., F.R.C.R.

 

13:00                       Adjournment

 

CLINICAL INTENSIVE COURSE
SWI Metalheads: Imaging Brain Iron

K2       11:00 -13:00               Organizers & Moderators:  Stefan Sunaert and Mark A. Van Buchem

EDUCATIONAL OBJECTIVES
Upon completion of this course participants should be able to:

  • Describe methods and underlying principles for obtaining and analyzing susceptibility weighted images;
  • Explain current thinking regarding iron metabolism and deposition within the brain; and
  • Describe several diseases of iron deposition within the brain and the application of susceptibility weighted imaging to diagnosis and study of these processes.

11:00                       SWI Basics, Applications and Pitfalls
Jürgen R. Reichenbach, Ph.D.

 

11:40                       Pathophysiology of Brain Iron
                               
John F. Schenck, M.D., Ph.D.

 

12:20                       Diseases of Iron Deposition
                               
Mark A. Van Buchem, M.D., Ph.D.

 

13:00                       Adjournment

 

MRI of Neural Plasticity

Room A1        11:00-13:00                Moderators: Jeffrey Joseph Neil and John G. Sled

11:00                       Introduction
                                Jeffrey Joseph Neil

11:12                       4.             Training Induced Volume Changes Seen by Structural MRI Correlate with Neuronal Process Remodelling

Jason Philip Lerch1, Adelaide P. Yiu2, Alonso Martinez-Cabal2, Tanyar Pekar2, Veronique D. Bohbot3, Paul Frankland2, R Mark Henkelman1, Sheena A. Josselyn2, John G. Sled1

1Mouse Imaging Centre, Hospital for Sick Children, Toronto, Ontario, Canada; 2Program in Neuroscience and Mental Health, Hospital for Sick Children, Toronto, Ontario, Canada; 3Douglas, Department of Psychiatry, McGill University, Montreal, Quebec, Canada

We correlated training induced volume changes seen by high-resolution mouse MRI with four cellular markers to test whether (1) alterations in neuron numbers/sizes; (2) alterations in astrocyte numbers/sizes; (3) increased neurogenesis/survival of new neurons; or (4) remodelling of neuronal processes best explain the MRI results. We detected a significant positive correlation between GAP-43 and structure volume, but found no correlation between MR volume and any other cellular measure. We can thus conclude that, among the hypotheses tested, the largest explanatory factor for learning induced MRI detectable volume changes is the remodelling of neuronal processes.

11:24                       5.             Do Congenitally Blind People Have a Stria of Gennari? First in Vivo Insights on a Subcortical Level

Robert Trampel1, Derek Veit Ott1, Robert Turner1

1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

The primary visual cortex V1 is characterized by an easily identifiable anatomical landmark: the heavily myelinated stria of Gennari. Using T1, T2, T2* or phase contrast, high resolution MRI studies can routinely identify the stria of Gennari in vivo. However, the development and function of the Gennari stripe is unclear. MRI at 7 Tesla with isotropic 0.5 mm voxels was used to scan the occipital brain of sighted and congenitally blind subjects. The stria of Gennari was reliably detected in both sighted and blind subjects, showing that this anatomical feature is not a developmental result of visual input, and it does not degenerate in the absence of visual input.

11:36                       6.             Cerebral Myelin Content Correlation with Mathematical Abilities in Young Children

Richard Davis Holmes1, Silvia Mazabel2, Burkhard Maedler3, Christian Denk, Linda Siegel4, Christian Beaulieu5, Alex MacKay6

1UBC MRI Research Centre, University of British Columbia, Vancouver, British Columbia, Canada; 2Department of Educational and Counselling Psychology, and Special Education, University of British Columbia; 3Philips Medical Systems; 4Department of Educational and Counselling Psychology and Special Education, University of British Columbia; 5Department of Biomedical Engineering, University of Alberta; 6Department of Physics and Astronomy, University of British Columbia

Structural imaging applied to children with wide ranging mathematical abilities has the potential to elucidate the question of what neural circuits underly computation based tasks. The present investigation analyzed the myelin water fraction images of 20 children in a standard space to deduce correlations between myelin content and math abilities. Subjects wrote a calculation-based test and an applied problem-based test. The results implicated occipital/parietal white matter, the  right anterior limb of the internal capsule and the left external capsule with positive correlations of 0.61,0.65 and 0.60, respectively.

 

11:48                       7.             Structural Brain Plasticity Visualized with Diffusion MRI Following a Learning and Memory Task

Tamar Blumenfeld-Katzir1, Ofer Pasternak2, Yaniv Assaf1

1Neurobiology Department, Tel-Aviv University, Tel-Aviv, Israel; 2Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States

We utilized DTI to follow up on micro-structural changes that occur following a spatial memory task. We scanned rats before and after water maze task and compared their MRI scans using voxel-based statistics. Significant changes in the various DTI parameters were found in a multitude of brain regions including the limbic system and white matter systems. The changes in the DTI indices were found to correlate with immuno-reactivity staining of myelin, synapses and astrocytes. Using these observations, we conclude that DTI can be used as an in-vivo probe of structural plasticity both in gray matter and white matter.

12:00                       8.             Hard-Wired or Soft-Wired ? Evidence for the Structural Plasticity of White Matter Networks Following Anterior Temporal Lobectomy

Mahinda Yogarajah1, Niels Focke2, Silvia Bonelli1, Pam Thompson1, Christian Vollmar1, Andrew McEvoy3, Mark Symms1, Matthias Koepp1, John Duncan1

1MRI Unit, National Society for Epilepsy, Chalfont St Peter, Bucks, United Kingdom; 2University of Goettingen, Germany; 3University College London Hospital, United Kingdom

Epilepsy is the most chronic, common neurological condition.  Many patients with temporal lobe epilepsy undergo anterior temporal lobe resection, but up to 40% of patients are at risk of language decline after surgery.  We carried out a longitudinal study using diffusion tensor imaging to assess the structural reorganisation of white matter after surgery.  In patients undergoing surgery in the language dominant hemisphere, there is an increase in FA in white matter connecting fronto-temporal regions.  The location of these increases and their correlation with language function suggest they may represent the structural plasticity of language networks after surgery.

12:12                       9.             Diffusion MRI of Short-Term Spatial Memory Related Brain Plasticity

Ido Tavor1, Yaniv Sagi1, Shir Hofstetter1, Efrat Sasson1, Yaniv Assaf1

1Neurobiology, Tel Aviv university, Tel Aviv, Israel

Neuroimaging studies of brain plasticity reveal long-term learning related structural changes in several brain regions. Animal studies revealed that short term micro-structural changes can be observed with diffusion MRI. Here, we study the diffusion MRI changes in a short term spatial memory task in humans. Subjects underwent two MRI scans separated by two hours of a learning session. We found that DTI parameters had changed in several brain regions, including the hippocampus, entorhinal cortex, amygdala and insula. The main result of this work is that DTI can follow on learning-induced micro-structural tissue changes, already 2 hours following the training episode.

12:24                       10.           A Demonstration of Neural Plasticity in Resting Brain Network

Kuang-Chi Tung1, Jinsoo Uh1, Hanzhang Lu1

1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States

We hypothesized that an important feature of the evoked activity, the plasticity of the neural response, may also be present in the resting condition and may provide critical information for understanding the nature and significance of the resting state brain activity. Using motor cortex as a model, we demonstrated for the first time that the resting brain activity can be altered after repetitive stimulation of the associated brain networks. This method may provide a new approach to study brain plasticity in humans and may find applications in studies of aging and neurodegenerative diseases.

12:36                       11.           Unilateral Infraorbital Denervation Leads to Plasticity in the Rat Whisker Barrel Cortex.

Xin Yu1, Stephen J. Dodd1, Seungsoo Chung1, John Isaac1, Judith R. Walters1, Alan P. Koretsky1

1NINDS, NIH, Bethesda, MD, United States

Interhemispheric plasticity may play a critical role during functional restoration following central/peripheral nervous system injuries in humans.  Previously, the interhemispheric plasticity in the rat somatosensory cortex (S1) following forepaw unilateral denervation has been studied in order to develop rodent models of plasticity detected in humans by fMRI. Here, the effects of unilateral infraorbital denervation (IO) to rat whisker responses were studied.  Large ipsilateral fMRI activation was detected after IO.  In addition, BOLD signals in the contralateral barrel cortex were significantly increased. This indicates that the unilateral IO caused plasticity of the whisker-barrel cortex ascending pathways and increased interhemispheric interactions.

12:48                       12.           fcMRI Plasticity Following Rat Median Nerve Injury and Repair at 9.4T

Rupeng Li1, Patrick Hettinger2, Younghoon Cho1, Christopher P. Pawela1, Maida Parkins2, Seth Jones2, Ji-Geng Yan2, Andrzej Jesmanowicz1, Anthony Hudetz3, Hani Matloub2, James Hyde1

1Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States; 2Plastic Surgery, Medical College of Wisconsin, Milwaukee, WI, United States; 3Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, United States

Plasicity happening to the resting state connectivity map following rat peripheral nerve injury and repair was shown using 9.4T. Unique patterns of plasticity could help monitoring the neuro-network function when functional test in not available.

Advanced Neuro Imaging of Dementing Diseases

Victoria Hall  11:00-13:00                Moderators: Mark A. van Buchem and Wolfgang Weber-Fahr

11:00                       13.           The Role of Iron in T2* Contrast and Transverse Relaxation of Beta-Amyloid Plaques in Alzheimer’s Disease

Mark David Meadowcroft1,2, James R. Connor3, Qing X. Yang1,3

1Radiology - Center for NMR Research, Pennsylvania State University - College of Medicine, Hershey, PA, United States; 2Neural and Behavioral Sciences, Pennsylvania State University - College of Medicine, Hershey, PA, United States; 3Neurosurgery, Pennsylvania State University - College of Medicine, Hershey, PA, United States

Conventional belief is that iron associated with beta-amyloid (Aβ) plaques is the underlying mechanism for plaque contrast in transverse imaging.  Through detailed histological MR examination in comparison to traditional histology methods utilizing iron chelation of plaques, this body of work has determined that there is a dual relaxation associated with human (Aβ)  plaques. Removal of iron from human (Aβ)  plaques still results in plaque MR imaging and relaxation.  The data indicate that iron content alone is not responsible for the hypo-intensities seen on the MR images and that there is a synergy between iron and plaque morphology on transverse relaxation.

11:12                       14.           Optimization of Susceptibility Weighted Imaging at 7T for Improved Detection of Alzheimer’s Amyloid Plaques Associated with Iron in Human Postmortem Brain

Yulin Ge1, Tang Lin1, Daniel K. Sodickson1, Edward Lin1, Jing Yang1, E Mark Haacke2, Mony de Leon1, Robert I. Grossman1, Thomas Wisniewski1

1New York University School of Medicine, New York City, NY, United States; 2Wayne State University, Detroit, MI

Due to markedly enhanced susceptibility contrast and signal-to-noise ratio at ultra-high-field MR, it is possible to detect amyloid plaques associated with iron deposition using susceptibility weighted imaging in patients with AD.

11:24                       15.           Quantitative Cerebral Blood Flow Changes in Huntington's Disease Measured Using Pulsed Arterial Spin Labeling

J. Jean Chen1, David H. Salat1, H. Diana Rosas, 12

1A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA, United States; 2Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, United States

Huntington's disease (HD) has been associated with wide-spread cortical and subcortical grey matter atrophy, in which the role of cerebral blood flow (CBF) abnormalities is potentially significant. However, low spatial resolution erodes the ability of conventional techniques to reveal spatially-specific CBF changes. In this work, we present, for the first time, HD-related quantitative CBF changes measured using pulsed arterial-spin labelling (PASL). Regressing out the effect of cortical thinning, our results still show significant underlying CBF reduction across the cortex. CBF also decreased in the striatum and hippocampus. CBF reduction patterns were found to be partially independent of structural atrophy.

11:36                       16.           Dynamic Changes in Brain Metabolites and Tissue Water Diffusion Following Oral Amino Acid Challenge in Cirrhotics with Hepatic Encephalopathy

Fiona Smith1, Hanan Mardini, Christopher Record, Andrew M. Blamire1

1Newcastle MR Centre & Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, United Kingdom

Liver cirrhosis kills more than 750,000 people worldwide each year.  Almost 30% of patients with cirrhosis experience hepatic encephalopathy (HE), a neuropsychiatric complication potentially linked to formation of cerebral edema driven by elevated blood ammonia. We used DTI and proton MRS to monitor edema and metabolite changes during induced hyperammonaemia by amino acid challenge in HE patients.  Elevated blood ammonia was accompanied by increased ADC and decreased myo-Inositol.  Absolute increase in blood ammonia significantly correlated with ADC and inversely correlated with myo-Inositol in the individual patients strongly supporting ammonia driven brain edema as a neurochemical mechanism for HE in cirrhosis. 

 

11:48                       17.           Joint Contribution of Structural and Perfusion MR Images for the Classification of Alzheimer’s Disease

Duygu Tosun1, Pouria Mojabi1, Mike W. Weiner1, Norbert Schuff1

1Center for Imaging Neurodegenerative Diseases, San Francisco, CA, United States

To determine the joint contribution of structural and arterial spin labeling MR imaging for the classification of Alzheimer’s disease (AD), we analyzed the cortical thickness and cerebral blood flow (CBF) measures jointly in a cross-sectional study of 24 AD and 38 healthy elderly controls using an integrated multimodality MRI processing framework and a cortical surface-based analysis approach. From the joint analysis, we infer that cortical atrophy dominates prediction of AD while CBF adds no significant value. One interpretation of the results is that CBF is diminished proportionately to brain tissue loss and therefore provides no additional information to structural alterations.

12:00                       18.           Neuroprotective Mechanism of Minocycline in an Accelerated Macaque Model of NeuroAIDS

Eva-Maria Ratai1,2, Chan-Gyu Joo1,2, Jeffrey Bombardier1, Robert Fell1, Julian He1,2, Reza Hakimelahi1,2, Tricia Burdo3, Jennifer Campbell3, Patrick Autissier3, Lakshmanan Annamalai4, Eliezer Masliah5, Susan Westmoreland, 2,4, Kenneth Williams3, Ramon Gilberto Gonzalez1,2

1Department of Radiology, A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States; 2Harvard Medical School, Boston, MA, United States; 3Biology Department, Boston College, Boston, MA, United States; 4Division of Comparative Pathology, New England Primate Research Center, Southborough, MA, United States; 5Department of Neurosciences, University of California at San Diego, La Jolla, CA, United States

HIV-associated neurocognitive disorders continue to be a significant problem.  Using the accelerated macaque model of neuroAIDS in combination with in vivo MR spectroscopy minocycline was found to be neuroprotective and able to reverse increased high energy metabolism, most likely localized to glia. Evaluating our observations, clues into the mechanisms underlying neuroprotection included reduction of microglial activation, reductions of CSF and plasma viral loads during treatment, and a reduction in a subset of circulating monocytes considered to be responsible for viral infection of the CNS by cell trafficking mechanisms.

12:12                       19.           The Role of the Uncinate Fasciculus in the Development of Dementia: A DTI-Tractography Study

Laura Serra1, Mara Cercignani1, Roberta Perri2, Barbara Spanò1, Lucia Fadda2,3, Camillo Marra4, Franco Giubilei5, Carlo Caltagirone2,6, Marco Bozzali1

1Neuroimaging laboratory, Fondazione IRCCS Santa Lucia, Roma, Italy; 2Department of Clinical and Behavioural Neurology, Fondazione IRCCS Santa Lucia, Roma, Italy; 3Department of Neuroscience, , University of Rome ‘Tor Vergata’, Rome, Italy; 4Institute of Neurology, Università Cattolica, Roma, Italy; 5Department of Neurology, II Faculty of Medicine University of Rome, ‘Sapienza’, Rome, Italy; 6Department of Neuroscience, University of Rome ‘Tor Vergata’, Rome, Italy

The uncinate fasciculus (UF) connects temporal and frontal regions, traditionally implicated by pathological damage in dementia. We aimed at assessing, using DTI and tractography, the role of UF damage in the progression from mild cognitive impairment (MCI) to Alzheimer’s disease (AD), and whether its involvement could distinguish between patients with AD and patients with dementia with Lewy Bodies (DLB). Fractional anisotropy was significantly reduced only in the UF of demented patients as compared to both, HS and a-MCI patients. This suggests that UF involvement is relevant for the development dementia, but it does not distinguish between AD and DLB.

12:24                       20.           Cerebral Microbleeds Are Predictive of Mortality in the Elderly

Irmhild Schneider1, Stella Trompet1, Anton J.M. de Craen1, Adriaan C.G.M. van Es1, Mark A. van Buchem1, Jeroen van der Grond1

1Leiden University Medical Center, Leiden, Netherlands

Cerebral microbleeds are commonly found in patients with ischemic stroke, intracerebral hemorrhage (ICH) and Alzheimer disease. In this study we investigated the prognostic value of microbleeds in terms of all-cause mortality and cardiovascular mortality in a population suffering from vascular disease or at high risk for developing this condition. We found that the presence of two or more microbleeds implicates an increased risk of overall death. Furthermore, only “non-CAA” type microbleeds were associated with increased risk of cardiovascular death. Therefore, CAA type small vessel disease cannot be considered as risk factor for (cardiovascular) mortality.

12:36                       21.           Tract Atrophy in Alzheimer’S Disease Measured Using Probabilistic Tractography

Hojjatollah Azadbakht1,2, Hamied A. Haroon1,2, David M. Morris1,2, Karl V. Embleton, 2,3, Stephen F. Carter4, Brandon Whitcher5, Julie Snowden6, Geoff J.M. Parker, 27

1Imaging Science and Biomedical Engineering, , School of Cancer and Imaging Sciences,, University of Manchester, Manchester, United Kingdom; 2The University of Manchester Biomedical Imaging Institute, University of Manchester, Manchester, United Kingdom; 3School of Psychological Science, University of Manchester, Manchester, United Kingdom; 4Wolfson Molecular Imaging Centre, University of Manchester, Manchester, United Kingdom; 5Clinical Imaging Centre, GlaxoSmithKline, London, United Kingdom; 6Greater Manchester Neuroscience Centre, Salford Royal Foundation Trust, Salford, United Kingdom; 7Imaging Science and Biomedical Engineering, School of Cancer and Imaging Sciences,, University of Manchester, Manchester, United Kingdom

The quantitative characterisation of atrophy can provide useful biomarkers for assessing the evolution of neurological conditions such as Alzheimer’s disease (AD). It is likely that atrophy caused by such conditions also affects white matter (WM) tracts via degenerative processes. If specific tract systems are more prone t¬¬o atrophy than others, then tractography-guided atrophy measurements may be more sensitive than less targeted methods which focus on global gray and/or white matter. In this work we apply a novel method for quantifying the width of WM tracts to look for evidence of tract atrophy in mild cognitive impairment (MCI) and AD subjects.

12:48                       22.           Increases in CBF by Donepezil Treatment Enhance Cingulate Functional Network Activity in Mild Alzheimer’s Disease

Wenjun Li1, Chunming Xie1,2, Jennifer Jones3, Malgorzata Franczak3, Piero Antuono3, Shi-jiang Li1

1Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States; 2Neurology, Southeast University, Nanjing, Jiansu, China,; 3Neurology, Medical College of Wisconsin, Milwaukee, WI, United States

Cholinergic inhibitor (Aricept®) has been shown to improve cognitive function in adults with Alzheimer’s disease (AD). Also, it has an effect on improving the cerebral blood flow (CBF) perfusion detected by PET technology. Previously we have found increased CBF in cingulate and posterior cingulated regions using a Pseudo-Continuous Arterial Spin Labeling (pCASL) MR technique. It is hypothesized that the increase in CBF after treatment could alter functional connectivity in related neural networks. The aim of the current study is to determine the changes in the functional connectivity in networks with significantly increased CBF after the drug treatment.

Strategies of Localization & Imaging Methodology

Room A4        11:00-13:00                Moderators: Anke Henning and M. Albert Thomas

11:00                       23.           Focused RF in High Field 1H-MRSI: Outer Volume Suppression by Local Excitation

Vincent O. Boer1, Ingmar J. Voogt1, Hugo Kroeze1,2, Bart Leo van de Bank1, A H. Westra2, Peter R. Luijten1, Dennis W.J. Klomp1

1Radiology, UMC Utrecht, Utrecht, Netherlands; 2MTKF, UMC Utrecht, Utrecht, Netherlands

An alternative to SAR demanding outer volume suppression is proposed for 7T MRSI. Low power suppression is achieved by using focused RF to locally saturate subcutaneous signals by using an RF headband; a close fitting, small element, eight-channel transmit receive array. Two sets of RF shims are defined to drive the RF headband; a ‘ring’ mode for outer volume suppression close to the elements and a quadrature mode for water suppression and excitation of the brain. High spatial resolution MRSI is shown within a short scan time.

11:12                       24.           Motion Artifact Reduction Using Bipolar Diffusion Gradients in Diffusion-Weighted Echo-Planar Spectroscopic Imaging

Yoshitaka Bito1, Koji Hirata1, Toshihiko Ebisu2, Yuko Kawai3, Yosuke Otake1, Satoshi Hirata1, Toru Shirai1, Yoshihisa Soutome1, Hisaaki Ochi1, Masahiro Umeda3, Toshihiro Higuchi4, Chuzo Tanaka4

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

Diffusion-weighted echo-planar spectroscopic imaging (DW-EPSI), using bipolar diffusion gradients, has been developed to reduce motion artifacts. Signal loss in signal accumulation, which is detrimental in diffusion-weighted spectroscopic measurements, is estimated by numerical analysis using bipolar diffusion gradients. Reduction of motion artifacts is demonstrated by applying DW-EPSI, using bipolar diffusion gradients, to a phantom and a rat brain in vivo. The results suggest that the effectiveness and limitations of this technique in reduction of motion artifacts and numerical analysis is helpful in investigating errors due to motion.

11:24                       25.           Spatial Localization Accomplished by Sensitivity Heterogeneity

Li An1, Steven Warach1, Jun Shen2

1National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States; 2National Institute of Mental Health, National Institutes of Health, Bethesda, MD, United States

This work demonstrates a new method that allows multi-compartmental spatial localization based on the heterogeneity of sensitivity profiles of phased array receiver coils.  This method offers an alternative to SENSE-CSI for performing spectroscopy using phased array coils. It allows the user to manually prescribe compartments following natural anatomical or physiological boundaries to reduce partial volume artifacts associated with conventional CSI and SENSE-CSI. In vivo application using PRESS and an eight-element phased array head coil demonstrates that this method can extract spectra from stroke tissue and normal tissue in 4 seconds.

11:36                       26.           Selective Homonuclear Polarization Transfer at 7T: Single Shot Detection for GABA in Human Brain

Jullie W. Pan1, Nikolai Avdievich1, Hoby P. Hetherington1

1Yale University School of Medicine, New Haven, CT, United States

Given its important role as the major inhibitory neurotransmitter, GABA is a well known target for detection in human brain. However, because of its overlap with many other resonances, editing is required for its unambiguous detection. We describe implementation of selective homonuclear polarization transfer to detect the C4 3.0ppm GABA in a single shot in human brain. This is based on a broad T1 based inversion pre-sequence suppression with a J-refocused acquisition. As implemented in human brain, we demonstrate the performance of this approach at 7T in spectroscopic imaging format with 1.44cc resolution.

11:48                       27.           Fast 3D Proton Spectroscopic Imaging of the Human Brain at 3 Tesla by Combining  Spectroscopic Missing Pulse SSFP and Echo Planar Spectroscopic Imaging

Wolfgang Dreher1, Peter Erhard1, Dieter Leibfritz1

1Dept. Chemistry, University of Bremen, Bremen, Germany

One of the limitations of the fast spectroscopic imaging sequence “spectroscopic missing pulse SSFP” are the rather long minimum total measurement time for 3D measurements with large matrix size. This drawback is eliminated by acquiring the echo-like signal under a symmetrically oscillating read gradient in slice direction. The sequence was implemented on a 3 Tesla head scanner and applied to healthy volunteers. Within 4:19 minutes only, a 3D measurement of the brain was performed with 32x32x16 matrix size and 0.33 ml nominal voxel size using weighted k-space averaging with a maximum of four accumulations in the k-space center.

12:00                       28.           Spectrally Selective Phosphocreatine Imaging on a 9.4T Whole-Body Scanner Using a Spatial-Spectral RF Pulse

Yi Sui1,2, Haoyang Xing2, Theodore Claiborne2, Keith R. Thulborn, 2,3, Xiaohong Joe Zhou, 2,4

1Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States; 2Center for Magnetic Resonance Research, University of Illinois Medical Center, Chicago, IL, United States; 3Department of Radiology, University of Illinois Medical Center, Chicago, IL, United States; 4Departments of Radiology, Neurosurgery and Bioengineering, University of Illinois Medical Center, Chicago, IL, United States

In this study, we report a spatial-spectral (SPSP) pulse that is tailored for selectively exciting the phosphocreatine (PCr) resonance at 9.4T while suppressing all other major phosphorus metabolites including inorganic phosphate and adenosine triphosphates. Using this pulse in conjunction with a RARE sequence, we have obtained PCr images from phantoms (50 mM) and the lower extremity of human volunteers in 10 minutes on a 9.4T whole-body scanner. With an in-plane spatial resolution of 7.5mm  x 7.5mm, the PCr images show anatomic details with an adequate signal to noise ratio (SNR=14).

12:12                       29.           1H MR Spectroscopy of the Human Prostate Using an Adiabatic Sequence with a SAR Optimized Endorectal RF Coil

Catalina Arteaga1, Uulke A. van der Heide1, Marco van Vulpen1, Peter R. Luijten2, Dennis W.J. Klomp2

1Radiotherapy, UMC Utrecht, Utrecht, Netherlands; 2Radiology, UMC Utrecht, Utrecht, Netherlands

Prostate 1H MRSI at 7T with fully adiabatic sequences like full-LASER allows polyamine detection. In addition, choline and creatine levels can also be depicted in prostate cancer patients even with hormone therapy.  We showed that fully adiabatic sequences can overcome the B1 inhomogeneities compared to semi-adiabatic sequences.

12:24                       30.           High Resolution GABA Mapping in Vivo Using a Slice Selective MEGA-MRSI Sequence at 3 Tesla

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

1Russell H Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States; 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States; 3The National Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD, United States

A spin echo based MEGA-MRSI sequence was developed to acquire MEGA-edited spectra of γ-aminobutyric acid (GABA) in an entire slice with excellent sensitivity. Co-editing of lipid and NAA signals was greatly suppressed by a dualband pre-saturation sequence and integrated outer volume suppression (OVS) pulses. Experiments in normal volunteers were performed at 3 Tesla using a 32-channel head coil. High signal-to-noise ratio spectra and metabolic images of GABA (and glutamate) were acquired from 4.5 cm3 voxels in a scan time of 17 minutes.

12:36                       31.           Qualitative Detection of Ceramide and Other Metabolites in Brain Tumor by Localized Correlated Spectroscopy

Rajakumar Nagarajan1, Whitney B. Pope1, Noriko Salamon1, Linda M. Liau2, Timothy Cloughesy3, M Albert Thomas1

1Radiological Sciences, University of California Los Angeles, Los Angeles, CA, United States; 2Neurosurgery, University of California Los Angeles; 3Neurooncology, University of California Los Angeles

Magnetic resonance spectroscopy (MRS) provides metabolic information about brain tumors complementary to what can be obtained from anatomic images. In contrast to other metabolism-based imaging techniques, MRS yields multiparametric data, does not require ionizing radiation, and can be performed in conjunction with magnetic resonance imaging studies. Magnetic resonance spectral patterns have been shown to be distinct for different tumor types and grades. Two-dimensional (2D) localized correlated spectroscopy (L-COSY) in patients with high and low grade gliomas provides better dispersion of several metabolites such as N-acetylaspartate (NAA), creatine (Cr) choline (Cho), ceramide (Cer), phosphoethanolamine (PE), glutamine/glutamate (Glx), lactate (Lac), myo-inositol (mI), taurine (Tau), etc. which has been a major difficulty in 1D MRS.

12:48                       32.           Increased Signal-To-Noise in High Field Localized Spectroscopy of the Temporal Lobe Using New Deformable High-Dielectric Materials

Andrew Webb1, Hermien Kan1, Maarten Versluis1, Nadine Smith1

1Radiology, Leiden University Medical Center, Leiden, Netherlands

The intrinsic B1 non-uniformities from standard volume resonators at high field are particularly problematic for localized spectroscopy of areas such as the temporal lobe, where low signal-to-noise results from a reduced B1 field. Using a recently developed high dielectric constant material placed around the head, increases in signal-to-noise of ~ 200% can be achieved in such problem areas without reducing the sensitivity in other areas of the brain.

MR Sensors & Reporters

Room A5        11:00-13:00                Moderators: Eric T. Ahrens and Assaf Gilad

11:00                       33.           Enzymatic Triggered Release of Imaging Probe from Paramagnetic Liposomes

Sara Figueiredo1, Enzo Terreno2, Joao Nuno Moreira3, Carlos F.G.C. Geraldes1, Silvio Aime2

1Dep. of Biochemistry and Technology and Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal; 2Department of Chemistry and Molecular Imaging Center, University of Torino, Torino, Italy; 3Lab. of Pharmaceutical Technology and Center for Neurosciences and Cell Biology, University of Coimbra, Coimbra, Portugal

The design of imaging probes reporting about a given enzymatic activity is an important task in Molecular Imaging investigations.

The aim of this work was to prepare paramagnetic liposomes encapsulating the clinically approved Gd-HPDO3A complex and able to release the imaging probe in the presence of a specific enzyme upregulated in a given disease.

To do this, an amphiphilic lipopeptide acting as substrate for MMP (Matrix Metallo Proteinases) was prepared and incorporated in liposomes.

It has been reporetd that in the presence of MMP like collagenase, the liposomes release its content, thus determining the detection of a T1 contrast enhancement.

 

11:12                       34.           A Novel Dual MRI-PARACEST/Fluorescent Probe for the Detection of Cathepsin-D Activity in Alzheimer's Disease

Robert Ta1,2, Alex Li1, Mojmir Suchy, 1,3, Robert Hudson3, Stephen Pasternak4,5, Robert Bartha1,2

1Imaging Research Group, Robarts Research Institute, London, Ontario, Canada; 2Medical Biophysics, University of Western Ontario, London, Ontario, Canada; 3Chemistry, University of Western Ontario, London, Ontario, Canada; 4Molecular Brain Research Group, Robarts Research Institute, London, Ontario, Canada; 5Clinical Neurological Sciences, University of Western Ontario, London, Ontario, Canada

A novel dual magnetic resonance/fluorescent probe has been designed for molecular targeting of Cathepsin D in Alzheimer's disease.  The MRI contrast of this probe has been detected using the on-resonance paramagnetic agent chemical exchange effect  (OPARACHEE) method.  Greater than a 1% OPARACHEE contrast was observed in 1.5 mM Tm3+-DOTA-Glycine in a 5% BSA phantom.  The dual probe demonstrated uptake into neuronal cells by confocal microscopy and had no toxic effects on these cells at the concentrations tested.

11:24                       35.           Self-Degrading, MRI-Detectable Hydrogels with Picomolar Target Sensitivity

Jason Colomb1, Katherine Louie1, Stephen P. Massia1, Kevin M. Bennett1

1School of Biological and Health Systems Engineering , Arizona State University, Tempe, AZ, United States

Nanostructured hydrogels have been developed as synthetic tissues, tissue scaffolds for cell and drug delivery, and as guides for tissue regeneration. A fundamental problem with hydrogels is that implanted gel structure is difficult to monitor noninvasively. Here we demonstrate that the aggregation of cationic magnetic nanoparticles, attached to specific macromolecules in biological and synthetic hydrogels, can be controlled to detect changes in gel macromolecular structure with MRI.  Sensitivity of the gels to target molecules is finely controlled using an embedded zymogen cascade amplifier and we show that these gels self-degrade when they come into contact with pM concentrations of enterokinase.

11:36                       36.           Direct Detection of Cytosine Deaminase Enzymatic Activity Using CEST MRI

Guanshu Liu1,2, Segun M. Bernard2,3, Terence Tse2, Piotr Walczak2,3, Michael T. McMahon1,2, Jeff W.M. Bulte2,3, Peter C.M. van Zijl1,2, Assaf A. Gilad2,3

1F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States; 2Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States; 3Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States

A new MRI method for assessing cytosine deaminase (CD) enzymatic activity was developed. This method allows the direct detection and quantification of CD by observing the changes in Chemical Exchange Saturation Transfer (CEST) signal when the substrates cytosine and 5-Fluorocytosine (5-FC) are converted to products uracil and 5-Fluorouracil (5-FU) by CD respectively. In addition, this method is capable of continuously monitoring the CD activity using the natural compounds in the cytosine/uracil system. Possible applications for this method include monitoring of in vivo CD activity and CD gene therapy for cancer.

11:48                       37.           A Novel Class of S-GalTM Analogs as 1H MRI  LacZ Gene Reporter Molecules

Praveen Kumar Gulaka1, Vikram D. Kodibagkar1,2, Jian-Xin Yu2, Ralph P. Mason, 12

1Biomedical Engineering, UT Arlington and UT Southwestern Medical Center at Dallas, Dallas, Tx, United States; 2Radiology, UT Southwestern Medical Center at Dallas, Dallas, Tx, United States

Extensive implementation of gene therapy as a therapeutic strategy for cancers has been hampered by difficulties in quantitatively assessing the success of gene transfection and longevity of gene expression. Therefore development of non-invasive reporter techniques based on appropriate molecules and imaging modalities may help to assay gene expression. We have evaluated a range of S-Gal™ analogs as novel 1H MR lacZ gene-reporter molecules in vitro and have identified C3-GD as an optimal agent for in vivo studies.

12:00                       38.           Multispectral MRI Contrast Through Cylindrical Nanoshell Agents

Gary Zabow1,2, Stephen Dodd1, John Moreland2, Alan Koretsky1

1NINDS, NIH, Bethesda, MD, United States; 2NIST, Boulder, CO, United States

Thanks to the processing control afforded by top-down microfabrication techniques, geometrically tailored magnetic microparticles have recently been shown able to produce tunable, multispectral MRI contrast.  Here we demonstrate a new form of such agent based on new cylindrical nanoshell structure designs.   These hollow magnetic cylinders can produce large NMR frequency shifts through the control of the cylinder materials, aspect ratios and wall thicknesses.  Apart from yielding distinct frequency shifted NMR peaks, it is also shown that these cylindrical nanoshell structures exhibit good mechanical robustness and automatically self-align (as is required) to the applied MRI B0 field.

12:12                       39.           Eu3+-Based PARACEST Agents with Intermediate Water Exchange Rates Also Act as T2 Exchange (T2exch) Contrast Agents

Todd C. Soesbe1, Federico A. Rojas-Quijano1, Matthew E. Merritt1, A. Dean Sherry1,2

1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States; 2Department of Chemistry, The University of Texas at Dallas, Dallas, TX, United States

In our initial in vivo murine studies of CEST agents, we observed a significant loss of MR signal in certain tissue types, most notably the kidneys (intravenous injection) and human cancer cell xenografts (intratumoral injection). This loss in signal was present even when the CEST saturation pulse was omitted from the imaging sequence, and appeared to be caused by a local decrease in T2 due to the presence of the CEST agent. We hypothesized that the proton exchange that enables the CEST effect can also cause a decrease in T2 for compounds with intermediate proton exchange rates.

12:24                       40.           MR Contrast from Ascorbic Acid (Vitamin C) in Phantoms and in Vivo

Christopher D. Lascola1, Talaignair Venkatraman1, Bjorn Engstrom1, Haichen Wang1

1Department of Radiology and Brain Imaging and Analysis Center, Duke University Medical Center, Durham, NC, United States

: L-ascorbic acid (vitamin C) is the most abundant intracellular antioxidant and an essential co-factor. Intracellular levels of ascorbic acid (AA) are remarkably high, where concentrations may exceed 10-30 mM. In this study, we show that AA in solution produces significant changes in T2 and T2* relaxivity at physiologically relevant concentrations. These results raise two important possibilities: first, that endogenous AA may be an important contributor to native T2 and T2* contrast in CNS and other tissues; and second, that both oxidized and reduced forms of ascorbic acid may have utility as novel MR contrast probes.

12:36                       41.           Hyperpolarized 89Y Complexes as PH Sensitive NMR Probes

Ashish Kumar Jindal1, Matthew E. Merritt1, Eul Hyun Suh1, Craig R. Malloy1,2, Alan Dean Sherry1,3, Zoltan Kovacs1

1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States; 2Veterans Affairs, North Texas Health Care System, Dallas, TX, United States; 3Department of Chemistry, University of Texas at Dallas, Richardson, TX, United States

Hyperpolarization followed by fast dissolution provides tremendous gains in SNR in both NMR and MRI experiments, but a primary bottleneck in its application is the T1 decay of the magnetization in the liquid state.  Due to its long T1, hyperpolarized 89Y makes an excellent candidate as an in vivo imaging agent.  Here we report the chemical shift dependence upon pH for two hyperpolarized 89Y complexes and clearly demonstrate how such complexes can be used as sensitive spectroscopy/imaging probes to measure pH.

12:48                       42.           Remote MRI Sensing of PH and Cell Viability Using Immunoprotective Microcapsules Crosslinked with Polycationic DIACEST Peptides

Dian Respati Arifin1,2, Kannie W.Y. Chan1,2, Guanshu Liu1,3, Amanda Cardona1, Muksit Jamil1, Jeff W.M. Bulte1,2, Michael T. McMahon1,3

1Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States; 2Cell Imaging Section, Institute for Cell Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States; 3F.M. Kirby Center for Functional Brain Imaging, Kennedy Krieger Institute, Johns Hopkins University School of Medicine, Baltimore, MD, United States

Cell transplantation is a potential treatment for various diseases such as type I diabetes, liver failure and cardiovascular disorders. Encapsulation of cells inside semi-permeable microcapsules offers immunoprotection for the cells and recipient. We have developed new biodegradable microcapsules using polycationic peptides from our library of CEST agents that are detectable by MRI. These DIACEST capsules are pH-responsive and can be used to monitor biological events, which are accompanied by pH changes. Human pancreatic cells encapsulated inside these microcapsules were alive and functional for at least 27 days in vitro. We also demonstrate that these microcapsules can detect cell apoptosis in vitro.

Transmit Technology

Room A6        11:00-13:00                Moderators: Kenneth M. Bradshaw and Tamer Ibrahim

11:00                       43.           1.5T On-Coil Current-Mode Class-D (CMCD) Amplifier with Amplitude Modulation Feedback and Voltage-Mode Class-D (VMCD) Preamplifier

Natalia Gudino1, Matthew J. Riffe1, Lisa Bauer2, Jeremiah A. Heilman3, Mark A. Griswold4

1Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States; 2Physics Department, Case Western Reserve University, Cleveland, OH, United States; 33Quality Electrodynamics, Mayfield Village, OH, United States; 4Radiology Department, Case Western Reserve University, Cleveland, OH, United States

We present a Current-Mode Class-D (CMCD) Feedback amplifier with class-D preamplification that avoids the characteristic DC losses of linear preamplification. We demonstrated a good wave profile of the AM feedback system that modulates the RF pulse and preliminary images that prove successful operation of the system in the scanner.

11:12                       44.           RF Sensor Considerations for Input Predistortion Correction of Transmit Arrays

Pascal Stang1, Marta Zanchi1, William Grissom1, Adam Kerr1, John Pauly1, Greig Scott1

1Electrical Engineering, Stanford University, Stanford, CA, United States

Transmit arrays promise accelerated excitation, B1 shimming, and the potential for SAR and RF safety management. Yet good results demand high-fidelity RF playback in a challenging multi-channel environment.  Parallel transmit RF systems must overcome a host of issues including mutual coupling, loading variations, RF amplifier non-linearity, ill-defined impedances, and memory effects.  We have proposed Vector Iterative Predistortion and Cartesian Feedback as input predistortion methods to address PTx challenges.  We now present our on-coil and in-line RF feedback sensors critical to these technologies, and discuss their relative capabilities in the context of PTx array control.

11:24                       45.           Efficient EPI Friendly 3x3 Array with Receive-Only Array Insert

Tamer S. Ibrahim1, Tiejun Zhao2, Fernando E. Boada3

1Departments of Bioengineering and Radiology, University of Pittsburgh, Pittsburgh, PA, United States; 2Siemens Medical Solutions; 3Department of Radiology, University of Pittsburgh

In this work, we will examine the efficiency of Tic Tac Toe RF array designs including the original 2x2 and new 3x3 versions and extend their usefulness to become more application friendly.   This will be achieved by yielding optimal SNR (through a combination with a separate 7-channel receive-only array) and by designing echo-planar imaging (EPI) compatible prototypes.  The results show excellent improvement in eddy current reduction and SNR enhancement with a receive-only array insert.

11:36                       46.           Constellation Coil

Yudong Zhu1, Ryan Brown1, Cem Deniz1, Leeor Alon1, Kellyanne Mcgorty1, Daniel Sodickson1

1New York University School of Medicine, New York, United States

An RF coil plays a central role in the induction of a B1 field for creating an excitation profile, and meanwhile, a concomitant E field that causes undesirable RF loss and SAR. A coil structure that supports flexible current distribution control is essential for management of both the excitation profile and RF power, and is hence a key factor in parallel Tx performances. We developed a “constellation coil” which prioritizes field optimization-based Tx/Rx improvement with a continuum structure, and accommodates scalability supporting highly parallel Tx/Rx. Preliminary 7T MRI results obtained with prototype parallel Tx and Rx constellation coils are presented.

11:48                       47.           Reduce Power Deposition Using Microstrip Array with Tilted Elements at 7T

Yong Pang1, Bing Wu2, Xiaoliang Zhang2,3

1Radiology and Biomedical imaging, University of California San Francisco, San Francisco, CA , United States; 2Radiology and Biomedical imaging, University of California San Francisco, San Francisco, CA, United States; 3UCSF/UC Berkeley Joint Graduate Group in Bioengineering, San Francisco & Berkeley, CA, United States

Power deposition increases with the static magnetic field strength. In this work, a microstrip array with tilted elements is built and the electric field E and magnetic field B1+ are simulated using FDTD method. Their ratio E/B is used to predict the power deposition for two type of different arrays: microstrip array with regular elements and tilted elements. Results show that using the tilted array, coil efficiency and decoupling between elements can be increased. The reduction in E/B ratio indicates possible reduction in power deposition.

12:00                       48.           High-Field Imaging at Low SAR: Tx/Rx Prostate Coil Array Using Radiative Elements for Efficient Antenna-Patient Power Transfer

Alexander Raaijmakers1, Ozlem Ipek1, Dennis Klomp1, Hugo Kroeze1, Bart van de Bank1, Vincent Boer1, Paul Harvey2, Cecilia Possanzini2, Jan Lagendijk1, Nico van den Berg1

1Radiotherapy, UMC Utrecht, Utrecht, Netherlands; 2Philips Healthcare, Best, Netherlands

Abdominal imaging at 7 T is challenging due to reduced RF penetration at 298 MHz. Conventional high-field surface coil arrays with stripline elements deposit high SAR levels and suffer from inhomogeneous B1-field distribution. We present results of a prototype coil array consisting of so-called radiative antennas. These elements emit power to the region of interest more efficiently. Simulations and volunteer measurements show reduced SAR levels and increased image homogeneity.

12:12                       49.           RF Coil Designs for 7T Cardiac Imaging

John Thomas Vaughan1, Carl j. Snyder1, Lance Delabarre1, Jinfeng Tian1, Can Akgun1, Gregor Adriany1, John Strupp1, Peter Andersen1, Eddie Auerbach1, Pierre-Francois Van de Moortele1, Kamil Ugurbil1

1University of Minnesota-Center for Magnetic Resonance Research, Minneapolis, MN, United States

Our objective was to investigate three RF coil approaches to human cardiac imaging at 7T.  The first approach used a 16-channel, whole body coil together with 16 channel local receivers.  The second approach used a 16-channel transceiver array.  And the third approach made use of a close fitting torso coil with local 16 channel receivers.  The three approaches were evaluated by image and efficiency data, as well as practical constraints such as lead placement, receiver coil accommodation, and human comfort.  All three coils were used successfully, and found to offer options and respective trade-offs for successful cardiac imaging at 7T.

12:24                       50.           16-Channel Tx/Rx Body Coil for RF Shimming with Selected Cp Modes at 7T

Stephan Orzada1,2, Stefan Maderwald1,2, Oliver Kraff1,2, Irina Brote1,2, Mark E. Ladd1,2, Klaus Solbach3, Pedram Yazdanbakhsh3, Achim Bahr4, Hans-Peter Fautz5, Andreas K. Bitz1,2

1Erwin L. Hahn Institute for Magnetic Resonance Imaging, Essen, NRW, Germany; 2Department of Diagnostic and Interventional Radiology and Neuroradiology, University Hospital Essen, Essen, NRW, Germany; 3High Frequency Engineering, University Duisburg-Essen, Duisburg, NRW, Germany; 4IMST GmbH, Kamp-Lintfort, Germany; 5Siemens Healthcare Sector, Erlangen, Germany

To increase the capability of a 7 Tesla 8-channel RF shimming system, a 16-channel Tx/Rx body coil was built to be used with a 16-channel Butler matrix for mode compression and an 8-channel variable power combiner. The array has a large field of view and shows good homogeneity in gradient echo images. RF shimming with mode compression and variable power combining was successfully performed in human volunteers.

12:36                       51.           Optimizing 7T Spine Array Design Through Offsetting of Transmit and Receive Elements and Quadrature Excitation

Qi Duan1, Daniel K. Sodickson1, Riccardo Lattanzi1, Bei Zhang1, Graham C. Wiggins1

1Center for Biomedical Imaging, Department of Radiology, NYU School of Medicine, New York, NY, United States

This abstract presents a novel 7T spine array design for optimizing SNR at the regions of interest. This design takes into account opportunities for quadrature excitation and the twisting of B1+ and B1- fields to optimize SNR within the ROIs. The design parameters were quantitatively optimized via full wave simulation. The benefits of the proposed design were validated via actual MR scan with higher SNR within ROI, more efficient excitation, and less peak local heating than alternative designs. This design can be easily extended for larger longitudinal coverage, providing a more efficient excitation and MR images without obvious signal nulls.

12:48                       52.           On the Reduction of the Transmit B1 Non-Uniformity and SAR Using a Single-Element Rotating RF Coil

Feng Liu1, Ewald Weber1, Adnan Trakic1, Hua Wang1, Stuart Crozier1

1The School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, St.Lucia, Queensland, Australia

In this work, we presented a complete technological solution for tailoring uniform RF fields and minimizing tissue heating for high field MRI. The success of the new B1 shimming technique is largely facilitated by a mechanically rotating RF coil (RRFC) configuration. The proposed method is explained with a biologically loaded, one-element rotating coil operating at 400 MHz. The coil is modelled using the method of moment (MoM) and tissue-equivalent sphere phantom is loaded and modelled using the Green’s function method. A sensitivity matrix is constructed based on the pre-characterized B1 and electric field profiles of a large number of angular positions around the imaged phantom, an optimization procedure is then employed for the determination of optimal driving configuration by solving the ill-posed linear system equation. Test simulations show that, compared with conventional bird-cage mode driving scheme, the proposed excitation scheme is capable of significant improvement of the B1 -field homogeneity and reduction of the local and global SAR values. This primary study indicates that the proposed RF excitation technology can effectively perform field-tailoring and might hold the potential of solving the high frequency RF problem.

Image Analysis Applications

Room A7        11:00-13:00                Moderators: Claudia Lenz and Simon K. Warfield

11:00                       53.           Automatic Computational Method for the Measurement of Neuronal Cell Loss in Transgenic Mouse
Model of AD

George Iordanescu1,2, Palamadai Venkatasubramanian1,2, Alice Wyrwicz1,3

1Center for Basic MR Research, Northshore University HealthSystem, Evanston, IL, United States; 2Pritzker School of Medicine, University of Chicago, Chicago, IL, United States; 3Biomedical Engineering, Northwestern University, Evanston, IL, United States

Loss of neurons and synapses is a key features that characterize Alzheimer’s disease (AD). A novel semi-automatic segmentation method is used to quantify the neuronal loss in the pyramidal cell layer in hippocampal CA1 subfield (PLCA1) in a very rapid progression AD model. The proposed method uses unsupervised support vector machines. The resulting distance to the classification hyperplane combines all classification features and measures the neuronal cell loss as indicated by the MR contrast. The distribution of the neuronal cell loss within the PLCA1 may be a useful tool to understand the mechanism of cell loss in AD.

11:12                       54.           Analysis of MRI Data Monitoring the Treatment of Polycystic Kidney Disease in a Preclinical Mouse Model

Stathis Hadjidemetriou1, Wilfried Reichardt1, Juergen Hennig1, Martin Buechert2, Dominik von Elverfeldt1

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

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the growth of kidney cysts and the eventual kidney failure in humans. A treatment for ADPKD is not yet available. Treatment development involves preclinical studies with a mouse ADPKD model. Such mice have been monitored longitudinally with high field animal MRI. In this work the mouse kidneys are segmented with an unsupervised, reliable, and reproducible method. A region of interest is identified and analyzed for its statistics and for kidney geometry. This information is incorporated into the graph cuts algorithm that delineates the kidneys. Extensive validation is presented.

 

11:24                       55.           Effects of Smoking on Mouse Adipose Tissue Volumes Measured by IDEAL at 11.7T

David Johnson1, Jiarui Lian1, Mohamed El-Mahdy1, Jay L. Zweier1

1Heart and Lung Research Institute, Ohio State University, Columbus, OH, United States

An imaging technique was developed to produce uniform, robust fat-water separation in mice at 11.7T using Iterative Decomposition of water and fat with Echo Asymmetry and Least-squares estimation method (IDEAL). Cigarette smoking (CS) C57BL/6 mice had less body weight and subcutaneous adipose tissue volumes as compared to controls. The volumes of muscle and other non-adipose tissues were not different between CS and control mice, supporting the hypothesis of a selective reduction in fat storage due to smoking.

11:36                       56.           T2* Evaluation of Iron Overload at 3T and Comparison  with 1.5 T

Daniele De Marchi1, Antonella Meloni1, Alessia Pepe1, Vincenzo Positano1, Luca Menichetti1, Petra Keilberg1, Chiara Ardenghi1, Federico Vivarini1, Saveria Campisi2, Massimo Lombardi1

1MRI Lab, “G. Monasterio Foundation” and Institute of Clinical Physiology, CNR, Pisa, Italy; 2A.O.  Umberto I, Siracusa, Italy

The relationship between T2* values at 3T and 1.5T over the range of clinical interest of tissue iron concentrations was evaluated by GRE multiecho sequences on a dedicated phantom and on thalassemia patients. A strongly significant linear relationship between T2* values at 1.5T and at 3T was found for both liver and phantoms data. The slope was about 0.6, with a negligible intercept. The distribution of T2* values in heart did not allow to establish the relationship between T2* values at 1.5T and at 3T in heart.

11:48                       57.           Accuracy of Wholebody Fat Quantification with MRI: A Comparison to Air-Displacement Plethysmography

Florian Klausmann1, Ute Ludwig1, Matthias Honal1, Daniel König2, Peter Deibert2, Sandra Huff1

1Department of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany; 2Department for Rehabilitation, Prevention and Sports Medicine, University Hospital Freiburg, Freiburg, Germany

Besides the total amount of adipose tissue, its distribution has recently been recognized as an important factor in the pathogenesis of metabolic diseases like diabetes mellitus. MRI is capable for space-resolved imaging of fat distributions in the human body. In this study, we present a fully automatic algorithm for fat quantification in MRI two-point Dixon data which considers partial volume effects of fat voxels, compensates B1-inhomogeneities in the MR images and separates subcutaneous and inner fat in the abdomen. MR quantification results were compared to air-displacement plethysmography measurements, which served as the standard of reference.

 

12:00                       58.           Fat Quantitation Using Chemical Shift Imaging and 1H-MRS in Vitro Phantom Model

Shenghong Ju1, Xingui Peng1, Fang Fang1, Gaojun Teng1

1Radiology, Zhongda Hospital, Southeast University, Nanjing, Jiangsu, China

Present study aims to evaluate the accuracy of CSI and MRS in fat quantification and composition by using phantom model at high field 7.0 Tesla MR.The ability for quantitative fat measurement is verified in phantoms. They are promising for further application in vivo quantitation of fat composition.

12:12                       59.           An Integrated Approach for Perfusion Lesion Segmentation Using MR Perfusion for Acute Ischemic Stroke

Dattesh D. Shanbhag1, Rakesh Mullick1, Sumit K. Nath1, Catherine Oppenheim2, Marie Luby3, Katherine D. Ku3, Lawrence L. Latour3, Steven Warach3, - NINDS Natural History of Stroke Investigators3

1Imaging Technologies, GE Global Research, Bangalore, Karnataka, India; 2Department of Neuroradiology, Université Paris-Descartes, Paris, France; 3NINDS, NIH, Bethesda, MD, United States

In this work, we demonstrate a fully automated, fast and robust analysis pipeline for segmenting the perfusion lesion on different PWI maps (MTT, Tmax, TTP) and mismatch in acute ischemic stroke setting. The automatically segmented perfusion lesion and mismatch volume showed a strong correlation of 0.9 and 0.88 respectively, when compared to manually segmented PWI lesion on MTT maps. Variability for perfusion lesion volume estimates were lower compared to manual inter-rater variability, but was higher for mismatch estimates. Overall, Tmax PWI lesion had a lower volume compared to MTT PWI lesion.

12:24                       60.           Quantitative Imaging of Cortical Abnormalities in Extratemporal Epilepsy

Heath Richard Pardoe1, Graeme D. Jackson1,2

1Brain Research Institute, Florey Neuroscience Institutes, Melbourne, Victoria, Australia; 2Department of Medicine, University of Melbourne, Melbourne, Victoria, Australia

In this study software-based analysis of structural MRI was used to map the thickness of the cortex in extratemporal epilepsy subjects with radiologically observable lesions. The technique was used to identify cortical abnormalities in the epilepsy patients. Non-rigid registration of the patient group and an age-matched group of controls to a custom template allowed voxel-wise comparison of the cortical thickness in each epilepsy subject with the control group using a standard score. Thresholds for the objective identification of cortical abnormalities were empirically determined by investigating the relationship between standard score and number of voxels exterior to manually delineated lesions.

12:36                       61.           3D Visualization and Quantification of Subdural Electrode Shift Due to Craniotomy Opening

Peter Sherman LaViolette1, Alastair Hoyt2, Scott D. Rand3, Kathleen M. Schmainda1, Wade M. Mueller2

1Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States; 2Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States; 3Radiology, Medical College of Wisconsin, Milwaukee, WI, United States

Epileptic patients with medically intractable seizure disorders are subject to implantation of subdural electrodes for the purpose of seizure localization.  It is assumed that these electrodes remain stationary during the reopening of the craniotomy defect at the time of resective surgery.  This study shows that brain compression changes and general grid shift both occur and move electrodes in non-trivial amounts.  This study builds a case for adoption of electrode/brain model reliance for electrode position determination instead of traditional visual assessment at the reopening of the craniotomy.

12:48                       62.           Localization of Subdural Electrodes on MRI Cortical Surface Images for Evaluation of Epilepsy Patients

Boklye Kim1, Jack Parent1, Oren Sagher1, Karen Kluin1, Charles R. Meyer1

1University of MIchigan, Ann Arbor, MI, United States

Presurgical evaluation of surgical treatment of epilepsy patients often requires implantation of subdural grid electrodes on the cortex. The exact locations of implanted electrodes are essential to evaluate cortical lesions related to seizure onsets and delineate eloquent brain areas. The process requires registration via multi-modality image warping and correction of post-craniotomy brain deformation. The loss of CSF fluid the presence of epidural or subdural hematoma from open craniotomy cause brain shifts. This work presents an mapping of electrodes from post-implant CT data to pre- or post surgery MRI by intermodality image warping to determine accurate positions involved in electrocortical stimulation.

Flow Quantification & Vessel Function

Room A8        11:00-13:00                Moderators: Tino H.G. Ebbers and Thoralf Niendorf

11:00                       63.           Coregistration of Wall Shear Stress and Plaque Distribution Within the Thoracic Aorta of Acute Stroke Patients

Michael Markl1, Stephanie Brendecke2, Jan Simon1, Alex Frydrychowicz3, Andreas Harloff2

1Diagnostic Radiology, Medical Physics, University Hospital, Freiburg, Germany; 2Neurology, University Hospital, Freiburg, Germany; 3Radiology, University of Wisconsin, Madison, United States

Flow-sensitive 4D-MRI (3D morphology and 3-directional blood flow) and segmental wall shear stress analysis were employed in 94 patients with aortic atherosclerosis. A one-to-one comparison of wall parameter distribution with plaque location was performed in a large number of complex aortic plaques. Critical wall parameters such as low wall shear stress and high oscillatory shear index were concentrated at the inner curvature of the aorta and near the outlet of the supra-aortic arteries. For most complex plaques a consistent location of critical wall parameters in wall segments adjacent to the atheroma suggested a close correlation of hemodynamics and advanced atherosclerosis.

11:12                       64.           Analysis of Right Atrial and Ventricular Flow Patterns with Whole Heart 4D Flow MRI – Comparison of Tetralogy of Fallot with Normal Volunteers

Christopher J. François1, Shardha Srinivasan2, Benjamin R. Landgraf1, Alex Frydrychowicz1, Scott B. Reeder1,3, Mark L. Schiebler1, Oliver Wieben1,3

1Radiology, University of Wisconsin, Madison, WI, United States; 2Pediatrics, University of Wisconsin, Madison, WI, United States; 3Medical Physics, University of Wisconsin, Madison, WI, United States

An appropriate understanding of cardiac function requires analysis of flow patterns through the heart. This is particularly true in congenital heart disease prior to and following repair, where reconstruction of a normally functioning heart would be desirable. This work describes the analysis of flow patterns in the right heart in normal volunteers and patients with Tetralogy of Fallot using whole heart 4D flow MRI.

11:24                       65.           Simultaneous Quantification of Blood Velocity and Oxygenation in Femoral Artery and Vein in Response to Cuff-Induced Ischemia

Michael C. Langham1, Jeremy Magland1, Felix W. Wehrli1

1Radiology, University of Pennsylvania, Philadelphia, PA, United States

Quantifying reactive hyperemia in the lower extremities is a common approach for assessing vascular dysfunction associated with peripheral arterial disease (PAD). Often assessment is limited to measuring a single physiologic parameter such as velocity, flow-mediated dilatation and blood oxygenation. As a first step toward the development of an integrated MRI examination of PAD we have combined velocity quantification technique with a field mapping pulse sequence allowing simultaneous time-course mapping of blood velocity and oxygenation in femoral artery and vein during cuff-induced hyperemia. The results of blood velocity and oxygenation quantification agree with those found in the literature.

11:36                       66.           5-Point, Ultra-Short TE, 3D Radial Phase Contrast: Improved Characterization of Complex and
Turbulent Flow

Kevin M . Johnson1

1Medical Physics, University of Wisconsin - Madison, Madison, WI, United States

The accuracy of PC MR is deteriorated by flow features common to pathology such as acceleration, unstable flow, and turbulence. Recently, ultra short TE 2D radial sequences have been shown to provide more reliable through plane flow measurements than standard PC.  Meanwhile, investigators have utilized conventional 3D PC sequences for the measurement of turbulence kinetic energy using signal losses.  In this work, we investigate a synergistic combination of ultra-short TE 3D radial trajectories and a 5-point velocity encoding scheme for improvements in both the velocity measurement accuracy and estimation of intra-voxel standard deviations utilized for turbulence mapping

11:48                       67.           Hadamard-Transform K-T PCA for Cine 3D Velocity Vector Field Mapping of Carotid Flow

Verena Knobloch1, Daniel Giese1, Peter Boesiger1, Sebastian Kozerke1

1Institute for Biomedical Engineering, Swiss Federal Insitute of Technology and University Zurich, Zurich, Switzerland

It has been shown recently that k-t PCA permits high acceleration without compromising the accuracy of single directional flow quantification. In this work 3D velocity fields are measured in a phantom and an in-vivo case and reconstructed with different acceleration factors. Pathline tracking is possible up to an acceleration factor of 10.

12:00                       68.           Metric Optimized Gating for Fetal Cardiac MR Imaging

Michael Shelton Jansz1,2, Mike Seed3, Joshua F. van Amerom1,2, Shi Joon Yoo3,4, Christopher K. Macgowan1,2

1Medical Biophysics, University of Toronto and Hospital for Sick Children, Toronto, Ontario, Canada; 2Medical Imaging, University of Toronto and Hospital for Sick Children, Toronto, Ontario, Canada; 3Pediatric Cardiology, University of Toronto and Hospital for Sick Children, Toronto, Ontario, Canada; 4Dignostic Imaging, University of Toronto and Hospital for Sick Children, Toronto, Ontario, Canada

Phase-contrast MRI of pulsatile flow typically requires cardiac gating; however, a gating signal is not necessarily available in utero for fetal cardiac imaging.  We propose a new technique for reconstructing ungated data where the gating is determined retrospectively by optimizing an image metric.  Simulations and in vivo data are presented to demonstrate the feasibility of this technique.

12:12                       69.           Objective Characterization of Disease Severity by Determination of Blood Flow Reserve Capacity of the Popliteal Artery in Intermittent Claudication

Bastiaan Versluis1, Marjolein HG Dremmen1, Patty J. Nelemans2, Joachim E. Wildberger1, Tim Leiner1, Walter H. Backes1

1Radiology, Maastricht Universitary Medical Centre, Maastricht, Netherlands; 2Epidemiology, Maastricht Universitary Medical Centre, Maastricht, Netherlands

Objective characterization of peripheral arterial disease (PAD) severity remains difficult purely on the basis of morphological assessement. We describe a method to determine rest flow and blood flow reserve capacity (BFRC) of the popliteal artery, using serial velocity encoded 2D MR cine PCA flow measurements. Using this method, we found a strong reduction in rest flow, maximum flow and BFRC in 10 patients with intermittent claudication compared to 10 healthy subjects. This method can potentially be used to supplement MR angiography to objectively characterize PAD disease severity and to monitor therapy efficacy in intermittent claudication.

12:24                       70.           Analysis of Complex Flow Patterns with Acceleration-Encoded MRI

Felix Staehle1, Simon Bauer1, Bernd André Jung1, Jürgen Hennig1, Michael Markl1

1Department of Diagnostic Radiology, University Hospital Freiburg, Freiburg, Germany

The phase contrast principle (PC) can be employed to measure flow acceleration by using acceleration sensitive encoding gradients. The aim of this study was to evaluate a newly developed gradient optimized acceleration-sensitive PC-MRI technique with full three-directional acceleration encoding of aortic blood flow. Results were compared to standard velocity encoded phase contrast MRI. In addition, the value of acceleration induced intravoxel dephasing as a new image contrast providing information about complex and vortical flow was investigated.

12:36                       71.           Novel Hybrid Real-Time Phase-Contrast Sequence

Jennifer Anne Steeden1,2, David Atkinson1, Andrew M. Taylor2, Vivek Muthurangu2

1Medical Physics, University College London, Gower Street, London, United Kingdom; 2Centre for Cardiovascular MR, UCL Institute of Child Health, 30 Guilford Street, London, United Kingdom

Real-time phase contrast (PC) imaging has a low temporal resolution because interleaved flow-encoded and compensated readouts must be acquired. We have developed a hybrid real-time PC sequence that acquires real-time flow-encoded and flow-compensated readouts in alternating blocks. The encoded data is subsequently matched to the compensated data, allowing the temporal resolution to be effectively doubled. This technique was demonstrated in 10 volunteers to adequately match the flow-compensated data to the flow-encoded data. It was also shown to accurately measure stroke volumes, with a good correlation against a reference gated sequence and an in-house real-time interleaved flow sequence.

12:48                       72.           Analysis and Correction of Background Velocity Offsets in Cine Phase-Contrast Imaging Using Magnetic Field Monitoring

Daniel Giese1,2, Maximilian Haeberlin1, Christoph Barmet1, Tobias Schaeffter2, Klaas Paul Pruessmann1, Sebastian Kozerke1,2

1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 2Division of Imaging Sciences, King's College London, London, United Kingdom

The sensitivity of phase contrast MRI to magnetic field gradient imperfections has long been recognized and a number of image-based approaches exist to partially correct for background velocity offsets. Image-based velocity offset correction assumes a sufficient number of static image pixels and often only phase offsets with 0th  and 1st order in space can be accounted for. In this work, a 16-channel magnetic field camera is employed to analyze and correct background velocity offsets in cine phase-contrast velocity imaging. It is demonstrated that phase offsets exhibit primarily constant and linear terms in space but do considerably vary in magnitude over time in triggered cine sequences necessitating heart-phase dependent correction.

SSFP & Non-Cartesian

Room A9        11:00-13:00                Moderators: Jin Hyung Lee and Krishna S. Nayak

11:00                       73.           An Analytical Description of Balanced SSFP with Finite RF Excitation

Oliver Bieri1

1University of Basel Hospital, Basel, Switzerland

Conceptually, the only flaw in the common SSFP signal theory is the assumption of quasi-instantaneous radio-frequency (RF) pulses. An exact analytical solution for finite RF balanced SSFP will be derived and it will be shown that finite RF effects can be quite significant even for moderate RF pulse durations. Thus care should be taken when interpreting SSFP signal based on the common Freeman-Hill formulae since only recently it was realized that besides finite RF pulses also magnetization transfer effects may induce a significant modulation in the steady state amplitude.

11:12                       74.           Simple Cross-Solution for Banding Artifact Removal in BSSFP Imaging

Qing-San Xiang1,2, Michael N. Hoff2

1Radiology, University of British Columbia, Vancouver, BC, Canada; 2Physics & Astronomy, University of British Columbia, Vancouver, BC, Canada

Balanced SSFP imaging (or TrueFISP, FIESTA) has broad clinical applications for its high time efficiency and desirable contrast. Unfortunately, banding artifacts are often seen in bSSFP images as signal modulation due to B0 inhomogeneity.  To reduce banding, phase-cycled bSSFP acquisitions have been used with various reconstruction algorithms, such as Maximum Intensity Projection (MIP), Sum of Squares (SOS), Nonlinear Averaging (NLA), and Complex Sum (CS).  However, none of these techniques remove banding completely. In this work, a novel elliptical signal model and a simple analytical “Cross-Solution (XS)” are presented. The latter is able to remove banding artifacts completely.

11:24                       75.           Spectral Profile Design for Multiple Repetition Time Balanced SSFP

R. Reeve Ingle1, Tolga Çukur1, Dwight G. Nishimura1

1Electrical Engineering, Stanford University, Stanford, CA, United States

A method for optimizing the spectral profile of a given multiple repetition time balanced SSFP (multi-TR bSSFP) sequence is proposed and analyzed via Bloch simulation and phantom imaging.  In this method, a linear model of transverse magnetization versus flip angle is constructed by perturbing pairs of flip angles and simulating the resulting change in transverse magnetization.  Least-squares analysis is used to compute flip angles that minimize the squared error between the linear model and a desired magnetization profile.  The method is demonstrated on a reference multi-TR bSSFP sequence, resulting in a 6 dB improvement in the passband-to-stopband ratio.

11:36                       76.           Extended Chimera SSFP

Oliver Bieri1, Klaus Scheffler1

1Radiological Physics, University of Basel Hospital, Basel, Switzerland

Only recently, a new type of steady-state free precession (SSFP) sequence was introduced, termed chimera SSFP. The chimera sequence consists of two alternating SSFP kernels: odd TR-intervals feature a balanced SSFP (bSSFP) type of protocol, whereas even TR-intervals undergo gradient dephasing (non-balanced SSFP) and hence the name. In contrast to the recently proposed sequence, the non-balanced SSFP kernel is played out with minimal TR → 0 and the constraint of identical flip angles for both kernels is discarded. Frequency response profile modifications achievable with the extended chimera sequence are discussed.

11:48                       77.           Suppression of Banding and Transient Signal Oscillations in Balanced SSFP Using a Spoiled RF
Pre-Phasing Approach

Jon Fredrik Nielsen1, Daehyun Yoon2, Douglas C. Noll1

1Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States; 2Electrical Engineering and Computer Sciences, University of Michigan, Ann Arbor, MI, United States

Balanced steady state free precession (bSSFP) offers high SNR efficiency and unique contrast mechanisms, but is prone to banding artifacts and transient signal oscillations. We present an RF “pre-phasing” approach for suppression of banding and transient oscillations in bSSFP.

12:00                       78.           Dual-Projection Cardiac and Respiratory Self-Navigated Cine Imaging Using SSFP

Liheng Guo1, Elliot R. McVeigh1, Robert J. Lederman2, J Andrew Derbyshire2, Daniel A. Herzka1

1Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States; 2Translational Medicine Branch, National Heart, Lung, and Blood Institute, National Institute of Health, Bethesda, MD, United States

A dual-projection self-navigated SSFP sequence is implemented to acquire navigation projections at two alternating angles during all TRs; it offers projections of high spatiotemporal resolution at two different orientations, thus providing a platform for 2D motion tracking and robust self-navigation, which can replace the standard ECG gating and patient breath hold. Preliminary post-processing of the projection data has shown that cardiac and respiratory motions can be automatically extracted and separated, and that free-breathing cardiac cine images can be automatically reconstructed to comparable quality as standard breath-hold images.

12:12                       79.           Optimized 3D Single Shot Trajectories by Radial Arrangement of Individual Petals (RIP)

Benjamin Zahneisen1, Thimo Grotz1, Kuan J. Lee1, Marco Reisert1, Juergen Hennig1

1University Hospital Freiburg, Freiburg, Germany

With the use of multiple localized, small receive coil arrays, single shot whole brain coverage becomes feasible for fMRI applications using undersampled reconstruction. Using a 3D-rosette trajectory and iterative, regularized reconstruction a 64³ volume can be acquired in 23ms with acceptable PSF-broadening. However, the analytical rosette offers only limited degrees of freedom for optimization. In this work we present an optimized 3D single-shot trajectory based on a radial arrangement of individual petals (RIP-trajectory). Compared to the “conventional” rosette trajectory it has a narrower PSF, no visible sidelobes and is faster (19.3ms) and therefore less sensitive to field inhomogeneities.

12:24                       80.           Image Domain Propeller FSE (IProp-FSE)

Stefan Skare1,2, Samantha Holdsworth1, Roland Bammer1

1Radiology, Stanford University, Stanford, CA, United States; 2Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden

In PROPELLER imaging, multiple blades are acquired in k-space and rotated around the center to cover all of k-space. This has proven useful to mitigate motion artifacts in Cartesian FSE. In this work, a new pulse sequence called Image domain Propeller FSE (iProp-FSE) is proposed as an alternative for T2-w imaging, having propeller blades in the image domain instead of k-space. Similar to PROPELLER, motion correction can be performed between the blades. Moreover, the averaging effect of all blades in the center of the image FOV increases the SNR locally, which is especially useful for multi-channel head coils.

12:36                       81.           Steer-PROP: A GRASE-PROPELLER Sequence with Inter-Echo Steering Gradient Pulses

Girish Srinivasan1,2, Novena Rangwala1,2, Xiaohong Joe Zhou1,3

1Center for Magnetic Resonance Research, University of Illinois Medical Center, Chicago, IL, United States; 2Department of Bioengineering, University of Illinois at Chicago, Chicago, IL, United States; 3Departments of Radiology, Neurosurgery and Bioengineering, University of Illinois Medical Center, Chicago, IL, United States

PROPELLER imaging has increasingly been used in motion-sensitive applications such as long anatomic scans and diffusion imaging. EPI-PROPELLER provides short scan times but is susceptible to off-resonance artifacts, producing distorted images. FSE-based PROPELLER, on the other hand, offers excellent immunity against off-resonance artifacts at the expense of acquisition efficiency. We propose a new PROPELLER sequence - Steer-PROP - which mediates the problems in EPI- and FSE-PROPELLER. This sequence has reduced the scan time by at least 3 times as compared to FSE-PROPELLER and avoided the off-resonance artifacts in EPI sequences.  Steer-PROP also provides a natural mechanism to effectively address a long-standing phase correction problem.

12:48                       82.           Image Reconstruction from Radially Acquired Data Using Multipolar Encoding Fields

Gerrit Schultz1, Hans Weber1, Daniel Gallichan1, Jürgen Hennig1, Maxim Zaitsev1

1Diagnostic Radiology - Medical Physics, University Hospital Freiburg, Freiburg, BW, Germany

In this contribution a radial imaging technique is presented in the context of nonlinear and non-bijective encoding fields. Efficient image reconstruction methods are described and analyzed. For multipolar encoding fields, the reconstruction can be performed in a particularly simple and useful way: The inverse Radon Transform to polar coordinates leads to undistorted images represented in polar coordinates. In the angular direction pixels are aliased equidistantly. Therefore a standard Cartesian SENSE algorithm is applicable for the unfolding process. The developed reconstruction method is applied to simulated as well as measured data to demonstrate each reconstruction step separately.




GOLD CORPORATE MEMBER LUNCHTIME SYMPOSIUM

GE Healthcare

Victoria Hall              13:00 - 14:00 

 

CLINICAL INTENSIVE COURSE

Hip & Pelvis Imaging : Case-Based Teaching

Room K1        14:00-16:00        Organizer & Moderator:  Christine Chung

 

EDUCATIONAL OBJECTIVES
Upon completion of this course participants should be able to:

  • Describe the MR appearance of the most common abnormalities of the hip joint and its surroundings;
  • Describe the differential diagnosis of such abnormalities; and
  • Identify four hip abnormalities which radiologists should not miss.

14:00       Pubalgia
Adam C. Zoga, M.D.

 

14:40       Femoroacetabular Impingement
Suzanne E. Anderson-Sembach, M.D., Ph.D.

 

15:20       Soft Tissue Injury
Christine Chung, M.D.

 

16:00       Adjournment

 

CLINICAL INTENSIVE COURSE
Advances in Spine Imaging

Room K2        14:00-16:00       Organizers:  Walter Kucharczyk and Pia C. Maly Sundgren

EDUCATIONAL OBJECTIVES
Upon completion of this course participants should be able to:

  • Implement new sequences and select coils that might be appropriate to imaging less cooperative or unstable patients;
  • Describe the potential for use of high-field MRI of the spine;
  • Describe situations when DWI/DTI might be useful to obtain information about a spine lesion; and
  • Explain different vascular malformations and how to image them with MRI.

Moderators: Claude Henri Manelfe, M.D. and Majda Thurnher, M.D.

 

14:00       The Role of New Sequences and Coils in Imaging Less Cooperative or Instable Patients
Danielle Balériaux, M.D.

 

14:25       Spine Imaging at High Field
John R. Hesselink, M.D.

 

14:50       Is There a Role for DWI/DTI in Spine Imaging
Majda M. Thurnher, M.D.

 

15:15       MRI of Vascular Malformations of the Spine
Stephanie Condette-Auliac, M.D.

Young Investigators Awards

Room A1        14:00-16:00    Moderators:  Richard L. Ehman and Michael Garwood  

14:00                       83.           Validation of Functional Diffusion Maps (FDMs) as a Biomarker for Human Glioma Cellularity

Benjamin M. Ellingson1,2, Mark G. Malkin2,3, Scott D. Rand1,2, Jennifer M. Connelly2,3, Carolyn Quincey3, Pete S. LaViolette2,4, Devyani P. Bedakar1,2, Kathleen M. Schmainda1,2

1Dept. of Radiology, Medical College of Wisconsin, Milwaukee, WI, United States; 2Translational Brain Tumor Program, Medical College of Wisconsin, Milwaukee, WI, United States; 3Dept. of Neurology and Neurosurgery, Medical College of Wisconsin, Milwaukee, WI, United States; 4Dept. of Biophysics, Medical College of Wisconsin, Milwaukee, WI, United States

The purpose of the current study was to comprehensively validate the assumptions made in human functional diffusion map (fDM) analyses and provide a biological and clinical basis for thresholds used in fDM tissue classification.

14:20                       84.           Detecting Blood Oxygen Level Dependent (BOLD) Contrast in the Breast

Rebecca Rakow-Penner1, Bruce Daniel1, Gary Glover1

1Department of Radiology, Stanford University School of Medicine, Stanford, CA, United States

Detecting and understanding breast tissue oxygenation may help characterize tumors, predict susceptibility to treatment, and

monitor chemotherapeutic response.  We have developed a robust methodology for detecting BOLD contrast in the breast and have tested this technique on healthy volunteers and patients.  We found that BOLD signal positively correlates to a carbogen stimulus in healthy glandular tissue.  In a small patient pilot study, we found that BOLD signal negatively correlates to a carbogen stimulus in breast cancer.

14:40                       85.           Quantitative 4D Transcatheter Intraarterial Perfusion MRI for Monitoring Chemoembolization of Hepatocellular Carcinoma

Dingxin Wang1, Brian Jin2, Robert Lewandowski2, Robert Ryu2, Kent Sato2, Mary Mulcahy3,4, Laura Kulik5, Frank Miller2, Riad Salem2,3, Debiao Li1, Reed Omary1,4, Andrew Larson1,4

1Departments of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, United States; 2Department of Radiology, Northwestern University, Chicago, IL, United States; 3Department of Medicine, Northwestern University, Chicago, IL, United States; 4Robert H. Lurie Comprehensive Cancer Center, Northwestern University, Chicago, IL, United States; 5Department of Hepatology, Northwestern University, Chicago, IL, United States

Quantitative 4D TRIP-MRI can be performed successfully in a combined x-ray DSA-MRI unit to monitor intra-procedural reductions in liver tumor perfusion during TACE procedures in patients with HCC.

15:00                       86.           Three Dimensional Rapid Diffusion Tensor Microimaging for Anatomical Characterization and Gene Expression Mapping in the Mouse Brain

Manisha Aggarwal1, Susumu Mori1, Tomomi Shimogori2, Seth Blackshaw3, Jiangyang Zhang1

1Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, MD, United States; 2RIKEN Brain Science Institute, Saitama, Japan; 3The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD, United States

Diffusion tensor imaging (DTI) can reveal superior contrasts than relaxation-based MRI in premyelinated developing mouse brains. Current challenges for the application of DTI to mouse brain imaging at microscopic levels include the limitation on the achievable spatial resolution. In this study, high resolution rapid DT-microimaging of the embryonic and adult mouse brains (up to 50-60 µm) based on a 3D diffusion-weighted gradient and spin echo (DW-GRASE) scheme with twin-navigator echo phase correction is presented. We also demonstrate successful 3D mappings of gene expression data from in situ hybridization to high resolution DTI images in the early embryonic mouse brain.

15:20                       87.           B1 Mapping by Bloch-Siegert Shift

Laura Sacolick1, Florian Wiesinger1, W. Thomas Dixon2, Ileana Hancu2, Mika W. Vogel1

1GE Global Research, Garching b. Munchen, Germany; 2GE Global Research, Niskayuna, NY, United States

Here we present a novel method for B1+ field mapping based on the Bloch-Siegert shift. The Bloch-Siegert shift refers to the effect where the resonance frequency of a nucleus shifts when an off-resonance RF field is applied. This shift is proportional to the square root of the RF field magnitude B12. An off-resonance RF pulse is added to an imaging sequence following spin excitation. This pulse induces a B1 dependent phase in the acquired image. A B1 map is calculated from the square of the phase difference between two images, with the RF pulse applied at two frequencies symmetrically around the water resonance. In-vivo Bloch-Siegert B1+ maps with 25.6 seconds/ 128x128 slice were found to be quantitatively comparable to 13 minute conventional double-angle maps. The method can be integrated into a wide variety of fast imaging sequences, and is compatible with EPI, alternative readout trajectories, receive array acceleration, etc. Insensitivity to B0, chemical shift, TR, T1, and magnetization transfer is shown as well.

15:40                       88.           Improved Arterial Spin Labeling After Myocardial Infarction in Mice Using Respiratory and Cardiac Gated Look-Locker Imaging with Fuzzy C-Means Clustering for T1 Estimation

Moriel H. Vandsburger1, Robert L. Janiczek1, Yaqin Xu1, Brent A. French1, Craig H. Meyer1, Christopher M. Kramer1, Frederick H. Epstein1

1University of Virginia, Charlottesville, VA, United States

Arterial spin labeling is used to quantify myocardial perfusion in mice, but not after myocardial infarction (MI). We developed a cardio-respiratory triggered ASL method which incorporates a fuzzy C-means clustering algorithm during image reconstruction in order to reduce respiratory motion artifact and improve perfusion quantification after MI. Using this technique, we measured myocardial perfusion in distinct reperfused infarct and remote zones of myocardium during the time course of infarct healing in mice. Our data indicate that while perfusion in remote zone myocardium is unchanged, infarct zone perfusion drops significantly 1 day post-MI and recovers by 28 days post-MI.

Abdominal Diffusion & Whole Body Diffusion

Room A5        14:00-16:00                Moderators: Dow-Mu Koh and Thomas C. Kwee

14:00                       89.           Whole-Body Magnetic Resonance Imaging, Including Diffusion-Weighted Imaging, for Diagnosing Bone Marrow Involvement in Malignant Lymphoma

Thomas Kwee1, Rob Fijnheer2, Inge Ludwig3, Henriëtte Quarles van Ufford1, Cuno Uiterwaal4, Marc Bierings5, Taro Takahara1, Rutger-Jan Nievelstein1

1Department of Radiology, University Medical Center Utrecht, Utrecht, Netherlands; 2Department of Hematology, Meander Medical Center, Amersfoort, Netherlands; 3Department of Hematology, University Medical Center Utrecht, Utrecht, Netherlands; 4Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, Netherlands; 5Department of Pediatric Hematology, University Medical Center Utrecht, Utrecht, Netherlands

This study aimed to determine the value of whole-body MRI, including diffusion-weighted imaging (DWI), for diagnosing bone marrow involvement in malignant lymphoma using blind bone marrow biopsy (BMB) as reference standard. To that end, 48 consecutive patients with newly diagnosed malignant lymphoma prospectively underwent whole-body MRI (T1-weighted and short inversion time inversion recovery [n=48] and DWI [n=44]) and BMB of the posterior iliac crest. Whole-body MRI (without and with DWI) was negative for bone marrow involvement in a considerable proportion of patients with a positive BMB. Therefore, whole-body MRI cannot replace BMB for bone marrow assessment in malignant lymphoma yet.

14:12                       90.           Comparison of DWIBS and 18F-FDG PET/CT in Newly Diagnosed Lymphoma

Jing Gu1, Yok-Lam Kwong2, Tao Chan1, Wing-Yan Au2, Queenie Chan3, JingBo Zhang1,4, Raymond Liang2, Pek-Lan Khong1

1Diagnostic Radiology, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China; 2Medicine, Queen Mary Hospital, The University of Hong Kong, Hong Kong, China; 3Philips Healthcare, Philips Electronics Hong Kong Limited, Hong Kong; 4Memorial Sloan-Kettering Cancer Center, United States

The aim of this study was to evaluate the diagnostic performance of DWIBS in detection of lymphoma compared with PET/CT, and to assess the correlation between ADC and SUV in lymphoma lesions. We found that (1) DWIBS provides satisfactory diagnostic accuracy in lymphoma compared with PET/CT, and with the advantage of no ionizing radiation. (2) There were significant differences in ADCmin and SUVmax between aggressive and indolent B-cell lymphoma. ADCmin may therefore be another useful quantitative marker for tumor characterization and classification. (3) Negative correlation was found between ADCmin and SUVmax suggesting an association between tumor cellularity and metabolic activity.

14:24                       91.           Apparent Diffusion Coefficient Predicts Biochemical Response in Neuroendocrine Liver Metastases Treated Using Targeted Radiolabelled Therapy

Dow-Mu Koh1, Keiko Miyazaki2, Matthew Orton2, Toni Wallace1, David J. Collins2, Martin O. Leach2, Val Lewington3

1Department of Radiology, Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom; 2CRUK-EPSRC Cancer Imaging Centre, Institute of Cancer Research, Sutton, Surrey, United Kingdom; 3Department of Nuclear Medicine, Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom

We investigated diffusion-weighted MR imaging (DW-MRI) for assessing treatment response of liver metastases of neuroendocrine origin to targeted radiolabelled therapy 90Y-DOTATOC. The quantitative apparent diffusion coefficient (ADC) appears to be a promising response and prognostic biomarker. Responders were found to have a lower pre-treatment value compared with non-responders; and also demonstrated a significant increase in ADC at 2 months after the first cycle of treatment. Response defined by ADC changes also showed good agreement with biochemical response.

14:36                       92.           Diffusion-Weighted MR Imaging of Pulmonary Lesions: Effectiveness of Apparent Diffusion Coefficient Quantification and Lesion-To-Spinal Cord Signal Intensity Ratio in the Lesion Characterization

Nevzat Karabulut1, Vefa Çakmak1

1Radiology, Pamukkale University, School of Medicine, Denizli, Turkey

Diffusion-weighted imaging (DWI) of lung is a useful adjunct to conventional chest MR imaging sequences improving lesion characterization. Differentiation of malignant tumors from benign lesions can be achieved using apparent diffusion coefficient (ADC) quantification and lesion-to-spinal cord signal intensity ratio (LSR). Due to increased cellularity and less extracellular space impeding the water diffusion, malignant tumors tend to have reduced ADC and increased LSR. Our results show that ADC quantification is more accurate than LSR for the differentiation of lung lesions. Because DWI is a non-invasive technique improving lesion characterization, it should be incorporated into routine chest MR imaging protocols.

14:48                       93.           Improving IVIM Derived F-Maps of Pancreatic Tumors with Automatic Duct and Vessel Segmentation

Thomas Joseph Re1,2, Mirium Klauss3, Andreas Lemke4, Frederik B. Laun2, Dirk Simon5, Riccardo Manfredi1, Roberto Pozzi Mucelli1, Stefan Delorme2, Bram Stieltjes2

1Radiology, University of Verona, Verona, Italy; 2Radiology, DKFZ, Heidelberg, BW, Germany; 3Radiology, University of Heidelberg, Heidelberg, BW, Germany; 4MS Computer Assisted Clinical Medicine, University of Heidelberg; 5Software Development for Integrated Diagnostics and Therapy, DKFZ, Heidelberg, BW, Germany

Maps of IVIM model derived perfusion fraction f (f-maps) of the pancreas show potential for the identification of pancreatic adenocarcinoma lesions which appear hypointense in these images. Unfortunately, since bile and pancreatic ducts also appear as hypointense in f-maps, their presence adjacent to tumors can lead to tumor delineation  errors.  A novel approach which automatically segmented vessels and ducts in the f-maps based on integrated diffusion coefficient D data was tested in 43 patients and proved to be superior to both the ADC or f-map for tumor delineation.

 

15:00                       94.           Higher Pre-Treatment Apparent Diffusion Coefficient Predicts Poorer Disease Survival in Patients with Colorectal Hepatic Metastasis

Henry Ho Ching Tam1, David J. Collins2, Gina Brown1, Ian Chau3, David Cunningham3, Martin O. Leach2,
Dow-Mu Koh1

1Department of Radiology, Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom; 2CRUK-EPSRC Cancer Imaging Centre, Institute of Cancer Research, Sutton, Surrey, United Kingdom; 3Department of Medical Oncology (Gastrointestinal), Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom

We report the use of DW-MRI for assessing response to chemotherapy and long-term outcome in patients with colorectal hepatic metastasis. Non-responders were found to have a higher pre-treatment apparent diffusion coefficient (ADC). High pre-treatment ADC was also associated with a shorter progression free survival time, independent of response to chemotherapy and other prognostic factors. This study demonstrates the potential of DW-MRI as a biologically relevant response and prognostic biomarker.

15:12                       95.           Value of Diffusion Weighted Imaging (DWI) as an Early Imaging Biomarker for Prediction of Therapy Effect in Patients with Colorectal Metastases Following Selective Internal Radiotherapy (SIRT)

Martin Zeile1, Christian Wybranski1, David Loewenthal1, Maciej Pech1, Frank Fischbach1, Ricarda Ruehl1, Holger Amthauer1, Jens Ricke1, Oliver Dudeck1

1Clinic for Radiology and Nuclear Medicine, University Clinic Magdeburg, Magdeburg, 39120, Germany

Clinical studies revealed the potential of diffusion weighted imaging (DWI) as a biomarker for predicting tumor response. 41 colorectal liver metastases in 18 patients who underwent SIRT were examined before, 1 to 3 days after and 6 weeks following radioembolization by MRI including DWI. Lesions were categorized in responding (RL) and non-responding (NRL) according to change in tumor volume after 6 weeks. On early MRI, NRL showed no change in apparent diffusion coefficient (ADC), while a significant decrease in ADC was noted for RL (p<0.0001). DWI was capable of predicting therapy response in patients with colorectal liver metastases following radioembolization.

15:24                       96.           Medullar Architecture Mapping of the Human Kidney in Vivo Using an Optimized DTI Protocol at 3 T

Petros Martirosian1, Christina Schraml2, Nina Franziska Schwenzer2, Günter Steidle1, Cristina Rossi1, Andreas Boss2, Vinod Kumar3, Michael Erb3, Uwe Klose3, Thorsten Feiweier4, Fritz Schick1

1Section on Experimental Radiology, University of Tübingen, Tübingen, Germany; 2Department of Diagnostic and Interventional Radiology, University of Tübingen, Tübingen, Germany; 3Section on Experimental Magnetic Resonance of CNS, University of Tübingen, Tübingen, Germany; 4Department of Magnetic Resonance, Siemens Healthcare, Erlangen, Germany

The aim of the present study was to develop an optimized DTI protocol for the assessment of the renal medullar architecture in healthy volunteers. Examinations were performed on a 3T MR scanner, using a respiratory triggered diffusion-weighted EPI sequence with a monopolar diffusion preparation scheme. Diffusion-sensitizing gradients with b-values of 400s/mm2 were applied along 30 different directions. Ten slices were acquired with a voxel size of 2×2×3mm3. Tractography was performed in order to visualize the architecture of renal medulla. The presented protocol provides high SNR and high spatial resolution with good discrimination between cortex and medulla and allows for detailed tractography of renal medulla.

15:36                       97.           Diffusion Tensor Imaging as a Biomarker of Diabetic Nephropathy

Lan Lu1, Gregory Lee1, Vikas Gulani1,2, John Sedor3,4, Katherine Dell, 4,5, Chris Flask1,2

1Department of Radiology, Case Western Reserve University, Cleveland, OH, United States; 2Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States; 3Department of Medicine, Case Western Reserve University, Cleveland, OH, United States; 4Rammelkamp Renal Research Center, MetroHealth Medical Center, Cleveland, OH, United States; 5Department of Pediatrics, Case Western Reserve University, Cleveland, OH, United States

Our understanding of and treatment options for Diabetic Nephropathy (DN) is limited by a lack of a non-invasive means to detect early-stage DN. In this study, we used Diffusion Tensor Imaging to quantitatively assess renal diffusion changes relative to estimated GFR (eGFR) in diabetic subjects. Our initial results suggest that medullary fractional anisotropy (FA) decreases with eGFR while Apparent Diffusion Coefficient is less sensitive. Further, FA differentiates subjects with mild DN (eGFR = 60-89) from healthy subjects (eGFR > 90), suggesting an opportunity for early detection of DN and progression as well as therapeutic intervention.

15:48                       98.           Diffusion-Weighted MR Imaging of Kidneys Using Targeted-SPLICE

Ning Jin1, Jie Deng2, Andrew C. Larson1,3

1Departments of Radiology and Biomedical Engineering, Northwestern University, Chicago, IL, United States; 2Children's Memorial Hospital, Chicago, IL, United States; 3Robert H. Lurie Comprehensive Cancer Center, Chicago, IL, United States

Diffusion-weighted (DW) imaging is particularly useful for functional interrogation of the kidney. Single-shot DW spin-echo echo-planner imaging (DW-SE-EPI) is commonly used for DW acquisition; however, this technique can experience image distortion and chemical shift artifacts. We recently developed targeted-SPLICE technique by combining the inner volume imaging technique with SPLICE for DWI without image distortion and blurring. The purpose of our study is to apply targeted-SPLICE technique for DWI in the kidneys and compare these targeted-SPLICE diffusion measurements to conventional DW-SE-EPI measurements. Targeted-SPLICE effectively reduced geometric distortion and image blurring and produced accurate diffusion parameter measurements in the kidney.

 

 

SPECIAL SESSION:
SMRT Forum: Safe Exposure Limits for Staff & Patients

Room A9        14:00 – 16:00        Organizers & Moderators:  Penny Anne Gowland and Ben A. Kennedy

EDUCATIONAL OBJECTIVES
Upon completion of this course participants should be able to:

  • State international staff exposure limits;
  • Explain means of interactions of magnetic fields of various relevant frequencies with the human body;
  • Describe what is known about the interactions of magnetic fields with the developing fetus; and\
  • Explain the issues around the EU directive

14:00       Interactions with the Body
Paul M. Glover, Ph.D.

 

14:20       Staff Exposure Data
Donald W. McRobbie, Ph.D.

 

14:45       Current and future ramifications for the MR workplace
Sija Geers-van Gemeren, Ph.D.

 

15:10       The EU Directive
Freddy Stahlberg, Ph.D.

 

15:35       Debate

 

16:00       Adjournment

CLINICAL INTENSIVE COURSE
MR Physics & Techniques for Clinicians

Room K1        16:30-18:30                Organizers & Moderators:  Marcus T. Alley and Michael Markl

EDUCATIONAL OBJECTIVES
Upon completion of this course participants should be able to:

  • Define and describe the fundamental principles of MR imaging, including the definition of spin magnetization, the Larmor relationship, relaxation phenomena, and the process of using the spin magnetization to produce an image;
  • Explain imaging pulse sequences based upon spin and gradient echoes, including fast spin-echo and echo planar techniques;
  • Design MR imaging protocols for diagnostic applications considering image contrast, spatial resolution, acquisition time, signal-to-noise ratio, and artifacts; and
  • Describe the principles of parallel imaging, high-field imaging, perfusion imaging, diffusion imaging, and functional MR imaging.

16:30       Spin Gymnastics I
Walter Kucharczyk, M.D., F.R.C.P.C.

 

17:10       Spin Gymnastics II
Donald B. Plewes, Ph.D.

 

17:50       K-space
Anja C. Brau, Ph.D.

 

18:30       Adjournment

 

EDUCATIONAL COURSE:
Tools & Tips for Mouse Imaging & Spectroscopy

Room K2        16:30 – 18:30              Organizers & Moderators:  Klaas Nicolay and Ivan Tkac

Upon completion of this course participants should be able to:

  • Select optimal anesthesia and physiological monitoring;
  • Design optimal protocols for efficient mouse screening;
  • Describe the most efficient MRI and MRS techniques for mouse screening; and
  • Optimize experimental protocols for maximum efficacy and high reproducibility.

16:30       Anesthesia and Physiological Monitoring
Brenda A. Klaunberg, V.M.D.

 

16:50       Tips for Advanced MRI Screening of Mice
               
Jason P. Lerch, Ph.D.

 

17:10       MRI in Mouse Models of Brain Disorders
               
Istvan Pirko, M.D.

 

17:30       MRI and Stem Cell Trafficking
               
Piotr Walczak, M.D.

 

17:50       Methodology of MRS in Transgenic Mouse Models
               
Malgorzata Marjanska, Ph.D.

 

18:10       MR Techniques for Myocardial Studies in Mice
               
Jeanine J. Prompers, Ph.D.

 

18:30       Adjournment

 

 

Parallel RF Transmission

Room A1        16:30-18:30                Moderators: Adam B. Kerr and Kawin Setsompop

16:30                       99.           Joint Design of Dual-Band Large-Tip-Angle RF and Gradient Waveforms in Parallel Excitation

William A. Grissom1, Adam B. Kerr, Pascal P. Stang2, Greig C. Scott2, Ileana Hancu3, Mika W. Vogel4, John M. Pauly2

1Electrical Engineering and Radiology, Stanford University, Stanford, CA, United States; 2Electrical Engineering, Stanford University, Stanford, CA, United States; 3GE Global Research, Niskayuna, NY, United States; 4Advanced Medical Applications Laboratory, GE Global Research, Munich, Bavaria, Germany

We introduce a new framework for optimizing the phase encoding locations of a 2D or 3D parallel excitation pulse in the large-tip-angle regime. The framework is analogous to the hard pulse approximation, and yields a straightforward analytical relationship between the pulses' spin-domain rotations and the phase encoding locations. This relationship can be exploited to optimize locations using gradient descent, or using optimization transfer for monotonic, parameter-free optimization. We apply our method to the design of dual-band (fat + water) spin echo parallel excitation pulses along 3D rungs trajectories.

16:42                       100.         Fast and Accurate Large-Tip-Angle RF Pulse Design for Parallel Excitation Using a Perturbation Analysis of the Bloch Equation

Hai Zheng1,2, Tiejun Zhao3, Tamer Ibrahim1, Fernando Emilio Boada1

1MR Research Center, University of Pittsburgh, Pittsburgh, PA, United States; 2Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, United States; 3Siemens Medical Systems, Malvern, PA, United States

The design of RF pulses in parallel excitation (PTX) commonly relies on the small-tip-angle approximation, which, although efficient, leads to distorted excitation patterns at large tip angles because of the intrinsic nonlinear nature of the Bloch equation. In this work, we introduce a fast and accurate method for large-tip-angle PTX RF pulse design based on a perturbation analysis (PTA) to the Bloch equation. Experimental data at 7T as well as computer simulations demonstrate the improvements produced by the proposed techniques without the need of prohibitively long calculation times.

16:54                       101.         Fast High-Flip PTx Pulse Design to Mitigate B1+ Inhomogeneity Using Composite Pulses at 7T

Rene Gumbrecht1,2, Joonsung Lee1, Hans-Peter Fautz3, Dirk Diehl4, Elfar Adalsteinsson1,5

1Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, MA, United States; 2Department of Physics, Friedrich-Alexander-University, Erlangen, Germany; 3Siemens Healthcare, Erlangen, Germany; 4Siemens Corporate Technology, Erlangen, Germany; 5Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States

Parallel RF transmission offers flexible control of ma magnetization generation and has been successfully applied at 7T for spatially tailored excitations and mitigation of in-plane B1+ inhomogeneity for slice-selection. Composite Pulses are known to have favorable robustness properties for large-flip-angle excitations in the presence of B1+ variations, but they have not yet been demonstrated on pTx systems. We propose a composite RF pulse design for pTx systems and demonstrate the method for B1+ mitigation in a 90º excitation pulse design.

 

17:06                       102.         Kt Points: Fast Three-Dimensional Tailored RF Pulses for Flip-Angle Homogenization Over an
Extended Volume

Martijn Anton Cloos1, Nicolas Boulant1, Michel Luong2, Guillaume Ferrand2, Christopher J. Wiggins1, Eric Giacomini1, Alain France2, Dennis Le Bihan1, Alexis Amadon1

1CEA, DSV, I2BM, NeuroSpin, LRMN, Gif-sur-Yvette, France; 2CEA, DSM, IRFU, SACM, Gif-sur-Yvette, France

Transmit-SENSE gives the opportunity to implement short excitation pulses with good flip-angle homogeneity at high field. For slice-selective pulses, this was previously demonstrated using a spoke k-space trajectory. Here we present a novel pulse design returning sub-millisecond pulses with excellent flip-angle homogenization over an extended volume. Experimental results are shown at 7T, demonstrating a 950-μs excitation pulse producing a 15±1.1° flip-angle distribution over a 16-cm spherical phantom having the same electrical properties as a human head.

17:18                       103.         Inner-Volume-Imaging Using Three-Dimensional Parallel Excitation

Johannes Thomas Schneider1,2, Raffi Kalayciyan1,3, Martin Haas2, Wolfgang Ruhm1, Olaf Doessel3, Juergen Hennig2, Peter Ullmann1

1Bruker BioSpin MRI GmbH, Ettlingen, Germany; 2Dept. of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany; 3Institute of Biomedical Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany

This study presents the first experimental realization of inner-volume-imaging using three-dimensional parallel excitation of arbitrarily shaped regions of interest. By using a temporally optimized 4-fold undersampled 3D k-space trajectory consisting of concentrical shells in combination with an 8-channel transceive RF-array, 3D selective excitation of an arbitrary volume could be achieved in only 5 ms. Featuring such short durations 3D-selective pulses are now on the verge of being used in common imaging sequences and have been successfully applied in first experiments of inner-volume-imaging in phantoms and fruits during this study.

17:30                       104.         SAR Reduction by K-Space Adaptive RF Shimming

Hanno Homann1, Kay Nehrke2, Ingmar Graesslin2, Olaf Dössel1, Peter Börnert2

1Karlsruhe University, Karlsruhe, Germany; 2Philips Research, Hamburg, Germany

Parallel transmission allows compensating for RF transmit field inhomogeneities and simultaneous SAR reduction by RF shimming. This study demonstrates that the trade-off between these two objectives can be overcome by using several different, adapted RF pulses: When sampling the center of the k-space, a highly uniform but relatively SAR-intensive excitation is performed to achieve optimal contrast. In the outer k-space, the homogeneity requirement is relaxed to reduce the average SAR. The concept is discussed theoretically; proof-of-principle is given based on phantom and in vivo images.

17:42                       105.         Parallel Transmit RF Design with Local SAR Constraints

Joonsung Lee1, Matthias Gebhardt2, Lawrence L. Wald3,4, Elfar Adalsteinsson1,4

1Electrical engineering and computer science, Massachusetts Institute of Technology, Cambridge, MA, United States; 2Siemens Healthcare, Erlangen, Germany; 3Department of Radiology, A. A. Martinos Center for Biomedical Imaging, Cambridge, MA, United States; 4Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States

The model compression method for local SAR esitmation dramatically decreases the complexity of the prediction of the local SAR calculation and enables the incorporation of local SAR constaints in pTX MLS RF design.

17:54                       106.         RFuGE –an Accelerated Imaging Method Combining Parallel Transmit RF Encoding Plus Gradient Encoding with Compressed Sensing Reconstruction

Muhammad Usman1, Shaihan J. Malik2, Ulrich Katscher3, Philip G. Batchelor1, Joseph V Hajnal2

1Imaging Sciences, King's College London, London, United Kingdom; 2Robert Steiner MRI Unit, Imaging Sciences Department, MRC Clinical Sciences Centre, Hammersmith Hospital, Imperial College London, London, United Kingdom; 3Sector Medical Imaging Systems Philips Research Europe, Hamburg, Germany

We describe a combination of Parallel Transmit generated radiofrequency encoding and undersampled gradient encoding that can be reconstructed using compressed sensing to achieve accelerated imaging with a non-linear encoding basis. The method, RF plus Gradient Encoding, (RFuGE) has been tested in simulation and successful reconstructions were achieved.

 

18:06                       107.         16-Channel Parallel Transmission in the Human Brain at 9.4 Tesla: Initial Results

Xiaoping Wu1, J. Thomas Vaughan1, Kamil Ugurbil1, Pierre-Francois Van de Moortele1

1CMRR, University of Minnesota, Minneapolis, MN, United States

It has been shown that parallel transmission (pTx), which consists of playing different RF pulses through independent transmit (Tx) channels, can be used to mitigate Tx B1 (B1+) nonuniformity and to achieve more homogeneous spatially selective RF excitation at high magnetic field. We have previously reported a successful implementation of Transmit SENSE in the human brain at 9.4 T with an 8 Tx channel system, which required addressing methodological issues such as k-space trajectory inaccuracies and large susceptibility induced δB0. Recently, our 9.4T system has been upgraded with a 16 Tx channel console. Here we report preliminary results of 2D (Transmit SENSE) and 3D (Spoke trajectories) pTx in the human brain at 9.4 T using a 16-channel RF coil.

18:18                       108.         Self-Refocused Adiabatic Pulse for Spin Echo Imaging at 7T

Priti Balchandani1, John Pauly2, Daniel Spielman1

1Radiology, Stanford University, Stanford, CA, United States; 2Electrical Engineering, Stanford University, Stanford, CA, United States

Adiabatic 180° pulses may be used to replace conventional 180° pulses in spin echo sequences to provide greater immunity to the inhomogeneous B1-field at 7T.  However, because the spectral profile of an adiabatic 180° pulse has non-linear phase, pairs of these pulses are used for refocusing, resulting in increased SAR and longer minimum echo times.  We have used the adiabatic SLR method to generate a matched-phase 90° for an adiabatic 180° pulse to obviate the need for a second 180° pulse.  The pulse pair was combined into a single self-refocused pulse to achieve the minimum echo time, and phantom and in vivo experiments were performed to validate pulse performance.

Diffusion Studies of Brain Anatomy

Victoria Hall  16:30-18:30                Moderators: Alexander L. G. Leemans and Carlo Pierpaoli

16:30                       109.         In Vivo Measurement of Cortical Anisotropy by Diffusion-Weighted Imaging Correlates with Cortex Type

Alfred Anwander1, André Pampel1, Thomas R. Knösche1

1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

High resolution diffusion-weighted imaging in conjunction with highly sensitive phase array acquisition coils can identify different anisotropic orientation depending on the cortex type. Motor cortex shows radial anisotropy while primary somatosensory cortex shows tangential anisotropy. This might relate to a strong wiring between neighboring cortical areas.

16:42                       110.         Skeleton Thickness Biases Statistical Power in Skeleton-Based Analyses of Diffusion MRI Data

Richard A E Edden1,2, Derek K. Jones3

1Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, MD, United States; 2FM Kirby Research Center for Functional MRI, Kennedy Krieger Institute, Baltimore, MD, United States; 3CUBRIC, School of Psychology,, Cardiff University, Cardiff, Wales, United Kingdom

DTI provides rotationally invariant information.   Additionally, DTI acquisitions are optimised to ensure that data are statistically rotationally invariant so that parameter variance is independent of the orientation of the fibre population within the brain. Against this backdrop, we focus on skeletonization-based methods for group comparisons of DTI data and show that they can reintroduce rotational dependence. Specifically, the power to detect group differences in a fibre can depend on its orientation. While the cause/solution to this problem are trivial, the effect on statistical inference is not – and should be viewed in the light of the increasing popularity of skeletonization-based methods.

16:54                       111.         Sex-Linked White Matter Microstructure of the Social and the Analytic Brain

Kun-Hsien Chou1, I-Yun Chen2, Chun-Wei Lan3, Ya-Wei Cheng2, Ching-Po Lin2,3, Woei-Chyn Chu1

1Institute of Biomedical Engineering, National Yang-Ming University, Taipei, Taiwan; 2Institute of Neuroscience, National Yang-Ming University, Taipei, Taiwan; 3Institute of Biomedical imaging and Radiological Sciences, National Yang-Ming University, Taipei, Taiwan

Empathizing, driven by the social brain, means the capacity to predict and to respond to the behavior of agents by inferring their mental status with an appropriate emotion. Systemizing, based on the analytic brain, is the capacity to predict and to respond to the behavior of non-agentive deterministic systems by analyzing input-operation-output relations and inferring the rules of systems. However WM associated with the social and analytic brain as indicated by sex differences remains to be investigated. In this study, we demonstrated WM microstructures with sexual dimorphism, which may reflected the neural underpinning of the social and analytic brain.

17:06                       112.         Diffusion Tensor Imaging of Brain White Matter Changes Across the Lifespan

Catherine Lebel1, Myrlene Gee1, Richard Camicioli2, Marguerite Wieler2, Wayne Martin2, Christian Beaulieu1

1Biomedical Engineering, University of Alberta, Edmonton, Alberta, Canada; 2Neurology, University of Alberta, Edmonton, Alberta, Canada

Lifespan studies of the normal human brain link the development processes of childhood with the degenerative processes of old age. Many diffusion tensor imaging (DTI) studies evaluate changes over narrow age ranges; few examine the lifespan. We used DTI to measure age-related changes in 12 white matter tracts in 392 healthy volunteers aged 5-83 years. Fractional anisotropy increased until adulthood, then decreased, while mean diffusivity followed an opposite trend. Trend reversals occurred between 18-43 years. Frontal-temporal connections demonstrated prolonged development and late reversals, while the fornix and corpus callosum develop earliest and have the most prolonged periods of decline.

17:18                       113.         Partial Volume Effect as a Hidden Covariate in Tractography Based Analyses of Fractional Anisotropy: Does Size Matter?

Sjoerd B. Vos1, Derek K. Jones2, Max A. Viergever1, Alexander Leemans1

1Image Sciences Institute, University Medical Center, Utrecht, Netherlands; 2CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom

Diffusion tensor imaging has been used extensively to investigate brain aging. Fiber tractography has shown a relation between age and fractional anisotropy (FA) along fiber tracts. Partial volume effects are known to affect tractography, and may also influence FA calculations along tracts. In this study, simulations and experiments have been performed to test whether tract volume is a covariate in FA calculations. A strong correlation between tract volume and FA has been found in both the simulations and experiments, proving that partial volume effects affect FA calculations, and that size is indeed a hidden covariate in tractography based FA analyses.

17:30                       114.         Microstructural Correlations of White Matter Tracts in the Human Brain

Michael Wahl1, Yi-Ou Li1, Joshua Ng1, Sara C. LaHue1, Shelly R. Cooper1, Elliott H. Sherr2, Pratik Mukherjee1

1Radiology, University of California, San Francisco, San Francisco, CA, United States; 2Neurology, University of California, San Francisco, San Francisco, CA, United States

In this 3T DTI study of 44 normal adult volunteers, we use quantitative fiber tracking to demonstrate that specific patterns of microstructural correlation exist between white matter tracts and may reflect phylogenetic and functional similarities between tracts.  Inter-tract correlation matrices computed from tract-based measures of fractional anisotropy (FA), mean diffusivity, axial diffusivity, and radial diffusivity, reveal that there are significant variations in correlations between tracts for each of these four DTI parameters.  Data-driven hierarchical clustering of FA correlational distances show that neocortical association pathways grouped separately from limbic association pathways, and that projection pathways grouped separately from association pathways.

17:42                       115.         A Novel Clustering Algorithm for Application to Large Probabilistic Tractography Data Sets

Robert Elton Smith1,2, Jacques-Donald Tournier1,2, Fernando Calamante1,2, Alan Connelly1,2

1Brain Research Institute, Florey Neuroscience Institutes (Austin), Heidelberg West, Victoria, Australia; 2Department of Medicine, The University of Melbourne, Melbourne, Victoria, Australia

Current clustering methodologies are not able to process very large data sets, such as those generated using probabilistic tractography. We propose a novel clustering algorithm designed specifically to handle a very large number of tracks, which is therefore ideally suited for processing whole-brain probabilistic tractography data. A hierarchical clustering stage identifies major white matter structures from the large number of smaller clusters generated. The method is demonstrated on a 1,000,000 track whole-brain in-vivo data set.

17:54                       116.         A Scalable Approach to Streamline Tractography Clustering

Eelke Visser1,2, Emil Nijhuis1,3, Marcel P. Zwiers1,2

1Donders Institute for Brain, Cognition and Behaviour, Radboud University Nijmegen, Nijmegen, Netherlands; 2Department of Psychiatry, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 3Department of Technical Medicine, University of Twente, Enschede, Netherlands

Finding clusters among the many streamlines produced by tractography algorithms can improve interpretability and can provide a starting point for further analysis. A problem with many clustering methods is their handling of large datasets. We propose to overcome this problem by repeatedly clustering complementary subselections of streamlines. The execution time of the algorithm scales linearly with the number of streamlines, while working memory usage remains constants. The method produces anatomically plausible and coherent clusters in a single subject. When applied to a large group dataset, results are similar and consistent across subjects.

18:06                       117.         Validation of DTI Measures of Primary Motor Area Cortical Connectivity

Yurui Gao1, Ann S. Choe2, Xia Li3, Iwona Stepniewska4, Adam Anderson

1BME, VUIIS, Nashville, TN, United States; 2BME, VUIIS, United States; 3EECS, VUIIS, United States; 4Psychological Sciences at Vanderbilt, United States

Since DTI tractography is used to examine the neural connectivity between specialized cortical regions of the brain, it is important to evaluate the agreement between the connectivity derived from DTI tractography and corresponding histological information. We reconstruct the projection regions connecting to the primary motor cortex (M1) of the squirrel monkey, based on histological segmentation and compare these regions with the locations of the terminals of DTI fibers penetrating the same M1 region. Quantitative comparison shows an approximate agreement but also limits of applying DTI tractography to predict M1 connectivity.

18:18                       118.         High Resolution Tractography in Macaque Visual System – Validation Against in Vivo Tracing

Laura M. Parkes1,2, Hamied A. Haroon1,2, Mark Augarth3, Nikos K. Logothetis, 2,3, Geoff JM Parker1,2

1School of Cancer and Imaging Sciences, University of Manchester, Manchester, United Kingdom; 2Biomedical Imaging Institute, University of Manchester, Manchester, United Kingdom; 3Max Planck Institute for Biological Cybernetics, Tubingen, Germany

The aim is to validate the connections identified with high angular resolution diffusion imaging in the post-mortem macaque visual system against true connections from the many detailed in vivo tracer studies. A probabilistic tractography approach is used, and comparisons are made between identified connections at different thresholds of connection strength, and the true connections. The accuracy of connections increases up until an acceptance threshold of 5%, beyond which accuracy is not greatly affected. 72% of connections were correctly identified at 5% threshold. The majority of false connections involved areas of higher level processing, particularly parietal and temporal regions.

Alternative fMRI Contrast Mechanisms

Room A4        16:30-18:30                Moderators: Jia-Hong Gao and Alan W. Song

16:30                       119.         Detection of an Earthworm Axon Current with Simultaneous MRS

Alexander Poplawsky1, Raymond Dingledine2, Xiaoping Hu3

1Neuroscience, Emory University, Atlanta, GA, United States; 2Pharmacology, Emory University, Atlanta, GA, United States; 3Biomedical Engineering, Emory University and Georgia Institute of Technology, Atlanta, GA, United States

Direct detection of axonal neural magnetic fields (NMFs) by magnetic resonance imaging has met with conflicting evidence. The objective of this study is to demonstrate the temporal signature of axonal NMFs in the free induction decay (FID), which provides the temporal resolution required to capture an axonal event. Simultaneous electrophysiology is used to time-lock earthworm action potentials to FID acquisition. Our data demonstrates clear evidence of a phase change that temporally corresponds to the electrophysiologically recorded action potential and is consistent with theoretical predictions.

16:42                       120.         Imaging Functional Decrease of the Cerebrospinal Fluid Volume Fraction with a Spin-Locking FMRI Technique

Tao Jin1, Seong-Gi Kim1

1Department of Radiology, University of Pittsburgh, Pittsburgh, PA, United States

A voxel of magnetic resonance imaging often contains blood, tissue water, as well as the cerebrospinal fluid (CSF). Recent studies have suggested that brain vascular activation could induce a change in the volume fraction of the CSF compartment that serves as a buffer for the brain cortex. However, current detection of CSF volume fraction and its functional change requires multi-compartment data fitting. In this work we aimed to image the CSF compartment directly using a spin-locking technique at 9.4 T. With a long spin-locking preparation, the parenchyma signal can be suppressed and a functional decrease of CSF volume fraction can be robustly detected during cat visual stimulation.

16:54                       121.         Time-Course of δR2 During Visual Stimulation and Hypercapnia Diffusion-Weighted FMRI Experiments

Daigo Kuroiwa1, Hiroshi Kawaguchi1, Jeff Kershaw1, Atsumichi Tachibana1, Joonas Autio1, Masaya Hirano2, Ichio Aoki1, Iwao Kanno1, Takayuki Obata1

1Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan; 2Advanced Application Center, GE Healthcare Japan, Hino, Tokyo, Japan

It has been suggested that the BOLD effect contributes to heavily diffusion-weighted (DW) fMRI signal changes. The BOLD effect is usually interpreted as a change in transverse relaxation rate (δR2). In this study, δR2 during visual stimulation (VS) and hypercapnia (HC) DW fMRI experiments was estimated using a multiple spin-echo EPI acquisitions after motion-probing gradients. δR2 showed dependence on b-value during VS, but not during HC. The results suggest that δR2 at high b-value may demonstrate a higher sensitivity to neuronal activation than at lower b-values.

17:06                       122.         Inter-Areal and Inter-Individual Variations in Diffusion-Weighted FMRI Signal

Toshihiko Aso1, Shin-ichi Urayama1, Hidenao Fukuyama1, Denis Le Bihan, 12

1Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto, Japan; 2CEA NeuroSpin, Gif-sur-yvette, France

Neuronal activation can be detected with heavily sensitized diffusion-fMRI (DfMRI). The striking temporal precedence of the diffusion response to BOLD in the visual cortex suggests a non-vascular source. A visual working memory task was implemented to investigate DfMRI responses outside visual cortex. We found very similar response patterns between well separated cortices showing temporal precedence over BOLD, while large individual variations were observed with BOLD responses. Discrepancies between DfMRI and BOLD responses were also observed, such as negative BOLD signals accompanying positive DfMRI responses supporting the assumption that the DfMRI and BOLD responses have different origins.

17:18                       123.         Exploring the Reproducibility and Consistency of Diffusion-Weighted Functional Magnetic Resonance Imaging During Visual Stimulation Using Population-Based Activation Map

Ruiwang Huang1, Bida Zhang2

1State Key Lab of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing , 100875, China; 2Siemens Mindit Magnetic Resonance, Siemens Healthcare MR Collaboration NE Asia,

Human brain functional studies have been generally performed with BOLD-fMRI, but the spatial location and distribution of the activation map is not accurate. Recently, it has been suggested that the diffusion-weighted functional magnetic resonance imaging (dFMRI) may be sensitive to the true neuronal activation. However, the influence of b-value on the activation region is not fully understood. Here we performed a visual stimulation study on twelve subjects with dFMRI (b-value=50/400/800/1200/1600s/mm2) and BOLD-fMRI, and constructed the population-based activation maps. The locations and distributions of dFMRI and BOLD-fMRI measurements were compared, and the consistency of dFMRI study was evaluated.

17:30                       124.         fMRI Using a Hyperpolarized Tracer Molecule

Ute Goerke1, Malgorzata Marjanska1, Manda Vollmers1, Isabelle Iltis1, Pierre-Gilles Henry1, Kamil Ugurbil1

1Radiology, Center for Magnetic Resonance Research, Minneapolis, MN, United States

For the first time, fMRI utilizing a hyperpolarized tracer 13C-labeled urea was performed. Since urea does not cross the blood-brain barrier, it is an ideal marker for perfusion changes caused by neuronal activity. The presented results were obtained in rats with forepaw stimulation. Despite the extremely low tracer concentration in the blood in gray matter, focal activated regions were robustly detected in all 13C fMRI experiments.

17:42                       125.         Neurovascular Coupling Relationship Between Spontaneous EEG and CBF Responses Is Sensitive to Anesthesia Depth

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

1CMRR, radiology, University of Minnesota, Minneapolis, MN, United States; 2Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States

In this study, hemodynamic response function (HRF) was estimated by “deconvolution” to describe the neurovascular coupling between spontaneous CBF and EEG signals in the rat brain acquired simultaneously under two anesthesia depths (1.8 and 2.0% isoflurane). We found that a small change in anesthesia depth by increasing 0.2% isoflurane could significantly alter HRF in two aspects: lengthening latency-to-peak and broadening dispersion. This result indicates that the neurovascular coupling quantified by HRF is sensitive to anesthesia depth and this phenomenon should have implication in quantifying the resting brain connectivity and stimulus-evoked BOLD in the anesthetized brains and understanding their underlying neurophysiology basis.

17:54                       126.         Behavioural Correlate of GABA Concentration in Visual Cortex

Richard A. E. Edden1,2, Suresh D. Muthukumaraswamy3, Tom Freeman, Krish D. Singh3

1Russell H Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins University, Baltimore, MD, United States; 2FM Kirby Center for Functional fMRI, Kennedy Krieger Institute, Baltimore, MD, United States; 3CUBRIC, School of Psychology, Cardiff University, United Kingdom

Edited MRS measurements of GABA concentration in visual cortex have recently been shown to correlate with functional metrics: the frequency of gamma ocillations, as measured by MEG; and BOLD signal change in fMRI. This study investigates whether these individual differences have behavioural consequences, using a psychophysical paradigm to measure orientation discrimination thresholds. Orientation discrimination has long been associated with GABAergic neurotransmission at a cellular level; we are able to draw a similar link at the level of individual performance differences.

18:06                       127.         Cortical Hemodynamics and GABAergic Inhibition. Resting GABA Levels in Human Visual Cortex Correlate with BOLD, ASL-Measured CBF and VASO-Measured CBV Reactivity

Manus Joseph Donahue1,2, Jamie Near1,2, Peter Jezzard1,2

1Clinical Neurology, Oxford University, Oxford, United Kingdom; 2Physics Division, FMRIB Centre, Oxford, United Kingdom

Neurovascular coupling between neuronal activity, energy metabolism and cerebral blood flow (CBF) is supported by synaptic excitation and inhibition. We show inverse correlations between synaptic inhibition (GABA concentration) and BOLD (R=0.68) and cerebral blood volume (CBV)-weighted VASO reactivity (R=0.75) in human visual cortex. A negative correlation between baseline GABA and baseline CBV (R=0.75) is found; however, a positive relationship between GABA and ASL reactivity (R=0.38) and baseline CBF (R=0.67) is found, which we attribute to blood velocity discrepancies. Results provide information on the relationship between cortical activity, GABAergic inhibition, and multimodal fMRI contrast. First two authors are equal contributors.

18:18                       128.         Hemodynamic and Metabolic Response to Hypoxia

Ashley D. Harris1, Richard A. E. Edden2,3, Kevin Murphy1, C John Evans1, Chen Y. Poon4, Neeraj Saxena5, Judith Hall5, Thomas T. Liu6, Damian M. Bailey7, Richard G. Wise1

1Cardiff University Brain Research Imaging Centre (CUBRIC), Cardiff University, Cardiff, United Kingdom; 2Russell H Morgan Department of Radiology and Radiological Science, The Johns Hopkins University, Baltimore, MD, United States; 3Cardiff University Brain Imaging Research Centre (CUBRIC) and Schools of Chemistry and Biosciences, Cardiff University, Cardiff, United Kingdom; 4School of Medicine, Cardiff University, Cardiff, United Kingdom; 5Anaesthetics and Intensive Care Medicine, Cardiff University, Cardiff, United Kingdom; 6Center for Functional MRI (fMRI), University of California, San Diego, San Diego, CA, United States; 7Health, Sport and Science, University of Glamorgan, Mid-Glamorgan, United Kingdom

MR spectroscopy to examine lactate and ASL perfusion imaging are used to study the response to 12% hypoxia in healthy subjects. Lactate and cerebral blood flow increased during hypoxia. Both lactate and blood flow are negatively related to oxygen saturation. The relationship between increased perfusion and lactate accumulation appears to be more complex; however, by understanding these relationships, we may gain insight into cerebral pathologies and conditions that result in hypoxemia.

Imaging of Metal & Ultrashort T2 Species

Room A5        16:30-18:30                Moderators: Jiang Du and Brian A. Hargreaves

16:30                       129.         MR Imaging Near Orthopedic Implants with Artifact Reduction Using View-Angle Tilting and Off-Resonance Suppression

Clemens Bos1, Chiel J. den Harder2, Gert van Yperen2

1MR Clinical Science, Philips Healthcare, Best, Netherlands; 2MR CTO, Philips Healthcare, Best, Netherlands

Metal orthopaedic implants are known to cause substantial artifacts in MR imaging of joints, such as slice distortions and displacements of signal in the readout direction. View angle tilting aims to correct for the displacements in readout direction. Off-resonance suppression is proposed as an extension to view angle tilting. Using different slice selection gradients during excitation and refocusing limits the spectral and spatial range from which undesired signal may originate. This combination of techniques has no inherent imaging time penalty and was demonstrated to reduce metal artifacts, both in vitro and in vivo.

16:42                       130.         SEMAC and MAVRIC for Artifact-Corrected MR Imaging Around Metal in the Knee

Christina A. Chen1, Weitian Chen2, Stuart B. Goodman1, Brian A. Hargreaves1, Kevin M. Koch3, Wenmiao Lu1, Anja C. Brau2, Christie E. Draper1, Scott L. Delp1, Garry E. Gold1

1Stanford University, Stanford, CA, United States; 2GE Healthcare Applied Science Lab, Menlo Park, CA, United States; 3GE Healthcare Applied Science Lab, Milwaukee, WI, United States

We have developed 2 three-dimensional MRI prototypes that correct for metal-induced artifacts, Slice Encoding for Metal Artifact Correction (SEMAC) and Multi-Acquisition Variable-Resonance Image Combination (MAVRIC). In 10 knees with metallic total knee replacements (TKR) scanned at 1.5T, SEMAC and MAVRIC both had significantly less artifact than conventional two-dimensional fast spin echo (FSE). In a model of the knee fitted to a TKR of known dimensions, SEMAC and MAVRIC had much smaller percent deviations from actual component dimensions than FSE, indicating their accuracy in measuring geometry in the presence of metal. MAVRIC and SEMAC are promising MR imaging techniques that may allow for improved musculoskeletal follow-up imaging of metallic implants and soft tissue structures surrounding metal in the knee.

16:54                       131.         Magnetic Resonance Imaging of Periprosthetic Tissues in the Presence of Joint Arthroplasty

Matthew F. Koff1, Kevin M. Koch2, Hollis G. Potter1

1Department of Radiology and Imaging, Hospital for Special Surgery, New York, United States; 2General Electric Healthcare, Waukesha, WI, United States

Significant in-plane and through-plane 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. Volunteers with joint replacements (hip, shoulder, or knee) were scanned using a 2D FSE sequence optimized for imaging around arthroplasty and a MAVRIC sequence. MAVRIC scans were effective in reducing the metal susceptibility artifact for all joints and also better  highlighted the extent of osteolysis. Higher resolution FSE images were effective for detection of formation of fibrous membrane around arthroplasties. This study further supports the use of MAVRIC for clinical implementation.

17:06                       132.         Imaging of Metallic Implant Using 3D Ultrashort Echo Time (3D UTE) Pulse Sequence

Jiang Du1, Kelly Borden1, Eric Diaz1, Mark Bydder1, Won Bae1, Shantanu Patil2, Graeme Bydder1, Christine Chung1

1Radiology, University of California, San Diego, CA, United States; 2Shiley Center for Orthopedic Research and Education, La Jolla, CA, United States

Magnetic resonance imaging (MRI) near metal implants suffers from severe artifacts due to large metal-induced field inhomogeneities. The steep field gradients near metal implants result in increased intra-voxel dephasing and a much shortened T2*. Clinical gradient echo (GE) sequences suffer from large signal loss. Spin echo (SE) type sequences only partly refocus the dephased spins, resulting in spatially dependent signal voids and pile-ups. Here we present a 3D ultrashort TE (UTE) sequence which employs short hard pulse excitation and 3D radial sampling with a nominal TE of 8 µs to image metallic implants with markedly reduced artifact.

17:18                       133.         kf ARC Reconstruction for Improving MRI Around Metal Using MAVRIC

Peng Lai1, Weitian Chen1, Christina Chen2, Kevin M. Koch3, Anja CS. Brau1

1Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States; 2Stanford University, Stanford, CA, United States; 3Applied Science Laboratory, GE Healthcare, Waukesha, WI, United States

This work developed a new method, kf ARC, for highly accelerated MAVRIC imaging around metal implants. The proposed method utilizes both k-space correlation and spectral correlation between adjacent spectral images to improve reconstruction. kf ARC was evaluated on 2 patients with metallic implants in comparison with conventional parallel imaging. Our results show that kf ARC can significantly improve image quality at high acceleration factors and is a promising approach to fast MAVRIC data acquisition.

17:30                       134.         Morphological and Quantitative Evaluation of Meniscal Calcifications by Novel 2D IR and 3D UTE MR Techniques

Patrick Omoumi1,2, Eric S. Diaz1, Jiang Du1, Sheronda S. Statum1, Won C. Bae1, Graeme Bydder1, Christine B. Chung1

1University of California, San Diego, San Diego, CA, United States; 2Cliniques Universitaire St Luc, Brussels, Belgium

Meniscal calcifications are frequent and likely alter the normal biomechanics of the meniscus. Although MR imaging is the non-invasive technique of choice for the evaluation of meniscal pathology, it does not allow the facile visualization of meniscal calcifications. This is due to a lack of contrast (both calcifications and menisci have relatively short T2 relaxation times), and a lack of saptial résolution with standard clinical sequences. We describe novel MR imaging techniques based on 2D-UTE inversion recovery and 3D-UTE data acquisition to address these factors. We assessed the ability of these sequences to allow the visualization, characterization and quantitative evaluation of meniscal calcifications.

17:42                       135.         Fiber Tracking of Dipolar Directions in the Meniscus

Nikolaus M. Szeverenyi1, Graeme M. Bydder1

1Radiology, University of California, San Diego, San Diego, CA, United States

This study examines a method to extract and use dipolar information to characterize an ex-vivo meniscus sample.  A goat meniscus was embedded in a spherical epoxy ball and the MR signal intensity examined as a function of orientation to a 3T static field.  Unaveraged dipolar interactions caused dramatic signal variations in sub-structures.  After correcting for coil sensitivity and co-registering all images, a principle dipolar direction was extracted for each voxel.  This directional data could be analyzed and viewed as a direction map, similar to DTI brain data.  The intensity fluctuations provided a FA map.  Fiber tracks were generated.

17:54                       136.         Ultrashort Echo Imaging (UTE) of Rotator Cuff Repair in an Ovine Model

Matthew F. Koff1, Hollis G. Potter1

1Department of Radiology and Imaging, Hospital for Special Surgery, New York, United States

The rotator cuff tendons typically display low signal on standard clinical images due to the highly ordered collagen within the tissue. Ultrashort echo (UTE) imaging creates contrast for visualization and for T2* quantitation. This study used T2* mapping to evaluate rotator cuff repair in an ovine model. Reparative surgery was performed to the supraspinatus tendon in sheep. Shoulders were scanned ex-vivo 8 weeks post-operatively. T2* values of repaired tendon were significantly longer than normal tendon. The T2* values decreased in magnitude along the length of the repair, but not significantly. This pilot study highlights the use of UTE for quantitative evaluation of soft tissue repair.

18:06                       137.         Detection of Dipolar Splitting in Rodent Tendons as a Function Axial Position with Double-Quantum Filtered Spectroscopic Imaging

Henry H. Ong1, Joseph J. Sarver2, Jason E. Hsu2, Louis J. Soslowsky2, Felix W. Wehrli1

1Laboratory for Structural NMR Imaging, Department of Radiology, University of Pennsylvania School of Medicine, Philadelphia, PA, United States; 2McKay Orthopaedic Research Laboratory, University of Pennsylvania, Philadelphia, PA, United States

Tendons are comprised of parallel collagen fibers that connect muscles to bone. Collagen-associated water has anisotropic rotational motion, which gives rise to residual dipolar splitting in 1H NMR. Double-quantum filtered (DQF) NMR and MRI can be used to observe the splitting and study the biophysical and structural properties of tendon. Here, we modified a DQF 1D spectroscopic imaging sequence to obtain 1H DQF spectra along the axis of the flexor digitorum profundus (FDP) tendons from rat hind limbs and show spectral differences in the region that wraps under the calcaneus, which experiences compressive forces.

18:18                       138.         Magnetization Transfer (MT) Segmentation of Foot Peripheral Nerves at 3 T.

Giulio Gambarota1, Bénédicte Mortamet2, Nicolas Chevrey3, Cristina Granziera4, Gunnar Krueger2, Nicolas Theumann3, Ralf Mekle3

1GlaxoSmithKline Clinical Imaging Center, London, United Kingdom; 2Healthcare Sector IM&WS S, Siemens Schweiz AG, Renens, Switzerland; 3Radiology, University of Lausanne, Lausanne, Switzerland; 4Neurology, Geneva University Hospital, Geneva, Switzerland

The ability of tracking peripheral nerves in foot could be of great benefit for a number of investigations, which include traumas, diabetes and infections. Previous approaches to nerve tracking have employed diffusion tensor imaging DTI. One limitation of DTI is the low signal-to-noise ratio due to short T2 (~30ms at 3T) of water protons in nerves.  Here, we propose a novel approach to nerve tracking, which exploits the difference in MT ratio between muscle and foot nerves.

Artifacts & Correction:  Non-Motion

Room A6        16:30-18:30                Moderators: Eric B. Beall and Bruno Madore

16:30                       139.         Z-Selective Multi-Spectral 3D Imaging: A MAVRIC-SEMAC Hybrid

Kevin M. Koch1, Kevin F. King1, Brian A. Hargreaves2, Graeme C. McKinnon1

1Applied Science Laboratory, GE Healthcare, Waukesha, WI, United States; 2Department of Radiology, Stanford University, Palo Alto, CA, United States

Both the MAVRIC and SEMAC methods have been shown capable of significantly reducing susceptibility artifacts near metallic implants.  Here, we demonstrate that advantageous features of both methods can be utilized in combination.  In particular, the z-selectivity of the SEMAC can be interfaced with the encoding mechanisms and spectral overlap utilized by MAVRIC.  In doing so, a technique that offers increased volume selectivity while maintaining smooth spectral image combinations is demonstrated.  Demonstrations of this hybrid approach on phantom and in-vivo implant scenarios are presented.

16:42                       140.         Dipole-Based Filtering for Improved Removal of Background Field Effects from 3D Phase Data

Samuel James Wharton1, Richard Bowtell1

1Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham, United Kingdom

A robust method for filtering 3D phase data dominated by rapidly spatially varying externally generated fields is presented. One or more dipole point sources situated outside of the region of interest are used to model and remove the unwanted background fields caused by remote tissue/air interfaces such as those that are present in the sinuses. The method was tested on simulated and experimentally acquired phase data and compared to other commonly used filtering methods, including Fourier filtering and polynomial fitting. The results show that the dipole-based filter outperformed the other methods in removing unwanted fields and preserving image contrast.

16:54                       141.         Improved Background Field Correction Using Effective Dipole Fitting

Tian Liu1, Ildar Khalidov2, Ludovic de Rochefort3, Pascal Spincemaille2, Jing Liu2, Yi Wang1

1Biomedical Engineering, Cornell University, New York, NY, United States; 2Radiology, Weill Cornell Medical College, New York, NY, United States; 3MIRCen, I2BM, DSV, CEA, Fontenay-aux-Roses, France

Effective dipole fitting removes susceptibility induced global background field. It assumes that each independent voxel outside a given region of interest (ROI) are responsible for the background field inside that ROI. It removes the field generated by these sources, while preserving the field arising from local susceptibility variations inside the ROI.

17:06                       142.         A Novel Approach for Separation of Background Phase in SWI Phase Data Utilizing the Harmonic Function Mean Value Property

Ferdinand Schweser1, Berengar Wendel Lehr2, Andreas Deistung2, Jürgen Rainer Reichenbach2

1Medical Physics Group, Department of Diagnostic and Interventional Radiology , Jena University Hospital, Jena, Germany; 2Medical Physics Group, Department of Diagnostic and Interventional Radiology, Jena University Hospital, Jena, Germany

In this contribution, we present, for the first time, a non-heuristic, parameter-free approach for high-precision separation of local phase and background phase contributions for in vivo SWI-data.

17:18                       143.         Analysis of Quadratic Field Distortions Using the Fractional Fourier Transform

Carlos Sing-Long1,2, Vicente Parot1,2, Carlos Lizama3, Sergio Uribe, 2,4, Cristian Tejos1,2, Pablo Irarrazaval1,2

1Department of Electrical Engineering, Pontificia Universidad Catolica de Chile, Santiago, Chile; 2Biomedical Imaging Center, Pontificia Universidad Catolica de Chile, Santiago, Chile; 3Department of Mathematics and Computer Science, Universidad de Santiago de Chile, Santiago, Chile; 4Department of Radiology, Pontificia Universidad Catolica de Chile, Santiago, Chile

In Magnetic Resonance Imaging (MRI) the distortions produced by field inhomogeneities can be corrected with post processing techniques, e.g. linear correction and conjugate phase reconstruction methods. However, these methods do not provide a theoretical framework to analyze the distortions. In this work, we propose the Fractional Fourier Transform (FrFT) as a way to study the distortions produced by quadratic field inhomogeneities. We analyze some commonly used sequences to exemplify the usefulness of this method. We also show how this analysis can be used to reconstruct artifact-free images obtained from non homogeneous fields.

17:30                       144.         Generalized Non-Linear SENSE Shimming

Daniel Nicolas Splitthoff1, Maxim Zaitsev1

1Dept. of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany

With the SENSE Shimming (SSH) approach a method was introduced recently that allows for estimating B0 field inhomogeneities based on a reference image and a series of points on a single free induction decay (FID). In the original approach the temporal evolution of the FID data is explained by field inhomogeneities, using linear approximations. Effects caused by relaxation and those caused by inhomogeneities can therefore not be distinguished and values can only be given relative to a baseline measurement. We here present an extension to the method, which takes into account a larger range of the FID in order to explain not only B0 inhomogeneities but relaxation as well and which therefore allows for accurate field map estimation based on a reference image and a single FID. Since the signal equation is non-linear, the linear fitting of the original approach has to be replaced by a non-linear optimization. The feasibility of the method is shown on in vivo data.

17:42                       145.         On the Feasibility of Single-Shot EPI During Higher-Order Shim Settling

Signe Johanna Vannesjö1, Lars Kasper1, Matteo Pavan1, Christoph Barmet1, Klaas Paul Pruessmann1

1Institute for Biomedical Engineering, ETH and University Zürich, Zürich, Switzerland

Susceptibility artefacts is a major problem in MRI, becoming more severe with higher field strengths and longer read-out trajectories. Updating the shim settings between acquisition of different slices allows for optimizing the shims to smaller subvolumes, but puts high requirements on the timing characteristics of the shim switching. Here the settling dynamics of the higher order shims were measured using a 3rd order dynamic field camera. Long-living (seconds) eddy currents were found, which had a significant effect on image quality. Based on measured k-space trajectories, it was possible to reconstruct phantom images acquired during eddy current settling.

17:54                       146.         Increasing Spoiling Efficiency in RF-Spoiled Gradient Echo Sequences by Averaging of Phase-Cycle Adapted K-Spaces

Jochen Leupold1, Jürgen Hennig1

1Dept. of Diagnostic Radiology, Medical Physics, University Hospital Freiburg, Freiburg, Germany

RF-spoiled gradient echo sequences (FLASH, SPGR, T1-FFE) require a spoiler gradient in order to suppress ghost artefacts. Here we show that two k-spaces can be adapted to the RF phase cycle such that averaging of them leads to elimination of these artefacts even if the spoiler gradient has only half of the moment that is requried for common RF-spoiled gradient echo acquisition.

18:06                       147.         Transient RF Spoiling for 3D Look-Locker Acquisitions

Trevor Wade1,2, Charles McKenzie1,3, Brian Rutt4

1Imaging Research Laboratories, Robarts Research Institute, London, ON, Canada; 2Biomedical Engineering, The University of Western Ontario, London, ON, Canada; 3Medical Biophysics, The University of Western Ontario, London, ON, Canada; 4Diagnostic Radiology and Richard M Lucas Center for Imaging, Stanford University, Stanford, CA, United States

Theoretical and experimental investigation of RF spoiling in the special case of accelerated 3D Look-Locker imaging has led to an improved value for the phase increment used in the standard RF spoiling scheme.  Poor choice of phase increment leads to an inversion recovery curve that deviates significantly from the theoretical ideal, leading to an inaccurate estimate of the recovery time constant.  Simulations were used to determine improved values for the phase increment based on minimizing summed squared differences, or time constant measurement accuracy. These were tested experimentally and found to be superior to previously reported values for most imaging parameters.

18:18                       148.         Parallel Imaging for Efficient Spike Noise Detection and Correction

Feng Huang1, Wei Lin1, Yu Li1, Arne Reykowski1

1Invivo Corporation, Gainesville, FL, United States

Spike noise is a term used to describe broadband electrical interference in an MRI system.  The result of spike noise can be seen in k-space as a bright dot, which will translate into some type of striping in the final image. Usually, the scan has to be repeated if random spike occurs.  A parallel imaging based method, COnvolution and Combination OperAtion (COCOA), has been proposed for non-rigid motion compensation. In this work, it is shown that COCOA can be used to robustly detect and correct random spikes in an efficient way. Hence repeated scan can be avoided.

Tumor Therapy Response

Room A7        16:30-18:30                Moderators: Dmitri Artemov and James O'Connor

16:30                       149.         Dynamic Contrast-Enhanced Magnetic Resonance Imaging for Early Therapy Evaluation of Combined Anti-EGFR Antibody and Irinotecan in Orthotopic Pancreatic Tumor Xenografts

Hyunki Kim1, Karri Folks1, Lingling Guo2, Jeffery Sellers3, Naomi Fineberg4, Cecil Stockard3, William Grizzle5, Donald Buchsbaum6, Desiree Morgan1, James George2, Kurt Zinn1

1Radiology, University of Alabama at Birmingham, Birmingham, AL, United States; 2Surgery, University of Alabama at Birmingham, Birmingham, AL, United States; 3Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, United States; 4Biostatistics, University of Alabama at Birmingham, Birmingham, AL, United States; 5Pathology, University of Alabama at Birmingham, Birmingham, AL, United States; 6Radiation Oncology, University of Alabama at Birmingham, Birmingham, AL, United States

This study evaluated DCE-MRI as an early prognostic tool for effective anti-EGFR therapy with/without concurrent chemotherapy in an orthotopic pancreatic-cancer murine model, and developed a novel timing-independent DCE-MRI biomarker for early therapy assessment, based on characterization of non-linear tumor response observed during serial imaging.

16:42                       150.         Bortezomib Treatment Reduces Tumor Blood Flow and Perfusion as Measured by Dynamic
Contrast-Enhanced 1H MRI

Ellen Ackerstaff1, Xiaorong Sun1,2, Mihai Coman (Deceased)1, Ya Wang1, Hung Tsung Hsiao1, Fuqiu He1, Ligang Xing1,2, Sean Carlin1, C Clifton Ling1, Jason A. Koutcher1, Gloria C. Li1

1Memorial Sloan-Kettering Cancer Center, New York, NY, United States; 2Shandong Cancer Hospital and Institute, Jinan, Shandong, China

The proteasomes inhibitor Bortezomib possesses anti-angiogenic and anti-tumor properties and appears to selectively interfere in the hypoxia pathway. Our study aims to determine biomarkers characterizing treatment response. We studied in a colorectal cancer model the effects of Bortezomib on the tumor vasculature by in vivo DCE MRI and on the tumor hypoxia response ex vivo using immunohistochemistry. Our data suggest that Bortezomib treatment modifies the tumor microenvironment by decreasing tumor perfusion. Our ex vivo data indicate a reduced hypoxia response in central regions of the tumor and an increased hypoxia response in the tumor rim in response to Bortezomib treatment.

16:54                       151.         Evaluation of the Relationship Between LSO2 MR Measurement and Hypoxia : Impact of an Antiangiogenic Treatment on a Gliosarcoma Model

Benjamin Lemasson1, Thomas Christen1,2, Raphaël Serduc3, Cecile Maisin1, Audrey Bouchet3, Christopoh Segebarth1, Géraldine Le Duc3, Chantal Rémy1, Emmanuel Louis Barbier1

1Inersm U836, Grenoble, France; 2Université Joseph Fourier, Grenoble Institut des Neurosciences, Grenoble, France; 3ESRF, Grenoble, France

Despite a highly vascular phenotype, most glioblastomas cells are in hypoxia. Monitoring of hypoxia could be useful for monitoring the effectiveness of anti-tumor therapies. In this study, we evaluate (i) the relationship between the oxygenation (lSO2) estimated by MRI and tissue hypoxia estimated by immunohistology and (ii) the impact of an antiangiogenic (Sorafenib) treatment on the vasculature (Blood volume fraction; BVf) and the lSO2 of gliosarcoma model (9L). lSO2 estimate by MRI was correlated to tumor hypoxia observed by immunohistochimistry. Results of this study also suggest that lSO2 could be a sensitive reporter of the hypoxic effects of antiangiogenic therapies.

17:06                       152.         Chronic Dosing with MLN0518 (Tandutinib), a Small Molecule PDGFRα/β Inhibitor, Reduces Tumour Growth, Hypoxia, and Perfusion in C6 Glioma Xenografts: An Investigation Using Susceptibility Contrast Enhanced MRI and Immunohistochemical Methods

Jessica Katherine Rowena Boult1, Simon Walker-Samuel1, Daniel P. Bradley2, Simon P. Robinson1

1CRUK and EPSRC Cancer Imaging Centre, The Institute of Cancer Research and Royal Marsden NHS Trust, Sutton, Surrey, United Kingdom; 2Imaging Sciences Group, Millennium: The Takeda Oncology Company, Cambridge, MA, United States

In this study, susceptibility MRI with ultra-small paramagnetic iron oxide (USPIO) and immunohistochemical methods were used to evaluate vascular and hypoxic response of C6 glioma xenografts to chronic treatment with MLN0518, a small molecule PDGFRα/β inhibitor. MLN0518 chronically limits the growth of C6 xenografts and reduces both the mean perfused vessel fraction and hypoxic area. No significant alteration in VSI, fractional blood volume or ADC were observed by MRI following 10 days treatment. These results are consistent with histological vessel measurements and quantification of necrosis, neither of which altered at this timepoint.

17:18                       153.         DCE-MRI as a Predictor of Outcome in Head and Neck Squamous Cell Carcinoma Patients with Nodal Metastases

A. Shukla-Dave1, N. Y. Lee1, J. F. Jansen1, H. T. Thaler1, H. E. Stambuk1, M. G. Fury1, E. Sherman1, S. Karimi1, Y. Wang1, D. Kraus1, S. G. Patel1, J. P. Shah1, D. G. Pfister1, J. A. Koutcher1

1Memorial Sloan-Kettering Cancer Center, New York, NY, United States

Currently one of the greatest challenges in the management of head and neck squamous cell carcinoma (HNSCC) is to identify and select prior to therapy, patients who are likely to fail the chosen treatment, for consideration of alternative risk adjusted therapies. The present study assesses whether pretreatment DCE-MRI parameters can reliably predict outcome in HNSCC patients with nodal metastases. DCE-MRI was performed in 74 patients studied prior to chemotherapy and radiation therapy (n=61) or surgery (n=13).  The results suggest that skewness of Ktrans was the strongest predictor of outcome in  HNSCC patients with stage IV disease.

17:30                       154.         Diffusion-Weighted Imaging of Ovarian-Related Peritoneal Carcinomatosis: Assessment of Chemotherapy Response in Relation to Anatomical Site

Stavroula Kyriazi1,2, David J. Collins1, Veronica A. Morgan2, Sharon L. Giles2, Nandita M. deSouza1,2

1CR-UK and EPSRC Cancer Imaging Centre, Institute of Cancer Research, Sutton, Surrey, United Kingdom; 2Royal Marsden NHS Foundation Trust, Sutton, Surrey, United Kingdom

Conventional biochemical and morphological criteria of chemotherapy efficacy in metastatic ovarian cancer are not sensitive in the early course of treatment and fail to reflect the frequently seen intra-patient differential response according to anatomical site of disease. The present study examines the value of Diffusion-Weighted Imaging in the early assessment of site-specific (peritoneal vs omental) chemotherapy response in ovarian-related carcinomatosis.

17:54                       155.         Intrinsic Susceptibility-Weighted MRI to Assess the Response of Combretastatin-A4-Phosphate During Radiotherapy for Prostate Cancer

Roberto Alonzi1, Peter J. Hoskin1, N Jane Taylor2, Quan S. Ng1, Henry Mandeville1, Uma Patel1, J James Stirling2, James A. d'Arcy3, David J. Collins3, Martin O. Leach3, Anwar R. Padhani2

1Marie Curie Research Wing, Mount Vernon Cancer Centre, Northwood, London, United Kingdom; 2Paul Strickland Scanner Centre, Mount Vernon Cancer Centre, Northwood, London, United Kingdom; 3CRUK-EPSRC Cancer Imaging Centre, Institute of Cancer Research & Royal Marsden Hospital, Sutton, Surrey, United Kingdom

Radiotherapy may be delivered in combination with vascular targeting agents. The performance of imaging biomarkers for response assessment may be compromised by the differing or conflicting effects between drug and radiation on tumor tissues. Previous studies have shown that DCE-MRI only partially describes the vascular changes in this setting. This study has evaluated the ability for Intrinsic Susceptibility-Weighted MRI to assess the response of Combretastatin-A4-Phosphate during radiotherapy for prostate cancer. We conclude that R2* has the potential to be an alternative, clinically useable, response biomarker for assessment of vascular disruptive therapy in combination with radiotherapy in prostate cancer.

 

18:00         155.5     ADC Changes with Time in Focal and Diffuse Myleoma Bone Disease as Indicators Of Disease Response and Progression

C. Messiou1, D. Collins1, V. Morgan1, S. Giles1, C. Parry-Jones1, F. Davies2, G. Morgan3, and N. deSouza1

1CRUK and EPSRC Cancer Imaging Centre,Department of Magnetic Resonace Imaging, Institute of Cancer Research/The Royal Marsden Hospital, Sutton, Surrey, United Kingdom, 2Myeloma Target Treatment Team, Institute of Cancer Research/The Royal Marsden Hospital, Sutton, Surrey, United Kingdom, 3Leukaemia and Molecular Genetics Team, Institute of Cancer Research/The Royal Marsden Hospital, Sutton, Surrey, United Kingdom

The predominance of fat in adult marrow demands a systematic approach to interpretation of diffusion weighted (DW) magnetic resonance imaging (MRI) in bone. In marrow disease return of normal fatty marrow following treatment results in increased restriction of water diffusion1 and leads to an ADC fall. Focal necrosis however results in a conflicting ADC rise. This study examines the time course of ADC changes in bone with treatment comparing progressors and responders in order to establish changes associated with response on DW MRI.

 

18:06                       156.         Dynamic Contrast-Enhanced Magnetic Resonance for the Monitoring of Neoadjuvant Chemoradiation Therapy in Rectal Adenocarcinoma: Initial Experience with 20 Patients

Giuseppe Petralia1, Gloria Castellazzi2, Paul Summers1, Roberto Di Filippi1, Moreno Pasin2, Maria Giulia Zampino3, Maria Cristina Leonardi4, Antonio Chiappa5, Stefano Viotti1, Luke Bonello1, Massimo Bellomi1

1Radiology, Istituto Europeo di Oncologia, Milan, Lombardia, Italy; 2Struttura Complessa di Radiologia/Diagnostica per immagini, Istituto Neurologico IRCCS- Fondazione Casimiro Mondino, Pavia, Lombardia, Italy; 3Medical Care Unit, Department of Medicine, Istituto Europeo di Oncologia, Milan, Lombardia, Italy; 4Radiotherapy, Istituto Europeo di Oncologia, Milan, Lombardia, Italy; 5General and Laparoscopic Surgery, Istituto Europeo di Oncologia, Milan, Lombardia, Italy

We prospectively monitored changes in contrast agent pharmacokinetics values in advanced rectal adenocarcinoma over the course of neoadjuvant chemoradiation (NACR) therapy using dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) and evaluated whether DCE-MRI findings correlated with response to NACR in 20 patients. ANOVA revealed no inter-group differences (complete responders, non responders, local downstaging) for mean pre- and post-therapy values, and no changes in values during therapy. T-tests showed significant differences in post-therapy median Ktrans and IAUC60 and in fractional change of Kep between complete and non-responsive groups. Median values of Ktrans and Kep significantly decreased, whilst Ve significantly increased post-therapy.

18:18                       157.         Vascular Effects of the Vascular Targeting Agent NGR-HTNF in Patients with Advanced Solid Cancer: A Dynamic Contrast Enhanced Magnetic Resonance Imaging (DCE-MRI) Study

Ingrid Desar1, Carla M.L. van Herpen1, J. J.A. van Asten2, W. Fiedler3, A.S. Govaerts4, J. N.H. Timmer-Bonte1, E. G.W. ter Voert2, Antonio Lambiase5, C. Bordignon5, A. Heerschap2, H. W.M. van Laarhoven1

1Medical Oncology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands; 2Radiology, Radboud University Nijmegen Medical Center, Nijmegen, Netherlands; 3Universitäts-Krankenhaus Hamburg-Eppendorf, Hamburg, Germany; 4EORTC Headquarters, Brussels, Belgium; 5Molmed, Milan, Italy

Vascular targeted TNF, NGR-hTNF, has antivascular properties. In a recent phase I study, it was not possible to select an optimal biological dose of NGR-hTNF from DCE-MRI measurements.(1) This study aims to examine the reasons for this. Our results suggests that this was caused by a combination of the following factors: (i) less adequate reproducibility in healthy liver tissue due to more than expected heterogeneity in vascular response, (ii) more than expected changes in healthy liver tissue which influences the amount of contrast between metastases and healthyliver tissue (iii) difference in the effect of NGR-hTNF between tumors related to tumor size and (iv) the development of soluble TNFá receptors.

Bowel & Female Pelvis

Room A8        16:30-18:30                Moderators: Georg M. Bongartz and Thomas Lauenstein

16:30                                       Introduction: Bowel
Thomas Lauenstein

16:42                       158.         Feasibility of Small Bowel Flow Rate Measurement with MRI – A Volunteer Study

Johannes M. Froehlich1,2, Michael A. Patak1, Constantin von Weymarn2, Nicole Graf3, Aleksis Doert2, Edwin Willemse2, Christoph A. Binkert2, Andreas Gutzeit2

1Institute of Diagnostic, Interventional and Pediatric Radiology, University Hospital, Bern, Switzerland; 2MR Research, Kantonsspital Winterthur, Winterthur, Switzerland; 3Clinical Trials Center, University Hospital, Zürich, Switzerland

The aim of our prospective volunteer study was to develop and validate a new MR technique based on phase-contrast pulse sequences to measure intraluminal flux of the gastrointestinal content in single segments of the small bowel. Time-resolved small bowel flux was successfully measured in single distended small bowel loops within all 10 volunteers. A mean flow-rate of 0.188 ml/sec (range 0.027-0.516ml/sec) with a standard deviation of 0.144ml/sec resulted. Phase-contrast sequences together with low gadolinium concentrations allow measuring even low flow-rates within the small bowel highlightening its physiology as validated with a high degree of accuracy (R=0.999) in a phantom study.

16:54                       159.         Validation of Software Assisted Small Bowel Motility Analysis

Michael A. Patak1, Stephan Raible2, Zsolt Szuecs-Farkas1, Roger Cattin2, Hanspeter Bouquet3, Urs Bill3, Jonas Steinhauser1, Peter Vock1, Johannes M. Froehlich1

1Institute of Diagnostic, Interventional and Pediatric Radiology, Inselspital, University Hospital, Bern, BE, Switzerland; 2Virtual Perception Group, University of Applied Sciences, Bern, BE, Switzerland; 3Sohard AG, Bern, Switzerland

MR analysis of small bowel motility is a new technique to identify and localize functional pathologies. A newly developed software prototype permitting semi-automatic measurement was evaluated in comparison to measurement by hand. 52patients, overall 110evaluations were included. Overall 97/110(88.2%) of the motility curves were in agreement with each other with 86/110(78.2%) presenting a parallel shifting of the curves. No significant difference(p=0.65) was found for the peristaltic frequencies, while the amplitudes differed significantly(p=0.011). The newly developed software prototype for quantification of small bowel peristalsis proves as a valuable tool for fast, standardized and accurate measurement of small bowel motility.

17:06                       160.         Macromolecular Dynamic Contrast Enhanced (DCE) MRI Characterizes Hyperpermeability of the Intestinal Microvasculature in a Colitis Model

Katrien Vandoorne1, Tegest Aychek2, Steffen Jung2, Michal Neeman1

1Biological Regulation, Weizmann Institute, Rehovot, Israel; 2Immunology, Weizmann Institute, Rehovot, Israel

In this work, we imaged and characterized blood vessels in the colon in an animal colitis model, where C57 black mice were exposed to DSS in the drinking water for 7 days, and developed a protocol for detection of alterations of the microvasculature in colitis. We showed with non-invasive macromolecular DCE-MRI, plasma protein leakage to the colon, highlighting the focal patches of colitis in post contrast 3D rendering. Macromolecular DCE-MRI demonstrated to be able to identify severe colitis and the loss of plasma proteins.

17:18                       161.         Assessment of Reflux-Induced Esophageal Compliance Using Concurrent Magnetic Resonance Imaging and High-Resolution Manometry

Jelena Curcic1, Andreas Steingoetter1,2, Reto Treier1, Elad Kaufman3,4, Zsofia Forras-Kaufman3, Mark Fox3,5, Werner Schwizer3, Michael Fried3, Peter Boesiger1

1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland; 2Institute of Radiology, Klinikum rechts der Isar, Technical University Munich, Munich, Germany; 3Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland; 4Institute for Surgical Pathology, University Hospital Zurich, Zurich, Switzerland; 5Nottingham Digestive Diseases Centre and Biomedical Research Unit, University Hospital, Nottingham, United Kingdom

The prevalence of the gastro-esophageal reflux disease (GERD) amounts to 10% to 20% worldwide and is higher in the western than in the eastern countries. However, the influence of aggressive gastric acid on the esophageal muscles is poorly described. Concurrent magnetic resonance imaging (MRI) and high-resolution manometry (HRM) were used to assess the esophageal compliance induced by reflux events in healthy volunteers and GERD patients. The results show significant esophageal distention difference but only small pressure difference between two groups. This indicates that esophageal distention may be a sensitive parameter for assessment of esophageal compliance even without invasive manometry measurement.

17:30                       Introduction: Female Pelvis
                               
Georg M. Bongartz

17:42                       162.         Evaluation of Magnetic Resonance Diffusion and Spectroscopy Measurements as Predictive Biomarkers in Stage 1 Cervical Cancer

Maria A. Schmidt1, Geoffrey S. Payne1, Veronica A. Morgan1, Sharon Giles1, Jane Bridges2, Thomas Ind2, Nandita deSouza1

1CRUK/ESPRC Cancer Imaging Centre, Institute of Cancer Research and Royal Marsden NHS Foundation Trust, MRI Unit , Sutton, England, United Kingdom; 2Gynaecological Oncology, Royal Marsden NHS Foundation Trust and Chelsea & Westminster Hospital, London, United Kingdom

This study applies functional MRI techniques (DWI and MRS) to cervical tumors with different histological characteristics (type, degree of differentiation and presence or absence of lymphovascular invasion) in order to investigate their potential as predictive biomarkers. There was a statistically significant difference between the ADC of well/moderately differentiated tumors compared with poorly differentiated tumors. There was no significant difference between the ADCs of the tumors when separated by other characteristics. There was no significant difference in tCho between any of the tumor categories investigated and no correlation between tumor ADC and tCho.

17:54                       163.         Oxygenation in Cervical Cancer and Normal Uterine Cervix Assessed Using BOLD MRI at 3 Tesla: Initial Experiences

Rami Robert Hallac1, Yao Ding1, Qing Yuan1, Roderick W. McColl1, Jayanthi Lea2, Robert D. Sims1, Paul T. Weatherall1, Ralph P. Mason1

1Radiology, UT Southwestern Medical Center at Dallas, Dallas, TX, United States; 2Ob-Gyn Oncology, UT Southwestern Medical Center at Dallas, Dallas, TX

BOLD MRI is sensitive to tumor vascular oxygenation and may provide an indication of tumor hypoxia. We have studied normal volunteers and women with locally advanced cervical cancer to evaluate the response to breathing oxygen. Tumors showed a BOLD signal intensity response between 2.5 and 20 % at 3 T. Normal cervical tissue and uterine lining also responded, but muscle tended to show no signal enhanced in T2* weighted signal. T2* maps showed ÄR2* = 4.23±3.2s-1 in normal cervix. Overall the procedure was well tolerated providing a non-invasive approach to investigating tumor oxygenation.

18:06                       164.         Diffusion Tensor Imaging at 7 Tesla as a Probe of Uterine Fibroid Morphology

Michael Jonathan Thrippleton1, Kirsty Irene Munro1, Mark E. Bastin2, Maurits A. Jansen2, Gavin D. Merrifield2, Scott I K Semple3, Anca Oniscu1, Andrew W. Horne1, Alistair R. Williams1, Graham McKillop4, Ian Marshall2, David E. Newby, 3,5, Hilary OD Critchley1

1Centre for Reproductive Biology, University of Edinburgh, Edinburgh, Lothian, United Kingdom; 2Department of Medical Physics, University of Edinburgh; 3Clinical Research Imaging Centre, University of Edinburgh; 4Department of Radiology, Royal Infirmary of Edinburgh; 5Centre for Cardiovascular Science, University of Edinburgh

We are developing MR biomarkers for assessing the mechanism and effectiveness of new medical treatments for uterine fibroids — benign growths of uterine muscle, present in up to 70% of women of reproductive age. In this abstract, we describe the results of development work aimed at probing the water diffusion properties of the ex-vivo fibroid uterus at 7 T; we measure the water diffusion parameters of fibroid tissue subtypes and compare diffusion eigenvector maps with macroscopic tissue appearance.

18:18                       165.         MR Imaging Evaluation of PCOS in Adolescents

Matthew Austin1, Alice Park2, R. Jeffrey Chang3, Michele A. Brown4

1Radiology, San Diego, CA, United States; 2University of California San Diego, San Diego, CA, United States; 3 University of California San Diego, San Diego, CA, United States; 4 University of California San Diego, San Diego, CA, United States

This study compares MRI appearance of the ovary in adolescent girls with and without PCOS. Subjects were 32 girls between the ages of 12 and 19 years; 16 girls with clinical and biochemical evidence of PCOS and 16 girls without PCOS. Two radiologists independently recorded ovarian volume, follicle count per ovary, and follicle size.  Average follicle count per ovary and ovarian volume were higher in PCOS subjects compared to non-PCOS subjects.  MR imaging appearance of the ovary differs between adolescent girls with and without PCOS. MR imaging may help evaluate young patients in whom transvaginal ultrasound is contraindicated.

Peaks of the Heart

Room A9        16:30-18:30                Moderators: Lidia Szczepaniak and Robert G. Weiss

16:30                                       Introduction
Robert G. Weiss

16:42                       166.         Reduced Myocardial Creatine Kinase Reaction Rates in Human Heart Failure: First Measurements at 3T

Michael Schär1,2, AbdElmonem M. El-Sharkawy1, Paul A. Bottomley1,3, Robert G. Weiss1,3

1Russel H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; 2Philips Healthcare, Cleveland, OH, United States; 3Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD, United States

A triple repetition time saturation transfer method is applied to measure pseudo-first-order rate-constant kf of the creatine kinase reaction in the hearts of 16 patients with heart failure and 9 healthy subjects for the first time at 3T. In heart failure, kf is reduced to 65% of the normal value, in agreement with prior reports at 1.5T using a different technique. Furthermore, the intrinsic 31P T1 of phosphocreatine did not differ significantly between these subjects, possibly permitting elimination of one protocol step. The resulting two repetition time saturation transfer method, TwiST, yields the same cardiac kf measures in less time.

16:54                       167.         In Vivo Creatine Kinase Kinetics in Diabetic Heart: Relationship to Cardiac Work.

Adil Bashir1, Robert J. Gropler1

1Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO, United States

In vivo measurements of creatine kinase kinetics provide a better measure of cardiac energy metabolism than PCr to ATP ratio. Using optimized magnetization transfer approach we have measured energy production in rat hearts at two levels of cardiac performance and found it to be closely coupled with work load in normal rat hearts. In diabetic hearts the PCr concentration was lower at rest and the energy production for cardiac work was maintained by higher CK rate constant. When cardiac work was increased the CK flux in diabetic animals did not increase in proportion to the work indicating impaired energy production.

17:06                       168.         Hyperpolarised [2-13C]Pyruvate Uniquely Reveals the Role of Acetylcarnitine as a Mitochondrial Substrate Buffer in the Heart

Marie Allen Schroeder1, Helen J. Atherton1, Philip Lee2, Michael S. Dodd1, Lowri E. Cochlin1, Kieran E. Clarke1, George K. Radda1,2, Damian J. Tyler1

1Physiology, Anatomy and Genetics, University of Oxford, Oxford, Oxfordshire, United Kingdom; 2Biomedical Sciences Institute, Singapore Bioimaging Consortium, Singapore, Singapore

Mitochondrial acetylcarnitine may be involved in balancing the glucose-fatty acid cycle in the heart. Here, we used hyperpolarised [2-13C]pyruvate with magnetic resonance spectroscopy to monitor the incorporation of acetyl-CoA formed by pyruvate dehydrogenase into the acetylcarnitine pool, and the metabolites of the Krebs cycle, in real-time and in vivo. Our results demonstrated that most pyruvate-derived acetyl-CoA entering the Krebs cycle does not immediately condense with oxaloacetate, but is first converted to acetylcarnitine. Examination of acetylcarnitine production from pyruvate-derived acetyl-CoA in vivo revealed that acetylcarnitine provides a rapidly mobilised mitochondrial buffer for oxidative substrate and may be fundamental in maintaining high, constant ATP levels in the heart.

17:18                       169.         Quantification of Myocardial Triglycerides: Ex-Vivo and In-Vivo Evaluations by Two-Point Water-Fat Imaging and 1H Spectroscopy

Chia-Ying Liu1, Alban Redheuil1, Ronald Ouwerkerk2, Charles Steenbergen3, Shenghan Lai4, Joao Lima1, David Bluemke5

1Department of Radiology, Johns Hopkins Hospital, Baltimore, MD, United States; 2The National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, United States; 3Department of Pathology, The Johns Hopkins University, Baltimore, MD, United States; 4Department of Epidemiology, Johns Hopkins School of Hygiene and Public health, Baltimore, MD, United States; 5Radiology and Imaging Sciences, National Institutes of Health, Bethesda, MD, United States

The concept of fat contained within the myocardium, has recently received attention because of its potential role in diabetic myocardial disease, obesity, and HIV infected individuals. Measurements of myocardial triglycerides in humans have been accessed using proton MR spectroscopy (1H MRS). We studied the accuracy of the dual-echo Dixon MRI in quantifying the fatty content of the myocardium in autopsies and patients. 1H MRS as an independent method was also applied for comparison.

17:30                       170.         Human Cardiac Creatine Kinase Flux Measurement at 3T Using 31P Magnetization Transfer MRS

Adil Bashir1, Robert J. Gropler1

1Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, MO, United States

31P magnetization transfer MRS can measure energy turnover in the myocardium through the creatine kinase (CK) reaction. The in vivo application of this technique has been lagging especially for human studies. We have developed an optimized strategy to measure adenosine diphosphate (ATP) production in human heart via CK system. This is the first demonstration of the technique for human studies at 3T. The high field magnet provides reduction in total experiment time and improved spectral resolution over 1.5T magnet. Our results also demonstrate that the energy production in diabetic heart is impaired.

17:42                       171.         Cardiac Spectroscopy in Chronic Fatigue Syndrome (CFS) Correlates with Autonomic Abnormalities on Standing and Stratifies Oxidative Function in Skeletal Muscle

Kieren Grant Hollingsworth1, David Emerys Jones2, Roy Taylor1, Julia Lindsay Newton3, Andrew Mark Blamire1

1Newcastle Magnetic Resonance Centre, Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom; 2Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom; 3Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, Tyne and Wear, United Kingdom

Studies of muscle metabolism in chronic fatigue syndrome (CFS) have often had contradictory results and suggested the presence of mixed phenotypes. Recent evidence has suggested that cardiac output is adversely affected in CFS.  12 female CFS/ME patients and 8 controls were recruited. Cardiac phosphorus spectroscopy, muscle exercise phosphorus spectroscopy and impedance cardiography were acquired. Cardiac PCr/ATP ratio was related to changes in cardiac index on standing and reduced PCr/ATP ratio was found to correlate with impaired oxidative function (half-times for PCr and ADP recovery).  Cardiac spectroscopy was found to be useful in stratifying oxidative function in CFS.

17:54                       172.         In Vivo 17O MRS Imaging for Assessing Myocardial Oxygen Metabolism in Rat Heart at 9.4T

Xiao-Hong Zhu1, Yi Zhang1, Wei Chen1

1Center for Magnetic Resonance Research, Department of Radiology,, Minneapolis, MN, United States

Heart, similar to brain, is a highly aerobic organ which consumes a large portion of oxygen utilized by the entire body. The myocardial oxygen metabolism provides essential energy for performing myocyte contraction/relaxation and maintaining normal cardiac functions. It is, thus, important to develop an in vivo MR imaging approach capable of noninvasively imaging the myocardial oxygen metabolic rate (MVO2). Recently, high-field in vivo 17O MRS imaging (MRSI) has been applied to imaging the rat brain oxygen metabolism. In this study, we exploit the feasibility of the 17O approach for imaging rat MVO2 at 9.4T with a brief inhalation of 17O-labeled oxygen gas under basal and workload conditions.

18:06                       173.         Myocardial Fat Content: Single Breath-Hold 1H-MR Spectroscopy at 3 T

Belen Rial1, Stefan Neubauer1, Matthew D. Robson1, Jurgen E. Schneider1

1Cardiovascular Medicine, Oxford University, Oxford, Oxfordshire, United Kingdom

Proton MR Spectroscopy provides a window into myocardial metabolism. Cardiac and respiratory motion still degrades the sensitivity of the method and hence metabolite detection. Some techniques for reducing this problem have recently emerged, however a compromise between feasible scan duration and easy implementation of these techniques in a clinical scanner has not been reached yet. In this study we demonstrate feasible single breath-hold 1H-MR spectroscopy in the human heart at 3 T, obtaining one unsuppressed-water spectrum and three metabolite spectra, which allowed reliable quantification of fat as percentage of water content in the myocardium of healthy volunteers.

18:18                       174.         Myocardial Lipids and Myocardial Function in Insulin Resistant Population.

Martin Krssak1,2, Yvonne Winhofer2, Christian Göbl2, Martin Bischof2, Gert Reiter3, Alexandra Kautzky-Willer2, Anton Luger2, Michael Krebs2, Christian Anderwald2

1Radiology, Medical University of Vienna, Wien, Austria; 2Internal Medicine III, Medical University of Vienna, Wien, Austria; 3Siemens Healthcare Austria, Graz, Austria

Myocardial lipid accumulation and myocardial function were measured by 1H MR spectroscopy and imaging in a group of non-diabetic insulin sensitive and metabolically matched non-diabetic insulin resistant women. No differences were found between these two groups, but hampered myocardial function and increased myocardial lipid accumulation was found in a group patients with type 2 diabetic mellitus, who served as a negative controls. Our results suggest that increased myocardial lipid content and restricted myocardial capacity are not linked to insulin resistance per se, but might develop after the manifestation of type-2 diabetes.

 

Molecular & Cellular Imaging Study Group
Room K1        18:45 - 20:45

 

18:45       Business Meeting

 

18:55       Scientific Meeting – “Advances in 19F Reporters & Cell Tracking Methods”

 

18:55       A Renaissance for 19F NMR: Novel Concepts & Opportunities in Cellular & Molecular Imaging
Ralph Mason, Ph.D., Department of Radiology, UT Southwestern Medical Center, Dallas, TX, USA

 

19:25       MRI-based Cell Tracking of Human Stem Cell Therapy in 20XX
Erik Shapiro, Ph.D., Departments of Diagnostic Radiology and Biomedical Engineering, Yale University, New Haven, CT, USA

 

19:55       MR Cell Tracking in Reperfused Myocardial Infarction with Microvascular Obstruction & Haemorrhage: Fluorine-19 MR Could be a Better Solution
Yuxiang Ye, Department of Experimental Physics, University of Wurzburg, Wurzburg, Germany

 

20:07       Towards in vivo Visualization of Pancreatic Beta-Cells in the Mouse: Molecular Imaging at 16.4 T
Sven Gottschalk, Ph.D., High Field MR Center, Max Planck Institute for Biological Cybernetics, Tubingen, Germany

 

20:19       Remote MR Sensing of pH & Cell Viability Using lipoCEST-filled Microcapsules
Kannie Chan, Ph.D., Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA

 

20:31       In vivo SWIFT Imaging of SPIO Labeled Stem Cells Grafted in the Heart
Shelly Zhang, Department of Radiology, University of Pennsylvania, Philadelphia, PA, USA

 

20:45       Adjourn


High Field Systems & Applications Study Group
Room K2        18:45 - 20:45

 

18:45       Business Meeting and Introduction of Election Winners

 

19:00       Vendor Update (5min talk, 5 min discussion)

 

19:00       GE, Gregory Hurst, Ph.D., GE Healthcare, Chagrin Falls, OH, USA

 

19:10       Siemens, Karsten Wicklow, Ph.D., Siemens AG, Erlangen, Germany

 

19:20       Philips, TBA

 

19:30       High Field Applications in a Clinical Setting

Peter Luijten, Ph.D., UMC Utrecht, Utrecht, The Netherlands

 

19:50       RF Safety for High Field: Guidelines

Mikhail Kozlov, Ph.D. and Robert Turner, Ph.D., Director, Department of Neurophysics Max-Planck-Institute for Human Cognitive and Brain Sciences, Leipzig, Germany

 

20:10       Panel Discussion

 

20:30       Adjourn


Diffusion & Perfusion Study Group
Victoria Hall  18:45 - 20:45               

 

18:45       Welcome and Introduction of New Committee

 

18:50       Discussion: Future Diffusion Workshop

 

19:55       Debate: Should the Diffusion-Perfusion Study Group be Split?

Pro - John Detre, M.D., Professor, University of Pennsylvania, Philadelphia, PA, USA

Con – Michael Moseley, Ph.D., Professor, Stanford University, Stanford, CA, USA

 

20:45       Adjourn


MR Flow & Motion Quantitation Study Group
Room A4        18:45 - 20:45             

 

18:45       Business Meeting and Introduction of New Committee Members

 

19:00       Scientific Program

 

19:00       Myocardial Motion Analysis with Tissue Phase Mapping

Daniela Föll, M.D., University Hospital Freiburg, Baden-Württemberg, Germany

 

19:15       4d Flow - Visualization and Post-Processing

Tino Ebbers, Ph.D., Linköping University, Linköping, Sweden

 

19:40       Review of CSF Flow Research & Potential Applications: Are We Getting There?

Noam Alperin, Ph.D., University of Miami, Miami, FL, USA

 

19:55       Discussion

 

20:40       Adjourn


MR of Cancer Study Group
Room A5        18:45 - 20:45             

18:45        Food and Beverage

 

19:00       Business Meeting

 

19:15       Scientific Meeting

 

19:15       It's Not All About Science: Today's Financial Challenges & Possibilities for the Young MR Cancer Scientist

Research Scientist Tom Scheenen, Ph.D., The Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands

 

19:30       The Science & Legacy of Professor Mildred Cohn (1913-2009)

Professor Hadassa Degani, Ph.D., Weizmann Institute of Science, Rehovot, Israel

 

19:45       The "Academic Rat Race": Challenges for New Principal Investigators in the United States

Associate Professor Kristine Glunde, Ph.D., Johns Hopkins University School of Medicine, Baltimore, MD, USA

 

20:00       Hot Topic Debate:

From Pre-Clinical Experiments & Pilot Studies into a Validating Clinical Study – Translational Bottlenecks

 

20:30       Adjourn


Musculoskeletal Study Group
Room A7        18:45 - 20:45                

 

18:45        Skeletal Muscle Energetics in Health & Disease; A Semi Historical Perspective

Sir George K. Radda, D.Phil., University of Oxford, Oxford, UK

 

19:05       NIH Osteoarthritis Initiative – Update

Erika Schneider, Ph.D., Cleveland Clinic, Cleveland, OH, USA

 

19:25       The International Workshops on Imaging Based Measures of Osteoarthritis – Goals, Achievements & a Preview

David Wilson, D.Phil., University of British Columbia, Vancouver, BC, Canada

 

19:45       Cartilage - Bone Interactions in Osteoarthritis

Sharmila Majumdar, Ph.D., University of California, San Francisco, CA, USA

 

20:05       Ultrashort Echo Time MR Imaging of Short T2 Tissues in Articular Cartilage of the Osteochondral Junction

Christine Chung, M.D., University of California, San Diego, CA, USA

 

20:25       New Developments in Musculoskeletal Imaging Using SWIFT-Class Sequences

Jutta Ellermann, M.D., Ph.D., University of Minnesota, Minneapolis, MN, USA

 

20:45       Adjourn


Psychiatric MR Spectroscopy & Imaging Study Group   
Room A8        18:45 - 20:45                

 

18:45        Business Meeting

 

19:00       Scientific Meeting – “Innovative Applications of MRS Tailored to Specific Psychiatric Disorders”

 

19:00       The Importance of Creatine to Cognitive Development & Mental Health

Kim M. Cecil, Ph.D., Professor of Radiology, Pediatrics and Neuroscience, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA

 

19:25       MRS Studies of Mood Disorders

Perry F. Renshaw, M.D., Ph.D., MBA, Professor of Psychiatry, University of Utah, Salt Lake City, UT, USA

 

19:50       Some Recent Developments in Spectral Editing: Preliminary Results in Schizophrenia

Peter B. Barker, D.Phil, Professor of Radiology, Johns Hopkins University, Baltimore, MD USA

 

20:15       Panel Discussion

 

20:40       Adjourn


White Matter Study Group
Room A9        18:45 - 20:45             

 

18:45       Business Meeting

 

19:00       Brief Presentations (2 Minutes Talk Followed by Discussion) by White Matter Study Group Poster Competition Participants On Their Posters

 

19:45       Panel Discussion: Will Advanced White Matter MR Techniques (mcT2, qMT, DSI, etc.) Ever Reach Wide-Spread Clinical Utility?

 

20:30       Location and Theme of the Next White Matter Study Group Workshop

Sean Deoni, Ph.D., Brown University, Providence, RI, USA

 

20:45       Adjourn

 

TUESDAY

SUNRISE EDUCATIONAL COURSE
CLINICAL INTENSIVE COURSE
Hot Topics in Body MRI

Room K1            07:00 – 08:00    Organizers:  Talissa Altes, Elmar Max Merkle and Bachir Taouli

EDUCATIONAL OBJECTIVES

Upon completion of days 1 and 2 participants should be able to:

·         Explain the physics of DWI methods in body imaging;

·         Apply DWI technique in their practice;

·         Design female pelvic and prostate MR protocols including DWI; and

·         Describe current results of DWI in oncology

Advanced Body Diffusion 1

Moderators: Bachir Taouli, M.D., and Harriet C. Thoeny, M.D.

07:00         Advanced Diffusion Physics Applied to Body Imaging
                 
Thomas L. Chenevert, Ph.D.

 

07:30         Diffusion Imaging of Focal and Diffuse Renal Diseases
                 
Harriet C. Thoeny, M.D

 

SUNRISE EDUCATIONAL COURSE
CLINICAL INTENSIVE COURSE
Tissue Contrast in MSK MRI - From Physics to Physiology

Room K2        07:00 – 08:00  Organizer & Moderator:  Bernard J. Dardzinski

EDUCATIONAL OBJECTIVES

Upon completion of this course participants should be able to:

  • Describe contrast mechanisms in MSK imaging, most notably in imaging of articular cartilage;
  • Describe the physics of advanced MR sequences;
  • Identify the most suitable new MR sequences for four important indications;
  • Implement current MR protocols for daily practice and be aware of the most useful indications for these techniques.

07:00         Relaxation Mechanisms in Collagen Rich Tissues
                 
Greg J. Stanisz, Ph.D.

 

07:30         Clinical Aspects of Tendon Disorders
                 
Eugene G. McNally, M.D., F.R.C.R., F.R.C.P.I.

 

 

SUNRISE EDUCATIONAL COURSE

Image Reconstruction

Victoria Hall  07:00 – 08:00  Organizer & Moderator:  Elfar Adalsteinsson

EDUCATIONAL OBJECTIVES

Upon completion of this course participants should be able to:

  • Describe the main steps involved in efficient non-Cartesian image reconstruction;
  • Formulate a generalized signal model incorporating gradient encoding, coil sensitivity and Bo inhomogeneity;
  • List the pro’s and con’s of Cartesian and non-Cartesian parallel MRI;
  • Compare compressed sensing, HYPR, and k-t BLAST with respect to their use of prior knowledge;
  • Describe the principles of separating water and fat signals; and
  • Name three different approaches for motion correction and appraise their potential to become routine methods

Non-Cartesian Trajectories and Off-Resonance Correction

 

07:00         Fast Image Reconstruction from Non-Cartesian Data
                 
Craig H. Meyer, Ph.D.

 

07:30         Off-Resonance Effects and Correction
                 
Bradley P. Sutton, Ph.D.

 

SUNRISE EDUCATIONAL COURSE

Imaging Biomarkers

Room A1     07:00 – 08:00     Organizers & Moderators:  Jeffrey L. Evelhoch and Sabrina M. Ronen

EDUCATIONAL OBJECTIVES

Upon completion of this course participants should be able to:

  • Describe what a biomarker is and how MR can be used as a biomarker;
  • Explain how biomarkers are qualified to be fit for their intended purpose;
  • List requirements for use of MR biomarkers in both preclinical studies and clinical trials; and
  • Give examples of how imaging biomarkers are being used in at least two of the following areas: multiple sclerosis, oncology, cardiovascular diseases and neurodegenerative diseases.

07:00         What Imaging Biomarkers Are and How They Are Used
                 
John C. Waterton, Ph.D.

 

07:30         Non-Imaging Biomarkers and Regulatory Aspects of Imaging Biomarkers
                 
H. Cecil Charles, Ph.D.

 

 

SUNRISE EDUCATIONAL COURSE

Brain: An Absolute Beginner’s Guide to Anatomical & Functional MRI

Room A4        07:00 – 08:00  Organizer & Moderator:  Geoffrey J.M. Parker

EDUCATIONAL OBJECTIVES

Upon completion of this course participants should be able to:

  • Identify the neuroanatomical and neurophysiological parameters which are accessible to MR measurement;
  • Describe the underlying physics of MR neuroimaging techniques;
  • Describe the data acquisition and analysis techniques most commonly used for anatomical and functional MRI of the brain;
  • Recognize the potential value of advances such as parallel imaging, fast imaging techniques and high magnetic field strengths for imaging the brain; and
  • Name typical clinical applications for which specific MRI techniques are suited.

07:00         Beginners Guide to Quantitative MRI
                 
Ralf Deichmann, Ph.D.

 

SUNRISE EDUCATIONAL COURSE

Potentials & Challenges of High-Field MRS

Room A5        07:00 – 08:00  Organizers & Moderators:  Rolf Gruetter and Ivan Tkac

EDUCATIONAL OBJECTIVES

Upon completion of this course participants should be able to:

  • Describe advantages and potentials of MRS at very high fields;
  • Identify problems and challenges of high field MRS;
  • Define the MRS detectable neurochemical profile of the brain;
  • Describe principles of metabolite quantification;
  • Assess spectral quality and identify main sources of spectral quality deterioration; and
  • Explain the importance of B0 shimming at high fields.

What High-Field MRS Can Provide

 

07:00       Potentials of High-Field Spectroscopy
Wolfgang Dreher, Ph.D.

 

07:30       How To Get Meaningful MRS Data
Robin A. de Graaf, Ph.D.

 

SUNRISE EDUCATIONAL COURSE

Modeling & Quantitative Analysis for Body DCE MRI

Room A6        07:00 – 08:00 Organizers: Henry Rusinek and Min-Ying Lydia Su

EDUCATIONAL OBJECTIVES

Upon completion of this course participants should be able to:

  • Describe various DCE models used for different organs including kidney, liver, breast, and prostate;
  • Describe analysis methods used to measure vascularity, permeability, and blood flow;
  • Implement Monte Carlo noise simulation method to predict parameter bias and precision;
  • Compare conventional compartmental kinetic models and distributed models;
  • Apply procedures for converting MRI signal intensity to tracer concentration; and
  • Explain current method for measuring vascular input function and analyzing its impact on obtained DCE parameters.

Moderators: David L. Buckley and Douglas C. Noll

 

07:00       Principles of Modeling & Simulations
Steven P. Sourbron, Ph.D.

 

07:30       Tracer Kinetics
Tong San Koh, Ph.D.

 

SUNRISE EDUCATIONAL COURSE

From Bench to Bedside to Bench: Translation of Animal Models to Clinical Practice & From Clinical Practice to Animal Models

Room A7        07:00 – 08:00  Organizers & Moderators: Pia C. Maly Sundgren and Afonso C. Silva

EDUCATIONAL OBJECTIVES

Upon completion of this course participants should be able to:

  • Describe the main MRI methods used in experimental studies to understand the underlying disease mechanisms;
  • Identify what is known about the underlying disease mechanisms, and which type of MRI investigations could be used for diagnosis and clinical investigation;
  • Describe the main MRI methods used in the clinical setting to diagnose the condition, and the rationale behind this; and
  • Make the translation from what is - and can be - done in experimental studies to what can be done clinically, and where animal models bring new insight to disease.

Traumatic Brain Injury

 

07:00       MRI Assessment of Cerebral Blood Flow and Macrophage Accumulation in Mouse Models for Traumatic Brain Injury
Lesley May Foley, B.Sc.

 

07:30       Translation of Traumatic Brain Injury into Human and Clinical Practice
Susan Durham, M.D.

 

SUNRISE EDUCATIONAL COURSE

Cardiovascular Imaging: Disease or Problem Based Teaching, Practical Protocols

Room A8    07:00 – 08:00           Organizers & Moderators: Victor A. Ferrari, Vivian S. Lee and Mitsue Miyazaki

EDUCATIONAL OBJECTIVES

Upon completion of this course participants should be able to:

  • Recognize recent advancements and requirements in 3T cardiovascular MRI, as compared to present 1.5T MRI;
  • Evaluate the strengths and limitations of current cardiovascular MRI techniques when applied to clinical diagnostic examinations;
  • Describe current clinical techniques for assessment of ischemic heart disease and various cardiac diseases using new methods;
  • Select the potential clinical applications of time-resolved techniques, and the technical challenges that will need to be resolved for wider applications; and
  • Apply current approaches optimally to these diseases.

Advances in 3T Cardiovascular MR

 

07:00       Clinical Need for High Field Strength in CMR
Ahmed Gharib, M.D.

 

07:20       B0 and B1 Shimming
Michael Schär, Ph.D.

 

07:40       Advanced Pulse Sequences
Krishna S. Nayak, Ph.D.

 

SUNRISE EDUCATIONAL COURSE

Trials & Tribulations: Multicenter Trial Headaches & Their Cures

Room A9        07:00 – 08:00       Organizers & Moderators: Nicola de Stefano &  Jeffrey Joseph Neil

EDUCATIONAL OBJECTIVES

Upon completion of this course participants should be able to:

  • Describe multiple methods for setting up and maintaining site quality and certification for multicenter imaging trials;
  • Explain the issues related to performing research involving INDs or IDEs;
  • Evaluate the sensitivity, specificity and reliability of current imaging methods to detect relevant quantitative changes within the brain; and
  • Describe the underlying principles for adopting and evaluating potential surrogate imaging markers for assessment of drug efficacy.

Basic Prerequisites for Multicenter/Multiscanner Trials

 

07:00       QA and Site Certification
Robert C. McKinstry, M.D., Ph.D.

 

07:30       Trial execution: methods to drive standardization
Matt A. Bernstein, Ph.D.

 

PLENARY SESSION

Clinical Needs & Technological Solutions: Osteoarthritis

Room A1        08:15-09:30                Organizers & Moderators: Christine Chung and Hollis G. Potter

08:15                       175.         Models for Studying Cartilage Biology in the Context of Osteoarthritis

Mary B. Goldring1

1Weill Cornell Medical College, Hospial for Special Surgery, New York, NY, United States

Human cartilage is complex tissue of matrix proteins varying from superficial to deep layers and from loaded to unloaded zones. During OA development normally quiescent chondrocytes with low matrix turnover undergo phenotypic modulation causing matrix destruction and abnormal repair. We have been investigating mechanisms by which GADD45β, a stress response signaling molecule involved in cartilage development, and ESE-1, an inflammation-induced transcription factor, regulate collagen remodeling during osteoarthritis. Studies using human surgical specimens and mouse models of OA will elucidate how these factors disrupt cartilage homeostasis, leading to the development of targeted therapies that block cartilage damage, promoting effective repair.

08:40                       176.         Mechanisms of OA/ Imaging Appearance

Garry E. Gold1

1Stanford University, Stanford, CA, United States

Osteoarthritis is a common form of arthritis that currently has no disease-modifying treatment.  Patients receive pain medication until end-stage treatment with total joint replacement.  Risk factors for osteoarthritis include joint trauma, obesity, and malalignment.  Currently, clinical management of osteoarthritis and testing of new treatments is done primarily using x-ray.  Recent advances in MRI have great potential to detect osteoarthritis before irreversible changes in the joint have occurred.  MRI can also image complications of joint replacements.  A review of osteoarthritis and an assessment of the potential of MRI to improve treatment will be presented.

09:05                       177.         Imaging Markers for Early Matrix Depletion

Sharmila Majumdar1

1University of California, San Francisco, San Francisco, CA, United States

Articular cartilage is composed of chondrocytes surrounded by a large extracellular matrix (ECM) composed of water and two groups of macromolecules: proteoglycan (PG) and collagen fibers.  ECM changes are said to precede morphological changes in articular cartilage and may prove to be early biomarkers of osteoarthritis. In MRI, these macromolecules restrict motion of water protons, affecting relaxation times and contrast agent uptake.  ECM changes such as PG loss, as reflected in measurements of:  1) T1ρ of water protons, 2) Delayed Gadolinium-enhanced MRI of cartilage (dGEMRIC) and collagen content and orientation changes probed using T2 relaxation time measures will be discussed.

 


CLINICAL INTENSIVE COURSE
(Admission limited to Clinical Intensive Course registrants only)

Advances in Multiple Sclerosis I

Room K1        08:15-09:15        Organizers:  Walter Kucharczyk and Pia C. Maly Sundgren

EDUCATIONAL OBJECTIVES
Upon completion of this course participants should be able to:

  • Explain brain plasticity;
  • Describe cases when MRI could appropriately be used as a biomarker for MS; and
  • Explain the rationale for using (or not) different dosages of contrast in MS patients.

Moderators: Nicola de Stefano and Alex Rovira

08:15       MRI in MS - State of the Art
Frederik Barkhof, M.D., Ph.D.

 

08:40       fMR Imaging for Evaluation of Brain Plasticity in MS
Alberto Bizzi, M.D.

 

09:05       Discussion

 

 

CLINICAL INTENSIVE COURSE
(Admission limited to Clinical Intensive Course registrants only)

Foot, Ankle & Knee Imaging: Case-Based Teaching

Room K2        08:15-10:05                Organizer:  Juerg Hodler

Moderator: Lynne S. Steinbach, M.D.

 

08:15       Foot and Ankle: Case-based
Kathryn J. Stevens, M.D.

 

09:10       Knee: Case-based
Hollis G. Potter, M.D.

 

 

CLINICAL INTENSIVE COURSE
(Admission limited to Clinical Intensive Course registrants only)

Basic Neuro: Intracranial Infections: Case-Based Teaching

Room K1        09:15-10:05          Moderators: Walter Kucharczyk and Pia C. Maly Sundgren

EDUCATIONAL OBJECTIVES

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

  • List the MR imaging characteristics of prions and viral infections in the brain and spine; and
  • List MR imaging characteristics of bacterial, fungi and parasites in the brain and spine.

Moderators: Walter Kucharczyk and Majda M. Thurnher

 

09:15       Prions and Virus
Walter Kucharczyk, M.D., F.R.C.P.C.

 

09:40       Bacterial, Fungi and Parasites
E. Turgut Tali, M.D.

 

 

CLINICAL INTENSIVE COURSE
Cardiac MRI: Case-Based Teaching

Room K1        10:30-12:30                Organizer: Georg M. Bongartz

EDUCATIONAL OBJECTIVES

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

  • Design appropriate scanning protocols for cardiac MR imaging;
  • Describe the basic clinical indications for cardiac MRI;
  • Discriminate various cardiac diseases by their typical properties in MRI;
  • Identify the pitfalls and challenges of the various Cardiac MRI techniques; and
  • Compare and optimally apply the pulse sequences used for cardiac perfusion, function, viability, and velocity imaging in MRI.

Moderators:  Orlando P. Simonetti and Matthias Stuber

 

10:30       Acute and Chronic Ischemic Disease
               
Jeanette Schulz-Menger, M.D.

 

10:50       Valvular Disease
               
Jens Bremerich, M.D.

 

11:10       Non-Ischemic Cardiomyopathy
               
Victor A. Ferrari, M.D.

 

11:30       Congenital Heart Disease
               
Albert de Roos, M.D.

 

11:50       Cardiac Tumors
               
Gunnar Lund, M.D.

 

12:10       Panel Discussion

 

 

CLINICAL INTENSIVE COURSE
Diffuse Liver Disease

Room K2        10:30-12:30    Organizers: Talissa Altes, Elmar Max Merkle and Bachir Taouli

EDUCATIONAL OBJECTIVES

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

  • Describe the current results of ultrasound elastography and serum markers for detection of liver fibrosis and cirrhosis ;
  • Evaluate the results of MRI to diagnose and quantify liver fat and iron;
  • Describe the results of MRI to detect liver fibrosis and cirrhosis; and
  • Explain the performance of MRI to detect HCC.

Moderators: Bachir Taouli, M.D. and Scott B. Reeder, M.D., Ph.D.

 

10:30       Non Invasive Detection of Liver Fibrosis with Transient Elastography and Serum Markers
               
Laurent Castéra, M.D.

 

11:00       Fat-Iron in the Liver
               
Scott B. Reeder, M.D., Ph.D.

 

11:30       Fibrosis-Cirrhosis
               
Bernard E. Van Beers, M.D., Ph.D.

 

12:00       HCC Detection
               
Claude B. Sirlin, M.D.

 

CLINICAL INTENSIVE COURSE
MRS in Clinical Practice

Room A9        10:30-12:30        Organizers: Walter Kucharczyk and Pia C. Maly Sundgren

EDUCATIONAL OBJECTIVES

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

  • Explain when MRS can be useful in the work-up of brain tumors… and its pitfalls;
  • Describe the role of MRS in differentiation of metabolic disorders;
  • Describe the role of MRS in diagnosis and treatment of psychiatric disorders; and
  • Describe the potential role of MRS to help define who is going to advance to severe dementia and who will have a “normal” aging.

Moderators:  Jeffry R. Alger and John D. Port

 

10:30       MRS in Metabolic Disorders
               
Alberto Bizzi, M.D.

 

10:55       MRS in Brain Tumor Diagnosis
               
Jeffry R. Alger, Ph.D.

 

11:20       MRS in Schizophrenia and Other Psychiatric Disease
               
John D. Port, M.D., Ph.D.

 

11:55       MRS in Mild Cognitive Impairment
               
Kejal Kantarci, M.D.

 

 

fMRI Calibration & Quantitation

Room A1        10:30-12:30                Moderators: Richard Hoge and Silvia Mangia

10:30                       178.         Per-Subject and Per-Brain-Region Hyperoxic (HO) and Hypercapnic (HC) BOLD Calibration to Investigate Neurovascular Metabolism Coupling Linearity

Clarisse Ildiko Mark1, G. B. Pike1

1McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada

Estimates of the coupling relationship (n) between changes in cerebral metabolic rate of oxygen (ΔCMRO2) and blood flow (ΔCBF) under neuronal activation, key in interpreting BOLD results, are highly sensitive to variability in individual subjects BOLD calibration (M)-values and brain regions.  We thereby sought to acquire precise calibration data under robust control of HC and HO levels, together with visual stimulation of varying frequency and voluntary motor tasks.  Based on low-variability M-values, our findings demonstrate a tightly coupled and linear flow-metabolism relationship in the visual cortex, an indication that oxygen demand from activated neurons across visual-frequencies is met by oxidative metabolism.

10:42                       179.         Baseline BOLD Correlation Accounts for Inter-Subject Variability in Task-Evoked BOLD Responses

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

1CMRR, radiology, University of Minnesota, Minneapolis, MN, United States; 2Biomedical Engineering, University of Minnesota, Minneapolis, MN, United States

To investigate whether subjects’ ongoing brain activity can affect their response to external stimulation, fMRI BOLD signals were acquired from human visual cortex under conditions with/without visual stimulation. It was found that correlation strength but not fluctuation magnitude of spontaneous (baseline) BOLD signals is positively correlated (R2 = 0.68, p-value = 2.3 × 10-4) with the amplitude of evoked BOLD responses to visual stimulus. This finding suggests that synchronization strength of ongoing brain activity may have an important effect on evoked brain activity, even at the early stage of sensory systems. Moreover, this study provides a neurophysiology basis for quantitatively understanding large inter-subject BOLD variability commonly observed in many fMRI studies.

10:54                       180.         Calibration of the Amplitude of FMRI Contrast (β) Using Fractional Volume of Gray Matter: The Spatial and Inter-Subject β Calibrations

Wanyong Shin1, Hong Gu1, Qihong Zou1, Pradeep Kurup1, Yihong Yang1

1Neuroimaging Research Branch, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD, United States

The amplitude of BOLD contrast during brain activation (commonly called β) is widely used in fMRI study to monitor the neuronal activity. However, it is observed that β varies substantially over subjects, which is referred as inter-subject β variation. In this study, we propose a new calibrated fMRI method based on fractional volume of gray matter measurement using FRASIER method in which the spatial β variations and the  inter-subject β variations are calibrated, and we show that the statistical power is significantly improved after the calibration in an fMRI study with a visual task.

11:06                       181.         Robustly Accounting for Vascular Reactivity Differences Across Subjects Using Breath-Hold

Kevin Murphy1, Ashley D. Harris1, Richard G. Wise1

1CUBRIC, Cardiff University Brain Research Imaging Centre, School of Psychology, Cardiff, United Kingdom

Separating BOLD vascular and metabolic responses is often achieved using hypercapnic challenges. A simple way of elevating blood CO2 concentrations to measure vascular reactivity is breath-holding. Two aspects of this vascular reactivity measure are often neglected: breath-holds are usually modelled as blocks even though CO2 accumulates over time and increases in CO2 differ between subjects, both of which must be considered when using vascular reactivity as a calibration tool. This study determines that the appropriate model for the BOLD breath-hold response is derived from end-tidal CO2 traces and that individual differences in CO2 increases must be taken into account.

11:18                       182.         The Relationship Between M in “calibrated fMRI” and the Physiologic Modulators of fMRI

Hanzhang Lu1, Joanna Hutchison2, Feng Xu1, Bart Rypma2

1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States; 2Center for BrainHealth, University of Texas at Dallas, Dallas, TX, United States

The “calibrated fMRI” technique requires a hypercapnia or hyperoxia calibration experiment in order to estimate the factor “M”. It would be desirable to be able to obtain the M value without the need of a gas challenge calibration. According to the analytical expression of M, it is a function of two baseline physiologic parameters, baseline CBF and baseline venous oxygenation, both of which have recently been shown to be significant modulators of fMRI signal. Here we studied the relationship among M, baseline CBF and baseline venous oxygenation, and assessed the possibility of estimating M from the baseline physiologic parameters.

11:30                       183.         Hemodynamic Responses Following Brief Breath-Holding and Visual Stimulation Reconcile the Vascular Compliance and Sustained Oxygen Metabolism Origins for the BOLD Post-Stimulus Undershoot in Human Brain

Jun Hua1, Robert Stevens1, Alan J. Huang1, James J. Pekar1, Peter C.M. van Zijl1

1Department of Radiology, The Johns Hopkins University, Baltimore, MD, United States

BOLD studies of visual stimulation show a post-stimulus undershoot, whereas breath-hold studies don’t. BOLD/CBF/CBV/arterial-CBV dynamics following visual stimulation and breath-hold were measured to investigate which mechanism (vascular/metabolic) dominates the undershoot. After visual stimulation, arterial-CBV/CBF returned to baseline in ~8s/15s, respectively, while BOLD undershoot lasted for ~30s, during which elevated post-arterial-CBV (2.4+/-1.8%) and CMRO2 (10.6+/-7.4%) were observed. Following breath-hold, BOLD/CBF/CBV/arterial-CBV all recovered within ~20s and no BOLD undershoot, elevated post-arterial-CBV and CMRO2 were observed. These data suggest that both delayed post-arterial-CBV return and enduring oxygen consumption affect the undershoot, with contributions estimated as 20+/-16% and 79+/-19%, respectively, under our experimental conditions.

11:42                       184.         BOLD Impulse Response Functions and Baseline-Dependent Response Adaptation

Basavaraju G. Sanganahalli1, Peter Herman1,2, Hal Blumenfeld3, Fahmeed Hyder4

1Diagnostic Radiology, Yale University, New Haven, CT, United States; 2Human Physiology, Semmelweis University, Budapest, Hungary; 3Neurology, Neurosurgery and Neuroscience, Yale University, New Haven, CT, United States; 4Diagnostic Radiology and Biomedical Engineering, Yale University, New Haven, CT, United States

BOLD impulse response functions (IRFs) show variability (i.e, presence/absence of a delayed undershoot) across different conditions (e.g., stimuli, regions). Could these BOLD-IRF differences be due to the system’s variable adaptive properties, which are known to differ with baseline? Extracellular data were compared with BOLD signal (11.7T) during forepaw stimulation under domitor and α-chloralose anesthesia in rats. BOLD-IRFs were nearly identical in the early phase but different in the late phase. Domitor, where responses are more adapted, featured a long time-constant undershoot. These results suggest that the late phase could potentially represent differences in adaptive properties across baseline states.

11:54                       185.         ATP Production by Oxidative Metabolism and Blood Flow Augmentation by Non-Oxidative Glycolysis in Activated Human Visual Cortex

Ai-Ling Lin1, Jia-Hong Gao2, Timothy Q. Duong1, Peter T. Fox1

1Research Imaging Institute, University of Texas Health Science Center at San Antonio, San Antonio, TX, United States; 2Brain Research Imaging Center, University of Chicago, Chicago, IL, United States

The purpose of the study was to investigate the contributions of oxidative verses non-oxidative metabolism to (1) ATP (energy) production (JATP); and (2) cerebral blood flow (CBF) augmentation, during neuronal activation. Cerebral oxygen metabolic rate, blood flow and lactate concentration were determined using concurrent fMRI and 1H MRS with visual stimulations at different flickering frequencies. Our results provide additional supportive evidences that (1)the energy demand for brain activations is small and is met through oxidative metabolism; and (2) CBF can be regulated by non-oxidative glycolysis, rather than by oxygen demand.

 

12:06         185.5W Modeling the Effect of Changes in Hematocrit, O2 Extraction Fraction, and Blood Volume Distribution on the BOLD Signaland Estimates of CMRO2 Change with a Calibrated BOLD Method
V. Griffeth1,2, and R. Buxton3

1Department of Bioengineering, University of California, San Diego, La Jolla, California, United States, 2Medical Scientist Training Program, University of California,San Diego, La Jolla, California, United States, 3Department of Radiology, University of California, San Diego, La Jolla, California, United States

 

We applied a calibrated-BOLD methodology to assess effects of caffeine consumption on coupling of CBF and cerebral metabolic rate of O2 (CMRO2responses to a visual stimulus. We found a large increase in &#916;CMRO2 after administration of caffeine, both as a fraction of the current baseline state and in a more absolute sense referred to the pre-caffeine baseline. More modest changes were found in the CBF response. The decrease of the CBF/CMRO2 coupling ratio n offsets the effects of the reduced baseline CBF due to caffeine and the larger fractional change of CBF with stimulation leaving the BOLD response unchanged.

12:18                       186.         Negative Cerebral Blood Flow and BOLD Responses to Somatosensory Stimulation in Spontaneously Hypertensive Rats

Renata Ferranti Leoni1,2, Draulio Barros de Araujo2, Afonso Costa Silva3

1Cerebral Microcirculation Unit , National Institute of Neurological Diseases and Stroke - NINDS/NIH, Bethesda, MD, United States; 2Department of Physics and Mathematics, University of Sao Paulo, Ribeirao Preto, Sao Paulo, Brazil; 3Cerebral Microcirculation Unit, National Institute of Neurological Diseases and Stroke - NINDS/NIH, Bethesda, MD, United States

The presence of sustained negative fMRI response to focal brain stimulation can be explained either by decreased local neuronal activity (neuronal surround inhibition) or by decreased cerebrovascular reserve (vascular steal effect). Here we measured the CBF and BOLD responses to somatosensory stimulation in spontaneously hypertensive rats (SHR) and normotensive controls, to test the origin of negative fMRI responses. 20/30 SHR, but only 3/25 normotensive rats, presented robust negative CBF and BOLD responses. We conclude that the negative fMRI responses were largely related to a vascular steal effect and not due to neuronal surround inhibition.

Diffusion: Pulse Sequences

Victoria Hall  10:30-12:30                Moderators: Roland Bammer and Jenifer A. McNab

10:30                       Debate:  Journeys into Space:  k or q

 

Delving Deeper into q (Space)
Derek K. Jones

 

Reaching into Outer (k) Space
Michael Moseley

 

10:42                       187.         Improving SNR Per Unit Time in Diffusion Imaging Using a Blipped-CAIPIRINHA Simultaneous Multi-Slice EPI Acquisition

Kawin Setsompop1,2, J Cohen-Adad1,2, J A. McNab1,2, B A. Gagoski3, V J. Wedeen1,2, L L. Wald1,2

1Radiology, A. A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States; 2Harvard Medical School, Boston, MA, United States; 3EECS, Massachusetts Institute of Technology, Cambridge, MA, United States

The acquisition of simultaneous slices using EPI has the potential to increase the number of diffusion directions obtained per unit time, thus allowing more diffusion encoding in HARDI and DSI acquisitions in a clinically relevant scan time. In this work, we apply simultaneous multi-slice method using a novel blipped-CAIPIRINHA technique to lower the g-factor penalty of parallel imaging. We validate the method using g-factor maps and bedpostx with HARDI acquisitions in the brain. We show that with this technique a 10 minutes, 64-direction HARDI acquisition can be acquired in ~3 minutes at no appreciable loss in SNR or diffusion information.

10:54                       188.         Diffusion Weighted Image Domain Propeller EPI (DW IProp EPI)

Stefan Skare1,2, Samantha J. Holdsworth1, Roland Bammer1

1Radiology, Stanford University, Stanford, CA, United States; 2MR-Center, Clinical Neuroscience, Karolinska Institute, Stockholm, Sweden

A new pulse sequence for diffusion imaging is presented, called image domain Propeller EPI (iProp-EPI). Here, propeller blades are acquired in the image domain ,distinct from other propeller-driven pulse sequences, such as PROPELLER and SAP-EPI, where blades are defined in k-space. iProp-EPI has significantly reduced distortions compared with EPI; is immune to spatially-varying non-linear phase changes; can correct for motion; and may be useful for multi-channel coils since the overlap between the blades results in a higher SNR in the image center where its most needed

11:06                       189.         Hadamard Slice-Encoding for Reduced-FOV Single-Shot Diffusion-Weighted EPI

Emine Ulku Saritas1, Daeho Lee1, Ajit Shankaranarayanan2, Dwight G. Nishimura1

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

High in-plane resolution and the ability to acquire a large number of slices are essential for diffusion-weighted imaging (DWI) of small structures, such as the spinal cord. Recently, a reduced-FOV method that uses 2D echo-planar RF excitation pulses to achieve high in-plane resolution was proposed. In this work, we present a Hadamard slice-encoding scheme to double the number of slices without any SNR or time penalty, with significant improvements to increase the SNR efficiency and reduce the inter-slice crosstalk. We validate our results with in vivo high-resolution axial DWI of the spinal cord.

11:18                       190.         Concurrent Higher-Order Field Monitoring Eliminates Thermal Drifts in Parallel DWI

Bertram Jakob Wilm1, Christoph Barmet1, Carolin Reischauer1, Klaas Paul Pruessmann1

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

Concurrent higher-order field monitoring is introduced to diffusion weighted imaging, which was enabled by using 19F NMR for a 3rd order dynamic field camera. Concurrent field monitoring captures the full field dynamics during each diffusion weighted acquisition simultaneously with the imaging coils’ data. Integrating this field information into image reconstruction eliminates the effects of thermal drifts along with those induced by eddy currents and other gradient imperfections. To benefit from a shortened TE and reduced susceptibility artifacts, higher-order reconstruction was extended to encompass parallel imaging by incorporating coil sensitivities in the encoding matrix.

11:30                       191.         Novel Strategy for Accelerated Diffusion Imaging

Stephan E. Maier1, Bruno Madore2

1Radiology Department, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States; 2Radiology Department, Brigham and Women's Hospital, Harvard Medical School , Boston, MA, United States

A method is presented here to exploit inherent redundancies in multi-b multi-direction datasets, for accelerated diffusion imaging. The approach is clearly not meant as an alternative to established acceleration methods such as parallel imaging and partial-Fourier imaging, but rather as a complement to these methods for additional imaging speed. We show how Fourier analysis along the b-factor and encoding direction parameter axes provides new insights into more efficient sampling of diffusion data with virtually no loss of information.

11:42                       192.         Comparison Between Readout-Segmented (RS)-EPI and an Improved Distortion Correction Method for Short-Axis Propeller (SAP)-EPI

Stefan Skare1, Samantha J. Holdsworth1, Kristen Yeom1, Patrick David Barnes1, Roland Bammer1

1Radiology, Stanford University, Palo Alto, CA, United States

Short-Axis readout Propeller EPI (SAP-EPI) and Readout-Segmented EPI (RS-EPI) have been proposed for use in high resolution diffusion-weighted (DW) imaging. SAP-EPI and RS-EPI share common characteristics, in that k-space is traversed by several EPI ‘segments’ in order to reduce the distortion and blurring that typically hampers EPI images. Previous work comparing RS-EPI and SAP-EPI concluded that SAP-EPI suffers from more blurring compared with RS-EPI despite attempts to correct for distortion. With an improved distortion correction method, we demonstrate that SAP-EPI results in similar image resolution to RS-EPI for a given SNR normalized for scan time/slice.

11:54                       193.         First Experimental Observation of Both Microscopic Anisotropy (UA) and Compartment Shape Anisotropy (CSA) in Randomly Oriented Biological Cells Using Double-PFG NMR

Noam Shemesh1, Evren Özarslan2, Peter J. Basser2, Yoram Cohen1

1School of Chemistry, Tel Aviv University, Tel Aviv, Israel; 2Section on Tissue Biophysics and Biomimetics, NICHD, National Institutes of Health, Bethesda, MD, United States

Randomly oriented compartments pose an inherent limitation for single-pulsed-field-gradient (s-PFG) methodologies such as DTI and q-space, and microstructural information (such as compartment shape and size) is lost. In this study, we demonstrate that the double-PFG (d-PFG) methodology can overcome the inherent limitations of s-PFG and extract accurate compartmental dimensions in fixed yeast. The size extracted from the fit is in excellent agreement with the size obtained from light microscopy. Moreover, we show that using different mixing times, the d-PFG experiment differentiates between spherical yeast and eccentric cyanobacteria. Our findings may be important in characterizing grey matter and other CNS tissues.

12:06                       194.         In Vivo Pore Size Estimation in White Matter with Double Wave Vector Diffusion Weighting

Martin A. Koch1, Jürgen Finsterbusch1

1Systems Neuroscience, University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Diffusion weighting with two gradient pulse pairs of independent direction (double wave vector diffusion weighting) can provide tissue structure information which is not easily accessible otherwise, such as cell size or shape. For free diffusion, it is irrelevant whether the diffusion gradients in the two weightings are parallel or antiparallel with respect to each other. In restricted diffusion, differences between these situations occur at short mixing times. Here, a DWV sequence with short mixing time is used to estimate the pore size in the human corticospinal tracts in vivo, and analytical expressions for cylindrical pores are used for data analysis.

12:18                       195.         Optimal Diffusion-Gradient Waveforms for Measuring Axon Diameter

Ivana Drobnjak1, Bernard Siow2, Daniel C. Alexander1

1Center for Medical Image Computing, Department of Computer Science, University College London, London, United Kingdom; 2Center for Advanced Biomedical Imaging, University College London, London, United Kingdom

Measuring microstructure parameters of brain tissue in vivo is a challenge in diffusion MRI. Non-standard diffusion-gradient pulses may provide more sensitivity to microstructure features. Here, we optimize the shape of the diffusion-gradient waveform, constrained only by hardware limits and fixed orientation, to give the best estimate of axon radius based on a simple model of the diffusion within white matter. Our results suggest that square-wave oscillating gradients maximize sensitivity to pore size over the set of PGSE sequences. They also show that the frequency of the waves increases as the radius size decreases.

Pulmonary MRI:  More Than Just A Lot of Hot Air

Room A4        10:30-12:30                Moderators: Talissa Altes and Yannick Crémillieux

10:30                       196.         Hyperpolarized 129Xe MR Imaging of Alveolar-Capillary Gas Transfer in Human Volunteers

Zackary I. Cleveland1,2, Gary P. Cofer1,2, Gregory Metz3, Denise Beaver3, John Nouls1,2, Sivaram Kaushik1,2, Monica Kraft3, Jan Wolber4, Kevin T. Kelly5, H Page McAdams2, Bastiaan Driehuys1,2

1Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States; 2Radiology, Duke University Medical Center, Durham, NC, United States; 3Pulmonary and Critical Care Medicine, Duke University Medical Center, Durham, NC, United States; 4GE Healthcare, Amersham, United Kingdom; 5Radiation Oncology, Duke University Medical Center, Durham, NC, United States

We demonstrate single breath-hold, 3D MRI of hyperpolarized 129Xe dissolved in the pulmonary tissues of humans. Dissolved 129Xe produces acceptable image quality because magnetization is efficiently replenished by diffusion from the airspaces. While ventilation images (3.0´3.0&´15 mm3 resolution) of healthy volunteers were generally homogeneous, dissolved 129Xe images (12.5´12.5´15 mm3) displayed higher signal intensities in the gravitationally dependent portions slices. Dissolved 129Xe images of COPD patients were also heterogeneous but displayed different, less directional, patterns. These results suggest that dissolved 129Xe MRI is sensitive to the gravity-dependent distribution of pulmonary perfusion and possibly disease related redistributions of pulmonary capillary blood volume.

10:42                       197.         Simultaneous Imaging of Ventilation Distribution and Gas Exchange in the Human Lung Using Hyperpolarized Xe129 MRI

John P. Mugler, III1, Talissa A. Altes1, Iulian C. Ruset2,3, Isabel M. Dregely2, Jaime F. Mata1, G Wilson Miller1, Stephen Ketel3, Jeffrey Ketel3, F William Hersman2,3, Kai Ruppert1

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

This work demonstrates the feasibility of using MRI of hyperpolarized Xe129 to acquire images in a single, short breath-hold period that simultaneously depict ventilation distribution and gas exchange in the human lung with matched spatial resolution.  The method presents new opportunities for quantifying relationships among gas delivery, exchange and transport, and shows significant potential to provide new insights into lung disease.

10:54                       198.         Mapping of 3He Apparent Diffusion Coefficient Anisotropy at Sub-Millisecond Diffusion Times in Sham-Instilled and Elastase-Instilled Rat Lungs

Xiaojun Xu1,2, Juan Parra-Robles3, Alexei Ouriadov1, Giles E. Santyr1,4

1Imaging Laboratories, Robarts Research Institute, London, Ontario, Canada; 2Department of Physics, University of Western Ontario, London, Ontario, Canada; 3University of Sheffield, Sheffield, United Kingdom; 4Department of Medical Biophysics, University of Western Ontario, London, Ontario, Canada

3He diffusion in the lungs is restricted by airway and alveoli walls and therefore is highly dependent on lung microstructure. 3He ADC has been shown to be sensitive to changes in terminal airway anatomy, specifically alveolar damage due to emphysema in both humans and animal models.  At the terminal airway, 3He diffusion has been demonstrated to be anisotropic, described by longitudinal diffusion coefficient (DL) and transverse diffusion coefficient (DT). The purpose of this work was to measure and compare DL and DT maps in sham-instilled and elastase-instilled Wistar rats at two sub-millisecond (360 μs and 800 μs ).

11:06                       199.         Evaluation of Emphysema Progression in Chronic Obstructive Pulmonary Disease (Copd); 3He 3D Adc Measurements Compared with Ct and Lung Function Test, Preliminary Results.

Frederik Hengstenberg1,2, Torsten Dorniok1, Sergei Karpuk3, Jørgen Vestbo2, Rahim Rizi4, Per Åkeson1, Peter Magnusson1, Lise Vejby Søgaard1

1Danish Research Centre for Magnetic Resonance, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark; 2Department of Cardiology and Respiratory Medicine, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark; 3Institute of Physics, University of Mainz, Mainz, Germany; 4Department of Radiology, University of Pennsylvania, PA, United States

There is a need for developing a more sensitive biomarker for monitoring progression of pulmonary emphysema in COPD.  In this study with 20 COPD patients and 5 healthy control subjects the use of the 3He apparent diffusion coefficient (ADC) in assessing progression was investigated in a one year longitudinal study comparing ADC measurements, CT densitometry and lung function tests. In a subgroup of emphysema patients a significant increase of ADC was detected, reflecting disease progression. 

 

11:18                       200.         Functional Lung Imaging of Childhood Asthma Using Radial MRI with Hyperpolarized Noble Gas

Sean Fain1, Rafael O'Halloran2, Eric Peterson3, James Holmes4

1Medical Physics, University of Wisconsin - Madison, Madison, WI, United States; 2Radiology, Stanford University, Stanford, CA, United States; 3Biomedical Engineering, University of Wisconsin - Madison, Madison, WI, United States; 4Applied Science Lab, GE Healthcare, Madison, WI, United States

Assessment of lung function in pediatrics poses significant challenges due to variable ability to cooperate with respiratory maneuvers.  Radial dynamic 3D imaging using multi-echo VIPR (ME-VIPR) acquisition with HP He-3 and I-HYPR reconstruction is used in a protocol designed to minimize breath-hold time for whole lung coverage with good isotropic resolution, and sufficient temporal resolution to adapt to the subject's ability to perform respiratory maneuvers. Diffusion-weighted MRI with HP He-3 MRI also provides a means to assess microstructure of the lung parenchyma without ionizing radiation. Preliminary results in 40 pediatric subjects at-risk for asthma are presented.

11:30                       201.         Simultaneous Acquisition of 3He Ventilation Images, ADC, T2* and B1 Maps in a Single Scan with Compressed Sensing

Salma Ajraoui1, Juan Parra-Robles1, Helen Marshall1, Martin H. Deppe1, Steve R. Parnell1, Jim M. Wild1

1University of Sheffield, Sheffield, United Kingdom

A novel interleaved sequence is presented in this work that allows acquisition of 3He ventilation, ADC, T2* and B1 maps simultaneously in-vivo. B1 maps were used to corrected the ventilation image for the artifacts due to the B1 inhomogeneities, while Compressed Sensing scheme was used to accelerate the temporal resolution. The sequence was tested in three healthy volunteers and the values of parameters obtained are in accordance with previously published results.

11:42                       202.         Measurement of Gas Flow and Oxygenation in Small Animal Lungs Using Hyperpolarized Gas

Stephen J. Kadlecek1, Puttisarn Mongkolwisetwara1, Kiarash Emami1, Masaru Ishii2, Jianliang Zhu3, Elaine Chia1, John M. Woodburn1, Rahim R. Rizi1

1Department of Radiology, University of Pennsylvania, Philadelphia, PA, United States; 2Department of Otolaryngology, Johns Hopkins University, Baltimore, MD, United States; 3Department of Surgery, University of Pennsylvania, Philadelphia, PA, United States

Measurement of pulmonary oxygen concentration in small animals using hyperpolarized gas is shown to be complicated by gas redistribution during the short breath-hold.  This additional complexity can be incorporated into a model which yields information about airway obstruction and is potentially itself of diagnostic value.

11:54                       203.         Lung MR Imaging with Ultra-Short TE at 3.0T System: Capability for Pulmonary Functional Loss Due to COPD

Yoshiharu Ohno1, Hisanobu Koyama1, Keiko Matsumoto1, Yumiko Onishi1, Daisuke Takenaka1, Munebu Nogami1, Nobukazu Aoyama2, Hideaki Kawamitsu2, Makoto Obara3, Marc van Cauteren3, Masaya Takahashi4, Kazuro Sugimura1

1Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan; 2Radiology, Kobe University Hospital, Kobe, Hyogo, Japan; 3Philips Healthcare, Tokyo, Japan; 4Radiology, The University of Texas Southwestern Medical Center, Dallas, TX, United States

Regional T2* measurement can be easier performed by using 3.0 T system than 1.5 T system in routine clinical practice.  We hypothesized that direct T2* measurement in the lung has potential to play a new method for pulmonary functional loss assessment at 3.0 T system.  The purpose of this study was to determine the capability of Lung MR imaging with ultra-short TE (uTE MRI) at 3T MR system for measurement of regional T2* in the lung and pulmonary functional assessment in normal and COPD subjects.

12:06                       204.         Lung Imaging in the Mouse with SWIFT

Curtis Andrew Corum1,2, Djaudat Idiyatullin1, Steen Moeller1, Ryan Chamberlain1, Deepali Sachdev2,3, Michael Garwood1,2

1Center for Magnetic Resonance Research, Dept. of Radiology, Medical School, University of Minnesota, Minneapolis, MN, United States; 2Masonic Cancer Center, Medical School, University of Minnesota, Minneapolis, MN, United States; 3Department of Medicine, Medical School, University of Minnesota, Minneapolis, MN, United States

Lung and especially lung parenchyma are especially difficult to image with MRI.  T2* times are in the sub-millisecond range and may require specialized hardware and methods to for optimum visualization or quantitative information.  Many lung pathologies such as inflamation (asthma), primary and metastatic neoplasms (cancer) would benefit from more robust and higher SNR methodologies.  SWIFT is a recently developed 3D radial imaging sequence, sensitive to ultra-short T2 and T2* signals.  We demonstrate for the first time, free breathing prospectively gated 1H SWIFT images of the mouse lung.  Lung parenchyma has significant signal and information content while bronchi appear dark.

 

12:18                       205.         Dynamic Oxygen-Enhanced MRI in Patients with Pulmonary Arterial Hypertension

Olaf Dietrich1, Daniel Maxien, Sven Thieme, Maximilian F. Reiser1, Konstantin Nikolaou

1Josef Lissner Laboratory for Biomedical Imaging, Department of Clinical Radiology, LMU Ludwig Maximilian University of Munich, Munich, Germany

Dynamic oxygen-enhanced MRI (O2-MRI) of the lung was applied in 11 healthy volunteers and in 20 patients with pulmonary arterial hypertension (PAH). Data was evaluated pixelwise by fitting a piecewise exponential model function with 4 parameters (relative enhancement, signal delay, wash-in/out times) to the signal time course. The individual parameter distributions were compared between volunteers and patients. The median values of the determined parameters were similar in both groups, but the ranges (16th to 84th percentile) of relative signal enhancement, signal delay and wash-out time constant were significantly increased in PAH patients.

Cell Tracking

Room A5        10:30-12:30                Moderators: Paula J. Foster and Erik M. Shapiro

10:30                       206.         A Multimodality Investigation of the Dynamics, Trafficking and Properties of Iron Oxide Core High-Density Lipoprotein in Experimental Atherosclerosis

Torjus Skajaa1,2, David Peter Cormode1, Peter Jarzyna1, Courtney Blachford3, Amanda Delshad1, Edward A. Fisher3, Ronald E. Gordon4, Zahi A. Fayad1, Willem J.M Mulder1

1Translational and Molecular Imaging Institute, Mount Sinai School of Medicine, New York, NY, United States; 2Dept. of Cardiology, Clinical Institute, Aarhus University Hospital (Skejby), Aarhus, Denmark; 3School of Medicine, New York University, New York, NY, United States; 4Department of Pathology, Mount Sinai School of Medicine, New York, NY, United States

FeO-HDL is a lipoprotein derived nanoparticle platform detectable by MRI, optical imaging and TEM. In the current study FeO-HDL was synthesized, applied to various cell lines in vitro and to apoE-KO and wild type mice in vivo. Characterization of FeO-HDL revealed close resemblance to native HDL. In vitro experiments confirmed the aforementioned and showed excellent biocompatibility. Upon intravenous administration in vivo MRI experiments on apoE-KO mice revealed their uptake in the lesioned vessel wall, which was confirmed histologically. Lipid exchange measurements showed lipid transfer from FeO-HDL to native lipoproteins. Conclusively we have shown that FeO-HDl closely resembles native HDL.

10:42                       207.         The Effects of Iron Oxide Labelling on the in Vitro Chondrogenic Potential of Three Human Cell Types

Sushmita Saha1, Steven Frederick Tanner2, Jennifer Kirkham1, David Wood1, Stephen Curran3, Xuebin B. Yang1

1Department of Oral Biology, University of Leeds, Leeds, W-Yorkshire, United Kingdom; 2Division of Medical Physics, University of Leeds, Leeds, W-Yorkshire, United Kingdom; 3Smith and Nephew Research Centre, York, United Kingdom

MRI has been used to monitor the distribution of labelled cells in studies related to cell therapy in regenerative medicine.  There has been debate on the effects of the Super-Paramagnetic Iron Oxide (SPIO) label on cellular differentiation along the chondrogenic lineage. Whilst previous studies have employed tissue staining to infer cartilage formation; here we use the quantitative reverse transcription polymerase chain reaction technique to assess the effects of the SPIO label on chondrogenic gene expression. The study has shown that inhibition of gene expression resulting from SPIO labelling is dependent on the target cell used.

10:54                       208.         Non-Invasive Monitoring of Human Dendritic Cell Migration in the CB17 Scid Mouse by Cellular MRI

Gregory A. Dekaban1, Xizhong Zhang2, Vasiliki Economopoulos3, Jennifer Noad3, Roja Rohani3, Adele Wang4, Megan Levings4, Ronan Foley5, Paula Foster3

1BioTherapeutics Research Laboratory, Robarts Research Institute, London , Ontario, Canada; 2BioTherapeutics Research Laboratory, Robarts Research Institute, London, Ontario, Canada; 3Imaging Research Laboratories, Robarts Research Institute; 4Department of Surgery, University of British Columbia; 5Department of Pathology and Molecular Medicine, McMaster University

The successful migration of adequate numbers of in vitro-generated human dendritic cells (DC) from the site of injection to a draining lymph node is a necessary and crucial step in order for a DC-based vaccine to be a successful immunotherapy for cancer and infectious disease.  Currently, less than 5% of injected DC migrate to a draining lymph node. How well a preparation of DC migrates is best assessed by conducting migration assays in vivo.  Here we demonstrated that migration of human DC labeled with superparamagnetic iron oxide nanoparticles can be tracked to  lymph nodes of CB17 scid mice.

11:06                       209.         Comparison of Rate of Islet Loss in Syngeneic, Allogeneic and Xenogeneic Grafts in Rat Using Quantification of Iron Oxide Labeled Islet Cells by 3D Radial UTE MRI.

Lindsey Alexandra Crowe1, Frederic Ris2, Sonia Nielles-Vallespin3, Peter Speier3, Michel Kocher4, Solange Masson2, Christian Toso2, Domenico Bosco2, Thierry Berney2, Jean-Paul Vallée1

1Department of Radiology, Geneva University Hospital, University of Geneva, Faculty of Medicine, Geneva, Switzerland; 2Cell Isolation and Transplant Center, Department of Surgery, Geneva University Hospital, Geneva, Switzerland; 3Siemens AG Medical Solutions, Erlangen, Germany; 4Biomedical Imaging Group, School of Engineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Vaud, Switzerland

In-vivo 3D difference ultra-short echo time (dUTE) imaging gives quantitative positive contrast images for serial examination by automatic segmentation of iron oxide labeled islet cell clusters transplanted into the liver. Coverage of the whole liver in the absence of cardiac and respiratory motion artifact, and isotropic resolution is obtained with uniform background suppression. Three types of grafts: syngeneic, allogeneic and xenogeneic, were studied over time in rat, with success of islet graft, effect of magnetofection and rate of islet loss measurably different.  The method shows promise for robust long term tracking of cell rejection in patients.

 

11:18                       210.         Long-Term MR Imaging of Immunocompetent and Immunodeficient Mice Reveals Distinct Differences in Contrast Clearance in the Brain

Stacey Marie Cromer Berman1,2, Assaf A. Gilad1,2, Jeff W. M. Bulte1,2, Piotr Walczak1,2

1Russell H. Morgan Dept. of Radiology and Radiological Science, Division of MR Research, The Johns Hopkins University School of Medicine, Baltimore, MD, United States; 2Cellular Imaging Section, Vascular Biology Program, The Johns Hopkins University School of Medicine, Baltimore, MD, United States

One important obstacle for correct interpretation of long-term MRI cell tracking is the possibility of persisting hypointense signal even after death of transplanted cells. In order to evaluate this challenge, SPIO-labeled neural stem cells were allografted into the brains of immunocompetent Balb/C mice, inducing cell rejection (dead cells) and immunodeficient Rag2 mice, with no cell rejection (live cells). The transplanted cells were monitored in vivo by MRI for 93 days. Unexpectedly, the MR hypointensities cleared more rapidly in non-rejecting Rag2 mice than in rejecting Balb/C mice, indicating that cell proliferation and migration may dominate clearance of MR signal.

11:30                       211.         MRI Tracking of Endogenous Neural Precursors Odor Induced Accumulation in the Mitral Cell Layer of the Rodent Olfactory Bulb

James P. Sumner1, Der-Yow Chen1, Stephen Dodd1, Elizabeth Wayne1,2, Yun Chen1,3, Dragan Maric1, Alan P. Koretsky1

1National Institutes of Health, Bethesda, MD, United States; 2University of Pennsylvania, United States; 3National Institute of Standards and Technology, Boulder, CO, United States

In the adult mammals, neural progenitor cells (NPCs) migrate to the olfactory bulb and differentiate into neurons.  These cells are believed to be involved in processing olfactory signals.  Here we demonstrate that high resolution MRI can be utilized to evaluate the affects of odor enrichment on new neurons in the olfactory bulb with anatomical layer specificity.  We found that amyl acetate enrichment resulted in the accumulation of NPCs in the mitral cell layer.  This in vivo method illustrates the advantages of using high resolution anatomical imaging in combination with cell tracking.

11:42                       212.         Using 19F MR to Monitor Delivery and Engraftment of Therapeutic Stem Cells in Vivo: Accuracy Evaluation

Yibin Xie1, Steven M. Shea2, Yingli Fu3, Wesley D. Gilson2, Tina Ehtiati2, Ronald Ouwerkerk4, Dorota Kedziorek3, Meiyappan Solaiyappan3, Gary Huang3, Steffi Valdeig3, Frank Wacker3, Dara L. Kraitchman3

1Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD, United States; 2Center for Applied Medical Imaging, Siemens Research Corporate, Inc., Baltimore, MD, United States; 3Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States; 4National Institutes of Health, Bethesda, MD, United States

The delivery and engraftment of therapeutic stem cells can be monitored by both 19F MRI and c-arm CT using alginate-poly-L-lysine-alginate microcapsules loaded with perfluorooctylbromide (APA-PFOB). MR tracking is advantageous for high sensitivity and absence of ionizing radiation. However it suffers from lower resolution. This study evaluates accuracy of tracking encapsulated mesenchymal stem cells using 19F MRI relative to c-arm CT. Results show a high identification and agreement in the spatial locations and volumes of the injection sites between MRI and CT demonstrating that MRI provides an accurate alternative to CT for tracking of encapsulated stem cells in vivo.

11:54                       213.         Surprising Results in the Use of MPIOs to Label Bone-Marrow Resident Monocytes for Immune Cell Tracking by MRI

Bradley Hann1,2, Kevin S. Tang3, Kevin M. Bennett2, Erik M. Shapiro, 3,4

1Biological Health System Engineering, Arizona State College, Tempe, AZ, United States; 2School of Biological and Health Systems Engineering, Arizona State University, Tempe, AZ, United States; 3Department of Biomedical Engineering, Yale University, New Haven, CT, United States; 4Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, CT, United States

The accumulation and presence of MPIOs in bone marrow was studied over seven days. High-resolution, serial in-vivo MRI was performed on mice injected with various quantities of MPIOs. MRI signal changes were monitored in bone marrow and muscle to study MPIO trafficking. In vivo labeling efficiency of bone marrow-resident monocytes was then quantified using flow cytometry. Unexpected results were obtained. It was found that MPIOs did not label monocytes in marrow. An alternative explanation for the success of MPIOs in immune cell trafficking is presented, centered around re-entrance of MPIOs into the circulation long after initial clearance from the vasculature.

12:06                       214.         MRI Visualization of Anatomical Connections in Vivo Using a Gadolinium Chelated Neural Tracer

Carolyn W. H. Wu1,2, Ning Liu3, Der-Yow Chen2, Vasalatiy Olga4, Alan P. Koretsky2, Gary L. Griffiths4, Roger B. Tootell3,5, Leslie G. Ungerleider3

1NeuroSpin, CEA de Saclay, Gif sur Yvette, Ile-de-France, France; 2NINDS, NIH, Bethesda, MD, United States; 3NIMH, NIH, Bethesda, MD, United States; 4IPDC/NHLBI, NIH, Rockville, MD, United States; 5MGH, Harvard University, Charlestown, MA, United States

A shortcoming of conventional neuroanaomy approaches to study neuronal circuitry is that it requires visualizing transported tracer in the post-mortem tissue. The goal of the study is to expand the MRI contrast media available for in vivo target-specific, mono-synaptic, neuronal tract tracing, by testing a new compound that conjugates conventional neuro-anatomical tracer CTB with GdDOTA. We show that CTBGdDOTA is a MRI neural tracer that allows in vivo visualization of mono-synaptically connected brain circuits, that is target-specific, bi-directional, very reproducible, and stable over a relatively long period of time. This agent opens the possibility for repetitive, chronic, and longitudinal studies.

12:18                       215.         In Vivo Monitoring of Bacterial Infections Using High-Field MR Microscopy

Volker Sturm1, Tobias Hertlein2, Thomas Basse-Lüsebrink1, Daniel Haddad3, Knut Ohlsen2, Peter Jakob1,3

1Experimental Physics 5, University of Würzburg, Würzburg, Germany; 2Institute for Molecular Infection Biology, University of Würzburg, Würzburg, Germany; 3Research Center for Magnetic Resonance Bavaria e.V., Würzburg, Germany

In vivo monitoring of bacterial infection allows effective testing of potential new drugs and active compounds. Therefore we investigate native (T2) and marker (19F) based MRI methods for those requirements. Here the T2 maps have been proved to be able to visualize the inflammation formation in a mouse muscle abscess model at even early stages (day 2), while the 19F- marker accumulate in the area of infection. The latter has the potential to deliver new insights into the process of host-pathogen interaction, even though the exact mode of accumulation had to be investigated further.

Gradients, Shims & Novel Systems

Room A6        10:30-12:30                Moderators: Labros S. Petropoulos and Michael S. Poole

10:30                       216.         Concurrent Higher-Order Field Monitoring for Routine Head MRI: An Integrated Heteronuclear Setup

Christoph Barmet1, Bertram Jakob Wilm1, Matteo Pavan1, Georgios Katsikatsos1, Jochen Keupp2, Giel Mens3, Klaas Paul Pruessmann1

1Institute for Biomedical Engineering, ETH and University, Zurich, Switzerland; 2Philips Research Europe, Hamburg, Germany; 3Philips Healthcare, Best, Netherlands

A higher-order concurrent field monitoring setup is introduced for routine head MRI. It enables the tracking of dynamic field evolution up to 3rd order concurrently with data acquisition. This is particularly important for non-reproducible field contributions, e.g. due to magnet heating, breathing or external fields. The field information allows for the correction of image artifacts at the reconstruction stage.

A heteronuclear approach – monitoring is performed on the 19F nucleus – guarantees perfect separation of monitoring and imaging experiment. As a result, scan protocols and procedures can remain unchanged, which greatly simplifies translation into clinical practice.

10:42                       217.         Coherent Excitation Scheme to Operate Pulsed NMR Probes for Real-Time Magnetic Field Monitoring

Pekka Sipilä1,2, Gerhard Wachutka2, Florian Wiesinger1

1GE Global Research, Munich, Bavaria, Germany; 2Institute for Physics of Electrotechnology, Munich University of Technology, Munich, Bavaria, Germany

Description of an apparatus for improving image quality during MRI-scan by measuring the magnetic fields with pulsed NMR probes. Closely interleaved excitation pulses, of which phase is in coherence with the precessing spins, offer high SNR also during short TR and high-resolution imaging. This offers more general functionality with respect to MR imaging parameters, and has not been achievable with previous magnetic field monitoring NMR probe designs. The applicability of the developed feedback based coherent excitation scheme to operate NMR probes for monitoring k-space trajectories is shown with a spiral acquisition scheme.

10:54                       218.         Fast MPI Demonstrator with Enlarged Field of View

Bernhard Gleich1, Jürgen Weizenecker2, Holger Timminger1, Claas Bontus1, Ingo Schmale1, Jürgen Rahmer1, Joachim Schmidt1, Jürgen Kanzenbach1, Jörn Borgert1

1Philips Technologie GmbH, Forschungslaboratorien, Hamburg, Germany; 2Fakultät für Elektro- und Informationstechnik, University of Applied Sciences, Karlsruhe, Germany

Magnetic particle imaging (MPI) is a new tomographic imaging modality that directly and quantitatively images iron oxide nanoparticle concentration without anatomical background signal. It combines high sensitivity with the ability of fast volumetric imaging. Current demonstrators either provide fast imaging or a large field of view. Here, a solution is proposed, that allows for both, fast imaging with large FOVs.

11:06                       219.         Development of a Simultaneous PET-MRI Breast Imaging System

Bosky Ravindranath1, Sachin S. Junnarkar2, David Bennett3, Xiaole Hong3, Ken Cheng3, Sean Stoll2, Martin L. Purschke2, Sri Harsha Maramraju1, Dardo Tomasi2, Sudeepti Southekal1, Paul Vaska2, Craig Woody2, David J. Schlyer2

1Biomedical Engineering, Stony Brook University, Brookhaven, NY, United States; 2Brookhaven National Laboratory, Upton, NY, United States; 3Aurora Imaging Technology Inc., North Andover, MA, United States

At Brookhaven National Laboratory, we are developing a MRI compatible dedicated breast PET scanner that will enable simultaneous PET-MRI imaging of the breast. We have developed and tested a prototype version of the PET system that has an average resolution less than 2 mm FWHM. Good quality MRI images were obtained with the PET system operating unshielded inside the field of view of a 1.5 T dedicated breast MRI. Our next goal is to acquire simultaneous PET-MRI images using the prototype PET and dedicated breast MRI system.

11:18                       220.         In Vivo Simultaneous MR/PET Images of the Rat Brain and Mouse Heart at 9.4 Tesla

Sri-Harsha Maramraju1,2, S.-David Smith2, Martin Purschke2, Sean Stoll2, Bosky Ravindranath1, Sergio Rescia2, Sachin Junnarkar2, Sudeepti Southekal1, Paul Vaska2, Craig Woody2, David Schlyer2

1Biomedical engineering, Stony Brook University, Stony Brook, NY, United States; 2Brookhaven National Laboratory, Upton, NY, United States

We have developed a MRI compatible PET tomograph for use inside a 9.4 T microMRI scanner. This synergistic integration resulted in simultaneous acquisition of MR and PET imaging of rodents with minimal mutual interference between the two systems. New MRI coils have been built that fit inside the PET detector and obtain high quality MR images. Simultaneous MR and PET images of a rat striata phantom, rat brain and gated mouse cardiac images have been acquired, providing the flexibility to perform both rat brain and mouse cardiac studies using the same PET detector inside MRI.

 

11:30                       221.         A Single-Axis Composite Shim Coil Insert for Spectroscopy in the Medial Temporal Lobe of the Human Brain

Parisa Hudson1, Chad T. Harris1, William B. Handler1, Timothy J. Scholl1, Blaine A. Chronik1

1Department of Physics and Astronomy, The University of Western Ontario, London, Ontario, Canada

High field magnetic resonance imaging (MRI) and spectroscopy (MRS) of the human brain suffer from large field inhomogeniety, caused by the presence of air inside the brain, due to the susceptibility differences between air and tissue. To correct for the large inhomogeneities that are consistent between subjects, we present a new approach that utilizes very efficient, short, single-axis composite shim coils used together with existing system shims.  These coils require less power, occupy less space, and perform better than a set of general purpose, high order shims.

11:42                       222.         Zero- To Third-Order Dynamic Shim Updating  of the Human Brain at 7 Tesla

Christoph Juchem1, Terrence W. Nixon1, Piotr Diduch2, Scott McIntyre1, Douglas L. Rothman1, Piotr Starewicz2, Robin A. de Graaf1

1MR Research Center, Yale University, New Haven, CT, United States; 2Resonance Research Inc., Billerica, MA, United States

The first realization of full zero- to third-order DSU with full preemphasis and B0 compensation is presented which allowed high quality shimming of the human brain at 7 Tesla. The achievable magnetic field homogeneity could be largely improved not only in comparison to global (i.e. static) zero- to third-order shimming, but also when compared to state-of-the-art zero- to second-order DSU.

11:54                       223.         Motor Design for an MR-Compatible Rotating Anode X-Ray Tube

Prasheel Lillaney1, Robert Bennett1, Rebecca Fahrig1

1Radiology, Stanford Univeristy, Stanford, CA, United States

This work discusses the development of an alternate motor design for rotating anode x-ray tubes to be used in hybrid x-ray/MR image guidance systems.  The novel aspect of our design is that we propose to use the MR fringe field to generate torque in our motor.  A proof of concept of our design has been assembled and can rotate at a maximum speed slightly above 450 RPM in a 45 mT external field.  With further research and optimization of parameters we are confident that we can meet the design constraints for typical x-ray tube motors.

12:06                       224.         Portable MRI Magnets and Spinning Micro-Detectors

Dimitrios Sakellariou1, Cédric Hugon1, Alan Wong1, Pedro Aguiar1, Guy Aubert2, Jacques-François Jacquinot3

1DSM/IRAMIS/LSDRM/SIS2M, CEA - Saclay, Gif-sur-Yvette, Essone, France; 2DSM / IRFU / Neurospin, CEA - Saclay; 3DSM / IRAMIS / SPEC, CEA - Saclay

The message of my presentation is that permanent magnet engineering together with ideas from solid-state NMR can give place to innovation in medical Magnetic Resonance. We demonstrate a new strategy to develop portable MRI magnets and show the first example of a high uniformity one-sided system. We also use spinning micro-detectors as a means to achieve high resolution microscopy by magic angle sample spinning in the stray field of a magnet. Ideas on magic angle field spinning will be the common denominator for these projects. Ideas and preliminary instrumentation will be presented.

12:18                       225.         Active Localized Shielding for Devices Within MRI Gradient Coils

Chad Harris1, William Handler1, Blaine Alexander Chronik1

1Physics and Astronomy, University of Western Ontario, London, Ontario, Canada

There are an increasing number of applications in which non-MRI active or passive devices are being introduced into the MRI system and required to operate normally while exposed to the static, RF, and audio-frequency (i.e. gradient) magnetic fields produced during normal scanning. In this study, we focus on gradient fields and consider the possibility of designing a very localized, active shield to cancel the time-varying magnetic fields for an arbitrary device located within the inside diameter of the gradient system.

Contrast Mechanisms in Quantitative Cartilage MRI

Room A7        10:30-12:30                Moderators: Matthew F. Koff and Mikka Niemenen

10:30                       226.         Imaging of the Zone of Calcified Cartilage (ZCC) Using 3D Ultrashort TE Pulse Sequences

Jiang Du1, Won C. Bae1, Sheronda Statum1, Renie Biswas1, Michael Carl2, Atsushi Takahashi2, Christine B. Chung1, Graeme M. Bydder1

1Radiology, University of California, San Diego, CA, United States; 2Global Applied Science Laboratory, GE Healthcare Technologies, Menlo Park, CA, United States

The zone of calcified cartilage (ZCC) is a highly modified mineralized region of articular cartilage that forms an important interface between cartilage and bone. It is a region that may change dramatically in osteoarthritis (OA). However, all current clinical sequences show a signal void for the ZCC because of its short T2 and thin structure. Here we present 3D UTE sequences for ZCC imaging using three contrast mechanisms: dual echo acquisition and echo subtraction, single adiabatic inversion recovery (SIR) and dual inversion recovery (DIR). The feasibility of these techniques was tested on five cadaveric patellae on a clinical 3T scanner.

10:42                       227.         Ultrashort TE Enhanced T2* Mapping of Cartilage:   a Pilot Clinical Study

Ashley Williams1, Yongxian Qian2, Constance R. Chu1

1Cartilage Restoration Laboratory, University of Pittsburgh, Pittsburgh, PA, United States; 2Magnetic Resonance Research Center, University of Pittsburgh, Pittsburgh, PA, United States

This work demonstrates the feasibility of in vivo 3-D UTE-T2* mapping of cartilage and examines the sensitivity of UTE-T2* to early cartilage degeneration compared to arthroscopic grading as the standard. UTE-T2* and standard T2 knee images were acquired on 10 subjects at 3T. Deep zone UTE-T2* values were significantly higher in softened cartilage compared to healthy (arthroscopic grade 1vs0, p<0.01).  Superficial zone UTE-T2* showed a trend for higher values in softened tissue compared to healthy (p=0.17). Standard T2  values showed no differences between healthy and softened cartilage. UTE-T2* mapping captures signal from deep cartilage better than standard T2 .

10:54                       228.         Change in the DTI Parameters of the Articular Cartilage with Progressive Proteoglycan Depletion

José G. Raya1, Gerd Melkus2, Silvia Adam-Neumair3, Olaf Dietrich4, Maximilian F. Reiser, Peter Jakob2, Christian Glaser

1Josef Lissner Laboratory for Biomedial Imaging, , University of Munich, Munich, Germany; 2Deparment of experimental physics V, University of Würzburg, Germany; 3Department of Clinical Radiology, University of Munich, Germany; 4Josef Lissner Laboratory for Biomedial Imaging, Department of Clinical Radiology, University of Munich, Germany

DTI has great potential for the early diagnosis of osteoarthritis since it is sensitive to the proteoglycan (PG) content and the integrity of the collagen network. In this work we investigate the effect of progressive PG depletion on the DTI parameters. DTI and T2 of human bone-on-cartilage samples as well as their PG content were measured before and after proteoglycan depletion. ADC showed a linear (r2=0.86, P<0.007) dependence with the PG loss. The diffusion anisotropy (FA and first eigenvector) remained unchanged. Measurements of the T2 relaxation time demonstrated that the collagen structure of the cartilage was unaffected by PG depletion.

11:06                       229.         Loading and Knee-Alignment Have Significant Influence on Cartilage T2 in Porcine Knee Joints

Toshiyuki Shiomi1, Takashi Nishii1, Hisashi Tanaka2, Youichi Yamazaki3, Kenya Murase3, Akira Myoui1, Hideki Yoshikawa1, Nobuhiko Sugano1

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

We developed a non-metallic pressure device to be used during MRI under variable loading or knee alignment conditions in excised porcine knee joints, and assessed the influence of loading and knee alignment on T2 mapping of the knee femoral cartilage.

11:18                       230.         Quantitative Mri Reveals Early Cartilage Degeneration in Acl-Injured Knees

Xiaojuan Li1, Daniel Kuo, Keerthi Shet, Christoph Stehling, Jonathan Cheng, Thomas Link, Benjamin Ma, Sharmila Majumdar

1Radiology, University of California, San Francisco, San Francisco, CA, United States

Patients with anterior cruciate ligament (ACL) injuries have a high risk of developing post-traumatic osteoarthritis. The goals of this study were: 1) to longitudinally evaluate cartilage matrix changes using T1ρ and T2 quantification; 2) to study the relationship between meniscal damage and cartilage degeneration. 12 patients with acute ACL-injures and 10 healthy controls were studied. Significantly elevated T1rho were observed at 1-year follow up. T1rho were more sensitive than T2 in detecting early changes in cartilage matrix in ACL-injured knees. Lesions in posterior horn of medial meniscus were correlated with accelerated cartilage degeneration in medial femoral condyle.

11:30                       231.         MRI of Bioregenerative Approaches in Cartilage Repair: Differentiation of Repair Tissue After Matrix-Associated Autologous Chondrocyte Transplantation Using a Hyaloronic Acid-Based or a Collagen-Based Scaffold with Advanced Morphological Scoring and Bioch

Goetz Hannes Welsch1,2, Tallal Charles Mamisch3, Lukas Zak4, Matthias Blanke2, Alexander Olk2, Stefan Marlovits4, Siegfried Trattnig1

1MR Center, Department of Radiology, Medical University of Vienna, Vienna, Austria; 2Department of Trauma and Orthpaedic Surgery, University Hospital of Erlangen, Erlangen, Germany; 3Department of Orthopaedic Surgery, University of Basel, Basel, Switzerland; 4Center for Joints and Cartilage, Department of Trauma Surgery, Medical University of Vienna, Vienna, Austria

Aim of the study was to compare cartilage repair tissue at the femoral condyle noninvasively after matrix-associated autologous chondrocyte transplantation (MACT) using Hyalograft® C (HC), a hyaloronic acid-based scaffold, to cartilage repair tissue after MACT using CaReS®, a collagen-based scaffold, with morphological and biochemical MRI. Differences in the surface of the repair tissue using morphological MRI and higher T2 values for the cartilage repair tissue depicted by biochemical T2 maps indicate differences in the composition of the repair tissue that was based on a collagen scaffold (CaReS®), compared to the hyaloronic acid-based scaffold (HC), even two years post-implantation.

11:42                       232.         In Vivo Quantification of Cartilage Regeneration in an Equine Model at 3T Following Gene Therapy

Daniel James Clark1, Guang Jia1, Maria Isabel Menendez2, Seongjin Choi1, Craig James Miller, Steffen Sammet1, David C. Flanigan3, Alicia Louise Bertone2, Michael V. Knopp1

1Radiology, College of Medicine, The Ohio State University, Columbus, OH, United States; 2Veterinary Clinical Sciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, United States; 3Orthopedics, OSU Sports Medicine Center, The Ohio State University, Columbus, OH, United States

Currently, there is no established human sized model for cartilage regeneration.  This study is the first to assess the time course of healing in vivo using quantitative MRI in live ponies with cartilage thicknesses comparable to humans in a 3T clinical scanner. We use several innovative, quantitative methods including delayed contrast-enhanced MRI of cartilage (dGEMRIC), dynamic contrast-enhanced MRI (DCE-MRI), and T2 mapping.  The results of this study strongly suggest that in vivo quantitative MRI can be used to monitor cartilage healing and characterize the physiological state of repaired tissue.

11:54                       233.         High Resolution Cartilage and Whole Organ Knee Joint Assessment: 3D Radial Fat-Suppressed Alternating TR SSFP

Jessica Leigh Klaers1, Ethan K. Brodsky1,2, Walter F. Block1,3, Richard Kijowski2

1Medical Physics, University of Wisconsin - Madison, Madison, WI, United States; 2Radiology, University of Wisconsin - Madison, Madison, WI, United States; 3Biomedical Engineering, University of Wisconsin - Madison, Madison, WI, United States

Effective cartilage imaging and whole organ joint assessment requires both high isotropic resolution and fat suppression or separation.  We present a single pass, 3D radial fat-suppressed Alternating TR (FS ATR) SSFP acquisition which provides ultra-high isotropic resolution of 0.33 mm (voxel volume of 1/27 mm3) throughout the entire knee joint and contrast the method against a two pass, 3D radial Linear Combination SSFP (LC-SSFP) method.  3D radial FS-ATR offers complete visualization of the articular cartilage surface, further enhancing the ability to appreciate submillimeter cartilage defects which is useful for longitudinal research studies of cartilage degeneration and simultaneous whole organ assessment.

12:06                       234.         Diffusivity and Kinetics of Gadopentetate in Articular Cartilage in Vitro
Elli-Noora Salo1, Mikko J. Nissi1,2, Katariina Aino Maria Kulmala1, Juha Töyräs1,3, Miika T. Nieminen4,5

1Department of Physics, University of Kuopio, Kuopio, Finland; 2Department of Clinical Radiology, Kuopio University Hospital, Kuopio, Finland; 3Diagnostic Imaging Centre, Kuopio University Hospital, Kuopio, Finland; 4Department of Medical Technology, University of Oulu, Oulu, Finland; 5Department of Diagnostic Radiology, Oulu University Hospital, Oulu, Finland

In the dGEMRIC method, full equilibrium of gadopentetate is required to quantify the proteoglycan content of articular cartilage. In this study, the diffusivity and kinetics of gadopentetate was studied by limiting equilibration only through the articular surface or deep cartilage. The distribution of gadopentetate in bovine cartilage samples was followed for 18 hours with repeated T1 mapping at 9.4 T. The results showed that full equilibration takes longer than previously assumed. Diffusion was faster through the articular surface. With equilibration through the articular surface, the superficial cartilage reached near-equilibrium relatively quickly, possibly allowing early visualization of superficial degenerative changes.

12:18                       235.         The in Vivo Transport of Anionic Contrast Agent Into Human Femoral Knee Cartilage

Eveliina Lammentausta1, Carl Johan Tiderius2, Leif E. Dahlberg2

1Department of Clinical Sciences, Malmö, Joint and Soft Tissue Unit, University of Lund, Malmö, Sweden; 2Department of Orthopaedics, Malmö University Hospital, Malmö, Sweden

The aim of the study was to investigate the distribution of Gd-DTPA2- into human knee cartilage in vivo at areas of different loading conditions. T1 relaxation time was measured before and regularly after triple does (0.3mM/kg) injection of Gd-DTPA2- for five healthy volunteers. Contrast agent transport was analyzed for three regions in femur and one in tibia, for deep and superficial cartilage separately. Different transport patterns were observed between weight-bearing and non-weight-bearing regions. The transport into deep cartilage was remarkably slower indicating transport only through cartilage surface.

New Angles on B1 Mapping

Room A8        10:30-12:30                Moderators: Ulrich Katscher and Yudong Zhu

10:30                                       Introduction
Hans-Peter Fautz, Ph.D.

10:54                       236.         Fast 2D B1 Mapping by K-Space Processing of Tagging Patterns

Wayne R. Dannels1, Andrew J. Wheaton1

1Toshiba Medical Research Institute, Mayfield Village, OH, United States

Measuring B1 transmit fields in vivo has importance in areas such as high field imaging, parallel transmission design, and quantitative imaging. A new method of acquisition and data analysis is presented for generating 2D B1 maps in vivo in as little as one TR. In this method saturation tag lines are applied before rapid imaging, tag lines are separated from the underlying image with k-space processing, and RF angles are computed from the tagging efficiency ratio.

11:06                       237.         Improved Phase-Based Adiabatic B1 Mapping

Franciszek Hennel1, Sascha Köhler1

1Bruker BioSpin MRI, Ettlingen, Germany

A method for the mapping of the radio-frequency transmission field is proposed that derives B1 values from the phase of the signal. The sequence consists of a block pulse to produce a B1-dependent nutation, followed by an inverse adiabatic half passage (IAFP) that converts the nutation phase to signal phase. Two ways to compensate the undesired dephasing caused by the IAFP are proposed: a rewinder RF pulse, or a matched adiabatic echo. The method provides an increased dynamic range compared to known phase-based B1-mapping sequences.

11:18                       238.         Flip Angle Taxonomy: Measuring Transmit (B1) Profile Distribution Without Imaging.

Roman Fleysher1, Lazar Fleysher1, Joel A. Tang2, Daniel Sodickson1

1Radiology, New York University, School of Medicine, New York, United States; 2Chemistry, New York University, New York, United States

A method of measuring transmit (micro-) coil profile (B1) distribution is presented. In as much as it does not use spatial encoding, it reaches fine resolution in B1 at very high signal-to-noise ratios. The procedure can be used to alleviate systematic errors in spectroscopic data analysis caused by transmit field non-uniformity or can be employed for a quick evaluation of transmit (micro-) coil performance.

11:30                       239.         Permittivity Determination Via Phantom and in Vivo B1 Mapping

Ulrich Katscher1, Philipp Karkowski1, Christian Findeklee1, Tobias Voigt2

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

Tissue permittivity might serve as diagnostic parameter, e.g., for oncology. However, the diagnostic use of the permittivity is significantly hampered by the lack of suitable methods to determine the permittivity in vivo. A possible approach for the determination of permittivity in vivo is given by analyzing the B1 map in the framework of standard MRI, called "Electric Properties Tomography" (EPT). Hitherto, studies were focussed on the ability of EPT to reconstruct the electric conductivity and local SAR. This study demonstrates the ability of EPT to determine the permittivity via numerous phantom and in vivo experiments.

11:42                       240.         Simultaneous 3D B1 and T1 Mapping Using the New Method of Slopes (MoS)

Sofia Chavez1, Greg Stanisz1,2

1Imaging Research, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada; 2Medical Biophysics, University of Toronto, Toronto, Ontario, Canada

A new 3D method for simultaneous B1 and T1 mapping is presented. It relies on the quasi-linear relationship between the measured SPGR signal and nominal flip angle near the origin and near the signal null. The B1 mapping estimation is similar to that already existing in the literature with a more practical implementation requiring flip angles < 180° which are readily available on most scanners. The B1 mapping data with an additional acquisition of  the SPGR signal  at a low flip angle allows for the proposed T1 mapping. MoS yields accurate T1 values (within 10% of  IR esimates)  for an entire brain volume in ~12 min.

11:54                       241.         Comparison Between RF Spoiling Schemes in the Actual Flip-Angle Imaging (AFI) Sequence for Fast B1 Mapping

Vasily L. Yarnykh1

1Department of Radiology, University of Washington, Seattle, WA, United States

The Actual Flip-angle Imaging (AFI) method allows fast B1 mapping based on the spoiled steady-state principle. The combination of diffusion-based gradient and RF spoiling mechanisms was recently shown to considerably improve accuracy of this method. Two RF spoiling techniques were proposed for AFI in the literature: a standard phase incrementing scheme with a constant value of the phase increment and a modified scheme with two intermittently applied phase increments dependent on the ratio n=TR2/TR1. This study compares the spoiling behavior of the AFI sequence and accuracy of B1 measurements between the above RF spoiling schemes.

12:06                       242.         SVD Based Calibration of Transmit Arrays

David Otto Brunner1, Klaas Paul Pruessmann1

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

Using transmit-receive arrays the acquisition of transmit and receive sensitivities are both of crucial importance but there are also great difficulties involved in bootstrapping such a process. In regions of low excitation, the receive sensitivities cannot be estimated correctly, leading to strong noise enhancement in the reconstructed images as well as in the transmit calibration data. This noise then propagates into the calculated transmit profiles hindering transmit calibration. In this work we present an acquisition and reconstruction technique that solves this entangled problem and allows finding concomitantly the signal optimal global RF shims and local receive channel combinations.

12:18                       243.         RF Field Profiling Through Element Design for High Field Volume Coils

Can Akgun1, Lance DelaBarre1, Carl J. Snyder1, Gregor Adriany1, Anand Gopinath2, Kamil Ugurbil1, John Thomas Vaughan1

1University of Minnesota-Center for Magnetic Resonance Research, Minneapolis, MN, United States; 2University of Minnesota-Department of Electrical and Computer Engineering, Minneapolis, MN

Multi-channel volume coils can be comprised of an array of transmission line elements operated as independent coils in multiple-channel transmit and receive configurations. In these designs, microstrip transmission elements have been implemented as magnetic field propagating elements. However, at high fields, RF in-homogeneities and inefficiencies require the optimization of these elements.  In this study, two different microstrip designs with varying impedance lines; one producing peak B1+ in the center and the other extending usable B1+ along the coil are investigated.  Simulation and image results for 8-channel volume coils incorporating these element designs were obtained using a phantom at 7T.




GOLD CORPORATE MEMBER LUNCHTIME SYMPOSIUM
Philips

Victoria Hall              12:30 - 13:30

 

CLINICAL INTENSIVE COURSE
Hot Topics: Emerging & Cross-Cutting Techniques in Pediatric Imaging

Room K1   13:30-15:30    Organizers & Moderators: Patricia Ellen Grant and Claudia M. Hillenbrand

EDUCATIONAL OBJECTIVES

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

  • Identify the main issues related to basic clinical pediatric (neuro-) radiology and translational imaging research in children;
  • Explain the basic steps and concepts associated with (a) cardiovascular MR planning and imaging, and (b) assessment of body organ integrity or disease (i.e., via perfusion and diffusion) in the pediatric population;
  • Evaluate the progress in fetal and neonatal imaging and to explain progress in advanced neuroimaging;
  • Demonstrate additional knowledge of clinically adaptable pediatric imaging strategies; and
  • Transfer and implement optimized pediatric protocols in their clinical or research practice. .

Part I: Emerging Techniques in Advanced Pediatric Neuroimaging

 

13:30       MR Imaging and Post-processing of the Developing Fetal Brain
Marie Schaer, M.D., Ph.D.

 

14:00       Neonatal Imaging - Opportunities and Challenges
Robert C. McKinstry, M.D., Ph.D.

 

14:30       Pediatric Neuroimaging & Spectroscopy: From Screening to Quantitative Follow-Up
Timothy P. Roberts, Ph.D.

 

15:00       fMRI and Assessment of Disease Involvement & Investigation of the Connectivity By Analyzing the Resting State in Pediatric Patients
Robert J. Ogg, Ph.D.

 

CLINICAL INTENSIVE COURSE
MR of Inflammatory Arthropathy

Room K2        13:30-15:30                Organizers: Juerg Holder and Hollis G. Potter

EDUCATIONAL OBJECTIVES

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

  • Recognize clinical findings and cellular mechanisms in inflammatory abnormalities;
  • Describe the most relevant inflammatory abnormalities on MR images; and
  • Optimize imaging protocols based on to clinical needs.

Moderators: Claude Henri Manelfe and Bassem Georgy

 

13:30       Inflammatory Arthropathy: Clinical Assessment
               
Steven R. Goldring, M.D.

 

14:10       Ankylosing Spondylitis
Anne G. Jurik, M.D.

 

14:50       Psoriatic Arthritis
Sabine Weckbach, M.D.

 

Thermotherapy, HIFU & Preclinical Interventions

Room A4        13:30-15:30                Moderators: Dennis L. Parker and Viola Rieke

13:30                       244.         Velocity Navigator Triggering for Motion Compensated PRF Thermometry

Florian Maier1, Axel Joachim Krafft1, Jürgen W. Jenne2,3, Rüdiger Dillmann4, Wolfhard Semmler1, Michael Bock1

1Medical Physics in Radiology, German Cancer Research Center (DKFZ), Heidelberg, Germany; 2Clinical Cooperation Unit Radiation Oncology, German Cancer Research Center (DKFZ), Heidelberg, Germany; 3Mediri GmbH, Heidelberg, Germany; 4Institute of Anthropomatics, Karlsruhe Institute of Technology, Karlsruhe, Germany

Proton resonance frequency shift thermometry is sensitive to motion. Artifacts are caused by tissue displacement and susceptibility changes. In this work, a novel navigator technique for triggering MR thermometry image acquisition is presented. Non-velocity and velocity encoded navigator signals were acquired without lengthening of TR. Based on the phase variation of non-encoded values and the estimated velocity, trigger events were generated. The measurements indicate that the proposed triggered segmented EPI pulse sequence allows for motion compensated thermometry of periodically moving tissue.

13:42                       245.         Fat-Referenced MR Thermometry in Heterogeneous Tissue Using IDEAL

Lorne Hofstetter1, Desmond Teck Beng Yeo2, Cynthia Davis2, Thomas K. Foo2

1GE Global Research, Niskayuna , NY, United States; 2GE Global Research, Niskayuna, NY, United States

Time-varying, non-temperature dependent phase changes affect the accuracy of conventional phase difference proton resonance frequency shift (PRFS) temperature mapping in the breast.  We demonstrate a fat-referenced PRFS technique capable of correcting for this phase variation. This new approach reduced temperature measurement error in the left breast by a factor of 3.6 and in the right breast by a factor of 2.5 when compared to conventional phase difference techniques (n = 1).

13:54                       246.         The Effects of Spatial Sampling Choices on MR Temperature Measurements

Nick Todd1, Josh De Bever2, Urvi Vyas3, Allison Payne4, Dennis L. Parker5

1Physics, University of Utah, Salt Lake City, UT, United States; 2Robotics, University of Utah, Salt Lake City, UT, United States; 3Bioengineering, University of Utah, Salt Lake City, UT, United States; 4Mechanical Engineering, University of Utah, Salt Lake City, UT, United States; 5Radiology, University of Utah, Salt Lake City, UT, United States

MR temperature maps are necessarily a discrete representation of a physical quantity that is continuously varying in both space and time. The HIFU focal spot size can be smaller than the imaging voxel dimensions.  Due to averaging effects, it is likely that different choices for the sampling grid location, voxel size, and scan time will lead to variations in the measured temperature distribution. In this abstract we present simulation and experimental results quantifying the effects of the sampling scheme on maximum temperature and thermal dose, and show the effects of zero-filled-interpolation post-processing on the measured maximum temperature and thermal dose.

14:06                       247.         Reference-Less PRFS MR Thermometry Using a Thin Open Border and the Harmonic Functions Theory: 2D Experimental Validation

R Salomir1, M Viallon1, Joerg Roland2, Sylvain Terraz1, Denis Morel3, CD Becker1, P Gross2

1Radiologie, Hopital Universitaire de Genève, Geneva, Switzerland; 2Siemens Medical Solutions, Erlangen, Germany; 3Anesthesiology, University Hospitals of Geneva, Geneva, Switzerland

A new method for reference-less MR thermometry is described based on the fundamental theoretical frame of harmonic functions. The method was implemented for a thin open border and validated for 2D situation with HIFU heating in phantoms and in vivo rabbit thigh, and also with baseline acquisition in volunteers liver. Measurement accuracy in liver under free breathing was as good as 0.5°C for 0.3 seconds temporal resolution. The method is insensitive to periodic or accidental motion, tissue expansion or drift, and to external perturbation from interventional device.

14:18                       248.         Hybrid Multi-Baseline and Referenceless PRF-Shift Thermometry

William A. Grissom1,2, Andrew B. Holbrook3, Viola A. Rieke2, Michael Lustig1, Juan A. Santos1, Aravind Swaminathan, Michael V. McConnell, Kim Butts Pauly2

1Electrical Engineering, Stanford University, Stanford, CA, United States; 2Radiology, Stanford University, Stanford, CA, United States; 3Bioengineering, Stanford University, Stanford, CA, United States

We introduce a new temperature estimation method that is a hybrid of multi-baseline and referenceless methods. From multi-baseline methods the hybrid method inherits the ability to estimate temperature in the presence of rapidly-varying background anatomical phase. From referenceless methods the hybrid method inherits robustness to smooth main field shifts during thermal therapy. The method is demonstrated in the heart and liver.

14:30                       249.         MRI Monitoring of Skull-Base Heating in Transcranial Focused Ultrasound Ablation

Yuexi Huang1, Junho Song1, Kullervo Hynynen1,2

1Sunnybrook Health Sciences Centre, Toronto, ON, Canada; 2Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada

In transcranial focused ultrasound ablation, the heating of the outer skull surface has been reduced by a hemispherical design of phased-array transducers and active cooling of the skull surface with water circulation. However, the potential heating of the skull base has not been brought into much attention. In this work, experiments were performed with a MR-guided transcranial focused ultrasound system on a full human skull sample to investigate the heating of the skull base. MR thermometry was applied to measure the temperature change of the phantom adjacent to the skull base. The distance of the foci to the bone was varied to measure a safety margin for avoiding significant skull base heating.

14:42                       250.         Temperature Measurement Nearby an Iceball Using the Proton Resonance Frequency Method: Recalculation of Susceptibility Artifacts.

Antje Kickhefel1, Rares Salomir2,3, Jörg Roland4, Patrick Gross4, Fritz Schick5, Clifford R. Weiss6

1Eberhard-Karls-University Tübingen, Tübingen,  Baden-Württemberg, Germany; 2University Hospitals of Geneva, Switzerland; 3 University Hospitals of Geneva; 4Siemens Healthcare, Erlangen, Germany; 5Eberhard-Karls-University Tübingen, Tübingen,  Baden-Württemberg, Germany; 6Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, United States

The study demonstrates that susceptibility artifacts in GRE phase image induced by ice ball can be corrected allowing the PRF method to be used to monitor the near zero temperature during cryoablation. Susceptibility artifacts were corrected in post-processing. First the susceptibility contrast between frozen and melted meat was determined and second the magnetic perturbation was calculated using a convolution filter in the k-space. The susceptibility artifacts were fully corrected. In conclusion, using an in-line post processing system, this method could be applied during clinical MR-guided cryotherapy, and allow for the non-invasive monitoring of near zero temperatures.

14:54                       251.         PRF Based MR-Thermometry on Abdominal Organs: A Pragmatic Comparison of Referenceless Vs
Multi-Baseline

Baudouin Denis de Senneville1, Sébastien Roujol1,2, Chrit Moonen1, Mario Ries1

1Laboratory for Molecular and Functional Imaging: from Physiology to Therapy, CNRS/ University Bordeaux 2, Bordeaux, Aquitaine, France; 2LaBRI, CNRS/ University Bordeaux 1, Talence, Aquitaine, France

Reliable temperature and thermal-dose measurements using PRF based MR-thermometry for MR-guided ablation therapy on abdominal organs require a robust correction of artefacts induced by the target displacement through an inhomogeneous and time-variant magnetic field. The presented study combines the two most promising candidates for this role, the multi-baseline and the referenceless method, with a real-time in-plane motion correction which permits thermal-dose calculations and evaluates the practical aspects of both methods in an ex-vivo RF-ablation and an in-vivo high-intensity focused ultrasound ablation of a porcine kidney.

15:06                       252.         Quantitative Perfusion Analysis for Transcatheter Intraarterial Perfusion MR Imaging

Dingxin Wang1, Johnathan Chung2, Robert Lewandowski2, Richard Tang2, Rachel Klein2, Reed Omary1,3,
Andrew Larson1,3

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

In this study, we presented a new quantitative TRIP-MRI perfusion analysis approach, and evaluated its efficacy in a gel perfusion phantom and in rabbits with VX2 liver tumors during TAE. Our results successfully evaluated the efficacy of this proposed perfusion analysis method for TRIP-MRI datasets in the perfusion phantom, and demonstrated the use of quantitative TRIP-MRI to monitor reductions in liver tumor perfusion during TAE.

15:18                       253.         MR-Based Dosimetry of  166holmium-Loaded Microspheres for Internal Radiation Therapy Treatment Planning

Peter Roland Seevinck1, Tim C. de Wit2, Gerrit Hendrik van de Maat1, Maarten A.D. Vente3, Mattijs Elschot3, Mark Konijnenberg4, Johannes F.W. Nijsen3, Chris JG Bakker1,2

1Image Sciences Institute, University Medical Center Utrecht, Utrecht, Netherlands; 2Dept. of Radiology, University Medical Center Utrecht, Utrecht, Netherlands; 3Dept. of Nucleair Medicine, University Medical Center Utrecht, Utrecht, Netherlands; 4Research and Development, Mallinckrodt Medical BV, Covidien, Petten, Netherlands

The potential of MRI for dose calculations of Holmium-166 loaded microspheres to enable MR-based treatment planning of transcatheter radioembolization of hepatic malignancies was investigated. MRI and SPECT experiments were conducted using an anthropomorphic agarose gel phantom containing tumor-simulating gel samples with known amounts of 166Ho-PLLA-MS. Excellent agreement was observed both qualitatively and quantitatively when comparing MR-based to SPECT-based dose maps to reference data obtained with a dose calibrator. In conclusion, MR-based dosimetry of 166Ho-PLLA-MS was demonstrated to be feasible, indicating the potential of MR-based dosimetry for planning, guidance and evaluation of transcatheter radioembolization treatment of hepatic malignancies with 166Ho-PLLA-MS.

Diffuse Liver Disease

Room A5        13:30-15:30                Moderators: Shahid M. Hussain and Meng Yin

13:30                       254.         Noninvasive Assessment of Liver Stiffness with Tagged MRI

Sohae Chung1, Elodie Breton1, Lorenzo Mannelli1, Hersh Chandarana1, Leon Axel1

1Radiology, NYU Langone Medical Center, New York, NY, United States

A pathological hallmark of the progression to cirrhosis is the development of liver fibrosis, so that monitoring the appearance and progression of liver fibrosis can be used to guide therapy. Fibrosis of the liver is known to result in increased mechanical stiffness, so that the assessment of liver stiffness is a key feature. In this study, we describe a new MRI liver assessment method by using the pulsations of the heart as an intrinsic motion source and by using magnetization-tagged MRI (tMRI) as a noninvasive method to image the motion of the liver for the assessment of liver stiffness.

13:42                       255.         Magnetic Resonance Elastography: Feasibility of Liver Stiffness Measurements in Healthy Volunteers at 3Tesla.

Lorenzo Mannelli1, Martin J. Graves1, Peter Beddy1, Ilse Joubert1, Andrew N. Priest2, David J. Lomas1

1Radiology, Addenbrooke's Hospital and University of Cambridge, Cambridge, England, United Kingdom; 2Medical Physics, Addenbrooke's Hospital and University of Cambridge, Cambridge, England, United Kingdom

In this study we evaluated liver stiffness in healthy volunteers using magnetic resonance elastography (MRE) at 3T with the same technique that has been successfully applied at 1.5T. This preliminary work demonstrates the feasibility of liver stiffness evaluation at 3T without modification of the approach used at 1.5T.

13:54                       256.         Influence of Perfusion on Tissue Stiffness Assessed with MR Elastography

Meng Yin1, Kevin J. Glaser1, Arunark Kolipaka1, Lizette Warner2, Jayant A. Talwalkar3, Armando Manduca1, Richard L. Ehman1

1Department of Radiology, Mayo Clinic, Rochester, MN, United States; 2Division of Nephrology & Hypertension, Mayo Clinic, Rochester, MN, United States; 3Division of Gastroenterology, Mayo Clinic, Rochester, MN, United States

This preliminary investigation provides evidence that MRE-assessed hepatic and renal stiffness in two controlled animal models has a dynamic component that can increase or decrease following a fluctuation in perfusion. The use of MRE to assess changes in tissue mechanics associated with the dynamic perfusion of tissue provides new insights into the natural history and pathophysiology of hepatic and renal diseases and may have significant diagnostic value. Diagnostic and longitudinal MRE studies should take into account potential dynamic perfusion effects as a potential cause of variability.

14:06                       257.         Automated T2* Estimation with Complex-Signal Based Weighted Least Squares Exponential Fitting

Shreyas S. Vasanawala1, Huanzhou Yu2, Ann Shimakawa2, Michael Jeng3, Jean H. Brittain4

1Department of Radiology, Stanford University, Stanford, CA, United States; 2Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States; 3Department of Pediatrics, Division of Hematology/Oncology, Stanford University, Stanford, CA, United States; 4Applied Science Laboratory, GE Healthcare, Madison, WI, United States

Patients who receive chronic red blood cell transfusion therapy are at risk for iron overload if not receiving appropriate iron chelation.  Quantification of iron deposition for therapeutic decision-making is vital.  We aim to evaluate a method of automated T2* mapping with a weighted least squares algorithm in pediatric patients with suspected hepatic iron deposition and to compare it with a conventional T2* mapping method. Twenty three patients ages 5 to 17 years were recruited. Good correlation was obtained between the methods with R2 of 0.97. It is noted that the simple exponential fitting technique likely over-estimates T2* at short T2*.

14:18                       258.         MRI of Liver Fibrosis by Fibrin-Fibronectin Targeted Contrast Agent

Darwin S. Gao1,2, Mingqian Tan3, Jerry S. Cheung1,2, April M. Chow1,2, Shu Juan Fan1,2, Kannie W.Y. Chan1,2, Kwan Man4, Zheng-Rong Lu3, Ed X. Wu1,2

1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China; 3Department of Biomedical Engineering, Case Western Reserve University, Cleveland, United States; 4Department of Surgery, The University of Hong Kong, Pokfulam, Hong Kong SAR, China

Liver fibrosis, associated with chronic liver injury, including hepatitis and alcohol intoxication, can progress to cirrhosis and hepatocellular carcinoma. It is characterized by an increased amount of extracellular matrix consisting of fibril-forming collagens and matrix glycoconjugates such as fibronectin The fibrin-fibronectin complexes in fibrotic liver, resulted from cross-linkage between fibrin/fibrinogen and fibronectin, may serve as a specific molecular target for contrast-enhanced MRI. Our preliminary results demonstrated that a fibrin-fibronectin targeted Gd contrast agent provided distinct contrast enhancement in fibrotic liver, as compared with a non-targeted Gd contrast agent, in an experimental model.

14:30                       259.         T2 Relaxation Time as a Surrogate Marker of Liver Fibrosis

Luiz Siqueira1, Michael Chew1, Peter F. Hahn1, Giles Boland1, Lawrence T. White2, Deborah Gervais1, Peter R. Mueller1, Alexander R. Guimaraes2,3

1Radiology, Massachusetts General Hospital/Division of Abdominal Imaging, Boston, MA, United States; 2Radiology, Massachusetts General Hospital/Martinos Center for Biomedical Imaging, Charlestown, MA, United States; 3Radiology, Division of Abdominal Imaging and Interventional Radiology, Boston, MA, United States

83 patients who underwent both liver MRI and liver biopsy for fibrosis staging within a 6 month period, between January 2004 and December 2008 were enrolled in this IRB approved retrospective study.   All biopsies were staged histologically (Ishak classification system (0-6)) and grouped into mild (stage (1-2) n=20), moderate (stage (3-4), n=17), severe (stage (5-6), n=46).   T2 relaxation time of liver parenchyma in patients was calculated by 2 point fit (mild 66.7 +/- 1.9msec; moderate 71.6 +/- 1.7msec; severe 72.4  +/- 1.4msec) with low standard error (~1.9msec), demonstrating statistically significant difference between degrees of mild vs. severe fibrosis (p<0.05).

14:42                       260.         Assessment of Liver Fibrosis: Comparison of Magnetic Resonance Elastography (MRE) and Diffusion-Weighted Imaging (DWI)

Frank H. Miller1, Yi Wang2, Robert McCarthy, Zongming Chen, Andrew Larson2, Laura Sternick, Daniel Ganger, Richard Ehman3, Josh Levitsky, Reed Omary2, Laura Merrick2, Bradley D. Bolster, Jr4, Sven Zuehlsdorff4, Saurabh Shah4, Paul Nikolaidis2, Vahid Yaghmai2

1Radiology , Northwestern University Feinberg School of Medicine, Chicago, IL, United States; 2Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States; 3Radiology, Mayo Clinic; 4Siemens Healthcare

We prospectively compared and assessed the discriminatory capabilities of MRE and DWI in detecting and staging hepatic fibrosis in patients with suspected chronic liver diseases using histopathologic analysis as the reference standard. Our study demonstrated that the stiffness values on MRE had a positive linear correlation with degree of liver fibrosis and had greater capability for discriminating stages of fibrosis compared to ADCs on DWI. Furthermore, the absence of fibrosis, mild fibrosis, moderate fibrosis, and late-stage fibrosis (F3-4) can be distinguished from one to another by stiffness values; however, the individual stages of fibrosis could not be differentiated by ADCs.

14:54                       261.         Non-Invasive Imaging of Diffuse Liver Disease Using Water T2 and Fat Fractions Obtained from a Breath Hold Radial GRASE Method

Maria I. Altbach1, Christian Graff2, Chuang Huang3, V Abraham1, Scott W. Squire1, Denise Bruck4, K Ray4, T Boyer4

1Radiology, University of Arizona, Tucson, AZ, United States; 2Division of Imaging and Applied Math, U.S. Food and Drug Administration, Silver Spring, MD, United States; 3Mathematics, University of Arizona, United States; 4Medicine, University of Arizona, United States

The diagnosis of inflammation, fibrosis, and steatosis is important in the characterization of diffuse liver disease such as Hepatitis C, non-alcoholic steatosis (NASH), and cirrhosis. Currently the diagnosis of these pathologies requires a liver biopsy which is an invasive procedure with associated morbidity and cost. Recently our group developed a novel radial gradient and spin-echo (GRASE) method which provides T2 and fat-water mapping with the advantage that the T2 estimation is independent of the presence of fat. The method is fast (data for T2 and fat-water mapping are acquired in a breath hold) and it provides high spatial resolution and motion insensitivity. In this work we provide the first results in patients with various liver conditions and compare T2 and fat-water information to biopsy results.

15:06                       262.         Field Strength Reproducibility of Hepatic Proton Density Fat Fraction Estimation  by a Complex-Data, T1-Independent, T2*-Corrected, Spectrum-Modeled MRI Technique

Benjamin Johnson1, Michael Schroeder1, Katie Hansen1, Geraldine HyeWon Kang1, Tanya Wolfson1, Anthony Gamst1, Scott B. Reeder2, Claude B. Sirlin1, Mark Bydder1

1University of California-San Diego, San Diego, CA, United States; 2University of Wisconsin, Madison, WI, United States

With over ten million Americans affected by non-alcoholic fatty liver disease (NAFLD), there is a need for a non-invasive biomarker of liver fat content.  Because confounders lead to inaccurate estimates of liver fat when using conventional MRI, advanced MRI techniques are being developed and refined to address these problems and accurately and precisely predict hepatic fat content.   We demonstrate the reproducibility across field strength of an advanced complex-based MRI technique that corrects for confounders such as T1 bias, T2*, spectral complexity of liver fat, eddy currents and noise bias.

15:18                       263.         T1 Independent, T2* Corrected Chemical Shift Based Fat-Water Separation with Accurate Spectral Modeling Is an Accurate and Precise Measure of Liver Fat

Catherine D. G. Hines1, Alex P. Frydrychowicz2,3, Dana L. Tudorascu4, Gavin Hamilton5, Karl K. Vigen2, Huanzhou Yu6, Charles A. McKenzie7, Claude B. Sirlin5, Jean H. Brittain8, Scott B. Reeder1,2

1Biomedical Engineering, University of Wisconsin-Madison, Madison, WI, United States; 2Radiology, University of Wisconsin-Madison, Madison, WI, United States; 3Diagnostic Radiology and Medical Physics, University Hospital Freiburg, Freiburg, Germany; 4Waisman Laboratory for Brain Imaging and Behavior, University of Wisconsin-Madison, Madison, WI, United States; 5Radiology, University of California-San Diego, San Diego, CA, United States; 6Applied Science Laboratory, GE Healthcare, Menlo Park, CA, United States; 7Medical Biophysics, University of Western Ontario, London, Ontario, Canada; 8Applied Science Laboratory, GE Healthcare, Madison, WI, United States

Accurate quantification of hepatic steatosis is essential for early detection of non-alcoholic fatty liver disease, which is increasingly common in Western societies. Quantitative IDEAL provides a means to measure hepatic steatosis in vivo, although its precision and accuracy are unknown.  40 patients were scanned twice using both quantitative IDEAL and MRS to assess accuracy and precision.  Analysis of Bland-Altman plots, concordance correlation coefficients, linear regression and confidence intervals indicate that quantitative IDEAL provides both highly accurate and precise fat-fractions using MRS as a reference and is a reliable method of in vivo fat quantification.

 

 

CLINICAL INTENSIVE COURSE
MR Physics & Techniques for Clinicians

Room K1        16:00-18:00                Organizers & Moderators: Marcus T. Alley and Michael Markl

EDUCATIONAL OBJECTIVES

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

  • Define and describe the fundamental principles of MR imaging, including the definition of spin magnetization, the Larmor relationship, relaxation phenomena, and the process of using the spin magnetization to produce an image;
  • Explain imaging pulse sequences based upon spin and gradient echoes, including fast spin-echo and echo planar techniques;
  • Design MR imaging protocols for diagnostic applications considering image contrast, spatial resolution, acquisition time, signal-to-noise ratio, and artifacts; and
  • Describe the principles of parallel imaging, high-field imaging, perfusion imaging, diffusion imaging, and functional MR imaging.

16:00       Spin Echo Imaging
Bernd A. Jung, Ph.D.

 

16:40       Gradient Echo Imaging
Brian A. Hargreaves, Ph.D.

 

17:20       Fast Spin Echo Imaging
Frank R. Korosec, Ph.D.

 

 

CLINICAL INTENSIVE COURSE
Multimodality Imaging of Angiogenesis

Room K2        16:00-18:00        Organizers: Anwar R. Padhani and Bachir Taouli

EDUCATIONAL OBJECTIVES

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

  • Describe basics of tumor angiogenesis;
  • Explain non-MRI methods to diagnose and quantify tumor angiogenesis; and
  • Explain MRI methods used to diagnose and quantify tumor angiogenesis.

Moderators: Anwar R. Padhani and Bernard E. Van Beers

 

16:00       CE-US
Nathalie Lassau, M.D., Ph.D.

 

16:30       Perfusion CT
Dushyant V. Sahani, M.D.

 

17:00       Perfusion Modeling for Tumor Angiogenesis
David L. Buckley, Ph.D.

 

17:30       Perfusion MRI
Anwar R. Padhani, M.R.C.P., F.R.C.R.

 

fMRI:  Limits & Techniques

Room A1        16:00-18:00                Moderators: Markus Barth and Ravi Menon

16:00                       264.         Echo Time Dependence of Laminar BOLD Activation at 7 Tesla

Peter Jan Koopmans1, Markus Barth1,2, David Gordon Norris1,2

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

We present a multi-echo fMRI study at 7 T with 0.75 mm isotropic voxels and TEs ranging from 4.8 to 56 ms. Layer dependent T2* values are reported for human V1 showing a gradient from lower T2* near white matter and higher near the cortical surface with a superimposed dip in the granular layer. We show that the intravascular contribution to GE-BOLD at 7 T is dominated by the pial compartment and that laminar activation profiles are TE dependent. The optimal TE to detect BOLD changes in parenchyma is ~28 ms considerably longer than previously thought as previous estimates have included venous blood.

16:12                       265.         Retinotopically Organized Left to Right Hemisphere Functional Connectivity in Human V1 Using High-Resolution FMRI at 7T

Jonathan Rizzo Polimeni1, Kyoko Fujimoto1, Bruce Fischl1,2, Douglas N. Greve1, Lawrence L. Wald1,3

1Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Harvard Medical School, Massachusetts General Hospital, Charlestown, MA, United States; 2Computer Science and AI Lab (CSAIL), Massachusetts Institute of Technology, Cambridge, MA, United States; 3Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA, United States

Functional connectivity analysis of resting-state fMRI data has been used to investigate large-scale networks of brain activity. Here investigate whether functional connectivity analysis exhibits sufficient spatial specificity to detect retinotopic organization of the cross-hemispheric correlations detected in cortical area V1. The observed pattern of functional connectivity follows the retinotopic layout—presumably due to the retinotopically-organized common drive from the retina via the LGN. This indicates that despite the indirect nature of these inter-hemispheric connections, an orderly topographic pattern is present and functional connectivity analysis possesses the specificity to detect small-scale organization of the connections within a single cortical area.

16:24                       266.         Detailed Topographic and Functional Mapping of Areas Within the Posterior Lateral-Occipital and HMT/V5 Complex at 3T Using Functional Grid Analysis

Hauke Kolster1, Ron Peeters2, Guy A. Orban1

1Lab. for Neuro- and Psychophysiology, KU Leuven, Leuven, Belgium; 2Radiology, UZ Leuven, Leuven, Belgium

We functionally mapped areas within the human posterior lateral-occipital (LOC) and hMT/V5 complex. Using a topographical alignment and correlating retinotopic with unsmoothed functional data we developed a fMRI group analysis, which is specific to within fractions of the individual areas. We demonstrate that the human MT/V5 complex includes the homologue of the macaque MT/V5 field-map cluster, consisting of areas V4t, MT/V5, MSTv, and FST. We further show that these areas can be sharply distinguished from neighboring areas in LOC based on functional characteristics and that a previously reported overlap of motion and shape responses coincides with areas V4t and FST.

16:36                       267.         Mapping the Early Spatiotemporal BOLD FMRI Response in the Barrel Cortex of Rats

Xin Yu1, Stephen Dodd1, Yoshiyuki Hirano1, Daniel Glen2, Ziad S. Saad2, Richard C. Reynolds2, Afonso C. Silva1, Alan P. Koretsky1

1NINDS, NIH, Bethesda, MD, United States; 2NIMH, NIH, Bethesda, MD, United States

BOLD-fMRI signals increase in the rat somatosensory cortex faster than the transit time of blood moving from arteries to veins, which enables us to measure the evolution of BOLD responses at early times after stimulation. Here, the rat barrel cortex activity was mapped at 0.2s temporal resolution in 2D GE-EPI images at 150mmx150μmx500μm using an 11.7T MRI. Activity-evoked BOLD signals were first observed at 0.8s, and shifted to adjacent penetrating venules at 1-1.2s, later propagating to the superficial draining veins. This indicates that BOLD-fMRI maps made prior to about 1 s will have minimal contribution from penetrating cortical venules.

16:48                       268.         Relative Timing of Brain Activations Revealed by Ultra-Fast MR Inverse Imaging (InI)

Fa-Hsuan Lin1, Thomas Witzel1, Tommi Raij, Jyrki Ahveninen, John Bellveau

1A. A. Martinos Center, Charlestown, MA, United States

We use the ultra fast MR inverse imaging (InI) to interrogate the feasibility to detect hemodynamic timing difference across the brain areas using a two-choice reaction time task. We hypothesize that the vascular response variability can be reduced in the group-level analysis such that neuronally related timing information can become distinct. The MRI and behavior results supported this hypothesize by showing statistically significant timing first at visual and then at motor cortices in our group data (N=23).

17:00                       269.         Investigation of Seizure Propagation Using EEG-FMRI and Dynamic Causal Modelling

Patricia Figueiredo1, Alberto Leal2

1Instituto Superior Técnico, Lisbon, Portugal; 2Department of Neurophysiology, Hospital Júlio de Matos, Lisbon, Portugal

One of the challenges of EEG-fMRI techniques in epilepsy is the investigation of the spatio-temporal dynamics of seizure-related BOLD signals. Here, we have employed Dynamic Causal Modelling (DCM) to test a number of competing models of discharge propagation within a network of functionally connected brain areas identified from EEG-fMRI data of ictal activity, in a patient with epilepsy associated with a hypothalamic hamartoma. Our results demonstrated the feasibility and utility of DCM in the study of the origin and propagation pathway of seizure activity, which may be of critical importance when deciding the surgical approach for epilepsy treatment.

17:12                       270.         Support Vector Machine Classification of FMRI Data in Image and K-Space Domains

Scott Peltier1, Jonathan Lisinski2, Douglas Noll, Stephen LaConte2

1Functional MRI Laboratory, University of Michigan, Ann Arbor, MI, United States; 2Computational Psychiatry Unit, Baylor College of Medicine, Houston, TX, United States

This work examines support vector machine (SVM) classification of complex fMRI data, both in the image domain and in the acquired k-space data.  We achieve high classification accuracy using image magnitude, image phase, and k-space magnitude data.  Additionally, we maintain high classification accuracy even when using only partial k-space data.

17:24                       271.         A Rapid Whole-Brain Classifier for Real-Time Functional MRI Feedback

Jeremy F. Magland1, Ze Wang2, Daniel Willard2, Anna Rose Childress2,3

1Department of Radiology, University of Pennsylvania Medical Center, Philadelphia, PA, United States; 2Department of Psychiatry, University of Pennsylvania Medical Center, Philadelphia, PA, United States; 3VA VISN 4 MIRECC, Philadelphia, PA, United States

Recent studies demonstrate that functional MRI subjects can learn to control activity in localized areas of the brain through the use of real-time fMRI feedback. Potential implications of this technology include a variety of therapies, such as pain management for patients suffering from chronic pain, and craving suppression in individuals with addictions. Whereas much is known about which specific brain regions to target in the case of pain management, less is known about which regions impact craving in addicted individuals. To address this challenge, we have implemented a real-time feedback system based on whole-brain classification.

17:36                       272.         Hadamard-Encoded FMRI for Reduced Susceptibility Dropout

Gary H. Glover1, Catherine E. Chang1

1Radiology, Stanford University, Stanford, CA, United States

The susceptibility difference between air and tissue induces intravoxel dephasing that causes signal dropout in BOLD fMRI. Thin slices can mitigate some of this loss but at a severe SNR efficiency penalty that is only partially offset by summing adjacent slices together. We propose a method that uses Hadamard encoding of two thin subslices per slice subsequently combined incoherently with UNFOLD to recover signal at no loss of SNR in uniform regions. Results using 2 2mm subslices and a hypercapnic challenge demonstrate a 10% increase in activation volume in frontal-orbital regions when compared with conventional 4 mm slice acquisitions.

 

17:48                       273.         Rapid Multiecho 3D Radial FMRI

Gregory R. Lee1, Jean Tkach1, Mark Griswold1,2

1Department of Radiology, Case Western Reserve University, Cleveland, OH, United States; 2Biomedical Engineering, Case Western Reserve University, Cleveland, OH, United States

A method to perform multi-echo BOLD functional MRI using an undersampled, multishot 3D radial trajectory is demonstrated.  The proposed view-ordering scheme is a 3D analog of bit-reversed view ordering and allows reconstruction at power of 2 undersampling factors (2,4,8,16).  Aliasing artifacts are periodic in time and can be removed via UNFOLD.  Whole brain images were reconstructed at five echo times (TE=7.3, 16.1, 24.9, 33.6 and 42.4 ms) while maintaining a temporal resolution of 798 ms / volume.  The multiple echoes can used to create dynamic T2* maps and may be combined via weighted summation (optimizing sensitivity over multiple T2* values).

DTI Brain:  Clinical Applications

Victoria Hall  16:00-18:00                Moderators: Hao Huang and Harald E. Moller

16:00                       274.         Atlas-Based Approach to Study White Matter Disruption in Alzheimer’s Disease

Xin Fan1, Guanghua Xiao2, Kristin Martin-Cook3, Roger Rosenberg3, Myron Weiner4, Hao Huang1

1Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States; 2Department of Clinical Sciences, University of Texas Southwestern Medical Center, Dallas, TX, United States; 3Department of Neurology, University of Texas Southwestern Medical Center, Dallas, TX, United States; 4Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX, United States

Conventional VBM (voxel-based-morphometry) approaches delineate the abnormality at the voxel level. However, it is the information reflected from whole white matter tracts that have clinical importance. In this study, with no a priori information, this novel atlas-based approach has been used to examine fractional anisotropy (FA) of DTI of all 50 major white matter tracts at the tract level to detect white matter disruption in Alzheimer disease (AD). The proposed method is highly efficient, accurate, makes comprehensive examination of all major tracts and allows comparison of disruption level of these tracts.

16:12                       275.         Converging Microstructural Evidence in Prodromal and Early Alzheimer’s Disease: Alteration of Commissural and Association Pathways, Sparing of Motor Pathways

Gwenaelle Douaud1, Saad Jbabdi1, Timothy Edward Behrens1, Ricarda Menke1, Achim Gass2, Andreas Monsch3, Anil Rao4, Brandon Whitcher4, Gordon Kindlmann5, Paul M. Matthews4, Stephen Smith1

1FMRIB Centre, University of Oxford, Oxford, Oxfordshire, United Kingdom; 2Departments of Neurology and Neuroradiology, University Hospital, Basel, Switzerland; 3Memory Clinic, Basel, Switzerland; 4GSK, CIC Hammersmith Hospital, London, United Kingdom; 5Department of Computer Science and Computation Institute, University of Chicago, Chicago, IL, United States

Using TBSS, we investigated white matter abnormalities in the largest diffusion study including healthy elderly, mild cognitive impairment and Alzheimer’s disease. We also used the ‘mode’ of anisotropy which specifies the shape of anisotropy. All diffusion tensor indices converged to show that the uncinate fasciculus, cingulum bundle, corpus callosum, anterior commissure and superior longitudinal fasciculus were affected.  We found a regional increase of mode and fractional anisotropy, often considered atypical for a degenerative disorder. Using tractography, we directly and quantitatively showed that these local increases were related to the neuropathological sparing of the motor-related pathways compared with the superior longitudinal fasciculus.

16:24                       276.         Gender Differences in the Dependence of Body Weight and Brain Connectivity Revealed by Diffusion
Tensor Imaging

Karsten Mueller1, Alfred Anwander1, Annette Horstmann1, Franziska Busse2, Burkhard Pleger1, Joeran Lepsien1, Michael Stumvoll2, Arno Villringer1, Harald E. Möller1

1Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany; 2Department of Medicine, University Hospital Leipzig, Germany

We revealed gender differences in the dependence between body weight and brain structure using diffusion tensor imaging. For the female volunteers, we observed a significant negative correlation between the body mass index (BMI) and fractional anisotropy (FA) in all parts of the corpus callosum. This correlation could not be found for male subjects. A negative correlation between BMI and axial diffusivity was significant for both  women and men. An additional effect was found for the female participants only: A positive correlation between BMI and radial diffusivity. The underlying physiological reasons are still unclear and need to be further investigated.

16:36                       277.         Diffusion Tensor Imaging of Time-Dependent Axonal and Myelin Degradation After Carbon Monoxide Intoxication: White Matter Tract-Specific Quantification by Tract Probabilistic Map

Chun-Yi Lo1, Wei-Che Lin1,2, Chih-Hsueh Wang1, Ai-Ling Hsu3, Ching-Po Lin1,3

1Institute of Biomedical Imaging and Radiological Sciences, National Yang Ming University, Taipei, Taiwan; 2Departments of Diagnostic Radiology, Chang Gung Memorial Hospital-Kaohsiung Medical Center, Kaohsiung, Taiwan; 3Institute of Brain Science, National Yang Ming University, Taipei, Taiwan

Patients with acute carbon monoxide (CO) intoxication may develop progressive white matter (WM) demyelination. We created WM parcellation atlas-based probabilistic maps of 5 major WM tracts. Automated tract-specific quantification of DTI parameters were performed to evaluation WM tract damage and the chronologic change in 17 patients with CO intoxication. The results revealed that decreasing fractional anisotropy were primarily driven by increasing radial diffusivity, which appeared to be more strongly correlated with demyelination in the initial presentation. Our finding supplements previous MRI studies by adding a level of anatomic detail to the relationship between white matter damage and cognitive dysfunction.

16:48                       278.         2D Distribution Analysis of DTI in Two Phenotypes of Dystonia Patients

An Vo1, Miklos Argyelan1, David Eidelberg1, Aziz M. Ulug1

1The Feinstein Institute for Medical Research, Manhasset, NY, United States

Hereditary dystonia is a neurological movement disorder where the subjects have abnormal motions due to muscle contractions.  We used a 2D distribution analysis with a physical brain model, which can automatically determine the different tissue types according the inherent diffusional characteristics. Seven dystonia patients with DYT1 genotype, four non-manifesting DYT1 mutation carriers and eight normal were studied.  The results show that the brain tissue can be characterized using diffusion parameters using distribution analysis in 2D.  There are considerable differences among three groups studied in terms of the parameters measured.  Our model stained the putamen a DYT1 subject suggestive of disease involvement in that area.

17:00                       279.         Bimanual Coordination and Corpus Callosum Microstructure in Young Adults with Traumatic Brain Injury

Karen Caeyenberghs1, Alexander Leemans2

1KULeuven, Leuven, Heverlee, Belgium; 2University Medical Center Utrecht, Netherlands

Deterioration of motor function is one of several clinical manifestations following traumatic brain injury (TBI). The aim of this study was to investigate the relationship between white matter (WM) integrity using diffusion tensor imaging (DTI) and bimanual motor performance in young TBI patients. A group suffering from moderate to severe TBI (N=25) and a control group (N=18) were scanned using DTI along with standard anatomical scans. Using ExploreDTI software, three corpus callosum subregions were evaluated. Bimanual performance was assessed using a motor switching task. This study provides evidence for a structural alteration of corpus callosum subregions in young adults with TBI that are correlated with motor functioning, inspiring new avenues for therapy.

17:12                       280.         DTI in Leukoencephalopathy with Brainstem and Spinal Cord Involvement and Elevated Lactate (LBSL): Local Strongly Increased FA and Reduced Diffusivity  as Well as Globally Reduced FA and Increased Diffusivity.

Marjan Steenweg1, Marjo van der Knaap, Frederik Barkhof2, Petra Pouwels3

1Child Neurology, VU University Medical Center, Amsterdam, Netherlands; 2Radiology, VU University Medical Center, Amsterdam, Netherlands; 3Physics & Medical Technology, VU University Medical Center, Amsterdam, Netherlands

LBSL is an inherited white matter (WM) disorder without known pathological basis. To gain insight into tissue microstructure, this study used high-resolution DTI (1.45x1.45x2mm) at 1.5T. Performing TBSS, a general increase in MD and decrease in FA was seen in the central cerebral WM, not always coinciding with signal abnormalities on conventional images. Strikingly, ROI-analysis showed small areas with an extremely low MD, together with low axial and radial diffusivity, and very high FA. Restricted diffusion has been described in leukoencephalopathies caused by myelin vacuolation, raising the question whether this also plays a role in LBSL.

17:24                       281.         7T DTI in Mild Chronic Traumatic Brain Injury: Assessment of the Superior Longitudinal Fasciculus and Cingulum Bundle

Dustin Cunningham1, Seongjin Choi1, John Corrigan2, Jennifer Bogner2, W Mysiw2, Cherian Renil Zachariah1, Michael V. Knopp1, Petra Schmalbrock1

1Radiology, The Ohio State University, Columbus, OH, United States; 2Physical Medicine and Rehab, The Ohio State University, Columbus, OH, United States

In order to differentiate mild chronic traumatic brain injury (TBI) patients from age matched healthy controls we explored the use of 7T diffusion tensor imaging (DTI) of the cingulum bundle (CB) and the superior longitudinal fasciculus (SLF). We observed qualitative and quantitative differences between the two groups that included statistically different fractional anisotropy (FA) values for a ROI placed in the CB and visually different fibers for the SLF in the right hemisphere of TBI patients. Our results are encouraging because they support the idea that DTI may be useful as a tool to diagnose and characterize mild chronic TBI.

17:36                       282.         Functional and Structural Connectivity of Default Mode Network in Patients with Schizophrenia: A Combined Resting-State FMRI and Diffusion Spectrum Imaging Study

Su-Chun Huang1, Fang-Chen Yeh2,3, Hai-Go Hwu4, Chih-Min Liu4, Chen-Chung Liu4, Fa-Hsuan Lin5, Wen-Yih Isaac Tseng, 2,5

1Institution of Medical Engineering, Taipei, Taiwan; 2National Taiwan University College of Medicine, Center for Optoelectronic Biomedicine, Taipei, Taiwan; 3Carnegie Mellon University , Department of Biomedical Engineering, Pittsburgh, PA, United States; 4National Taiwan University Hospital, Department of Psychiatry, Taipei, Taiwan; 5National Taiwan University, Institute of Biomedical Engineering, Taipei, Taiwan

With the combination of resting-state fMRI and DSI, the relationships between FC, SC and clinical PNASS scores were investigated in patients with schizophrenia. Significant correlations between FC and PNASS scores were found in three pairs of DMN, namely the IPL-IPR, the IPL-PCCR, and the IPR-PCCL pairs. However, the SC showed no significant correlation with PNASS score. Our results suggest that FC of DMN associates with the severity of the clinical symptoms more strongly than SC. Moreover, after ignoring three drug-naïve patients, the SC between IPR and PCCL was negatively correlated with FC, implying that alteration of FC might down regulate SC. To clarify this, a longitudinal study is warranted to study the interactions between FC and SC, and their effects on clinical symptoms during the disease course.

17:48                       283.         Automated Tract-Specific Quantification Using Probabilistic Atlas Based on Large Deformation Diffeomorphic Metric Mapping and Its Application to Alzheimer's Disease

Kegang Hua1, Kenichi Oishi1, Hangyi Jiang1, Xin Li1, Jiangyang Zhang1, Kazi Dilruba Akhter1,2, Michael I. Miller3,4, Van Zijl C.M. Peter1,5, Marilyn Albert6, Constantine G. Lyketsos7, Michelle M. Mielke7, Susumu Mori1,2

1Department of Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States; 2F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States; 3Center for Imaging Science, Johns Hopkins University, Baltimore, MD, United States; 4Department of Biomedical Engineering, Johns Hopkins University , Baltimore, MD, United States; 5F.M. Kirby Research Center for Functional Brain Imaging , Kennedy Krieger Institute, Baltimore, MD, United States; 6Department of Neurology, Johns Hopkins University School of Medicine, Baltimore, MD, United States; 7Department of Psychiatry, Johns Hopkins Bayview Medical Center, Baltimore, MD, United States

Tractography is widely used to define locations of specific tracts in the white matter and perform tract-specific quantification of various MR parameters such as FA and MD. However, tractography requires placements of ROIs to extract tracts of interest, which involves subjective and expert judgment. In this presentation, an automated tract-specific quantification approach is demonstrated based on pre-defined population-averaged tract information and a highly non-linear image transformation technique. This tool was applied to an Alzheimer’s disease population and age-matched control. The results show accurate tract identification and consistent diffusivity abnormality of the forceps major.

 

Cardiovascular Interventions & Catheter Tracking

Room A4        16:00-18:00                Moderators: Michael Bock and Reza Razavi

16:00                       284.         Preclinical Evaluation of an MR-EP Suite Including an MR-EP Navigator and Dedicated MR-EP Catheters

Sascha Krueger1, Ronald Holthuizen2, Jouke Smink2, Steffen Weiss1, Oliver Lips1, Bernd David1, Daniel Wirtz1, Steen Fjord Pedersen3, Dennis Caulfield4, Julian Bostock4, Gang Gao4, Phani Chinchapatnam4, Tobias Schaeffter4, Reza Razavi4

1Philips Research Europe, Hamburg, Germany; 2Philips Healthcare, Best, Netherlands; 3MR Research Centre, Skejby Hospital, Aarhus, Denmark; 4Division of Imaging Sciences, King's College, London, United Kingdom

Cardiac arrhythmias, e.g. atrial fibrillation and ventricular tachycardia, are increasingly treated by electrophysiological (EP) interventions. Applying MR for guiding these interventions offers advantages like 3D visualization of the cardiac soft tissue in relation to the catheter, visualization of the treatment effect and absence of ionizing radiation. Making the step towards clinical MR-guided EP interventions requires a focus on RF safety of the devices, localization accuracy of the catheters, guidance of the procedure, intra-cardiac signal quality and procedure workflow. Here, an MR-EP suite based on an MR-EP Navigator application with a real-time interface to the MR system and therapy equipment is demonstrated along with specialized MR-EP catheters. These catheters are based on RF-safe concepts for both, MR- and EP functionality. RF-safety, localization accuracy and EP signal quality of these devices, and the operation of the MR-EP suite and the workflow of the MR-EP Navigator are demonstrated in a series of pre-clinical MR-guided EP experiments.

16:12                       285.         Visualizing RF Ablation Lesions Real-Time at 3Tesla

Sathya Vijayakumar1,2, Eugene G. Kholmovski1, Gene Payne1, Joshua Blauer3, Christopher Gloschat3, Jayne H. Davis4, Rob MacLeod, 3,4, Kimberly Lilbok5, Gaston Vergara5, Mike Guttman6, Kamal Vij6, Chris J. McGann, 27, Dennis L. Parker1, Nassir F. Marrouche5

1UCAIR, Department of Radiology, University of Utah, Salt Lake City, UT, United States; 2CARMA Center, University of Utah, Salt Lake City, UT, United States; 3Dept. of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States; 4CVRTI, University of Utah, Salt Lake City, UT, United States; 5Dept. of Cardiology, University of Utah, Salt Lake City, UT, United States; 6Surgivision Inc,, Irvine, CA, United States; 7Drpt. of Cardiology, University of Utah, Salt Lake City, UT, United States

In this work, we present the real-time imaging of lesions as they form on a porcine model.

16:24                       286.         MRI-Compatible 12-Lead ECGs with MHD Separation: Application to Cardiac MRI Gating, Physiological Monitoring and Non-Invasive Cardiac-Output Estimation

Zion Tsz Ho Tse1, Charles L. Dumoulin2, Gari Clifford3, Michael Jerosch-Herold1, Daniel Kacher1, Raymond Kwong4, William Gregory Stevenson4, Ehud Jeruham Schmidt1

1Radiology, Brigham and Women's Hospital, Boston, MA, United States; 2University of Cincinnati College of Medicine, Cincinnati, OH, United States; 3Health Sciences and Technology, Massachusetts Institute of Technology, Boston, MA, United States; 4Cardiology, Brigham and Women's Hospital, Boston, MA, United States

An adaptive filtering procedure, based on a set of ECG measurements performed outside and inside the MRI, is presented in order to separate between the real ECG and Magneto-HydroDynamic (MHD) signals in 12-lead ECGs acquired within a 1.5T MRI. The cleaned ECG improves cardiac gating and preserves S-T segment fidelity for physiological monitoring. The integrated MHD magneto-hydrodynamic signals provide non-invasive beat-to-beat cardiac output estimations. The proposed method was validated in five normal healthy subjects, including an athlete exercising inside the magnet, and a patient with frequent Premature Ventricle Contractions.

16:36                       287.         RF-Safe, Multi-Polar, Diagnostic MR-EP Catheter Employing Resistive Leads and a Transformer-Based Transmission Line

Daniel Wirtz1, Bernd David1, Steffen Weiss1, Sascha Krueger1, Oliver Lips1

1Imaging Systems & Intervention, Philips Research Europe - Hamburg, Hamburg, Germany

RF heating of a diagnostic multi-polar EP mapping-catheter equipped with resistive leads for ECG signal transmission was investigated by electromagnetic simulations and subsequent measurements. The influence of wire resistance and number of wires in the catheter has been adressed. The simulations were validated by fiberoptic temperature measurements on a prototype catheter employing resistive leads.

Furthermore, the effect of a transformer-based transmission line connected to a tracking coil on RF heating at the catheter tip, the ring electrodes and near the tracking coil was analyzed. Favourable distributions of the transformers along the safe transmission line resulting in minimum SAR were derived.

 

16:48                       288.         Roadmaps Incorporating Respiratory and Cardiac Motion for X-Ray Fused with MRI

Anthony Zahi Faranesh1, Peter Kellman1, Robert J. Lederman1

1Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States

X-ray fused with MRI provides 3D roadmaps for x-ray cardiovascular interventional procedures.  This work incorporates respiratory and cardiac motion into the roadmaps to enhance image guidance.  Cardiac and respiratory motion is measured from real-time MRI images and then fit to an affine model.  Separate models are used for individual anatomic structures, to accommodate complex regional motion.  The 3D roadmaps are then deformed based on cardiac and respiratory phase to better reflect physiological motion during the procedure.

17:00                       289.         Feasibility of MR-Thermometry with Blood Suppression on the Human Heart at 3T

Silke Hey1, Alexandru Cernicanu2, Baudouin Denis de Senneville1, Sebastien Roujol1, Mario Ries1, Chrit T. W. Moonen1, Bruno Quesson1

1Laboratory for Molecular and Functional Imaging, Bordeaux, France; 2Philips Healthcare, France

Ventricular tachycardia and atrial fibrillation can be treated by catheter radio-frequency ablation where PRFS-based MR thermometry is a candidate to provide intra-procedural feedback.  However, MR thermometry of the heart is challenging. As blood suppression is preferable to avoid artifacts in the myocardium, we explore three different options, namely double inversion recovery (DIR), motion-sensitized driven equilibrium (MSDE), and inflow saturation (IS). The effectiveness of the blood suppression and its effect on the temperature stability in the septum is evaluated in eight healthy volunteers for 50s of free-breathing using VCG cardiac triggering and navigator respiratory compensation.

17:12                       290.         Direct MRI-Guided Needle Access to the Heart and Blood Vessels

Christina E. Saikus1, Kanishka Ratnayaka1,2, Israel M. Barbash1, Ozgur Kocaturk1, Anthony Z. Faranesh1, Robert J. Lederman1

1Translational Medicine Branch, Division of Intramural Research, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD, United States; 2Cardiology Division , Children's National Medical Center, Washington DC , United States

Inherent soft-tissue contrast and multi-planar imaging of MRI without ionizing radiation makes it appealing for guidance of traditional and complex cardiovascular access.  In this work, we have utilized real-time MRI to guide peripheral vascular access in addition to more precise targeting of direct cardiac access to the right ventricle in swine.  MR imaging with compatible devices provides valuable anatomical information to the operator and enables trajectory planning and procedure monitoring to ensure a safe and efficient entry to the heart and vasculature.

17:24                       291.         Catheter Tracking Using Transmit Array System

Haydar Celik1,2, Ibrahim Davut Mahcicek2, Ergin Atalar, 2,3

1Electrical and Electronics Engineering, Bilkent University , Ankara, Turkey; 2National Magnetic Resonance Research Center (UMRAM), Ankara, Turkey; 3Electrical and Electronics Engineering, Bilkent University, Ankara, Turkey

Although, soft tissue contrast of MRI is effectively high, visualization of the internal devices, such as guidewires and catheters, is not straight forward. In order to achieve better identification of these devices, various tracking techniques have been developed. Passive tracking methods are easy to implement, but they are not sufficiently reliable. The main problem of active tracking techniques is uneasy device handlings. They need to be connected to imager with cables. In addition, these cables create safety problems. There are also hybrid methods, using inductively coupled RF (ICRF) and receive coupled RF (RCRF) coils. In our study, we propose a new method using ICRF coils and transmit array system. Presented method enables simultaneous acquisition of anatomy and catheter images.

17:36                       292.         Excite by Light: A Novel MR-Safe Method of Catheter Tip Tracking

Reiner Umathum1, Axel Joachim Krafft1, Michael Bock1

1German Cancer Research Center, Heidelberg, Germany

A novel method for MR-safe catheter tip tracking was investigated. RF-modulated light is converted into a current at the tip of an interventional catheter driving a small resonant circuit tuned to the 1H resonance frequency and exciting a small liquid reservoir locally. The generated MR signal is read out with conventional MR imaging coils so that the catheter tip can be effectively visualized against a dark signal background.

17:48                       293.         Prospective Motion Correction Using an MR-Tracking Tetrahedron for Intra-Cavitary MRI

Lei Qin1, Ehud J. Schmidt1, W. Scott Hoge1, Juan Santos2, Clare Tempany-Afdhal1, Kim Butts-Pauly3, Charles L. Dumoulin4

1Radiology, Harvard Medical School, Boston, MA, United States; 2Electrical Engineering, Stanford University, Stanford, CA, United States; 3Radiology, Stanford University, Stanford, CA, United States; 4Radiology, Cincinnati Children's Hospita, Cincinnati, OH, United States

Intra-cavitary imaging coils have been developed to achieve higher spatial resolution. However, they suffer more severely from motion artifacts since both the anatomy and the coil are moving while image acquisition occurs. We propose integrating a Tetrahedron-shaped active MR-tracking coil into an intra-cavitary imaging coil for motion detection, and to perform prospective motion (rotation and translation) corrections in real-time, so that the entire image can be acquired in a “static” frame of reference. Experiments show significant image quality improvements for both in-plane and through-plane motion correction.

Diffusion, Biophysics & Modeling

Room A5        16:00-18:00                Moderators: Klaas Nicolay and Markus Nilsson

16:00                       294.         Variation of ADC with Cell Cycle Phases: A Study Using Synchronized HL-60 Cells

Junzhong Xu1, Jingping Xie1, Jerome Jourquin2, Daniel C. Colvin1, Mark D. Does1, Vito Quaranta2, John C. Gore1

1Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States; 2Cancer Biology, Vanderbilt University, Nashville, TN, United States

Proliferating tumors usually contain a much higher fraction of cells in active cell division phases, so for a full understanding of the diffusion properties of tumors it is necessary to understand the changes that occur in cells in different phases. Here we report how oscillating gradient spin echo (OGSE) methods detect intracellular changes of synchronized HL-60 cells at different phases, while conventional pulsed gradient spin echo (PGSE) methods cannot distinguish changes at sub-cellular dimensions due to relatively long diffusion times. This feature means OGSE methods may provide extra contrast for detecting cancer.

16:12                       295.         Determining the Biophysical Mechanisms of Intracellular Water Diffusion and Its Response to Ischemia in Perfused Cell Cultures

Kevin D. Harkins1,2, Jean-Phillipe Galons3, Joseph L. Divijak1, Theodore P. Trouard1,3

1Biomedical Engineering, University of Arizona, Tucson, AZ, United States; 2Vanderbilt University Institute of Image Science, Vanderbilt University, Nashville, TN, United States; 3Radiology, University of Arizona, Tucson, AZ, United States

It was initially discovered nearly two decades ago that the apparent diffusion coefficient (ADC) drops 30-50% after the onset of ischemic stroke. Despite its clinical utility, there is still no consensus on the biophysical cause of the drop in the ADC. In this work, oscillating gradient and pulsed gradient diffusion experiments were performed on perfused cell cultures to measure the ADC of intracellular water over a wide range of diffusion times. Results indicate that the biophysical mechanisms that influence ADC are diffusion time dependent, where diffusion measured at short diffusion times is highly sensitive to the intrinsic diffusion of intracellular water and the diffusion measured at longer diffusion times is more sensitive to cell size.

16:24                       296.         Acute Diffusion MRI Measurements Predict Chronic Axonal Function Assessed Using Electrophysiology

Joong Hee Kim1, David S. K. Magnuson2, Sheng-Kwei Song1

1Radiology, Washington University , St. Louis, MO, United States; 2Neurological Surgery and Anatomical Sciences & Neurobiology, University of Louisville, Louisville, KY, United States

Diffusion tensor imaging (DTI) has been widely employed to assess central nervous system white matter integrity in animal models and patients. Herein, we demonstrate for the first time that the axonal injury marker derived by DTI as early as 3 hours post-spinal cord contusion, a time point when no existing modality is capable of assessing underlying axonal injury or the neurological disability, reflects injury severity and accurately predicts long-term neurological function.

16:36                       297.         Early Detection of Tumor Treatment Response with Temporal Diffusion Spectroscopy

Daniel C. Colvin1, Mary E. Loveless1, Mark D. Does1, Zou Yue1, Thomas E. Yankeelov1, John C. Gore1

1Vanderbilt University Institute of Imaging Science, Vanderbilt University, Nashville, TN, United States

Temporal diffusion spectroscopy methods, which employ rapid oscillations of the motion sensitizing diffusion gradient, are capable of probing diffusion times orders of magnitude shorter than those typically achieved with conventional pulsed gradient methods.  Consequently, the apparent diffusion coefficient (ADC) measured with these methods may provide a more accurate assessment of tumor response to therapy due to their ability to detect structural variations over much shorter length scales.  Results in a 9L tumor model in rats in vivo demonstrate that these methods can detect variations in ADC within 24 hours of chemotherapeutic treatment, when conventional methods showed no such change.

16:48                       298.         Apparent Exchange Rate of Water in Human Brain Matter Revealed by a Novel Pulse Sequence

Markus Nilsson1, Daniel Topgaard2, Sara Brockstedt, Freddy Ståhlberg1,3, Jimmy Lätt1,4

1Department of Medical Radiation Physics, Lund University, Lund, Sweden; 2Physical Chemistry, Lund University, Lund, Sweden; 3Department of Diagnostic Radiology, Lund University, Lund, Sweden; 4Center for Medical Imaging and Physiology, Lund University Hospital, Lund, Sweden

Results using a novel diffusion sensitive imaging sequence generating a potentially useful contrast mechanism: the apparent exchange rate of water, related to the and cell membrane permeability. Diagnostics and prediction of treatment outcome of various pathologies might benefit from the additional information gained by knowledge of the water exchange rate. The sequence was evaluated in phantom as well as in vivo.

 

17:00                       299.         Neurite Beading Is Sufficient to Decrease the Apparent Diffusion Coefficient Following Ischemic Stroke

Matthew D. Budde1, Joseph A. Frank1

1Radiology and Imaging Sciences, National Institutes of Health, Bethesda, MD, United States

Within minutes of an ischemic stroke, the apparent diffusion coefficient (ADC) dramatically decreases in the infarcted brain tissue. Although the ADC change is likely related to cell swelling, the precise biophysical mechanism remains elusive.  In this report, it is demonstrated that swelling of axons and dendrites, collectively known as neurites, causes the cell membrane to exhibit a beaded morphology.  A simulation of diffusion in beaded neurites was performed and validated in an ex vivo model of beading in sciatic nerves.  The results demonstrate that beading of the cell membrane is sufficient to decrease ADC following acute ischemic stroke.

17:12                       300.         Accounting for Free and Restricted Diffusion Processes in Single- And Double-PFG Experiments Using a Novel Bi-Compartmental Phantom

Noam Shemesh1, Evren Özarslan2, Amnon Bar-Shir3, Peter J. Basser2, Yoram Cohen1

1School of Chemistry, Tel Aviv University, Tel Aviv, Israel; 2Section on Tissue Biophysics and Biomimetics, NICHD, National Institutes of Health, Bethesda, MD, United States; 3Chemistry Department, Tel Aviv University, Tel Aviv, Israel

White-matter voxels which are contaminated with CSF or water diffusing in perpendicular crossing fibers constitute systems in which free and restricted diffusion are superimposed. To study the microstructural information that can be obtained in such settings, we prepared a bi-compartmental phantom in which free water (Gaussian diffusion) are superimposed with water in microcapillaries (restricted diffusion). Both single- and double-PFG experiments were conducted. We find that at low q-values, the signal arising from free water masks that of restricted diffusion and that microstructural information can only be obtained at higher q-values. We also applied these findings to a crossing fibers phantom.

17:24                       301.         Feasibility of Measuring Microstructural Features of Systems with Intermediate Exchange and Sub-Cellular Compartmentalization Using Diffusion MRI

Irina Kezele1, Philip Batchelor2, Cyril Poupon1, Jean-François Mangin1, Denis Le Bihan1, Daniel C. Alexander3

1NeuroSpin, CEA, Gif-sur-Yvette, France; 2King's College , London, United Kingdom; 3University College , London, United Kingdom

We propose an analytic three-compartment diffusion model where the intra-cellular architecture and exchange between the compartments are considered. This model can explain cell characteristic sizes and cell-membrane permeability, the features that are suggested to be related to different soft tissue pathologies (e.g., malignancy). Using the proposed model, we deliver an optimized imaging protocol to measure the relevant model parameters. The simulation results demonstrate the accuracy of estimating the parameters with both negligible and moderate membrane permeability, assuming pulsed-gradient spin-echo sequence and scanner parameters suitable for small animal imaging. The potential for new biomarker definition at the micro-scale is thus suggested.

17:36                       302.         Monte Carlo Study of a Two-Compartment Exchange Model of Diffusion

Els Fieremans1, Dmitry S. Novikov1, Jens H. Jensen1, Joseph A. Helpern1,2

1Radiology, New York University School of Medicine, New York, United States; 2Center for Advanced Brain Imaging, Nathan S. Kline Institute, Orangeburg, NY, United States

Chemical exchange models have been frequently applied to quantify diffusion measurement in living tissues. Here we investigate numerically a two-compartment exchange (Kärger) model as applied to diffusion in a system of parallel cylinders with permeable walls, which serves as a model for axons in white matter. We show that the Kärger model accurately predicts the diffusivity and the diffusional kurtosis when the membranes are sufficiently impermeable. The exchange time can then be derived from the time-dependence of the diffusional kurtosis. For larger permeabilities, the Kärger model overestimates the actual exchange time.

17:48                       303.         A Joint PDF for the Eigenvalues and Eigenvectors of a Diffusion Tensor

Sinisa Pajevic1, Peter J. Basser2

1CIT, NIH, Bethesda, MD, United States; 2NICHD, NIH, Bethesda, MD, United States

We propose a joint probability density function (pdf) of the eigensystem of a 2nd-order estimated diffusion tensor, which we show decouples into a product of  pdfs of its eigenvalues and eigenvectors for a well-designed MR experiment and moderate SNR.  This finding provides the foundation for the development of a rigorous and general statistical hypothesis-testing framework valid for measured DTI data.

Manganese-Enhanced MRI

Room A6        16:00-18:00                Moderators: Ichio Aoki and Alan P. Koretsky

16:00                       304.         Mapping of Cellular Layers in Mouse Brain and Spinal Cord Using Magnetization Transfer and Manganese

Takashi Watanabe1, Jens Frahm1, Thomas Michaelis1

1Biomedizinische NMR Forschungs GmbH am MPI für biophysikalische Chemie, Göttingen, Germany

This work demonstrates the complementary and combined use of magnetization transfer and manganese administration in T1-weighted MRI of the brain and spinal cord of living mice. The off-resonance irradiation effectively suppresses the signal intensity of the white matter, while the bright signals of dense cellular assemblies are much less affected. This differential effect well complements the contrast induced by manganese administration. Thus, magnetization transfer may distinguish neuron-rich tissue from adjacent myelin-rich tissue. Furthermore, quantitative evaluations indicate a higher sensitivity for manganese when combined with magnetization transfer.

16:12                       305.         In Vivo Manganese-Enhanced MRI of Retinotopic Mapping in Superior Colliculus

Kevin C. Chan1,2, Jiang Li3, Iris Y. Zhou1,2, Kwok-fai So3, Ed X. Wu1,2

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

This study explores the capability of high-resolution 3D Mn-enhanced MRI (MEMRI) for in vivo retinotopic mapping of the rat superior colliculus (SC) upon partial transection of the intraorbital optic nerve. Upon intravitreal Mn2+ injection into both eyes, all animals in Group 1 (n=8) exhibited significantly lower signal intensity in the lateral side of the left SC compared to the left medial SC and right control SC 1 week after superior optic nerve transection in the right eye. Partial transection at other regions of the optic nerve in Group 2 (n=7) led to hypointensity in other regions of the left SC. The results of this study demonstrated the feasibility of high-resolution MEMRI for in vivo, 3D mapping of retinotopic projections in the SC upon reduced anterograde axonal transport of Mn2+ ions at sites of partial transections in the anterior visual pathways. Future MEMRI studies are envisioned that measure the retinotopic changes in normal development, disease, plasticity and therapy in longitudinal studies.

16:24                       306.         In Vivo Evidence of Axonal Transport Perturbation in a Mouse Model of Tauopathy : A Track-Tracing
Memri Study

Anne Bertrand1,2, Minh D. Hoang2, Dmitry Novikov2, Susan Pun2, Pavan Krishnamurthy1, Hameetha Banu1, Benjamin Winthrop Little2, Einar M. Sigurdsson1, Youssef Zaim Wadghiri2

1Physiology and Neuroscience, NYU Medical Center, New York, NY, United States; 2Radiology, NYU Medical Center, New York, NY, United States

We report a track-tracing MEMRI in a mouse model of tauopathy (P301L line). We compared transgenic and wild-type animals at an early stage (6 month-old), using a long timeframe protocol (9 consecutive MR examinations for each mice) and a mathematical modelization of axonal transport using a drift-diffusion model. We show that P301L mice display significant differences in 2 parameters of axonal transport : the value of the peak of Mn, and the time of the peak of Mn. We also observed trends in drift velocity V, leakage rate λ and apparent speed of Mn transport that were smaller in TG mice that in WT. This provides the first in vivo evidence of axonal transport impairment assessed by MRI in a model of tauopathy.

16:36                       307.         Logan Graphical Analysis for Quantitative Evaluation of Calcium Channel Activity in the Pituitary Gland Using Manganese-Enhanced MRI (MEMRI)

Christoph Leuze1,2, Ichio Aoki1, Yuichi Kimura1

1National Institute of Radiological Sciences, Chiba, Japan; 2Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Sachsen, Germany

Logan graphical analysis (LGA), common in PET for the quantitative analysis of neuroreceptors, was performed with MRI to investigate the influence of stimulants and inhibitors on the Calcium channel activity in animal brain tissue. In this study LGA is applied to data which was acquired by measuring the concentrations of Manganese (Mn) in tissue and blood over a certain period of time after Mn-injection. The Mn uptake between experiments was varied by the excitatory neurotransmitter Glutamate and the Calcium channel blocker Verapamil. The analysis successfully delivers information about the varying in- and outflow of Mn from blood to tissue.

 

16:48                       308.         MEMRI Monitoring of Manganese Release and Transport in the Rat Brain Following Convection-Enhanced Delivery (CED) of Manganese (III)-Transferrin

Christopher H. Sotak1,2, Alan P. Koretsky3

1Biomedical Engineering, Worcester Polytechnic Institute, Worcester, MA, United States; 2Radiology, University of Massachusetts Medical School, Worcester, MA, United States; 3NINDS/LFMI, National Institutes of Health, Bethesda, MD, United States

Convection-enhanced delivery (CED) of manganese(III)-transferrin (Mn(III)-Tf) into the rat brain was used to investigate its properties as an in vivo MRI contrast agent.  The spatio-temporal evolution of MEMRI signal enhancement and calculated T1 relaxation times following Mn(III)-Tf infusion was comparable to that observed following CED of Mn2+ alone.  Furthermore, Mn2+ released following intrastriatal Mn(III)-Tf infusion was transported along the striatonigral pathway and the temporal dynamics were in excellent agreement with the neuronal tract tracing studies that employ Mn2+ alone.  The results of this study are consistent with the release and subsequent transport of Mn2+ following receptor-mediated endocytosis of Mn(III)-Tf.

17:00                       309.         Quantitative Multi-Parametric Assessment of a Radiation-Induced Encepholodysplasia CNS Model Using Magnetic Resonance Imaging

Shigeyoshi Saito1,2, Kazuhiko Sawada3, Xue-Zhi Sun, Kai-Hsiang Chuang4, Tetsuya Suhara, Iwao Kanno, Ichio Aoki

1Tohoku Univeristy, Sendai, Miyagi, Japan; 2National Institute of Radiological Sciences, Chiba, Japan; 3Tsukuba International University, Tsukuba, Ibaraki, Japan; 4Singapore Bioimaging Consortium, Singapore

In vivo evaluation of radiation damage in the CNS is important for the assessment and treatment. In this study, we non-invasively assessed neonatal brain of development disorder induced by prenatal x-ray exposure with quantitative MRI. Changes in T1 induced by intracellular Mn2+ contrast agents were observed in the CNS of normal and radiation irradiated rats. Diffusion and transverse relaxation time (T2)  were assessed. For the assessment of acquired images, the rats were killed humanely for a histological study with Hematoxylin-Eosin (cell density and necrotic changing), Activated Caspase-3 (apoptotic changing), and Glial fibrillary acidic protein (astrogliosis).

17:12                       310.         Induced T1, T2* and Phase Changes Following Manganese Systemic Administration at 14.1T

Rajika Maddage1, José P. Marques2,3, Rolf Gruetter2,4

1Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne , Lausanne, Switzerland; 2Laboratory of Functional and Metabolic Imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 3Department of Radiology , University of Lausanne, Lausanne, Switzerland; 4Department of Radiology, University of Lausanne and Geneva, Switzerland

Manganese enhanced MRI studies have been increasingly used in animal neuroimaging thanks to its T1 shortening properties and enhancement specificity. The aim of this study was to quantitatively evaluate at 14.1T the dynamic evolution of T1, T2* in different regions of the rat brain during manganese systemic administration and to access its impact on phase imaging. Preliminary results show enhancement in the hippocampus and cortex in phase imaging making it a potential tool to trace Mn2+ enrichment.

17:24                       311.         Dynamics of Mn Transport in the Mesolimbic System Reveal Neural Projections from the Nucleus Accumbens in Vivo

Jessica A. M. Bastiaansen1,2, Xiaowei Zhang1, Davit Janvelyan1, Scott E. Fraser1, Russell E. Jacobs1

1Biological Imaging Center, California Institute of Technology, Pasadena, CA, United States; 2CIBM, EPFL, Lausanne, Switzerland

The Nucleus Accumbens (NAc) plays a fundamental role in the neural reward circuit. Herein, we investigated the feasibility of MEMRI to map neural circuitry, activation and anatomy in the rodent reward system in vivo. Using MEMRI and SPM, we monitored Mn dynamics along the afferent and efferent projections from the NAc after a stereotaxic injection of MnCl. Spatiotemporal connectivity in the mesolimbic system was visualized in vivo, providing a paradigm for future studies on the neurophysiological basis of addiction using MEMRI.

17:36                       312.         Repeated T1 Mapping in Brain Following Clinical Dosage of Teslascan

Pål Erik Goa1, Christian Brekken2, Anders Thorstensen2, Brage Høyem Amundsen2, Asta Kristine Håberg3

1Dept. of Medical Imaging, St. Olavs University Hospital, Trondheim, Norway; 2Dept. of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; 3Dept. of Neuromedicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway

Whole-brain T1-mapping was performed before and 1 day, 4 days and 7 days after administration of clinical dosage of Teslascan in 8 healthy male volunteers. ROI was defined in Hippocampus, Caudate Nucleus and Corpus Callosum, and the T1 relaxation time at different timepoints after injection was compared to baseline values. Only in hippocampus at day 1 after injection was a statistically significant reduction in T1 observed. At later timepoints for the hippocampus, and for caudate nucleus in general only a trend towards reduced T1 was observed. For Corpus Callosum no T1 changes were observed.

17:48                       313.         The Dose Makes the Poison - Studying Toxicity in MEMRI Applications

Barbara Gruenecker1, Sebastian Frank Kaltwasser1, Yorick H. Peterse1, Philipp G. Saemann1, Mathias Schmidt1, Carsten T. Wotjak1, Michael Czisch1

1Max Planck Institute for Psychiatry, Munich, Germany

Different fractionated manganese injections schemes for MEMRI applications have been applied to study their influence on the animals’ health and stress response and MRI signal intensity in the brain of the often used mouse strain C57BL/6N. 8 applications of 30 mg/kg MnCl2 injected at an interval of 24 hours (8x30/24) were found to produce least toxic side effects while simultaneously producing highest MRI intensity and contrast compared to 6 injections of 30 mg/kg (6x30/48) and 3 injections of 60 mg/kg applied injected with 48 hours intervals. This method may allow functional MRI in freely behaving animals exposed to prolonged paradigms.

 

Spectroscopic Quantification Methodology

Room A7        16:00-18:00                Moderators: Robin A. de Graaf and Roland Kreis

16:00                       314.         In Vivo Simultaneous Measurement of Glutamine Synthetase and Glutamate Dehydrogenase Activity in the Hyperammonemic Rat Brain Using Localized 1H and 15N MRS

Cristina Cudalbu1, Bernard Lanz2, Paul R. Vasos3, Yves Pilloud2, Vladimír Mlynárik2, Rolf Gruetter2,4

1Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL) , Lausanne, Switzerland; 2Laboratory for Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland; 3Laboratory for Biomolecular Magnetic Resonance, Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; 42Departments of Radiology, Universities of Lausanne and Geneva, Switzerland

15N MRS is an alternative approach to 13C MRS in studying glutamate-glutamine metabolism and can provide a more straightforward interpretation. For this study we developed a new pulse sequence in order to simultaneously measure [5-15N]Gln and [2-15N]Gln+Glu for a direct measurement of the net glutamine synthesis rate (Vsyn-Vnt), Vsyn and VGDH under 15N-labeled ammonia infusion in the rat brain, using in vivo localized 15N MRS interleaved with 1H MRS. We obtained from the 1H data a net synthesis flux (Vsyn-Vnt)=0.035±0.001µmol/min/g. By fitting the in vivo 5-15N Gln and 2-15N Glu+Gln time courses, Vsyn=0.24±0.03µmol/min/g, VGDH=0.030±0.001µmol/min/g. Finally, the apparent neurotransmission rate, Vnt=0.21±0.03µmol/min/g.

16:12                       315.         GABA Concentration in Frontal Eye Field Predicts Oculomotor Distractibility

Richard AE Edden1,2, Petroc Sumner3, Aline Bompas3, Krish D. Singh3

1Russell H Morgan Department of Radiology and Radiological Sciences, The Johns Hopkins University, Baltimore, MD, United States; 2FM Kirby Research Center for Functional MRI, Kennedy Krieger Institute, Baltimore, MD, United States; 3CUBRIC, School of Psychology, Cardiff University, Cardiff, United Kingdom

Recent developments in the quantitation of GABA through edited MRS allow the behavioural consequences of individual differences in local GABA concentration to be studied. Such studies provide an important window into the workings of the healthy brain and a multimodal probe to investigate pathology.  Eye movements, known to be altered in many pathologies, are  thought to be planned in frontal eye fields (FEF). In this study we measure GABA concentration in a functionally-localised FEF region and show that GABA predicts saccade distractibility in healthy controls; this novel approach suggests further studies into the biochemical origins of neuropathologic behavioural deficits.

16:24                       316.         MR Spectroscopy Without Water Suppression for the Determination of Proton Exchange Rates in the
Human Brain

Erin Leigh MacMillan1, Daniel Guo Quae Chong1, Wolfgang Dreher2, Anke Henning3, Chris Boesch1, Roland Kreis1

1Department of Clinical Research, University of Bern, Bern, Switzerland; 2Dept. Chemistry, University of Bremen, Bremen, Germany; 3Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland

MRS without water suppression can detect exchangeable proton resonances, particularly downfield of water.  Employing a two-acquisition scheme with alternating up- or down-field metabolite inversion prior to PRESS, both the metabolite and water spectra were obtained from the human brain in-vivo.  The experiment was performed with and without a water inversion prepulse with varying inversion times (TI).  The magnetization transfer curves were fit with a Bloch-McConnell two-site exchange model to determine exchange rates, with initial estimates yeilding lifetimes (1/Km¨w) ranging from 90ms to >2s, which offer information about pH and chemical microenvironments, and may aid in the understanding of CEST effects.

16:36                       317.         Modeling of 13C MRS Data of Cerebral Glucose Metabolism Comparing Mild Hypoglycemia with
Euglycemia in Humans

Kim C.C. van de Ven1, Marinette van der Graaf1,2, Alexander A. Shestov3, Bastiaan E. de Galan4, Cees J.J. Tack4, Pierre-Gilles Henry3, Arend Heerschap1

1Radiology, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 2Clinical Physics Laboratory, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands; 3Center for Magnetic Resonance Research, University of Minneapolis, Minneapolis, MN, United States; 4General Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, Netherlands

During hypoglycemia the supply of the brain with glucose is reduced. The aim of this study was to examine the direct effects of hypoglycemia on cerebral glucose metabolism by 13C MRS with infusion of [1-13C]glucose. 13C-label from glucose gets incorporated into isotopic positions in downstream amino acids. To estimate metabolic kinetics the time dependent uptake curves were modeled with a one-compartment model of cerebral glucose metabolism. Assuming similar labeling in plasma [3-13C]lactate, the flux through the TCA cycle, given by VTCA , were comparable for both groups indicating that brain metabolism is maintained during mild hypoglycemia.

16:48                       318.         Quantification and Differentiation of CK and ATPase Fluxes Between Human GM and WM Using 3D 31P CSI and Saturation Transfer

Xiao-Hong Zhu1, Fei Du1, Qiang Xiong1, Hongyan Qiao1, Xiao Liu1, Jianyi Zhang2, Xiaoliang Zhang3, Kamil Ugurbil1, Wei Chen1

1Center for Magnetic Resonance Research, Department of Radiology,, Minneapolis, MN, United States; 2Department of Medicine, University of Minnesota, Minneapolis, MN, United States; 3University of California San Francisco, San Francisco, CA, United States

In vivo 31P MRS in combine with saturation transfer provides a useful tool for noninvasively measuring the cerebral metabolic fluxes of creatine kinase (CK) and ATPase reactions. However, 3D imaging of these metabolic fluxes in human brain is challenging owing to limited sensitivity and complicated quantification model when a short (desired) repetition time is used. In this study, we demonstrate that with advanced 31P MRS imaging approach and a newly developed quantification method, it is possible to image the CK and ATPase reaction rate constants and fluxes in human brain at 7T. We found that these fluxes were several folds higher in the grey matter than white matter. This study demonstrates not only the superior sensitivity achievable at high/ultrahigh field, but also the great potential of 31P approach for studying cerebral HEP metabolism and neuroenergetics associated with brain function and dysfunction.

17:00                       319.         Improved Quantification of Mitochondrial Exchange, TCA Cycle Rate and Neurotransmission Flux Using 1H{13C} MRS Measurements of C4 and C3 of Glutamate and Glutamine

Bernard Lanz1, Lijing Xin1, Rolf Gruetter1,2

1Laboratory for functional and metabolic imaging, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Departments of Radiology, Universities of Lausanne and Geneva, Lausanne and Geneva, Switzerland

[2-13C]acetate infusion coupled with 13C MRS enables the separated assessment of glial and neuronal Krebs cycle fluxes with higher accuracy than 13C labeled glucose, due to the asymetric metabolism of acetate in the brain. However, the faster neuronal Krebs cycle induces a strong dilution of the 13C labeled glutamate on the neuronal side, resulting in lower 13C MRS signal than with glucose. In this study, we analyzed with Monte-Carlo simulations the precision of the fitted metabolic fluxes with separated GluC3/GlnC3 curves obtained with 1H{13C} MRS as well as the impact of the neuroglial partition of glutamate on the fluxes.

17:12                       320.         Composition of Fatty Acids in Adipose Tissue by In Vivo 13C MRS at 7T

Ivan Dimitrov1, Jimin Ren2, Deborah Douglas2, Jeannie Davis2, A Dean Sherry2, Craig R. Malloy2

1Philips Medical Systems, Cleveland, OH, United States; 2Advanced Imaging Research Center, University of Texas Southwestern Medical Center, Dallas, TX, United States

The risk of many chronic diseases may be influenced by the composition of fatty acids in adipose tissue, particularly the ratio of saturated to unsaturated fats and the ratio of omega-6 to omega-3 fats. However, the chemical shift dispersion of 1H MRS is not sufficient for full analysis of chemical composition. Broadband proton-decoupled 13C NMR spectra of subcutaneous adipose tissue were obtained in healthy subjects.  After corrections for T1 and nuclear Overhauser effects, the poly-, mono-, and saturated fat composition was 18%, 49%, and 32%, respectively. 13C NMR is a rich source of information about adipose composition in humans.

17:24                       321.         Influence of Regional Macromolecule Baseline on the Quantification of Neurochemical Profile in Rat Brain

Lijing Xin1, Vladimir Mlynárik1, Hongxia Lei2, Rolf Gruetter, 12

1Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland; 2Department of Radiology, University of Lausanne, Lausanne, Switzerland

The aim of present study was to measure the macromolecule baselines from four different volumes of interest including cortex, hippocampus, striatum and a mixture of brain structures, and then to assess their influence on the quantification of metabolites. Minor differences were found between the macromolecules acquired from specific regions and a large volume containing various cerebral structures. A slight variability in the shape of the macromolecule baseline introduced by data processing can affect calculated concentrations of less well characterized metabolites. The use of a generic experimental macromolecule baseline provides a sufficiently accurate measurement of the neurochemical profile in rat brain.

17:36                       322.         Short Echo Time H1 Chemical Shift Imaging Data Quantification in the Mouse Brain at 11.7T Using a Constrained Parametric Macromolecular Model

Hélène Ratiney1, Yann Le Fur2, Michaël Sdika2, Sophie Cavassila3

1Université de Lyon, CREATIS-LRMN; CNRS UMR 5220; Inserm U630; INSA-Lyon; Université Lyon 1, Villeurbanne, France; 2Université Aix-Marseille II, CRMBM, CNRS UMR 6612, Marseille, France; 3Université de Lyon,, CREATIS-LRMN; CNRS UMR 5220; Inserm U630; INSA-Lyon; Université Lyon 1, Villeurbanne, France

Short echo time chemical shift imaging (SE-CSI) data quantification at 11.7T in the mouse brain is challenging because the magnetic field inhomogeneity impact the quality of both water suppression and  spectral resolution and macromolecular contamination can vary from voxel to voxel. We propose to derive from macromolecular CSI acquisition a constrained parametric macromolecular model to incorporate strong prior knowledge into the fitting of the SE-CSI. Evaluation of this approach on in vivo data acquisition is proposed and discussed.

17:48                       323.         Spectroscopy of the Human Prostate at 3 Tesla Using Surface Coil: Age-Related Changes

Jan Weis1, Antonina Bergman1, Francisco Ortiz-Nieto1, Mikael Häggman2, Håkan Ahlström1

1Dept. of Radiology, Uppsala University Hospital, Uppsala, Sweden; 2Dept. of Urology, Uppsala University Hospital, Uppsala, Sweden

Single-voxel spectroscopy and 2D spectroscopic imaging of the prostate at 3 T was performed using standard surface coil. Spectra of 53 healthy volunteers were processed using customized LCModel. It was found that metabolite-to-citrate spectral intensity ratios were significantly lower in older individuals than in younger. Our results demonstrate that the prostate spectroscopy at 3 T is feasible using surface coil. LCModel provides a high level of accuracy for analysis of prostate spectra. Our results indicate that each 1H MRS study of the human prostate should include age-matched controls.

Functional MRI of Kidneys

Room A8        16:00-18:00                Moderators: Hersh Chandarana and Harriett C. Thoeny

16:00                                      Introduction
 Vivian S. Lee

16:24                       324.         Intravoxel Incoherent Motion (IVIM) and Diffusion Tensor Imaging (DTI) in Healthy Kidney: Influence of Renal Flow Challenge

Eric Edward Sigmund1, Pierre Hughes Vivier1, Nicole Lamparello1, Dabang Sui1, Artem Mikheev1, Henry Rusinek1, Vivian S. Lee1, Lei Zhang1, Hersh Chandarana1

1Radiology, New York University Langone Medical Center, New York, NY, United States

Renal fluid transport is a superposition of flow, resorption, and diffusion, and diffusion-weighted imaging (DWI) in the kidney is correspondingly complex.  Advanced DWI protocols have emerged, such as intravoxel incoherent motion (IVIM) for flow/diffusion separation, and diffusion tensor imaging (DTI) for measurement of flow or structural anisotropy.  We employed these two approaches in a cohort of  normal volunteers undergoing MRI at baseline and following two flow challenges (hydration and furosemide).  Six diffusion metrics (apparent diffusion coefficient ADC, tissue diffusivity Dt, perfusion fraction fp, pseudodiffusivity Dp, mean diffusivity MD, fractional anisotropy FA) were evaluated for reproducibility, tissue contrast, and challenge response.

16:36                       325.         Determination of Glomerular Filtration Rate in Cirrhotic Patients by MR Renography: Pilot Study

Pierre-Hugues Vivier1,2, Pippa Storey1, Jeff L. Zhang1, Akira Yamamoto1, Kristopher Tantillo1, Ruth P. Lim1, James S. Babb1, Henry Rusinek1, Devon John3, Lewis W. Teperman3, Kent Friedman4, Judith Benstein5, Edward Skolnik5, Vivian S. Lee1

1Radiology, NYU Langone Medical Center, New York, New-York, United States; 2LITIS Laboratory EA4108, School of Medicine and Pharmacy, Rouen, France; 3Transplant Clinic, NYU Langone Medical Center, New York, New-York, United States; 4Nuclear Medicine, NYU Langone Medical Center, New York, New-York, United States; 5Nephrology, NYU Langone Medical Center, New York, New-York, United States

Glomerular filtration rate (GFR) assessment based on creatinine formulas is highly inaccurate in cirrhotic patients, despite its utmost importance. We prospectively investigated the feasibility, accuracy, precision and reproducibility of MR-GFR measurements in 20 cirrhotic patients undergoing routine liver MRI, using a protocol that added less than 10 additional minutes and 3 mL gadoteridol. Urinary clearance of 99mTc-DTPA served as reference GFR. MR-GFR values were more accurate and precise than creatinine-based GFR values. Reproducibility was comparable to the reference method.

16:48                       326.         Accurate and Precise Measurement of Renal Filtration and Vascular Parameters Using DCE-MRI and a 3-Compartment Model.

Paul S. Tofts1, Marica Cutajar1,2, Iosif Mendichovszky3, Isky Gordon2

1Imaging Physics, Brighton & Sussex Medical School, Brighton, East Sussex, United Kingdom; 2Radiology and Physics, UCL Institute of Child Health, London, United Kingdom; 3University of Manchester, Manchester, United Kingdom

The precision and accuracy of a recent compartmental model of renal DCE-MRI is investigated. Precision is assessed by repeated examination of 15 normal volunteers; accuracy is assessed by comparison with published values (where available). Local filtration (Ktrans) is reproducible (instrumental sd 15%) and accurate (0.25 min-1), giving GFR 115 mL min-1. Mean Transit Time (5.9 s) is reproducible (sd 6%) and a candidate biomarker. Blood flow is reproducible to 12%, although absolute values are high. Filtration fraction is more reproducible (8%) although lower than published values. Normal kidney volume was measured as 214 mL/1.73m2.

17:00                       327.         Multiphase True-FISP ASL in the Kidney

Caroline L. Hoad1, Eleanor F. Cox1, Alexander G. Gardener1, Devasuda Anblagan1, Susan T. Francis1

1School of Physics and Astronomy, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom

Multiphase True-FISP ASL is implemented in the kidney. This technique provides a robust method to map the transit time, perfusion rate and longitudinal relaxation time of the kidney in a total acquisition time of less than 5 minutes. Maps of these parameters are shown, with transit time maps depicting a clear increase in transit time from feeder vessels to the outer edge of the renal cortex, and perfusion maps displaying significant differences between renal cortex, medulla, and feeder vessels. The mean transit time to the renal cortex was 368±52 ms, mean perfusion rate 246±21 ml/100g/min and mean T1 1132±63 ms.

17:12                       328.         Effect of Iodixanol, a Iso-Osmolar Radio-Contrast Agent on Intra-Renal Oxygenation by BOLD MRI

Lu-Ping Li1, JoAnn Carbray1, Maria Papadopulou-Rosenzweig2, Richard Solomon3, Pottumarthi V. Prasad1

1Radiology, Northshore University Healthsystem, Evanston, IL, United States; 2Radiation Medicine, Northshore University Healthsystem, Evanston, IL, United States; 3Nephrology, University of Vermont, Burlington, Burlington, VT, United States

Radiocontrast nephropathy (RCN) is the 3rd common cause of in-hospital mortality in patients with pre-existing kidney insufficiency. Although low- and iso-osmolal radiocontrast are in general believed to be safer than older ionic and high-osmolal agents, the issue remains controversial. Renal hypoxia plays a role in the pathophysiology of RCN and  BOLD MRI was previously shown to be useful in monitoring the changes in intra-renal oxygenation with iothalamate, a 1st generation ionic high osmolality agent.  Here, we report our preliminary findings using iodixanol, a 3rd generation nonionic iso-osmolality agent, that suggest similar trends as reported earlier with iothalamate.

17:24                       329.         Optimisation of Oxygen-Enhanced Imaging in the Kidney

Katherine Frances Holliday1,2, Josephine H. Naish1,2, Jean Tessier3, Geoffrey J M Parker1,2

1Imaging Sciences, The University of Manchester, Manchester, United Kingdom; 2Biomedical Imaging Institute, Manchester, United Kingdom; 3Early Clinical Development, AstraZeneca, Macclesfield, United Kingdom

In this work we have optimised two sequences commonly used in Oxygen-Enhanced MRI (OE-MRI), Inversion-prepared Half Fourier Turbo Spin Echo (IR-HASTE) and Spoiled Gradient Echo (SPGR), for use in the kidneys. We then compared their abilities in vivo in a single subject. Finally we carried out a dynamic OE-MRI study in the kidneys of a small group of healthy volunteers. We showed that through the parameterisation of the dynamic signal curve obtained during gas switch-over, it is possible to create maps which distinguish between regions in the kidney with differing oxygen delivery.

17:36                       330.         An Arterial Spin Labeling Approach to Kidney Perfusion:  Assessing Reproducibility in Native and Transplanted Kidneys

Nathan S. Artz1, Elizabeth A. Sadowski2, Andrew L. Wentland1, Songwon Seo3, Arjang Djamali4, Sean B. Fain1,2

1Medical Physics, University of Wisconsin-Madison, Madison, WI, United States; 2Radiology, University of Wisconsin-Madison, Madison, WI, United States; 3Biostatistics and Medical Informatics, University of Wisconsin-Madison, Madison, WI, United States; 4Nephrology, University of Wisconsin-Madison, Madison, WI, United States

An ASL-FAIR approach was used to measure kidney perfusion in the cortex of 10 native kidneys and 15 transplanted kidneys in subjects with a wide range of kidney function. Exams were repeated within each visit and on two separate days and evaluated for reproducibility. The average within day Interclass Correlation Coefficient (ICC) was 0.93 with a Coefficient of Variation (CV) of 7.6% and the average between day ICC was 0.91 with a CV of 10.6%.  This ASL method is reproducible in the cortex of the kidney. The data also provides guidelines for differentiating normal and abnormal perfusion variation during longitudinal assessment.

17:48                       331.         Early Detection of Transplant Rejection by In Vivo 19F MRI

Ulrich Flögel1, Su Song2, Inga Kreideweiß1, Zhaoping Ding1, Oliver Witzke2, Jürgen Schrader1

1Institut für Herz- und Kreislaufphysiologie, Heinrich-Heine-Universität, Düsseldorf, NRW, Germany; 2Klinik für Nephrologie, Universitätsklinikum Essen, Germany

This study was aimed at developing an approach for the early in vivo detection of organ rejection in a murine heterotopic abdominal heart transplantation model. As contrast agent emulsified perfluorocarbons (PFCs) were used, which are biochemically inert and are known to be phagocytized by monocytes/macrophages. 1H/19F MRI enabled us to detect the initial immune response not later than 3 days after surgery, when conventional parameters did not reveal any signs of rejection. The results show that intravenously applied PFCs accumulate in areas affected by rejection and can be sensitively detected by 1H/19F MRI at a field strength of 9.4 T.

Endogenous Contrast Imaging

Room A9        16:00-18:00                Moderators: Ravinder Reddy and David J. Tozer

16:00                       332.         Observation of Frequency Shifts Induced by Chemical Exchange in Brain Tissue

Karin Shmueli1, Steve Dodd2, T-Q Li3, Jeff H. Duyn1

1Advanced MRI Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States; 2Functional and Molecular Metabolism Section, Laboratory of Functional and Molecular Imaging, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, United States; 3Department of Medical Physics, Karolinska Huddinge, Stockholm, Sweden

Water-macromolecular exchange has been proposed to explain brain gray and white matter frequency (phase) contrast. We extended previous observations of exchange-induced frequency shifts (fexch) in protein solutions by performing chemical shift imaging experiments using reference chemicals (TSP and dioxane) to observe positive fexch in fixed human and fresh pig brain tissue. Substantial negative GM-WM δfexch was observed which was similar for all tissues and references but opposite to in-vivo GM-WM frequency contrast, implying that tissue magnetic susceptibility may have a greater contribution. Exchange should therefore be included in frequency con