fMRI: Connectivity & Networks

13:30         3595.     Correlation Modulation Networks to Assess Changes in Functional Connectivity with Task Difficulty

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Mayuresh S. Korgaonkar¹, Susan Fiore¹, Candice J. Perkins¹, Nancy K. Squires¹, Zengmin Yan¹, Mark E. Wagshul¹

¹Stony Brook University, Stony Brook, New York, USA

Correlation modulation network analyses allow the evaluation of condition specific functional interactions between brain regions. Our previous results show that there is differential recruitment of brain regions in a task difficulty modulated verb generation task. Using the correlation modulation approach, we sought to evaluate the following: 1. If the connectivity between language regions is modulated by experimental conditions – particularly between generating verbs as compared to passive viewing of non-words and difficult as compared to easy to generate verbs; and 2. How these condition-specific modulations of connectivity differ between young and old subjects.

14:00         3596.     Effect of Hemodynamic Spatial Variability on Granger-Based Long Term Causality

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Gopikrishna Deshpande¹, George Andrew James¹, Xiaoping Hu¹

¹Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA

Causal relationships between cortical regions can be inferred from fMRI using Granger causality (GC). However, GC may be affected by spatial variability of the hemodynamic response (HRF). We examine the effect of HRF variability on the causal influences in a neural network that evolves slower than the HRF variability and TR. Simulations showed that the HRF variability leads to erroneous results. Furthermore, we show that the true causality could be recovered by using summary measures derived from the BOLD data instead of the raw fMRI time series. These findings are illustrated using data obtained from a fatigue motor task.

14:30         3597.     Network Reduction for Interpreting Large Scale Brain Networks

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Gopikrishna Deshpande¹, Randall Stilla, Krish Sathian, Xiaoping Hu¹

¹Georgia Institute of Technology and Emory University, Atlanta, Georgia, USA

In this work, we illustrate the utility of multivariate Granger causality analysis for characterizing large brain networks and introduce a new procedure for removing unimportant nodes while retaining the important ones in the network. This method was applied to tactile perception fMRI data which demonstrated the co-existence of top-down and bottom-up mechanisms in tactile perception.

15:00         3598.     Localization of the Language Network Using Resting State Functional Connectivity MRI and Diffusion Tensor Tracking

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Joshua S. Shimony¹, Adrian A. Epstein¹, S Neil Vaishnavi¹, Mark W. Sansbury¹, Jeff G. Ojemann², Abraham Z. Snyder¹, Marcus E. Raichle¹

¹Washington University School of Medicine, St. Louis, Missouri, USA; ²University of Washington School of Medicine, Seattle, Washington, USA

Although the language network is localized around the left sylvian fissure in a great majority of the population, there is a significant amount of variability in localization between individuals.  Localization in individuals is of great interest for pre-surgical planning to help decrease the morbidity from left temporal lobe surgery.  The purpose of this project was to study the variability of the language network in individuals and to validate its localization by correlating the results using a functional method, resting state functional connectivity MRI, and an anatomic method, diffusion tensor tracking.

13:30         3599.     Discrepencies Between Functional Connectivity Measured with BOLD and CBF in Major Depressive Disorder

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Richard Cameron Craddock¹, Christopher B. Glielmi², Paul E. Holtzheimer³, Xiaoping P. Hu², Helen S. Mayberg

¹Georgia Tech, Atlanta, Georgia, USA; ²Georgia Tech and Emory University, Atlanta, Georgia, USA; ³Emory University, Atlanta, USA

Functional connectivity was compared between CBF and BOLD for networks associated with depression.  Overall there was consensus with striking differences.

14:00         3600.     Spatially Independent Component Analysis for Automatically Delineating Brain Functional Connectivity with Resting-State FcMRI

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Quan Zhu¹, Chung-Yi Yang², Eldom Toh³, John H. Gilmore³, Weili Lin³

¹Duke University, Durham, North Carolina, USA; ²National Taiwan University Hospital, Taiwan; ³University of North Carolina at Chapel Hill, Chapel Hill, USA

In this work, automatic procedures were developed to determine the components that most likely reflect brain functional connectivity for resting-state fMRI images using spatial independent component analysis (sICA).   The developed approaches were then utilized to depict cortical connectivity in neonates (2-4wks), one-year and two-year old children.

14:30         3601.     Detecting Direct and Indirect Functional Connections Using Granger Causality

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Zhenyu Zhou¹,², Yonghong Chen¹, Guojun He¹, Paul Wright¹, Mingzhou Ding¹, Yijun Liu¹

¹University of Florida, Gainesville, USA; ²Southeast University, Nanjing, People's Republic of China

An analysis approach that based on the Granger causality method is proposed to study the directional effective influence between brain regions in fMRI data. Granger causality was employed to extracted BOLD signals to investigate effective connectivity in the brain network. Data from an emotion task were used to validate this method, and the emotion pathway was clarified illustrated focus on the right amygdala. The presented results, exploring directional influences between activated brain regions, indicated that the Granger causality mapping combined with  principal component analysis could improve existing applications of traditional pairwise Granger causality mapping method in human brain  connectivity studies.

15:00         3602.     A Comparison of the Abilities of Structural Equation Modeling, Autoregressive Analysis, and Granger Causality to Detect Path Weight Differences in Effect Connectivity Results Calculated from Real FMRI Time Series Data [Not Available]

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Suzanne Theisen Witt¹, M Elizabeth Meyerand¹

¹University of Wisconsin, Madison, Wisconsin, USA

Structural equation modeling (SEM), autoregressive analysis (AR), and Granger causality (GC) are three commonly used methods for calculating effective connectivity from fMRI data.  A comparison of these methods’ abilities to detect differences in path weights between two different simple motor tasks is presented.  The results of the comparison suggest that, although the path weights estimated using SEM exhibit a much larger dynamic range than those obtained using AR and GC, these latter two methods may be as good or better than SEM at detecting path weight differences.

13:30         3603.     The Effects of Time Length on Resting-State Functional Connectivity

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Jun Xie¹, Gao-Hong Wu¹, Shi-Jiang Li¹

¹Medical college of Wisconsin, Milwaukee, USA

In this study, we investigated the effects of time length on resting-state functional connectivity. EPI data were acquired at 3T in 10 resting normal subjects. The patterns of motor cortex connectivity were compared using different scan time lengths. Our data suggest that about 400 second scanning provides the best tradeoff between the quality of connectivity map and scan time.

14:00         3604.     Spatiotemporal Dynamics of Low Frequency Fluctuations in BOLD FMRI of Rats

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Waqas Majeed¹, Matthew Magnuson¹, Shella Keilholz¹

¹Georgia Institute of Technology / Emory University, Atlanta, Georgia, USA

This abstract presents:

1) Spatial patterns evolving over time in low frequency BOLD fluctuations in rat cerebral cortex

2)Preliminary classification of these fluctuations into different 'states'

14:30         3605.     Measuring Connectivity in Sensory Cortex Using an FMRI Adaptation Paradigm

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Laura M. Parkes¹, Rishma Vidyasagar¹, Stephen Folger²

¹University of Liverpool, Liverpool, UK; ²Elon University, USA

fMRI adaptation paradigms probe neural activity on a millisecond timescale. We investigate whether this approach can be developed to measure ‘connectivity’ between two regions in the somatosensory cortex. Paired vibrotactile pulses are given to digits 2 and 4 at intervals of 50, 200 and 400ms. A reduction in BOLD amplitude is seen in all subjects at 200ms compared to 50ms and 400ms. This could be due to the first pulse inhibiting neighbouring regions, reducing excitability, and so reducing the response to the second pulse. This demonstrates a method of directly measuring the influence and timing of interactions between sensory regions.

15:00         3606.     The Anatomical Basis of Rest Functional MRI

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Aviv Mezer¹, Yossi Yovel¹, ofer Pasternak¹, Tali Gorfine¹, yaniv assaf¹

¹Tel Aviv University, Tel Aviv, Israel

Basal activity measured with fMRI raised tremendous interest among neuroscientists since functional brain activity could be retrieved while the subject rests (resting state fMRI). We show here that the basis of the resting-state fMRI signal – the blood oxygenation level dependent (BOLD) contrast – has a strong anatomical basis in addition to its functional components. We found high similarity between the clusters of the repeated BOLD measures and atlas segmentation. We suggest that multi-dimensional brain MRI acquisition can be used for parcellation of the brain into regions that could not be extracted with conventional MRI.

fMRI: ICA & Clustering Analysis

13:30         3607.     Independent Vector Analysis for Group FMRI Processing

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Jong-Hwan Lee¹, Matthew Marzelli¹, Ferenc A. Jolesz¹, Seung-Schik Yoo¹

¹Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts, USA

We propose to develop an independent vector analysis (IVA) scheme to address the permutation problem of the conventional ICA-based group processing scheme. IVA operates to increase independence across output vector components while maintaining dependence among scalar elements within each output vector component (i.e. across frequency bins within the same output index). The ¡®dependence¡¯ in group fMRI processing is analogous to mutual/similar activation patterns across subjects, which are comparable to the group trend in activation.

14:00         3608.     A Method for Group Difference Enhancement by Constraining Mixing Coefficients of ICA Framework

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Jing Sui¹, Vince Calhoun¹,²

¹The Mind Research Network, Albuquerque, USA; ²University of New Mexico, Albuquerque, USA

We proposed a novel algorithm called CCICA (constrained coefficient ICA) by incorporating prior statistical group information as constraint into the general ICA framework. Our algorithm improved the capability for identifying the independent component showing the largest group difference related to the mixing coefficients. Applications to both hybrid and real fMRI data demonstrate that CCICA is a promising method for identification of components that can best distinguish schizophrenia patients and healthy controls, and further, it may be more sensitive for extracting features that can serve as potential brain imaging biomarkers of disease.

14:30         3609.     Assessing Reliability of ICA Estimates by Resampling and Clustering

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Radu Mutihac¹

¹University of Bucharest, Bucharest, Romania

Analysis of artificially generated fMRI-like data drawn from a single-shot gradient-echo MR EPI block-based visual stimulation paradigm was performed by the stochastic neuromorphic extended Infomax algorithm implementing spatial independent component analysis (sICA). Reliability assessment of the results was carried out by resampling-based techniques and clustering. Fourier and wavelet transforms, which contain weak implicit models of temporal noise, and whitening, which is driven by an explicit noise model, were employed to resampling and setting the appropriate thresholds. Variance estimate that is highly correlated with the separation error was used as model selection criterion for optimizing the parameters of the sICA algorithm.

15:00         3610.     fMRI Clustering Based on Connectivity Profiles

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samuel emeriau¹,², Fabien Giersky³, Laurent Pierot³, Eric Bittar¹

¹Université de Reims Champagne-Ardennes, Reims, France; ²Philips Systèmes Médicaux, Suresnes, France; ³University Hospital of Reims, Reims, France

fMRI clustering based on connectivity profiles offers two major advantages in comparison with the classical clustering method: it allows dealing with the problem of spatial correlation of noise that can lead to bad mergings in functional domain and it allows defining a new functional dimension exclusively based on the data without taking the paradigm into account trough specified regressors. The resulting clusters form a partition of the data in homogeneous regions according to both spatial and functional connectivity points of view.

fMRI: Mechanisms

13:30         3611.     Investigating the Source of BOLD Nonlinearity

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Nanyin Zhang¹, Xiao-Hong Zhu¹, Wei Chen¹

¹University of Minnesota, Minneapolis, Minnesota, USA

The nonlinear effects in BOLD signal have posed a serious problem in rapid ER fMRI designs. To solve this problem, detailed investigation of the source of BOLD nonlinearity is essential. However, little effort has been spent in separating the potential source of neuronal activity attributing to the nonlinearity observed in BOLD data. The obscurity in this issue seriously impedes accurate modeling of BOLD nonlinearity. Therefore, to find the originality of the BOLD nonlinearity, we have employed a paired-stimulus paradigm in absence of neuronal refractoriness and measured the corresponding BOLD responses. The results indicate that the BOLD nonlinearity can completely be vascular origin.

14:00         3612.     Transient and Steady-State Components of the FMRI BOLD Signal in Somatosensory Cortex

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Michael Marxen¹, Tara L. Dawson¹, Fred Tam¹, Simon J. Graham¹,²

¹Baycrest Centre for Geriatric Care, Toronto, Canada; ²University of Toronto, Toronto, Canada

Previous MEG studies have demonstrated transient and steady-state evoked reponses to vibrational touch stimuli to a finger with spatially separated dipole locations in primary somatosensory cortex. The goal of this study is to extract transient and steady state components from the fMRI BOLD response to repeated vibrational stimuli of different durations. In the first three subjects of an ongoing larger study, we found differences in the transient and steady-state activation maps that may reflect transiently and continuously firing neuronal populations. A paired comparison with MEG transient and steady-state dipole locations is in progress.

14:30         3613.     Steady-State to Transient Change of CMR_O2: Dynamic Calibrated FMRI at 11.7T

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Basavaraju Ganganna Sanganahalli¹, Peter Herman¹, Fahmeed Hyder¹

¹Yale University, New Haven, Connecticut, USA

We studied the relationship between fMRI BOLD, evoked CBF and the electrical activity of neuronal origin. The BOLD, CBF, CBV and LFP were examined in experiments where the number of the stimuli (2mA, 0.3ms) at rat forepaw was increased from one to four with varying inter pulse interval (IPI) of (167ms, 333ms, 666ms). We found variable dependencies of each measured component (BOLD, CBF, CBV, LFP) with IPI. We found that CMR _O2 contributed to BOLD even with IPI of less than 200 ms (i.e., 6 Hz). These results suggest that BOLD at high field (of 11.7T) has sensitivity to reveal a significant CMRO2 component for extremely short events

15:00         3614.     Assessment of the Significance of Temporal Delays in the BOLD Signal Response to a CO2 Stimulus

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julien poublanc¹, Jay Shou Han², Danny Michael Mandell¹, Jeffrey A. Stainsby³, Joseph A. Fisher⁴, David J. Mikulis¹, Adrian P. Crawley¹

¹Toronto Western Hospital, Toronto, Canada; ²Toronto General Hospital, Toronto, Canada; ³GE Healthcare, Toronto, Canada; ⁴Toronto General Hospital , Toronto, Canada

Cerebrovascular reactivity imaging combines BOLD MRI with inhaled CO2 to measure brain’s autoregulatory capacity.  Although the magnitude of the BOLD signal is primarily employed to assess reactivity, the temporal delay of the BOLD response contains useful information, investigated in this study.  We calculated a time delay parameter that significantly correlates with the reactivity parameter, as well as with the time to minimum of the dynamic susceptibility contrast images.  We have also observed that the main time delay  occurs not on onset of hypercapnia but arises from a late return to baseline after the ETpCO2 has already decreased.

13:30         3615.     Quantifying the FMRI BOLD Signal to Characterize the Event-Related Electrophysiological Response

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Zhongming Liu¹, Bin He¹

¹University of Minnesota, Minneapolis, Minnesota, USA

In the present theoretical study, we establish a linkage between the quantified BOLD effect size and  the event-related electrophysiological response. Based upon an assumed linear neurovascular coupling, the BOLD effect size at each voxel can be explicitly interpreted as proportional to the time integral of the power of the event-related local synaptic current flow. This relationship contributes to a more rigorous theoretical framework for fusing fMRI and EEG/MEG, which leads to an advanced high-resolution multimodal neuroimaging technique.

14:00         3616.     Towards a Quantitative Relationship Between the BOLD Signal and Deoxyhemoglobin Measured by Near-Infrared Spectroscopy

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Dharmesh R. Tailor, MD, PhD¹, Yu Chen, PhD, Ravinder Reddy, PhD

¹University of Pennsylvania, Philadelphia, Pennsylvania, USA

A quantitative relationship is established between the gradient-echo and the spin-echo based BOLD signal and the deoxyhemoglobin concentration measured by near-infrared spectroscopy in the rat brain. This approach provides a more direct means of calibrating the BOLD signal using the recently proposed hyperoxia approach. Furthermore, spin-echo based methods are shown to be sensitive not only to dissolved oxygen but also to deoxyhemoglobin directly. Additionally, spin-echo based T1?-weighted imaging in demonstrated in humans to yield detectable signal changes due to a change in fraction of inspired oxygen.

14:30         3617.     Baseline Cerebral Blood Flow Modulates Functional Perfusion Activation Maps But Not BOLD Activation Maps

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Joy Liau¹, Joanna Perthen¹, Thomas T. Liu¹

¹University of California at San Diego, La Jolla, California , USA

This study examines the dependence of functional perfusion or cerebral blood flow (CBF) and BOLD activation maps on baseline CBF.  We used a caffeine dose (200mg) to reduce the baseline CBF and found concurrent decreases in the activation map area based on the CBF response but not the BOLD response.  Also, measures of baseline CBF accounted for a significant portion of the inter-subject variability in CBF activation map area. Factors that can modulate baseline CBF, such as age, medication, and disease, should therefore be carefully considered in the interpretation of studies that use functional CBF activation maps.

15:00         3618.     Strong Correlation of Spin-Echo BOLD Signal with Neuronal Activity in Rat Cortex During Forepaw Stimulation

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Ikuhiro Kida¹, Toru Yamamoto¹

¹Hokkaido University, Sapporo, Japan

The relation between signal in neuroimaging techniques and the neuronal activity is essential to investigate brain function. However, the correlation of the BOLD signals with neuronal activity is still unclear. We investigated whether the spin-echo (SE) BOLD signal correlates with neuronal activities during rat forepaw stimulation with various stimulus currents and frequencies (0.5-2.0 mA and 1-10 Hz). We found that the SE-BOLD signal linearly increases with the integration of somatosensory evoked potential amplitude for all stimulus conditions. This result indicates that the SE-BOLD signals may elucidate the neural activity quantitatively.

fMRI: Multimodal & Single Trial

13:30         3619.     Retrospective Synchronization (Resync) Avoids the Residual MRI Gradient Artefact in EEG-MRI Experiments

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Hendrik Mandelkow¹, Pascal Halder², Daniel Brandeis², Peter Boesiger¹

¹University and ETH Zurich, Zurich, Switzerland; ²University of Zurich, Zurich, Switzerland

We present a new software synchronization method which improves the post- processing of EEG-fMRI data for the purpose of removing the notorious MRI gradient artefact. Furthermore, we propose a new procedure for quantifying and comparing the cleaning performance of different post-processing algorithms for EEG-fMRI data. The comparison based on in-vivo data as well as simulations of the MGA at high bandwidth shows that the retrospective synchronisation algorithm can improve or even replace hardware synchronisation as well as other post- processing methods such as slice timing correction and PCA. 

14:00         3620.     Comparison of SQUID and MR Detection for Weak Magnetic Fields

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Martyn Paley¹, Eugeny Krjukov¹, LiSze Chow¹

¹University of Sheffield, Sheffield, UK

This study compares the sensitivity of a single channel SQUID and a 3T MRI system using phantoms and investigates axonal bursts in the median nerve using transcutaneous electrical nerve stimulation (TENS) stimulation using the SQUID.

14:30         3621.     Simultaneous FMRI/CBV and EEG During Spike-Wave Seizures in WAG/Rij Rats

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Asht Mangal Mishra¹, Damien John Ellens, Ulrich Schridde,¹², Joshua Ethan Motelow¹, Michael J. Purcaro¹, Fahmeed Hyder¹, Hal Blumenfeld¹

¹Yale University School of Medicine, New Haven, Connecticut, USA; ²YMPI for Biological Cybernetics, Tübingen, Germany

In absence and other generalized seizure disorders, an abnormal electrical activity termed as spike-wave discharges (SWD) is observed by EEG. fMRI during SWD in humans and animal absence epilepsy models show both increases and decreases in BOLD signals. Here we show regional BOLD increases/decreases during SWD accompanied by CBV increases/decreases in nearly the same areas for anesthetized WAG/Rij rats. Further work will be needed to determine if regions of BOLD decreases during SWD represent vascular steal, a primary neuronal mechanism, or a defect in neurovascular coupling. These findings will be important for the interpretation of various fMRI signals in human absence epilepsy.

15:00         3622.     Simultaneous Single Unit and BOLD FMRI Recordings

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D Aksenov¹, Limin Li¹, G Iordanescu¹, Alice M. Wyrwicz¹

¹ENH Research Institute, Evanston, Illinois, USA

Brain hemodynamic functional signal and the corresponding neuronal activity are recorded in an awake, behaving rabbit at high fields.

13:30         3623.     Detection of Single-Trial Events in BOLD FMRI Without Prior Stimulus Information

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Cesar Caballero¹, Natalia Petridou¹, Sue Francis¹, Ian Dryden¹, Li Bai¹, Penny Gowland¹

¹University of Nottingham, Nottingham, UK

The aim of this work is to map in space and time the brain’s response to single stimuli without prior knowledge of stimulus timing. Detection of single-trial events in BOLD fMRI time series is a challenge especially in the presence of physiological and systematic fluctuations. Here, a procedure based on Wiener deconvolution is proposed to detect single-trial events with no prior information on stimuli timing. Automatic detection is carried out only assuming a general shape for the hemodynamic response function, and employing tissue-dependent noise characterization. This technique allowed identification of individual trials, and the spatiotemporal evolution of the BOLD response.

14:00         3624.     Increased Statistical Power of in Event-Related Real-Time FMRI (ErfMRI) Using Individual Hemodynamic Response Functions: First Results at 3T and 7T

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Maurice Hollmann¹, Tobias Moench¹, Sebastian Baecke¹, Michael Luchtmann¹, Claus Tempelmann¹, Joerg Stadler², Johannes Bernarding¹

¹University of Magdeburg, Magdeburg, Germany; ²Leibniz Institute for Neurobiology, Magdeburg, Germany

Assumptions about the hemodynamic response function (HRF) are used as basis in many fMRI analysis methods. However, the variability of the HRF between subjects, and intra-subject between different brain regions may reduce the statistical power if this assumptions are improper. Acquiring more data to counteract this effect is generally not feasible in real-time fMRI. We analyzed the functional data in event-related real-time fMRI with individual region-based HRF estimates acquired during the experiment-session prior to the main measurement. Using individual HRF estimates instead of the SPM canonical HRF led to an improvement in the statistical significance by an average of 25%.

14:30         3625.     Effects of High Field MR Scanner on Simultaneous EEG Data Quality for Single-Trial Discrimination

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Cheng-Yu Wei¹, Robin I. Goldman¹, Paul Sajda¹, Truman R. Brown¹

¹Columbia University, New York, New York, USA

The emerging technology of recording simultaneous EEG/fMRI allows direct measuring and comparison of brain responses to stimuli. Being able to follow changes in attention, adaptation or habituation on a single trial basis by using single trial EEG data to reveal brain regions which correlate with variations in these should considerably advance our understanding of cognitive processing. The simultaneously recorded EEG at 3T, examined with power spectrum analysis were of high quality to allow these single-trial investigations. Quality Assurance tests confirmed that fMRI data, in terms of spatial and temporal SNR, was acceptably stable across time to carry out brain functional studies.

15:00         3626.     A Model Phantom for Investigating Concurrent EEG/fMRI

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Gerða Björk Geirsdóttir¹, Matthew J. Brookes¹, Karen J. Mullinger¹, Winston X. Yan¹, Peter Morris¹, Richard W. Bowtell¹

¹University of Nottingham, Nottingham, UK

Simultaneous EEG/fMRI is a technique that makes functional imaging with high spatiotemporal resolution possible.  However, artefacts induced in EEG recordings by the MR scanner make this challenging. The use of an EEG phantom to conduct simultaneous EEG/fMRI experiments provides a means for validating and improving artefact correction techniques, and for investigating possible sources of the observed artefacts.  Here, two different types of saline loaded agar phantoms are described, a dipole phantom which enables measurements of signals with a specific time-course, and a flow phantom with an added aqueduct designed specifically to mimic blood flow.

Bone

14:00         3627.     Advantages of Isotropic Voxel Size for Classification of Trabecular Bone Struts and Plates in Micro-MR Images

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Branimir Vasilic¹, Jeremy Magland¹, Michael Wald¹, Felix W. Wehrli¹

¹University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA

A new method, based on local inertial anisotropy, has recently been introduced to classify trabecular elements into rods and plates. It relies on a locally calculated tensor of inertia to estimate the class (rod/plate) to which each voxel in the image belongs as well as the orientation of the corresponding rod or plate. While the structure of trabecular bone is anisotropic and can be used to justify the use of high-resolution imaging with an anisotropic voxel size, we show here that images acquired with isotropic voxel size have advantages in faithfully representing the underlying structure of trabecular bone.

14:30         3628.     On-Line Prospective Registration of Trabecular Bone MR Images for Longitudinal Examinations

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Chamith S. Rajapakse¹, Jeremy Magland¹, Felix W. Wehrli¹

¹University of Pennsylvania School of Medicine, Philadelphia, USA

In micro-MRI studies of trabecular bone designed to evaluate structural changes in response to therapeutic intervention, follow-up scan volumes do not typically align with the baseline data due to inaccuracies in patient positioning and scan prescription. These limitations can be overcome by incorporating prospective registration into the acquisition protocol. The technique is based on registering 3D localizer images, acquired prior to the high-resolution images, on-site with an algorithm relying on maximizing the correlation between baseline and follow-up localizers. In phantom and human subject studies it is shown that prospective registration yields very close matching between baseline and follow-up imaging volumes.

15:00         3629.     Proton NMR Study of Transverse Relaxation of Rabbit and Rat Cortical Bone

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Henry H. Ong¹, Suzanne L. Wehrli², Felix W. Wehrli¹

¹University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania, USA; ²NMR Core Facility, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA

The NMR signal from cortical bone results from protons in collagen as well as water in the Haversian system. Characterizing transverse relaxation behavior may provide insight into bone composition and architecture. Here, we calculated T2* and T2 components of rabbit and rat cortical bone specimens from bi-exponential fits of FIDs and CPMG signal decays. Both species showed a similar short T2* component arising from collagen. The rat showed a larger short T2 fraction, suggesting a smaller fraction of Haversian canals compared with rabbit. The majority of the bone signal is comprised of water with T2* and T2 values of 200-400us.

15:30         3630.     Density, Structure and Texture Quantitation of Bone Trabeculae at 3.0 Tesla

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Gary Paul Liney¹, Clare P. Bernard¹, Chris M. Langton, Lindsay W. Turnbull¹

¹University of Hull, Hull, UK

1) To validate the use of bone volume fraction (BVF) derived from MRI as a surrogate measure of volumetric density. 2) To investigate the structural and textural relationships of bone trabeculae. 3) To compare imaging coils and sequences in terms of their ability to demonstrate these relationships in clinically relevant protocols, and to obtain an optimised protocol for in vivo acquisitions.

14:00         3631.     A Distance Weighted Directional Gradient Method for Fully Automatic Bone Segmentation of Knee MRI

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Feng Huang¹, Xiaoming Chen², Deliang Ye¹, Sarah Hertel³

¹Invivo Corporation, Gainesville, Florida, USA; ²University of Florida, Gainesville, Florida, USA; ³Invivo Corporation, Pewaukee, Wisconsin, USA

Fully automatic knee segmentation is desired since it is both time- and cost-efficient. The widely adopted Chan-Vese (CV) model could be used to implement a fully automatic segmentation technique. However, direct application of CV model on knee segmentation has a difficulty in separating different bones (Femur, Tibia and Patella) since these bones have similar intensity level. In this study, a distance weighted directional gradient method is proposed to automatically separate these bones, and define masks for further bone segmentation. With this technique, different bones can be isolated and fully automatic bone segmentation can be achieved without using any prior shape information.  The proposed method was tested on 14 data sets of knee MRI. Results show that the proposed location detection technique can always provide accurate bone locations.

14:30         3632.     Accuracy in Trabecular Bone Structural Measurement from High-Resolution Images Acquired with GRAPPA-Based Parallel Imaging

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Ben Hyun¹, Suchandrima Banerjee¹,², Sharmila Majumdar¹,²

¹University of California, San Francisco, San Francisco, California , USA; ²University of California, Berkeley, Berkeley, California , USA

High-resolution magnetic resonance images of the distal radius were acquired to assess the accuracy of bone micro-architecture measurements using GRAPPA-based parallel imaging. Unaccelerated and accelerated images were acquired then analyzed using 2D histomorphometric based analysis to assess image fidelity and reproducibility.

15:00         3633.     Comparison of Mechanical Properties of Trabecular Bone Derived from μMRI and μCT

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Chamith S. Rajapakse¹, Jeremy Magland¹, Suzanne L. Wehrli, X Henry Zhang², X Sherry Liu², X Ed Guo², Felix W. Wehrli¹

¹University of Pennsyslvania School of Medicine, Philadelphia, USA; ²Columbia University, New York, USA

Studies have shown that prediction of bone strength can be improved by including structural properties in the analysis in addition to bone density. The aim of this work was to address to what extent mechanical properties of trabecular bone (TB), measured in terms of Young’s and shear moduli, derived from _μMRI, compare with those obtained by _μCT at high resolution. To answer this question TB samples were imaged using _μMRI and _μCT. The data indicate that mechanical constants correlate well between the two modalities and the correlation can be improved by correcting for the bone volume fraction mismatch between them.

15:30         3634.     Investigation of Subchondral Bone Cysts and Cartilage Defects Using in vivo 9.4T MRI in a Model of Osteoarthritis

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David D. McErlain¹,², Joe S. Gati,², Vasek Pitelka,², Jeffrey Mason,², Rob Bartha,², David W. Holdsworth,²

¹Robarts Research Institute, London, Canada; ²The University of Western Ontario, London, Canada

The main purpose of this study was to use high-field MRI, combined with micro-computed tomography, to assess the various bone and cartilage abnormalities associated with a rodent model of Osteoarthritis.  The use of pre-clinical models allows for the testing of future pharmacological interventions to treat Osteoarthritis.  The benefit of using this technology allows us to scan live rats repeatedly, over 4 week intervals, in less than an hour per session.

From these images, we have quantified the loss of cartilage within the knee joint, as well as the appearance of subchondral bone cysts, after the rat undergoes surgical destabilization.

Spine

14:00         3635.     Comparison of Lumbar Artery Anatomy and Degenerative Disc Disease in Healthy Controls and Patients with Low Back Pain Combination of Dynamic, Contrast Enhanced Perfusion and MR-Angiogram in the Lumbar Spine Using a 3Tesla MRI

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Shadfar Bahri¹, L. Tugan Muftuler¹, Hon J. Yu¹, Min- Ying Su¹, Jamshid Tehranzadeh¹, Anton Hasso¹, Orhan Nalcioglu¹, Vance Gardner²

¹University of California, Irvine, USA; ²Orthopaedic Education and Research Institute of Southern California, Orange, USA

This study investigates the feasibility of a lumbar MRA and vertebral body-perfusion in a single examination. Since the lumbar arterial anatomy has not fully been investigated in vivo so far, the role of the segmental arteries in perfusion of the vertebral body and ultimately delivery of nutrients to the avascular disc is of interest. 31 Healthy controls and patients with back pain have been scanned and the segmental arteries and discs were graded. The control group (8) all showed healthy discs and normal arterial anatomy. The patient group (23) showed 22/23 (94.7%) unhealthy discs and 13/23 (56.5%) stenotic or occluded segmental arteries.

14:30         3636.     Apparent Diffusion Coefficient and Fractional Anisotropy in the Vertebral Bone Marrow [Not Available]

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Yu Ueda¹, Tosiaki Miyati¹, Naoki Ohno¹, Yuko Motono¹, Asuka Kouhara¹, Masaki Hara², Yuta Shibamoto², Harumasa Kasai², Miyuki Asahi²

¹Kanazawa University, Kanazawa, Japan; ²Nagoya City University Hospital, Nagoya, Japan

To assess the state of cancellous tissue, we analyzed ADC and fractional anisotropy (FA) in the vertebral bone marrow using single shot diffusion echo planar imaging. A strong negative correlation was found between ADC and DXA-BMD below moderate marrow fat fraction. Significant correlation was noted between ADC and fat fraction. There was a positive correlation between FA and DXA-BMD, and no correlation between FA and FF in the vertebral bone marrow. In conclusion, diffusion analyses with ADC and FA make it possible to obtain more detailed information of the structure of cancellous tissue and the bone metabolism.

15:00         3637.     Mapping Bone Marrow Composition in the Lumbar Spine at 3.0 Tesla

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Gary Paul Liney¹, Clare P. Bernard¹, Chris M. Langton, David J. Manton¹, Lindsay W. Turnbull¹

¹University of Hull, Hull, UK

1) To compare data from two quantitative fat imaging methodologies acquired in the lumbar spine. 2) To map the inter-vertebral and age related variations in fat fraction at high spatial resolution. 3) To assess the relationship between volumetric density and marrow content.

15:30         3638.     MR Spectroscopy in Intervertebral Disc -- A Feasibility Study

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Jin Zuo¹, Azucena Rodriguez¹, Xiaojuan Li¹, Thomas Link¹, Jeffrey C. Lotz¹, Sharmila Majumdar¹

¹Univ. of California, San Francisco, San Francisco, California , USA

Intervertebral disc degeneration usually begins with biochemical changes within the disc. Quantifying the concentration of the metabolites in the discs would provide objective and important information that is associated with disc degeneration. In this study, the non-invasive single voxel MR spectroscopy was used to assess the concentration of metabolites in intervertebral disc on cadaveric discs. The peak height ratios of the metabolite was correlated with the Pfirrmann grading scheme. In addition, a preliminary in vivo human study was conducted.

Ultra-Short TE MRI in Musculoskeletal Imaging

13:30         3639.     Ultrashort TE (UTE) Imaging with Off-Resonance Saturation: Creating High Contrast for Short T2 Tissues

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Jiang Du¹, Atsushi Takahashi², Christine B. Chung¹, Graeme M. Bydder¹

¹University of California, San Diego, San Diego, California , USA; ²GE Healthcare Technologies, Menlo Park, California , USA

The human body contains a variety of short T2 tissues, including cortical and trabecular bone, tendon, ligaments, etc. Magnetization from these tissues can not be spatially encoded between excitation and acquisition before the signal has completely decayed. These short T2 tissues have a much broader absorption lineshape than the long T2 tissues, making them more sensitive to an appropriately placed off-resonance irradiation. Here we present a technique which combines ultrashort TE (UTE) acquisition with magnetization transfer effect to directly image short T2 tissues with high signal and contrast on a clinical 3T scanner.

14:00         3640.     Quantitative Characterization of the Connective Tissues of the Fingers in Cadaveric Specimens: T1 and T2* Measurements Using Ultrashort Echo Time (UTE) MR Imaging in 3T

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Berna Dirim¹,², Jiang Du¹, Sheronda Statum¹, Richard Znamirowski¹, Byung Pak¹, Graeme Bydder¹, Christine B. Chung¹

¹University of California San Diego, San Diego, California , USA; ²Izmir Ataturk Egitim ve Arastirma Hastanesi , Izmir, Turkey

Little or zero signal is detected from the short T2 tissues with routinely used pulse sequences. UTE pulse sequences can detect signals from these tissues; allow them to be imaged and quantified. We present UTE imaging (minimal TE = 8 &[micro]s)and quantitative T1 and T2* characterization of the connective tissues. Six frozen hand specimens were used. Dual echo UTE pulse sequence, for T1 measurement a UTE saturation recovery technique and T2* measurement UTE acquisition with variable TE delays were applied. UTE sequences provide high signal imaging of them and T1, T2* measurements to evaluate them using a clinical scanner.

14:30         3641.     Ultrashort TE (UTE) Imaging of the Extensor Tendon Functional Entheses of the Finger

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Richard Znamirowski¹, Mark Bydder¹, Christine B. Chung¹, Jiang Du¹, Atsushi Takahashi², Won Bae¹, Sheronda Statum¹, Graeme M. Bydder¹

¹University of California, San Diego, San Diego, California , USA; ²GE Healthcare Technologies, Menlo Park, California , USA

Entheses are regions where tendons, ligaments or joint capsules are connected to bone. Conventional clinical magnetic resonance (MR) imaging has not been helpful in demonstrating the key tissues present in normal entheses. All these tissues have short transverse relaxation times (T2s), and show little or no signal with typical clinical pulse sequences which have echo times (TEs) of about 8-20 msec or longer. As a result the component tissues of entheses have not previously been identifiable with imaging. Here we report ultrashort TE (UTE) imaging of finger enthesis with high spatial resolution and contrast using a purpose designed finger coil.

15:00         3642.     A Comparison of UTE Versus SPRITE for Robust MR Imaging of Short T₈ Components

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Alexandre A. Khrapitchev¹, Nicola R. Sibson¹, Matthew D. Robson¹, Andrew M. Blamire,¹²

¹University of Oxford, Oxford, UK; ²University of Newcastle, Newcastle, UK

This is a practical comparison between SPRITE and UTE on a 7T animal system. SPRITE is more suitable for imaging of extremely short T₈ species, but requires some extra care to avoid damaging gradient systems. UTE can provide shorter examination times but is more challenging to implement and is sensitive to gradient imperfections.

Small Animal Musculoskeletal Imaging

13:30         3643.     Simultaneous Non-Invasive Determination of Tissue Perfusion, Arterial Blood Pressure and Peripheral Vascular Resistances in Mice

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Jacques Ménard¹, Eric Giacomini¹, Céline Baligand¹, Didier Bertoldi¹, Pierre Carlier²

¹Institute of Myology , Paris, France; ²Institute of Myology, Paris, France

We developed a new multiparametric 1H-NMR approach to explore non-invasively the muscular microcirculation in mice. Using a custom-developed setup, we have automated a procedure that allows dynamic determination of skeletal muscle perfusion, systemic blood pressure and vascular resistances in mice. Within a single NMR examination, this non-invasive NMR method can be used to explore the microcirculation control in mouse models. As an application, we showed in vivo that peripheral vascular resistances were increased in the skeletal muscle of db/db mice suffering from type-2 diabetes mellitus.

14:00         3644.     Simultaneous High-Resolution Imaging of Mouse Knee and Ankle at 3.0T Using a Specially Designed Dual Array Coil
[Not Available]

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Zhigang You¹, Wingchi Edmund Kwok¹, Steve Proulx¹, Edward Schwarz¹

¹University of Rochester, Rochester, New York, USA

We have been conducting longitudinal mice knee studies to evaluate arthritides.  To enable evaluation of extra-articular manifestations of arthritides and development of multi-organ models, we developed a dual RF coil for simultaneous imaging of mouse knee and ankle at 3T.  Since this coil covers only the joint regions needed to be imaged, the total effective coil volume is minimized resulting in high SNR to support high-resolution imaging with 100-micron level resolution.  Preliminary data on transgenic mice show this coil can provide information potentially useful for the development of multi-organ models.  It should be useful for longitudinal mouse studies of arthritides.

14:30         3645.     MR Texture Analysis of Regenerating Mouse Muscle at 7T: An In-Vivo Study

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Sandra Même¹, Catherine Sébrié², Jean-Claude Beloeil¹, Brigitte Gillet²

¹CNRS CBM UPR4301, Orléans, France; ²ICSN CNRS UPR2301, Gif-sur-Yvette, France

The mdx mouse is a model of human muscular dystrophy characterized by a genetic deficiency for dystrophin which leads to numerous spontaneous muscle fibers degeneration-regeneration cycles which are difficult to interpret. A mouse model of muscle injury (with injection of notexin) involving a single well-defined cycle of degeneration-regeneration was studied to distinguish between these two processes, using  both MRI texture analysis and histological data. More precisely the aim of this study was to a) monitor the muscle degeneration-regeneration process and b) to define more precisely the local variations of the muscle texture after notexin injection .

15:00         3646.     In Vivo MRI of Rabbit Intervertebral Disc Degeneration at 9.4 T: MR Parameters Quantification Allows Identification of Degenerative Discs

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Fanny Noury¹, Sandra Même¹, Jean-Claude Beloeil¹, Bich-Thuy Doan¹,²

¹CBM - CNRS UPR4301, Orleans, France; ²ICSN - CNRS UPR2301, GIF-SUR-YVETTE, France

Intervertebral disc (IVD) degeneration is a complex process characterized by biochemical and structural changes. To study these mechanisms, we follow up the in vivo IVD degeneration by MRI on a rabbit animal model of human lumbar diseases at 9.4 T. To our knowledge, this is the first in vivo study of rabbit IVD degeneration at high magnetic field.

We were able to establish a disc degeneration phase classification to characterize the disc degeneration processes chronology.

This work is a part of a larger project, aiming to estimate the efficiency of new disc restitution methods in rabbit.

Cartilage

13:30         3647.     Enhancement of MT, CEST and NOE Contrast Via Intermolecular Multiple Quantum Coherences

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Wen Ling¹, Uzi Eliav¹, Xu Yang², Gil Navon¹, Alexej Jerschow²

¹Tel Aviv University, Israel; ²New York University, New York, New York, USA

We demonstrate that using intermolecular multiple-quantum coherences can enhance contrast in MTC/CEST/NOE experiments in proportion to (Mz/Mo)p, where Mz  is the the saturated level of the z-component of the magnetization, Mo its value in equilibrium and l is the coherence order used. These methods are demonstrated on a series of glycosaminoglycan (GAG) samples, and also for a piece of bovine articular cartilage.

14:00         3648.     in-vivo T₈ Mapping and DGEMRIC of Human Hip Cartilage at 1.5T

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Matthew F. Koff¹, David W. Stanley², Michele R. D'Apuzzo¹, Robert T. Trousdale¹, Kimberly K. Amrami¹, Kenton R. Kaufman¹

¹Mayo Clinic, Rochester, Minnesota, USA; ²GE Healthcare, Proctor, Minnesota, USA

This study evaluated in-vivo T1 and T2 values of hip cartilage. Coronal T2-weighted images centered on the femoral head were acquired. After administration of Gd-DPTA2- followed by walking and rest, coronal T1-weighted images were acquired. Bulk and depth dependent T1 and T2 values of acetabular and femoral cartilages were calculated. No differences between the bulk T1 or T2 values were found. Femoral cartilage T1 values increased significantly from the superficial zone to the deep zone. The current T1 and T2 values are similar to subjects with known pathologies. The combined scanning method enables a comprehensive quantitative analysis of hip cartilage.

14:30         3649.     SPGR and GRE Cartilage Imaging of the Knee at 3T with Water Excitation and 2D Autocalibrating Parallel Imaging

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Richard Kijowski¹, Reed Busse², Scott Reeder¹, Kuya Takami¹, Philip Beatty³, Anja Brau³, Anthony Vu⁴

¹University of Wisconsin, Madison, USA; ²General Electric Healthcare, Madison, USA; ³General Electric Healthcare, Menlo Park, USA; ⁴General Electric Healthcare, Waukesha, USA

The purpose of this study was to document the feasibility of performing dark fluid SPGR and bright fluid GRE cartilage imaging at 3T using water excitation (SSI) and an autocalibrating 2D-accelerated parallel imaging technique called ARC.  SSI-SPGR and SSI-GRE sequences with and without ARC parallel imaging were performed twice on the knees of 8 asymptomatic volunteers.  SNR efficiency and CNR efficiency measurements were performed using a double acquisition addition/subtraction method. ARC accelerated SPGR and GRE cartilage imaging without causing a reduction in SNR and CNR efficiency.

15:00         3650.     High-Resolution Morphological and Biochemical Imaging of Articular Cartilage of the Ankle Joint at 3.0 T Using a New Dedicated Phased Array Coil: In-Vivo Reproducibility Study

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Goetz Hannes Welsch¹, Tallal Charles Mamisch², Michael Weber¹, Stefan Nemec¹, Klaus Bohndorf³, Siegfried Trattnig¹

¹Medical University of Vienna, Vienna, Austria; ²University of Berne, Berne, Switzerland; ³Klinikum Augsburg, Augsburg, Germany

MRI of thin cartilage layers puts challenging demands on imaging techniques. High resolution with sufficiently SNR has to be achieved without prolonging acquisition time too much. High-field-MRI, advanced coil technology, sophisticated sequences and imaging techniques provide the basis of the imaging protocol used in this study.The object was to determine the precision of high-resolution isotropic 3D-TrueFISP imaging of ankle cartilage and to show the feasibility of quantitative T2-imaging.To best of our knowledge this is the first study to evaluate in-vivo high-resolution morphological isotropic(0.31x0.31x0.31mm3) TrueFISP-imaging and biochemical T2-mapping within the ankle joint in a clinically acceptable scan-time of each about 10 minutes.

13:30         3651.     Quantitative and Qualitative Assessment of Multiple New 3T Cartilage Imaging MR Pulse Sequences

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Richard Kijowski¹, Jessica Klaers¹, Kuya Takami¹, Kirkland Davis¹, Michael Tuite¹, Kazuhiko Shinki¹, Anthony Vu², Scott Reeder¹, Walter Block¹, Reed Busse³

¹University of Wisconsin, Madison, USA; ²General Electric Healthcare, Waukesha, USA; ³General Electric Healthcare, Madison, USA

This study was performed to compare multiple promising new MR pulse sequences for evaluating the articular cartilage of the knee joint at 3T. FSE-Cube, MENSA, IDEAL-GRASS, IDEAL-SPGR, COSMIC, and VIPR-SSFP sequences were performed on the knees of 10 asymptomatic volunteers and 5 patients with osteoarthritis.  SNR and CNR measurements were obtained. A qualitative assessment of image quality was performed by 3 musculoskeletal radiologists.   All sequences had certain strengths and weaknesses with no clear cut “winner” in the quantitative and qualitative comparison.  The relative advantages and disadvantages of each sequence may make them best suited for different cartilage imaging applications.

14:00         3652.     Correlation of DTI Derived Metrics with Synovial Fluid Inflammatory Cytokines from Patients of Arthritis with Inflammation of the Knee Joint

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Manoj Kumar¹, Vikas Agarwal¹, Ram KS Rathore², Amit Prasad¹, Jitesh Kumar Singh², Ram Nath Mishra¹, Kashi N. Prasad¹, Rakesh K. Gupta¹

¹Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India; ²Indian Institute of Technology, Kanpur, India

The inflammation that accompanies the pain and swelling associated with inflammatory arthritis is mediated by complex interactions of inflammatory cytokines. DTI was performed in 7 arthritis patients with inflammation (three osteo and four rheumatoid arthritis). JAVA based software was used for DTI data process as well as cartilage segmentation. Synovial fluid was taken from knee joints of these patients and inflammatory cytokines were quantified by ELISA technique. The Pearson’s correlation between DTI derived metrics and inflammatory cytokines was significant. DTI derived metrics and inflammatory cytokines may be used as surrogate markers for the activity of disease in arthritis patients.

14:30         3653.     Quantification of Capillary Blood Flow and Endothelial Permeability in Inflammatory Joint Diseases: MR-Perfusion Results

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Sabine Weckbach¹, Steven P. Sourbron¹, Mike Notohamiprodjo¹, Hans Hatz², José Raya¹, Maximilian F. Reiser¹, Christian Glaser¹

¹University Hospital Munich- Grosshadern, Munich, Germany; ²Klinik Feldafing, Feldafing, Germany

By using a two-compartment model and an MR sequence with high temporal resolution a separate quantification of blood flow and permeability in patients with inflammatory joint diseases seems possible with stable and plausible results. Compared to previous studies a direct measurement of capillary blood flow and a ROI-based mapping of perfusion parameters might improve sensitivity and specificity with regard to future therapy control studies.

15:00         3654.     Assessment of T1 and T2 MRI Parameters as a Predictors of Cartilage Implants Maturation: The Equine Subject Study

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Vladimir Juras¹,², Pavol Szomolanyi,²³, Zuzana Majdisova,²³, Siegfried Trattnig³

¹Medical University of Vienna, Vienna, Austria; ²Slovak Academy of Sciences, Bratislava, Slovakia; ³MR Centre / Highfield MR, Medical University of Vienna, Vienna, Austria

Qualitative and quantitative assessments of MR relaxation parameters T1 and T2 in equine articular cartilage were compared to histology grading. Equine subjects were treated by Matrix-associated Autologous Chondrocyte Implantation (MACI) with three different implant routinely used in clinical applications. The degree of the maturation process could be determined by zonal T2 organization and by absolute quantification of relative R1 of native and repaired cartilage. T2 reflects the matrix organization, whilst R1 is related to proteoglycans content. The results proved that MRI can be prospectively used as a non-invasive imaging modality for post operative monitoring following autologous chondrocyte implantation.

13:30         3655.     T_1ρ Relaxation Evaluation of Knee OA in  a Guinea Pig Model

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Chenyang Wang¹,², Matt Fenty¹, Ari Borthakur¹, George Dodge², Ravinder Reddy¹

¹University of Pennsylvania, Philadelphia, Pennsylvania, USA; ²Thomas Jefferson University, Philadelphia, Pennsylvania, USA

Osteoarthritis (OA) is a painful and costly medical condition, affecting millions of people every year. In this study, we intend to demonstrate the feasibility of using T_1ρ MRI to monitor the progression of OA in a spontaneous animal model. The animal model is based on Dunkin-Hartley guinea pigs, which have been shown to spontaneously develop OA as they age.  In addition, T_1ρ MRI has been shown to be sensitive to OA changes in human and bovine cartilage.  Since T_1ρ MRI is non-invasive, this animal model of OA can be used to evaluate the efficacy of potential OA therapies in vivo.

14:00         3656.     7 Tesla MR - Initial Results on T2 and T2* Mapping of Healthy Articular Cartilage and Cartilage Repair Tissue

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Goetz Hannes Welsch¹, Tallal Charles Mamisch², Sebastian Quirbach¹, Timothy Hughes³, Oliver Kraff⁴, Mark E. Ladd⁴, Christoph Zilkens⁵, Oliver Bieri⁶, Klaus Scheffler⁶, Siegfried Trattnig¹

¹Medical University of Vienna, Vienna, Austria; ²University of Berne, Berne, Switzerland; ³Siemens Medical Solutions, Erlangen, Germany; ⁴University of Essen, Essen, Germany; ⁵University od Duesseldor

Ultra-high-field whole body systems (7.0T) have high potential in future human in-vivo MRI. In musculoskeletal MRI mainly biochemical imaging of articular cartilage may benefit. Here T2 mapping has shown its potential, also in the evaluation of zonal variation as an indicator of hyaline or hyaline-like articular cartilage, however implying high spatial resolution. Thus the aim of our study was to show the feasibility of T2 and additionally T2* relaxation measurements at 7T MRI as well as to evaluate its potential in an initial patient study after matrix associated autologous chondrocyte transplantation (MACT) within the knee.

14:30         3657.     Reproducibility of Automatic Quantitative Analysis of the Articular Cartilages from MEDIC and WeDESS Magnetic Resonance Images of the Knee at 1.5T [Not Available]

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Jurgen Fripp¹,², Valer Jurcak², Ross Holt³, Sebastien Ourselin¹, Craig Engstrem², Stuart Crozier²

¹BiomedIA Lab, e-Health Research Center, Brisbane, Australia; ²University of Queensland, Brisbane, Australia; ³Southernex Imaging, Australia

We present a cartilage segmentation approach for MRIs of the knee and test the reproducibility and test-retest error found when acquiring weDESS and MEDIC images from healthy volunteers at 1.5T.

15:00         3658.     dGEMRIC at 7 Tesla - Feasibility Study

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Siegfried Trattnig¹, Goetz H. Welsch¹, Katja Pinker¹, Timothy Hughes², Oliver Kraff³, Mark Ladd³, Pavol Szomolanyi¹,⁴, Oliver Bieri⁵, Klaus Scheffler⁵, Tallal C. Mamisch⁶

¹MR Centre - Highfield MR, Vienna, Austria; ²Siemens AG, Erlangen, Germany; ³University Hospital, Essen, Germany; ⁴Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia; ⁵

For the quantification of glycosaminoglycan content in articular cartilage delayed Gadolinium Enhanced Magnetic Resonance Imaging of Cartilage (dGEMRIC) is the method of choice.

Ultrahigh field (7T) systems are increasingly used for clinical studies in patients, which provide higher resolution and which may improve diagnostic accuracy.

In this  study the feasibility of dGEMRIC technique at 7T was shown in phantoms and in volunteers with a range between pre-and postcontrast T1 values at 7T similar to 3T. However, to get reliable results inversion recovery technique for T1 mapping has to be performed and the calculation of the delta relaxation rate is mandatory.

13:30         3659.     Novel Usages of Distance Function in Fully Automatic Articular Cartilage Segmentation

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Feng Huang¹, Xiaoming Chen², Deliang Ye¹, Sarah Hertel³

¹Invivo Corporation, Gainesville, Florida, USA; ²University of Florida, Gainesville, Florida, USA; ³Invivo Corporation, Pewaukee, Wisconsin, USA

In this study, we propose to use distance function to attack several difficulties in cartilage segmentation. Distance function of an object is defined as the smallest distance from a point in the domain to the object. Given segmented bones, distance function of these bones can be calculated. In this work, distance function is proposed to:  1) reduce the search region of cartilages; 2) segment cartilages based on the smoothness of cartilage thickness when there is no contrast between cartilages and surrounding soft tissues; 3) separate contacted cartilages when there is no obvious contrast between them; 4) provide thickness map for cartilages. The proposed method was tested on twelve MRI data sets.

14:00         3660.     Development of T-Scores for the Diagnosis of Osteoarthrosis of the Patellofemoral Joint Using Quantitative MR Volumetry of Cartilage

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Sabine Weckbach¹, Annie Horng¹, Gudrun Pforte¹, Raya José¹, Felix Eckstein², Martin Hudelmeier³, Maximilian F. Reiser¹, Christian Glaser¹

¹University Hospital Munich- Grosshadern, Munich, Germany; ²Paracelcus Medical University, Salzburg, Austria; ³Insitute of Anatomy, Salzburg, Austria

The purpose of this study was to evaluate T-scores based on quantitative cartilage volumetric parameters for the diagnosis of patellofemoral osteoarthritis. Sensitivities and specificities obtained for selected cutoff values suggest that T-scores based on quantitative cartilage volumetric parameters may be a suitable adjunct for the diagnostic workup of OA in population based studies / approaches.

14:30         3661.     Kinematic Biochemical Studies of Cartilage Transplants at 3Tesla

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Siegfried Trattnig¹, Tallal Ch. Mamisch², Christina Plank¹, Pavol Szomolanyi¹,³, Sebastian Quirbach¹, Goetz H. Welsch¹

¹MR Centre - Highfield MR, Vienna, Austria; ²Inselspital, Bern, Switzerland; ³Institute of Measurement Science, Slovak Academy of Sciences, Bratislava, Slovakia

A flexible knee coil which allows to assess quantitative cartilage MR data in different positions from 40° flexion to full extension was applied to examine in T2 and diffusivity values in the femoral cartilage of volunteers and patients after autologous chondrocyte transplantation (ACI). Changes of T2 and diffusivity in cartilage could be demonstrated by position dependent contact of two cartilage layers alone. Since repair tissue shows a different behaviour in the contact zone compared to healthy cartilage a possible marker for an improved evaluation of the repair tissue quality after ACI may be available providing biomechanical information on cartilage transplant.

15:00         3662.     3D GRE Sequence with Two Different Flip Angle Excitation Pulses for Zonal T1- Mapping of Articular Cartilage at 3T:  One-Year Follow-Up in Patients After Matrix-Associated Autologous Chondrocyte Transplantation (MACT) of the Knee Joint

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Katja Pinker¹, Pavol Szomolanyi², Goetz Welsch¹, Tallal Charles Mamisch³, Stefan Marlovits⁴, Siegfried Trattnig¹

¹MR Centre of Excelllence, Vienna, Austria; ²Slovak Academy of Sciences, Bratislava, Slovakia; ³Inselspital, Bern, Switzerland; ⁴Medical University Vienna, Vienna, Austria

To evaluate the global and zonal distribution of glycosaminoglycans (GAG) in normal weight-bearing cartilage and repair tissue by dGEMRIC method using a 3D GRE sequence with a 35/10° flip angle excitation pulse combination and to monitor the development of zonal and global GAG content in MACT over one year.

Musculoskeletal Miscellaneous

13:30         3663.     Magnetization Transfer Effects in Human Median Nerve at 3 T [Not Available]

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Giulio Gambarota¹, Ralf Mekle¹, Rolf Gruetter¹,²

¹Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; ²University of Lausanne and University of Geneva , Switzerland

The values of magnetization transfer (MT) ratio are well established for most clinical relevant tissues. However, despite the potential of MT contrast to assess demyelination, which is one of the common features of a number of peripheral nervous system (PNS) pathologies, no measurements of MTR have been performed to date on human PNS. The purpose of this study was to determine the MTR in human median nerve to provide baseline values of MTR for the PNS in healthy volunteers.

14:00         3664.     High-Resolution MR Imaging of the Foot: Magnetization Transfer Effects in Foot Peripheral Nerves

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Giulio Gambarota¹, Ralf Mekle, Rolf Gruetter¹,²

¹Ecole Polytechnique Federale de Lausanne, Lausanne, Switzerland; ²University of Lausanne and University of Geneva, Switzerland

MT contrast in foot nerves could be of interest for early detection of diabetes-induced peripheral neuropathy. In this work, we sought to image foot nerves and to measure the MT ratio (MTR), at 3 T. A substantial reduction of MTR was observed in the nerves (MTR in 25-35% range), compared to muscle (42-50% range). The results of this study indicate that the high signal-to-noise ratio afforded at the field strength of 3 T and the use of high-sensitivity coils allows not only for the visualization of foot nerves but also for quantitative assessment of their intrinsic MR properties.

14:30         3665.     Consistent Automated Scan Planning of Shoulder

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Chiel JM den Harder¹, Johan W. de Jong¹, Clemens Bos¹, Marius van Meel¹, Daniel Bystrov², Harald Heese², Arjan W. Simonetti¹

¹Philips Medical Systems, Best, Netherlands; ²Philips Research Laboratories, Hamburg, Germany

Consistent planning of MRI scans of patients who undergo a shoulder examination is very important. It enables radiologists to investigate the patients’ anatomy with a preferred ‘orientation’. However, planning between operators may be biased due to their training, competence and experience. To deal with this problem, an automated scan planning for shoulder examinations was developed and a feasibility study was performed. The study showed that the proposition of the system was in line with manual planning of an experienced operator. The automated scan planning procedure can be integrated into the examination protocol, thus improving workflow and achieving a one push button examination.

15:00         3666.     MRI of an Egyptian Mummy on Clinical 1.5 and 3 T Whole Body Imagers

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Michael Bock¹, Peter Speier², Sonia Nielles-Vallespin², Michael Szimtenings², Karin Leotta¹, Frank Rühli³

¹Deutsches Krebsforschungszentrum (dkfz), Heidelberg, Germany; ²Siemens Medical Solutions, Erlangen, Germany; ³University of Zurich, Zürich, Switzerland

Non-destructive proton MRI of the head of an Egyptian mummy was performed on 1.5 T and 3 T clinical MRI systems. Three different pulse sequences were used that offered echo times below 1 ms to overcome the low SNR due to the short T2* of the mummified tissue. Of these, a 3D radial pulse sequence offered the highest SNR per unit time, and 3D data sets of excellent quality could be acquired in less than 1 hour.

13:30         3667.     Responsiveness of BOLD MRI to Short-Term Temperature Changes of the Rabbit Knee Joint in Inflammatory Arthritis

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Cristina Otilia Nasui¹, George Nathanael, Elka Miller, Jaques Belik, Adrian Crawley, Andrea S. Doria

¹Hospital for Sick Children, Toronto, Canada

BOLD MRI is a suitable tool to assess local tissue oxygen levels as dependent on local temperature with most significant responsiveness changes noted in the knee contralateral to the knee where arthritis was induced. Physiologic compensatory mechanisms in the contralateral joint may explain these results.  Further assessment of responsiveness of BOLD MRI in arthritic joints with higher magnetic field scanners may confirm the current results and enhance potential changes.

14:00         3668.     Isotropic MRI of the Ankle at 3.0T Using 3D-FSE-Cube with Extended Echo Train Acquisition (XETA)

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Garry E. Gold¹, Reed F. Busse², Kathryn J. Stevens¹, Eric Han³, Anja C.S. Brau³, Philip J. Beatty³, Christopher F. Beaulieu¹

¹Stanford University, Stanford, California , USA; ²GE Healthcare, Madison, Wisconsin, USA; ³GE Healthcare, Menlo Park, California , USA

Two-dimensional fast spin-echo (2D-FSE) is frequently used to evaluate the ankle joint.  This approach is limited, however, by partial volume artifacts and slice gaps.  Volumetric acquisition with isotropic resolution overcomes these limitations and allows reformations in multiple planes.  We compared 2D-FSE in the ankle at 3.0T with 3D-FSE-Cube, a new technique with a variable refocusing flip angle eXtended Echo Train Acquisition (XETA) and 2D-accelerated autocalibrated parallel imaging (ARC) to achieve isotropic resolution in clinical feasible scan times.  3D-FSE-Cube showed high signal-to-noise and had the ability to reformat in any plane, making multiple 2D acquisitions unecessary.   3D-FSE-Cube is a promising method for clinical ankle imaging.

14:30         3669.     Spectroscopic Imaging Using Interleaved Projection Sampling Along the 3D Cartesion Phase and Slice Encodings (SIPPS): Application to Articular Cartilage

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Jiang Du¹, Christine B. Chung¹, Graeme M. Bydder¹

¹University of California, San Diego, San Diego, California , USA

Fat water separation is of important clinical applications. Conventional fat saturation pulse is efficient but may provide non-uniform fat suppression and reduced water signal in regions of field inhomogeneity. Two-point or multi-point Dixon techniques are extensively investigated for robust fat water separation. Here we present a time efficient and robust fat water separation technique based on spectroscopic imaging using interleaved projection sampling along the 3D Cartesian phase and slice encodings (SIPPS), which provides high resolution 3D water and fat images at a series of resonance frequencies.

15:00         3670.     Orientational Effect on Achilles Tendon Investigated with Ultrashort TE Spectroscopic Imaging (UTESI) Sequence

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Jiang Du¹, Byung C. Pak¹, Atsushi Takahashi², Richard Znamirowski¹, Sheronda Statum¹, Graeme M. Bydder¹, Christine B. Chung¹

¹University of California, San Diego, San Diego, California , USA; ²GE Healthcare Technologies, Menlo Park, California , USA

Fat water separation is of important clinical applications. Conventional fat saturation pulse is efficient but may provide non-uniform fat suppression and reduced water signal in regions of field inhomogeneity. Two-point or multi-point Dixon techniques are extensively investigated for robust fat water separation. Here we present a time efficient and robust fat water separation technique based on spectroscopic imaging using interleaved projection sampling along the 3D Cartesian phase and slice encodings (SIPPS), which provides high resolution 3D water and fat images at a series of resonance frequencies.

Muscle

13:30         3671.     Mapping of Movements in the Dynamically Contacting Human Triceps Surae Muscles Using a Computer Controlled Hydraulic Foot-Pedal Device with Velocity Encoded Phase Contrast MRI

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Dongsuk Shin¹, Ryuta Kinugasa², Chandan Mishra², John Hodgson¹, V. Reggie Edgerton¹, Shantanu Sinha²

¹University of California, Los Angeles, California , USA; ²University of California, San Diego, California , USA

The new hydraulic foot-pedal device was developed to create the dynamic and active muscle contractions inside the MRI bore. In comparison to the isometric contraction mode, the velocity/displacement behavior was changed, providing new insights in muscle-tendon mechanics previously undetectable under the isometric contraction mode.

14:00         3672.     Three-Dimensional Muscle Models of the Human Triceps Surae Muscle-Tendon Complex

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Dongsuk Shin¹, Sheng-Wei Chi¹, Jiun-Shyan Chen¹, John Hodgson¹, V. Reggie Edgerton¹, Shantanu Sinha²

¹University of California, Los Angeles, California , USA; ²University of California, San Diego, California , USA

We propose a newly developed three-dimensional FE model that incorporates the aponeurosis-tendon unit as well as soleus muscle. The outcome of the model demonstrates the inhomogeneous strain distribution along the aponeurosis-tendon complex under different MVC levels, which is in good agreement with our previously reported PC-MRI data. The model suggests geometrical changes in the muscle-tendon system, recruitment of active/passive components, and ankle rotation all may contribute to non-uniform strain distribution.

14:30         3673.     Muscle Functional Magnetic Resonance Imaging Using Ultrafast Imaging

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Noriyuki Tawara¹, Osamu Nitta², Hironobu Kuruma², Mamoru Niitsu², Akiyoshi Itoh³

¹Japan Institute of Sports Sciences, Kita-ku, Japan; ²Tokyo Metropolitan University, Arakawa-ku, Japan; ³NIHON University, Funabashi-sity, Japan

Exercise selectively increases the signal intensities (SI) of active muscles in T2-weighted magnetic resonance (MR) images. Investigators in sports medicine and other related fields have utilized T2 maps to investigate skeletal muscle activity during exercise. However, scan time of T2-weighted MR images is usually for a few minutes. So, we can choose only the location that is secured for long time. In this paper, we report the speed-up of fusion image of magnetic resonance imaging for visualization of muscle activity. Spin-echo echo-planar-imaging (SE-EPI) that is ultrafast imaging has weak-point that is low spatial resolution. In order to compensate for weak-point, we used TrueFISP that is ultrafast imaging of high spatial resolution. And we proposed the new method using fusion SE-EPI and TrueFISP. We compared skeletal muscle�fs T2 relaxation curve between SE-PEI and multiple spin echo (MSE) that is conventional method, SE-EPI is similar to MSE in short TE. In short TE than 75 ms, SE-EPI indicated the possibility of use in pulse sequence of T2-weighted MR images. Also, a 1/13 was able to shorten it than MSE sequence in MRI�fs scanning time.

15:00         3674.     Quantitative Assessment of Muscle Degeneration in DM1 Patients Using MRI [Not Available]

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bassem Hiba¹, Nathalie Richard¹, Luc J. Hébert², Christophe Vial³, Mimoun Nejjari¹, Jean francois Remec³, Chantale coté², Francoise Bouhour³, Jack Puymirat*², Marc Janier¹,⁴

¹Université Lyon1, Lyon, France; ²Laval CHU, Québec, Canada; ³Wertheimer Hospital, Lyon, France; ⁴Hospices Civils de Lyon, Lyon, France

MRI is a very promising technique for muscle degeneration exploration, even though only some descriptive or qualitative results were reported in the literature. We propose a quantitative exploration of muscle degeneration in Steiner’s myotonic dystrophy using MRI (particularly in Tibialis Anterior muscles). 17 DM1 patients and 6 controls were included in the study, normal and degenerated tissue volumes, oedema volume and the fat to water ratio were assed from MR images. The proposed measurements were validated comparing with relative isometric strength measured by a hand-held dynamometer.

13:30         3675.     Evaluation of Muscle Fiver Tractography by Single-Shot Diffusion Tensor STE EPI

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Jyunichi Hata¹, Kazuo Yagi¹, Keigo Hikishima¹, Ryou Takaki¹, Yuuji Komaki¹

¹Tokyo Metropolitan University, Arakawa, Japan

The STE method can achieve high SNR in the diffusion weighted image of the skeletal muscle. We mounted DT STE-EPI on 1.5T MRI scanner and evaluated Toractography of the human skeletal muscle. Result, It is necessary to impress about at least b-value 800-1000 [s/mm2] to the muscle fiber tracking as well as central nerve area. The muscle fiber toractography showed the anatomical structure similar to fiber structure measured by other modalities. Muscle fiber Toractography will do a contribution to the muscle disease diagnosis, the muscle function evaluation, and the sport medicine in the future.

14:00         3676.     Continuous Arterial Spin Labeling in Progressive Peripheral Vascular Disease

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Wen-Chau Wu¹, Jiongjiong Wang¹, Ping Wang¹, John A. Detre, Temitope Olufade, Thomas F. Floyd¹

¹University of Pennsylvania, Philadelphia, USA

Measurement of muscle perfusion in the extremities is feasible using arterial spin labeling (ASL) MRI. In this study, we utilize continuous ASL (CASL) to measure the perfusion in patients with peripheral vascular disease. Flow variability is analyzed for individual muscle groups and correlated to the disease severity assessed by the ankle to brachial index (ABI). Results show that CASL flow measurements correlate with disease state as measured by ABI, but also demonstrate a retained microvascular flow reserve in the presence of early to intermediate vascular disease. Progression of disease is followed by diminished flow reserve and delayed hyperemic response.

14:30         3677.     Magnetisation Transfer Ratio in Leg Muscle, and Sciatic Nerve Size in Hereditary Demyelinating and Chronic Inflammatory Demyelinating Polyneuropathy

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Peter Oliver Cowley¹, Mario Miranda¹, John Thornton², Lisa Strycharczuk1¹, Hiten Mehta¹, Mary Reilly¹, Martin Koltzenburg¹, Tarek Yousry¹

¹National Hospital for Neurology and Neurosurgery, London, UK; ²National Hospital for neurology and neurosurgery, London, UK

Sciatic nerve cross-sectional area in the thigh and calf-muscle magnetisation transfer ratios (MTRs) were determined in patient groups with inherited (CMT1a) and acquired (CIDP) peripheral neuropathies and a control group (n=10 in each group).  Sciatic nerve areas were significantly enlarged in both disease groups, to a greater degree in CMT1a (p<0.001).  MTRs were reduced in affected muscle groups, the reduction correlating with age (and presumed disease duration) in the CMT group.

15:00         3678.     Relaxation Times of Human Skeletal Muscle Metabolites at 7T [Not Available]

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Ligong Wang¹, Nouha Salibi², Mark E. Schweitzer¹, Ravinder R. Regatte¹

¹Center for Biomedical Imaging, NYU School of Medicine, New York, USA; ²Siemens Medical Solutions, Malvern, Pennsylvania, USA

This study reports ultra high field (7T) proton relaxation times of lipid metabolites in human tibialis anterior muscles. T1 and T2 relaxation times of lipid phantom (corn oil) and healthy human volunteers (n=3) were measured using single voxel 1H MR spectroscopy of skeletal muscle. The T1 values of TMA, Cr-CH3, IMCL-CH2, and EMCL-CH2 for TA muscle at 7T are 1310, 1516, 1605, and 1479 ms, while the T2 values of the corresponding metabolites are 62.4, 56.81, 57.9, and 58.5 ms. The relaxation numbers can be utilized for the absolute quantification of skeletal muscle metabolite concentrations and optimization of sequence parameters.

Renal Parenchyma & Perfusion

14:00         3679.     Renal Cortical and Medullar Oxygenation Changes After Oxygen Challenge: Evaluation with BOLD MRI

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Hersh Chandarana¹, Mohit Naik¹, Pippa Storey¹, Vivian Lee¹, Bachir Taouli¹

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

In this study we evaluated the effect of inhaled oxygen on changes in renal cortical and medullary T2* signal with BOLD imaging in patients with normal renal function. Our study demonstrates significant increase in oxygenation of the medulla (mean 12.2%) and to a lesser extent in the cortex (2.4%), confirming that in normal kidneys, the medulla is more hypoxic than the cortex and demonstrates significant change in oxygenation after oxygen challenge.

14:30         3680.     Clinical Value of MR-Based Quantification of Renal Perfusion Parameters with a Separable Two-Compartment Model

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Ulrike Attenberger¹, Henrik Michaely², Steven Sourbron³, Mike Notohamiprodjio³, Christian Glaser³, Maximilian Reiser³, Stefan Schoenberg²

¹Ludwig-Maximilians University Munich, Munich, Germany; ²University of Heidelberg, Germany; ³Ludwig-Maximilians University Munich, Germany

The combination of MR angiography and MR perfusion (MRP) measurements offers a promising method for detection of macrovascular and microvascular renal disease in a single exam. So far, there is no ideal technique for direct measurement of renal function.

We used a separable two-compartment model for quantification of renal perfusion paramters in this study and investigated the diagnostic accuracy of a combined MRA/MRP approach compared to the final clinical diagnosis. 25 patients underwent renal perfusion measurements and renal MR angiograpyh at a 3.0T scanner (Siemens Magnetom Tim Trio). The sequence parameters of the SR-TurboFLASH sequence were: TR / TE/ TI [ms] 203/0.90/101, flip angle 12º, bandwith [Hz/Px] 900, matrix  192x134, FOV[mm3] 450x373, temporal resolution [slice/s] 5, parallel imaging GRAPPA 2. The sequence parameters of the 3D MRA sequence were: TR/ TE [ms] 3.11/ 1.09, flip angle 23º, bandwidth [Hz/Px] 510, matrix 512x85%, FOV [mm²] 400x81.3%, phase oversampling [%] 8, interpolated slice thickness 0.9 [mm], voxel size [mm3] 0.65, spatial resolution [mm³] 0.9x0.8x0.9, scan time [s] 19.

From all patients the final clinical diagnosis was obtained as a reference standard. 15 patients were classified as ill based on the final clinical diagnosis. 3 patients with renal artery stenoses, 5 patients with renal insufficience in compensated retention, 7 patients after renal transplantation with postoperative complications

MRA alone had a sensitivity of 73% and specifity of 90%.  MRP reached a sensitivity of 100% and a specifity of 70% respectively. In combination MRA and MRP revealed a sensitivity of 100% and specifity of 90%.

We could show that the combination of both methods - MRA and MR perfusion - heightens overal diagnostic accuracy. Especially in patients with renoparenchymal diseases the additional information of perfusion measurements increases the diagnostic specifity.

15:00         3681.     Dual Navigator Gated FAIR True-FISP Pulse Sequence for Renal Perfusion Imaging

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Ruitian Song¹, Ralf Berthold Loeffler¹, Claudia Maria Hillenbrand¹

¹St. Jude Children's Research Hospital, Memphis, Tennessee, USA

A dual navigator gated FAIR True FISP pulse sequence has been developed and implemented. Two navigators are applied to gate tagging and imaging slices, respectively. Since both slices are gated and followed to the same reference position, the imaging slice is prevented from moving to the edge of or out of the inversion slice. Error caused by not or not fully tagged spins could be eliminated in measuring renal perfusion rate, and pixel-mismatch between the tagging and control images could also be improved.

15:30         3682.     MR-Based Semi-Automated Quantification of Renal Perfusion Functional Parameters with a Two-Compartment Model - An Interobserver Analysis

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Ulrike Attenberger¹, Steven Sourbron¹, Mike Notohamiprodjio¹, Christian Glaser¹, Maximilian Reiser¹, Stefan Schoenberg², Henrik Michaely²

¹Ludwig-Maximilians University Munich, Munich, Germany; ²University of Heidelberg, Mannheim, Germany

Dynamic contrast-enhanced magnetic resonance imaging of the kidneys offers promising approaches for the assessment and differentiation of renovascular and renoparenchymal diseases. For the determination of both renal first-pass perfusion (plasma flow, plasma mean transit time) and renal filtration (tubular flow, tubular mean transit time) parameters we used a separable two-compartment model. The purpose of this study was to evaluate interobserver agreement in the quantitative assessment of renal functional parameters as it is known, that variability of functional parameters is a well-addressed problem. 12 consecutive patients (4 men, 8 women, mean age 51 years) underwent renal perfusion measurements after intravenous injection of 7 ml Gd-BOPTA (Multihance®, Bracco) at 4 ml/s at 3.0T (Magnetom Tim Trio). The sequence parameters of the SR-TurboFLASH sequence were: TR / TE/ TI [ms] 203/0.90/101, flip angle 12º, bandwidth [Hz/Px] 900, matrix  192x134, FOV[mm3] 450x373, temporal resolution [slice/s] 5, parallel imaging GRAPPA 2.Two independent observers placed regions of interest (ROIs) manually on an axial slice, one in the abdominal aorta for determination of arterial input function, one at the air-tissue interface for retrospective respiratory motion correction. Fitting the data on a pixel-by-pixel basis to the two-compartment model maps of the perfusion parameters and tubular filtration parameters were obtained. Pixels with plasma volume > 10 ml/100ml were selected to segmente a cortical ROI. The model fit was repeated on a ROI basis to produce the cortical averages. Correlations of all values were significant (p<0.05). A paired t-test yielded significant differences for plasma flow values (p=0.004). The data shows a systematic difference for the plasma flow parameter, while plasma mean transit time parameter seems to be most stabile.The difference in flow parameters reflects a user-dependent bias in AIF selection, which may be minimized in future work by incorporating (semi)automated segmentation to identify the lumen of the aorta.

14:00         3683.     QUIPSS II with Interleaved Thin-Slice TI1 Periodic Saturation for FAIR Sequence

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Ruitian Song¹, Ralf Berthold Loeffler¹, Claudia Maria Hillenbrand¹

¹St. Jude Children's Research Hospital, Memphis, Tennessee, USA

QUIPSS II with interleaved thin-slice TI₁ periodic saturation has been developed and integrated into a FAIR TrueFISP ASL experiment for the quantification of renal perfusion.  A periodic thin-slice saturation pulses were applied alternatively on both sides of the imaging slice from TI₁ to TI_1s (TI₁ stop time). It has been shown that the bolus width can be controlled by changing TI₁ and the better matched saturation slice profiles can be achieved.  The renal perfusion rate could be quantified more accurately with our technique

14:30         3684.     Evaluation of Dysfunctional Renal Transplants Using Low-Dose MR Renography

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Louisa Bokacheva¹, Henry Rusinek¹, Keyma Prince¹, Manmeen Kaur¹, Thomas Diflo¹, Devon John¹, Judith Benstein¹, Laura Barisoni-Thomas¹, Vivian Lee¹

¹New York University School of Medicine, New York, USA

Dynamic contrast-enhancement MR imaging of the kidneys (MR renography) was used to evaluate patients with normally functioning renal transplants and with transplants during dysfunctional episodes caused by acute tubular necrosis and mild rejection. Contrast concentration versus time curves for renal cortex and medulla were evaluated. The maximum cortical concentration was shown to be significantly lower in ATN cases than in normal or rejected kidneys. The cortical and medullary concentrations at 120 s after the start of acquisition were also significantly lower in kidneys with ATN than in normal or rejected kidneys. The differences between rejected and normal kidneys were insignificant. These findings suggest that MR renography can be used to elucidate the nature of the renal transplant dysfunction.

15:00         3685.     Glomerular Filtration Rate Measurements by Dual-Injection MR Renography

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Jeff Lei Zhang¹, Henry Rusinek¹, Louisa Bokacheva¹, Qun Chen¹, Pippa Storey¹, Chekema Prince¹, Vivian S. Lee¹

¹New York University, New York, New York, USA

Dual-injection MR renography has been proposed as an improved diagnostic marker of renovascular disease. Technical challenges include optimal split of one dose for two injections and appropriate analysis of the second renography dataset. Monte Carlo simulation showed that with overall dose of 12 ml 6-8 ml should be used for the second injection, and with dose1 of 4 ml, standard deviation of GFR1-GFR2 was less than 5.1 ml/min. For patients without RAS, GFR1 and GFR2 have a high correlation coefficient R2 = 0.81, and for 30 cases (out of 40) the difference (GFR1 – GFR2) was within [-10, 10] ml/min.

15:30         3686.     MR Diffusion Tensor Imaging of the Kidney with Parallel Imaging – Initial Clinical Experience

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Mike Notohamiprodjo¹, Christian Glaser¹, Karin Anna Herrmann, Ulrike Attenberger, Stefan Schoenberg, Maximilian Reiser, Henrik Michaely

¹University Hospitals Munich, Munich, Germany

The purpose of this study was to evaluate the feasibility of MR-Diffusion Tensor Imaging (DTI) of the kidney with integrated parallel imaging in volunteers and patients with various renal diseases.

10 volunteers and 27 patients with various renal pathologies underwent MR-DTI. MR-DTI allows a good discrimination between cortex and medulla and visualization of renal architecture alterations, e.g. by tumors or parenchymal disease. Differentiation of simple cysts, cystic and solid renal cell cancer was possible. The results suggest that MR-DTI with integrated parallel imaging may be a useful tool to study and monitor renal ultrastructure.

Hyperpolarized Gas Lung MRI

14:00         3687.     Lung Ventilation Mapping with Bolus Inhalation of He-3 and Dynamic Projection He-3 MRI Using I-HYPR Reconstruction

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Ryan Cullen Lipscomb¹, Rafael Louis O'Halloran¹, James H. Holmes¹, Sean B. Fain¹

¹University of Wisconsin, Madison, Wisconsin, USA

Rapid 2D hyperpolarized He-3 MRI with projection and iterative highly constrained back-projection (I-HYPR) reconstruction was applied to dynamic imaging of a compact inhaled bolus in a healthy human volunteer at a temporal resolution of 54ms. High resolution upslope and arrival time parametric maps were calculated from the acquired time series data, illustrating and quantifying regional differential ventilation. This technique could prove valuable in assessment and treatment planning for chronic obstructive lung diseases such as cystic fibrosis and asthma.

14:30         3688.     Highly Constrained Backprojection (HYPR) for ³He-MRI Spontaneous Breathing and Insufflation Protocols in Rats

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Katarzyna Cieslar¹, Achraf Al Faraj¹, Vasile Stupar¹, Sophie Gaillard¹, Yannick Cremillieux¹

¹Creatis-LRMN, UMR CNRS, Université Lyon 1, LYON, France

High temporal resolution is particularly important in small animals studies due to high breathing rates of rodents. Angular undersampling of radially acquired data can increase the temporal resolution but results in poor image quality. HYPR reconstruction can be used to preserve high image SNR despite undersampling. We present the application of HYPR to 3He imaging of rats lungs. Visualisation of respiratory dynamics during insufflation and spontaneous breathing protocol was performed.

15:00         3689.     Hyperpolarized-Gas Lung Imaging Using a Single-Shot Spiral Acquisition

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Hao Tan¹, Weitian Chen¹, Peng Hu¹, G. Wilson Miller¹, Talissa A Altes¹, Jaime F Mata¹, Eduard E de Lange¹, Gordon D Cates¹, Ray F. Lee², Craig H. Meyer¹, John Mugler III¹

¹University of Virginia, Charlottesville, Virginia , USA; ²New York University, New York, New York, USA

Hyperpolarized-gas MRI using ³He can provide quantitative information about lung structure and function. This noninvasive method is of great interest for studying lung diseases such as chronic obstructive pulmonary disease and asthma. In this study, we developed two single-shot spiral sequences towards that goal. In the first sequence, we used a preparation acquisition to obtain a field map before the imaging spiral readout. In the second sequence, we used a single-shot spiral with multiple gradient echoes and reconstructed images iteratively. Both sequences yielded reconstructed images with spatial resolution and image quality comparable to standard GRE images.

15:30         3690.     Rapid Motion Mapping of Hyperpolarised Gas Flow Using K-T Subsampling Methods

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Xavier Maître¹, Shaihan J. Malik², Pascal Hagot¹, Emmanuel Durand¹, Luc Darrasse¹, David J. Larkman², Jacques Bittoun¹

¹CNRS (UMR8081), Univ. Paris-Sud, Orsay, France; ²Robert Steiner MRI Unit, London, UK

Hyperpolarised helium-3 imaging allows visualising airways during inhalation of the gas. Time-of-flight approaches have been developed to enable the high temporal resolution required to track the gas motion through the human airways with true 10 ms temporal resolution. The method is valid as long as the flow velocity remains constant over the total acquisition time. To suite physiological respiratory conditions, a 4-fold k-t undersampling of the dynamic images was performed and data reconstructed using k-t BLAST. Here, total acquisition times as low as 2.8 s were obtained in a mouth-trachea cast phantom with little loss in signal to noise ratio.

Bowel Imaging

14:00         3691.     Dynamic MRI Evaluation of Small Bowel Peristalsis Pattern Using Software: A Feasibility Study

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Sooah Kim¹, Christophe ChefdHotel², Laura Rueff¹, Ruth P. Lim¹, Vivian S. Lee¹

¹New York University, New York, New York, USA; ²Siemens Corporate Research, Princeton, New Jersey, USA

Ten patients referred for MR enterography were evaluated at 1.5 T using 2D dynamic steady state free precession sequence. 5 small bowel segments were selected per patient, and outer luminal diameter of each segment was measured manually on each dynamic images. Data were plotted over time. ROIs of same selected bowel segments were defined using semi-automated Fourier based software. Average temporal variance of the intensity values were plotted over time. Data and analysis time from both methods were compared, and both showed paralytic pattern of abnormal segments with inflammatory bowel disease. Normal bowel demonstrated periodic sinusoidal contraction. Analysis time per each patient was 20 minutes for manual and 1 minute for software. MRI assessment of small bowel peristalsis pattern using software provides a rapid assessment in inflammatory bowel disease.

14:30         3692.     Factors Influencing Small Bowel Water Content: Fibre Intake, Fasting and Feeding

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Eleanor F. Cox¹, Caroline L. Hoad¹, Luca Marciani¹, Robin C. Spiller¹, Penny A. Gowland¹

¹University of Nottingham, Nottingham, UK

A novel MRI method was used to evaluate the effect of fibre content of an evening meal on the next morning’s fasting small bowel water content (SBWC) and to determine the effect on SBWC of switching from a fasting to a fed state. Feeding after overnight fasting caused a significant fall in SBWC, which continued to fall even after gastric emptying had begun. The fibre content of the previous night’s meal had no significant effect on SBWC measured the following morning. This important data will help understand the effects of fasting and feeding on the absorption and secretion of water in the small bowel.

15:00         3693.     Dynamic Contrast Enhanced MRI Evaluation of Small Bowel Crohn's Disease: A Correlation with Histopathologically Quantified Microvascular Density

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Shonit Punwani¹,², Manuel Rodriguez-Justo², Alan Bainbridge¹, Enrico De Vita¹,², Rebecca Greenhalgh², Steve Halligan¹,², Stuart Taylor¹,²

¹University College London, London, UK; ²University College London Hospital, London, UK

The aim of this study was to assess  quantitative and semi-quantitative in-vivo DCE-MRI parameters in predicting histopathologically quantified small bowel wall microvascular density (MVD) in resection specimens from patients with known ileal Crohn’s disease. In vivo DCE-MRI of disease affected bowel was performed pre-operation. Post surgical small bowel resection specimens were scanned to enable detailed imaging-histopathology matching. Histological sections were taken through the area of bowel corresponding to the DCE-MRI images. Quantitation of mural microvascular density (MVD) was performed with CD34 staining. DCE-MRI determined slope of enhancement was found to be strongly negatively correlated with MVD. SoE measurements may have potential in assessing disease and monitoring anti-angiogenic therapy in patients with Crohn’s disease affecting small bowel.

15:30         3694.     Diffusion-Weighted Imaging in the MR Evaluation of Acute Abdominal Pain in Pregnancy

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Jesse L. Wei¹, Martin P. Smith¹, Neil M. Rofsky¹, Ivan Pedrosa¹

¹Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA

Assessment of acute abdominal and pelvic pain in pregnancy is a challenge that is being addressed by the use of non-contrast MR imaging, including motion-insensitive T2W single-shot fast spin echo for anatomic assessment of structures; and T1W in-and-out of phase, T2W fat-suppressed, and time of flight imaging for characterization of structures based on intrinsic tissue contrast, flow, and susceptibility. We retrospectively analyze the utility of diffusion-weighted imaging as an additional imaging technique to provide another form of image contrast. We find that diffusion weighted images (b=1000) demonstrate increased signal intensity in 5 of 7 inflamed appendices in a population of 37 patients.

Body Diffusion & Whole Body Imaging

14:00         3695.     Respiratory Gated Body Diffusion Weighted Imaging (DWI) Avoiding Prolongation of Scan Time: Tracking Only Navigator Echo (TRON) Technique: Improvement for High B Value DWI

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Tomohiko Horie¹, Tarou Takahara, Tetsuo Ogino, Tomoyuki Okuaki, Masatoshi Honda¹, Isao Muro¹, M.V. Cauteren, Yutaka Imai¹

¹Tokai University School of Medicine, Isehara, Japan

High b value DWI uses a long TE, which results in poor tracking due to increased time lag between navigator and slice excitation. Two software developments have recently been introduced. In this study, we investigated image quality and scanning time using the new TRON version at high b value. Image quality of new TRON was comparable to RT. Relative scanning time to FB was 104% with TRON and 272% with RT. The use of TRON concept and reduction of time lag in navigator sequence allows us practical high b value DWI in a short scan time.

 14:30         3696.     Combination of High-B-Value Diffusion-Weighted MRI and MR Cholangiopancreatography as the Optimal Non-Invasive Modality for Diagnosis of Pancreatic Adenocarcinoma [Not Available]

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Hiroki Haradome¹, Akihisa Nakamura¹, Shinju Suzuki¹, Nobuaki Matumoto², Toshiaki Nitatori¹, You Atomi²

¹Kyorin University School of Medicine., Mitaka, Tokyo, Japan; ²Kyorin University School of Medicine, Mitaka, Tokyo, Japan

Although contrast-enhanced dynamic multi-detector-CT have evolved as the mainstay for pancreatic cancer detection and staging, non-invasive modalities are desired for screening in risk groups of the pancreatic cancer, in particular. Both high-b-value diffusion-weighted MRI (DWI) and MR cholangiopancreatography (MRCP) is non-invasive modalities for detecting pancreatic cancer with a high sensitivity and specificity. We evaluated the utility of combination of DWI and MRCP for diagnosis of pancreatic adenocarcinoma. Combination of DWI and MRCP was the optimal non-invasive modality for diagnosis of pancreatic adenocarcinoma without radiation exposure and contrast agent.

15:00         3697.     Prospective Comparison Multi Contrast with Diffusion Weighted Imaging Whole Body MRI, Whole Body PET-CT and Whole Body CT for Staging Advanced Melanoma

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valerie laurent¹,², isabelle dufour claude³, pierre olivier¹, pierre andre vuissoz, olivier bruot¹, denis regent¹, jacques felblinger²

¹brabois hospital, vandoeuvre les nancy, France; ²H.Poincare university, vandoeuvre les nancy, France; ³general electric health care, BUC, France

Prospective study to compare multicontrast with DWI whole body MRI, whole body PET CT, whole body CT for staging advanced melanoma and to evaluate benefits of DWI sequence in addition oncologic MRI protocol. 38 patients were examined using multicontrast whole body MRI (STIR,T1w after contrast and DWI).The same day, whole body PET-CT et whole body CT were performed. Mc wb MRI with DWI was the most sensitive to detect lesions compared to PET CT and CT. The DWI permits to detect 20% supplementary lesions.  The wb DWI is required in addition to T2w and T1w for oncologic whole body MRI

15:30         3698.     High Resolution Whole-Body MRI Applications at 1.5 Tesla and 3 Tesla: A Comparative Study

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Gerwin P. Schmidt¹, Bernd J. Wintersperger, Anno Graser, Andrea Baur-Melnyk¹, Maximilian F. Reiser, Stefan O. Schoenberg

¹University Hospitals Munich, Munich, Germany

WB-MRI is feasible at 3 Tesla and has comparably good image quality to 1.5 Tesla. Yet, 3 Tesla whole-body MRI shows significantly more artifacts, but with only mild to moderate impact on image assessment. Overall scan time is further reduced at 3 T with the use of PAT at constant image resolution. 

Iron Effects in Hepatic Imaging

14:00         3699.     High Speed Multiple Echo Acquisition (HISTO): A Rapid and Simultaneous Assessment of Fat and Iron Content in Liver by ¹H-MRS

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Nashiely Pineda-Alonso¹, Qin Xu¹, Puneet Sharma², Diego Martin³, Xiaoping Hu¹

¹Emory University, Atlanta, USA; ²Emory Clinic, Atlanta, USA; ³Emory University. School of Medicine, Atlanta, USA

Proton MR Spectroscopy (1H MRS) offers a means for noninvasively determining hepatic lipids (HL) and provides acceptable spectral resolution and high sensitivity even with low amounts of HL. 1H-MRS is also used to accurately quantify the iron overload in the liver. In this work, we introduce a technique that allows the rapid, accurate and simultaneous assessment of fat and iron content which could be applied for single breath hold liver MRS. The feasibility and accuracy of this technique has been demonstrated experimentally in phantoms and applied to patients with fatty liver disease.

14:30         3700.     Effect of Superparamagnetic Iron Oxides on Hepatic Apparent Diffusion Coefficient at 3T in Human Subjects with Chronic Liver Disease

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Masoud Shiehmorteza¹, Chad Andrew Kohl¹, Sameer M. Mazhar¹, Takeshi Yokoo¹, Nicholas Pinto¹, Richard Znamirowski Znamirowski¹, Lillian O. Pacheco¹, Michael S. Middleton¹, Claude B. Sirlin¹

¹Liver Imaging Group, San Diego, California , USA

Iron accumulation may occur in chronic liver disease and by shortening T2* may alter tissue ADC values. To assess the potential effect of intrahepatic iron on ADC measurements, we compared the ADC values at 3T in 15 human subjects with chronic liver disease before and after superparamagnetic iron oxide (SPIO) administration. We found that administration of exogenous iron causes a mild but statistically significant elevation in hepatic ADC. We speculate that endogenous iron may have a similar effect and may modify the relation between ADC and fibrosis stage in chronic liver disease.

15:00         3701.     Safety Assessment of Double-Contrast MR Imaging of Liver Disease

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Chad Andrew Kohl¹, Sameer M. Mazhar¹, Takeshi Yokoo¹, Alyssa D. Chavez¹, Nicholas Pinto¹, Lillian O. Pacheco¹, Jennifer Berry¹, Zana Parman², Tarek Hassanien², Joel Lavine², Jeffrey Schwimmer², Claude B. Sirlin¹, Michael Simca Middleton¹

¹Liver Imaging Group, San Diego, California , USA; ²UCSD, San Diego, California , USA

Double-contrast (SPIO/Gd) enhanced MR imaging has been used to assess hepatocellular carcinoma and liver fibrosis and may be more accurate for characterization of liver nodules than single-contrast MR imaging. Although each of these types of contrast agents are individually FDA-approved for MR imaging, their sequential use is not FDA-approved. Our aim is to assess the safety of sequential double-contrast MR imaging in patients with liver disease. Based on prospective data from 56 subjects there is no greater risk with sequential use of Feridex® and Magnevist® than with individual use of either agent alone.

15:30         3702.     Spleen R2 and R2* in Iron Overloaded Patients with Sickle Cell Disease and Thalassemia Major

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Casey John Brewer¹, Thomas D. Coates¹, John C. Wood¹

¹Childrens Hospital Los Angeles, Los Angeles, California , USA

Many sickle cell disease (SCD) and thalassemia major (TM) patients require chronic blood transfusions that result in massive iron overload of their organ tissues.  MRI has been used to quantify organ iron but little study has been done on the spleen.  We quantified splenic iron in SCD and TM patients by retrospectively analyzing their hepatic MR scans.  Splenic R2 was attenuated relative to R2* and SCD patients loaded more iron into their spleens than TM patients.  It is concluded that splenic R2 and R2* have a different relationship than do liver R2 and R2* and that the spleen is a major site of iron loading in SCD but not TM patients.

Hepatobiliary

13:30         3703.     Perfusion MRI of the Whole Liver Using 4D Thrive: Feasibility of Focal Liver Lesion Characterization Using Parametric Maps

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Kenneth Coenegrachts¹, Johan Ghekiere¹, Vincent Denolin², Gabriele Beck³, Gwen Hérigault³, Marc Haspeslagh¹, Peter Daled¹, Shandra Bipat⁴, Jaap Stoker⁴, Hans Rigauts¹

¹AZ St.-Jan AV, Brugge, Belgium; ²Philips Medical Systems, Benelux, Belgium; ³Philips Medical Systems, Best, Netherlands; ⁴Academic Medical Center, Amsterdam, Netherlands

In this preliminary study, the presented 4D THRIVE sequence seems feasible for perfusion-based T1w CE-MRI and allows calculation of parametric maps. The 4D THRIVE sequence seems promising for the qualitative differentiation of malignant and benign focal liver lesions using parametric maps. Although T1w CE-MRI has been used for perfusion imaging of the liver this technique remains developmental and the best measurement method is still to be determined. Once the methodology is established, rigorous multi-observer studies will be required to validate perfusion MRI and determine its impact on the ability to differentiate malignant from benign liver lesions.

14:00         3704.     SPIO-Enhanced FLAIR Echo-Planar Imaging in the Depiction of Hepatic Malignant Tumors: Comparison with T2-Weighted Fast Spin-Echo and T2*-Weighted Fast Field-Echo Imaging

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Yoshihiko Fukukura¹, Takuro Kamiyama, Ryutaro Higashi, Koji Takumi, Toshikazu Shindo, Masayuki Nakajo

¹Kagoshima University Graduate School of Medical and Dental Sciences, Kagoshima, Japan

SPIO-enhanced echo-planar FLAIR images showed higher accuracy in the detection of hepatic malignant tumors.

14:30         3705.     Usefulness of Superparamagnetic Iron Oxide-Enhanced T1-Weighted Echo-Planar MR Imaging for Assessment of Positive Enhancement in Hepatic Hemangioma [Not Available]

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Nagaaki Marugami¹, Satoru Kitano¹, Shinji Hirohashi², Junko Takahama¹, Kimihiko Kichikawa¹

¹Nara Medical University, Kashihara, Japan; ²Gyoumeikan Hospital, Osaka, Japan

SPIO-enhanced T1-weighted Echo-plannar MR imaging is useful in diagnosis of hepatic hemangioma with the finding of positive enhancement.

15:00         3706.     Variable Performance of Chemical Shift-Based Multipoint Water-Fat Separation MRI and Its Impact on the Diagnosis of Fatty Liver

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Hyeonjin Kim¹, Sara E. Taksali, Sylvie Dufour, Douglas Befroy, T Robin Goodman¹, Kitt Falk Petersen, Gerald I. Shulman, Sonia Caprio, R Todd Constable¹

¹Yale University School of Medicine, New Haven, Connecticut, USA

In this report we address the variable performance of chemical shift-based multipoint water-fat separation MRI and its influence on the diagnosis of fatty liver in 28 humans by using 1H-MRS as a reference, 2-point Dixon and 3-point IDEAL. Our results demonstrate that the performance of multipoint water-fat separation MRI significantly depends on the choice of sampling strategy, post-data processing algorithm and pulse sequence. Therefore, to minimize errors in the diagnosis of fatty liver using multipoint water-fat separation MRI, it may be necessary to establish a cutoff fat content for normal liver specific to each imaging protocol¡¯s sequences and sequence parameters.

13:30         3707.     Dynamic Gadolinium-Enhanced Liver Imaging Using LAVA Dual Echo with Water Reconstruction

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Russell Norman Low¹,², Scott Boles², Neeraj Panchal²

¹Sharp and Children's MRI Center, San Diego, California , USA; ²San Diego Imaging, San Diego, California , USA

LAVA-IDEAL generates water images from a dual echo 3D FSPGR acquisition using a 2-point Dixon reconstruction algorithm. Dynamic liver imaging with LAVA-IDEAL during the arterial and portal venous phases is characterized by nearly perfect separation of fat and water signal, images with high contrast, minimal artifacts and excellent depiction of liver lesions.

14:00         3708.     Hepatic Steatosis Results in a Reduction in the Apparent Diffusion Coefficient (ADC) of Liver Parenchyma

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Oliver Wignall¹, Erica Scurr¹, David Collins², Choon-Hua Thng³, Dow-Mu Koh²

¹Royal Marsden Hospital, Sutton, UK; ²Institute of Cancer  Research, Sutton, UK; ³National Cancer Centre, Singapore, Singapore

This study compares the ADC values of liver parenchyma in areas with and without fatty infiltration as determined by in-phase and opposed-phase T1-weighted MR imaging. The mean ADC of areas of fatty infiltration is significantly lower than that of normal liver. A linear relationship was established between ADC and the percentage of fat infiltration as estimated by the ratio of in-phase and opposed-phase signal intensities in steatotic liver. This has implications for DWI assessment of diffuse liver disease.

14:30         3709.     Noninvasive Evaluation of Nonalcoholic Fatty Liver Disease (NAFLD) Using 1H and 23Na Magnetic Resonance Imaging and Spectroscopy in a Rat Model

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Paige Nicole Hopewell¹,², Navin Bansal¹

¹Indiana University School of Medicine, Indianapolis, Indiana, USA; ²Purdue University, West Lafayette, Indiana, USA

With increasing prevalence of the metabolic syndrome, non-alcoholic fatty liver disease (NAFLD) is now the most common chronic liver disease in humans. This study employed extensive lipid profiling via 1H MRS to demonstrate temporal changes in lipid content, resolving 8 lipid resonance peaks plus water in vivo, with water- and fat-suppressed 1H MRI. Single-quantum- (SQ) and multiple-quantum-(MQF) filtered 23Na MRI were employed to evaluate cellular energy status as NAFLD progressed in a MCDD rat model.

15:00         3710.     Overestimation of Liver Fat Content in Fast Dixon-Based MRI Method Compared with Multi-Voxel MR Spectroscopy Quantification

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Paul E. Sijens¹, Mireille A. Edens¹, Roy Irwan¹

¹UMCG, Groningen, Netherlands

A recently published Dixon-based MRI method for quantifying liver fat content using dual-echo breath-hold gradient echo imaging was validated by phantom experiments and compared with results of biopsy in two patients [Radiology 2005;237:1048-1055]. We applied this method in ten healthy volunteers and compared the outcomes with the results of MR spectroscopy (MRS), the gold standard in quantifying liver fat content. Novel was the use of spectroscopic imaging yielding the variations in fat content across the liver rather than a single value obtained by single voxel MRS. Compared with results of MRS, liver fat content according to MRI was too high in nine subjects (range 3.3-10.7% vs. 0.9-7.7%) and correct in one (21.1 vs. 21.3%). Furthermore, in one of the ten subjects the MRI fat content according to the Dixon-based MRI method was incorrect due to a (100-x) versus x percent lipid content mix-up. Despite systematic overestimation of liver fat contents by MRI, Spearman's correlation between the (in 1 case adjusted) MRI liver fat contents with MRS was high (r = 0.927, P < 0.001). The problem with the Dixon-based MRI method for the assessment of liver fat content, is that, at the lower end range, liver fat content is systematically overestimated by approximately 3%.

13:30         3711.     Rapid Evaluation of Liver Fat Content Using In-Out-Phase Imaging in Nonalcoholic Fatty Liver Disease

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Ronald Borra¹,², Sakari Salo¹, Kirsti Dean¹, Riikka Lautamäki², Pirjo Nuutila², Markku Komu¹, Riitta Parkkola¹,²

¹Turku University Hospital, Turku, Finland; ²University of Turku and Turku University Hospital, Turku, Finland

This study shows the possibilities for liver fat content (LFC) quantification with in-out-phase imaging in patients with type 2 diabetes, at high risk for nonalcoholic fatty liver disease (NAFLD). Signal intensity differences between in-phase and out-phase images were correlated linearly with ¹H MRS measurements of LFC (P<0.001, r=0.94) and provided a cut-off point at 5.1%, the normal upper limit for LFC. Our findings suggest that in-out-phase imaging can be used for rapid and reliable discrimination between normal or increased LFC in patients with NAFLD.

14:00         3712.     Human Liver Transplant Graft Steatosis: Evaluation with MRI

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David John Lomas¹, Kieren G. Hollingsworth¹, Richard T. Black¹, Jane C. Smith¹, Toby Prevost², Chris J. Watson¹, Neville V. Jamieson¹, Graeme J. Alexander¹, Alexander E. Gimson¹

¹University of Cambridge & Addenbrooke's Hospital, Cambridge, UK; ²University of Cambridge, Cambridge, UK

Steatosis in donor liver grafts adversely affects outcome in human transplantation. This study investigates whether rapid MRI steatosis quantification in ex-vivo grafts, immediately prior to transplantation, correlates firstly with the currently used surgical “eyeball” and subsequent pathology “time zero” biopsy assessment; and secondly with the biochemical parameters measured in the first week post transplant that reflect early graft performance. Thirty nine grafts were examined and MRI quantification correlated significantly with the other two assessments but was the only one of the three to correlate significantly with any of the serum markers of early graft performance.

14:30         3713.     Quantification of Hepatic Steatosis with MRI: Correction for Bias from Noise and T1

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Chia-Ying Liu¹,², Charles A. McKenzie², Huanzhou Yu³, Jean H. Brittain⁴, Scott Brian Reeder¹

¹University of Wisconsin-Madison, Madison, Wisconsin, USA; ²University of Western Ontario, London, Canada; ³GE Healthcare, Menlo Park, California , USA; ⁴GE Healthcare, Madison, Wisconsin, USA

Quantification of hepatic steatosis is a significant unmet need for the diagnosis and treatment monitoring of patients with non-alcoholic fatty liver disease. MRI is capable of separating water and fat signals to quantify steatosis. Unfortunately, the non-zero mean noise in magnitude images and confounding T1 effects can lead to incorrect estimation of the true fat fraction. We demonstrate two approaches to reduce noise bias: magnitude discrimination and phase-constrained reconstruction, and two methods to reduce T1 bias: small flip angle and dual flip angle method. Bias on fat-fraction estimates was minimized using these methods.

 15:00         3714.     Liver Steatosis Quantification Using MRI: A Prospective Comparative Study with Liver Biopsy

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nicolas mennesson¹, Jérôme Dumortier¹, Sophie Cavassila², Olivier Beuf², Jean-Yves Scoazec³, Frank Pilleul,¹²

¹Hospices Civils de Lyon, Lyon, France; ²INSA-Lyon, Université Lyon 1, Villeurbanne, France; ³Faculté de médecine RTH Laennec, Lyon, France

The diagnosis of steatosis does have important therapeutic implications, because active management of obesity and a reduction in steatosis may improve liver injury and decrease the progression of fibrosis. Double-echo imaging (DEI) such as simple method have been used in order to substitute liver biopsy which is the gold standard. For this study, forty patients with suspected chronic liver diseases were prospectively investigated by MR imaging and liver biopsy. The fat/water ratio had a positive correlation with steatosis grade on liver biopsy (p < 0.0001), the coefficient of linear regression corresponding to r = 0.798. So, Fat/Water ratio (cutoff value ¡Ý at .93) revealed liver steatosis defined by the presence of equal or more 20 % of intracellular lipids with a sensitivity of 93 % and a specificity of 86 %.

 13:30         3715.     Characterization of Liver Fibrosis Using Fat-Suppressed Ultrashort TE (FUTE) Imaging and Multipoint Water-Fat Separation MRI in Patients with Hepatitis C Virus (HCV)-Induced Liver Fibrosis

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Hyeonjin Kim¹, Matthew D. Robson², Maolin Qiu¹, Jinghua Wang¹, Joseph K. Lim, Philip S. Murphy³, R Todd Constable¹

¹Yale University School of Medicine, New Haven, Connecticut, USA; ²John Radcliffe Hospital, Oxford, UK; ³Pfizer, Sandwich, UK

The feasibility of ultrashort echo time (UTE) imaging in assessing liver fibrosis was explored in patients with different stages of hepatitis C virus (HCV)-induced liver fibrosis.  As hepatic steatosis and concomitant iron overload are common features in many chronic liver diseases, the quantification of hepatic fat content and T2* mapping are also performed and their effect on the quantification of short T2 components is addressed.  Our results suggest that fat-suppressed UTE (FUTE) imaging may potentially provide a means of non-invasively discriminating the end stage of liver fibrosis from its milder forms in the presence of steatosis and/or iron overload.

14:00         3716.     Correlation Between Different Stages of Hepatic Fibrosis and in Vivo Metabolic Profile by 1H Magentic Resonante Spectroscopy

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Beatriz Martínez-Granados¹, M. Carmen Carmen Martínez-Bisbal¹,², Daniel Monleón³, Luís Martí-Bonmatí⁴, José Manuel Manuel Rodrigo³, Juan del Olmo³, Antonio Ferrández³, Bernardo Celda¹,²

¹Universitat de Valencia, Burjassot, Spain; ²ISC III, Burjassot, Spain; ³Hospital Clínico Universitario, Valencia, Spain; ⁴Hospital Universitario Dr. Peset, Valencia, Spain

The aim of this study is to verify the potential clinical applications of in vivo liver 1H-MRS metabolic alterations for improving the diagnosis of different liver fibrosis stage. MRS 1.5T (SV at TE=136 ms) studies were performed in 50 patients with clinical fibrosis. Different resonances (lipids, choline, TMAO and glucose) were assigned and identified using ex vivo HR-MAS (11T) and literature data. Statistical significant differences between (-CH3 lipid)/H2O and (glucose+-CH=CHCH2- lipid+glycogen)/H2O ratios and the four fibrosis stages were found. The in vivo liver 1H-MRS profiles and their correlation with fibrosis adds non-invasively quantitative metabolic information to liver pathology diagnosis.

14:30         3717.     Effect of Autologous Bone Marrow Cell Infusion Therapy in Patient with Liver Cirrhosis on Ferucarbotran-Enhanced MR Imaging: A Preliminary Report

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Mi-Suk Park¹, Ja Kyung Kim

¹Yonsei University, Severance Hospital, Seoul, Republic of Korea

Our study is an initial, preliminary report about the effect of ABMI therapy in the patients with liver cirrhosis on ferucarbotran-enhanced MR Imaging. There was a gradual reduction of SPIO uptake after ABMI with increase of liver volume and serum albumin level, which might reflect the progenitor cell proliferation and reduction in Kupffer cell. However, further investigation with contrast agents tagging with bone marrow cells may be needed to evaluate the precise effect of ABMI therapy in the patients with liver cirrhosis.

15:00         3718.     Non-Invasive Diagnosis of Liver Fibrosis - Comparison Between MR Elastography and Supersonic Imaging in an Animal Study

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Najat Salameh¹, Jean-Luc Gennisson², Benoit Larrat², Thomas Deffieux², Michael Tanter², Ralph Sinkus², Bernard Edgard Van Beers¹, Mathias Fink²

¹Université Catholique de Louvain, Brussels, Belgium; ²Laboratoire Ondes et Acoustiques, Paris, France

In this study, we validate the Supersonic Shear Imaging method, by comparing the elasticity measurements obtained with SSI to those obtained with MRE in a model of dietary steatohepatitis in the rat. The elastography measurements were correlated to the percentage of fibrosis obtained at morphometry.

13:30         3719.     Quantification of SPIO Enhancement Measured by T2 and T2* Mapping in Chronic Liver Disease: A Preliminary Report
[Not Available]

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Yong Eun Chung¹, Mi-Suk Park¹, Eun Ju Kim, Myoung Soo Kim¹, Hua-Sun Kim¹, Myeong-Jin Kim¹, Jin-Young Choi¹, Ki Whang Kim¹

¹Yonsei University Health System, Seoul, Republic of Korea

This study evaluate feasibility of T2 and T2 mapping on pre- and post-contrast multi echo fast field echo sequence in chronic liver disease patient.

14:00         3720.     MR Imaging Findings in Patients with Hereditary Hemorrhagic Telangiectasia and Liver Involvement

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Guenther K. Schneider¹, Alexander Massmann², Miles A. Kirchin³, Roland Seidel¹, Peter Fries¹, Urban W. Geisthoff⁴, Arno Buecker¹

¹Saarland University Hospital, Homburg/Saar, Germany; ²Saarland University Hospital,, Homburg/Saar, Germany; ³Bracco Imaging S.p.A., Milan, Italy; ⁴Hospitals of the City of Cologne, Cologne, Germany

Hereditary hemorrhagic telangiectasia (HHT) also known as Rendu-Osler-Weber disease is an autosomal-dominant inherited vascular disorder associated with mucocutaneous, pulmonary, cerebral and visceral arteriovenous malformations. Hepatic affection of HHT results in a wide spectrum from discrete changes of the liver parenchyma and hepatic vessels to high morbidity and mortality due to right heart insufficiency. The study shows the variety of different HHT-related findings in the liver on magnetic resonance imaging and magnetic resonance angiography: hepatomegalia, nodular hyperplastic changes of the liver parenchyma, dilated tortuous intrahepatic vessels, increased hepatic artery and portal vein diameter as well as right heart insufficiency.

14:30         3721.     T1-Weighted DCE MRI with Gd-EOB-DTPA as a Liver Function Test: A Comparison of Two Methods for Deconvolutional Analysis

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Henrik Nilsson¹, Anders Nordell², Lena Douglas², Roberto Vargas³, Eduard Jonas¹, Lennart Blomqvist³

¹Karolinska Instiutet, Stockholm, Sweden; ²Karolinska University Hospital, Stockholm, Sweden; ³Institution for Molecular Medicine and Surgery Karolinska Institutet, Stockholm, Sweden

The aim of this study was to assess the feasibility to use dynamic T₁-weighted Gd-EOB-DTPA-enhanced MRI for the evaluation of segmental liver function in 20 healthy human volunteers. Hepatic Extraction Fraction (HEF), earlier described and used in hepatobiliary scintigraphy, was chosen as marker of hepatocyte function. For deconvolutional analysis (DA), Fourier transforms with an appended tail and Singular Value Decomposition (SVD) were used. The results obtained with the two methods for DA were compared. We found that it is possible to calculate HEF on a segmental level, and that the two methods yields similar results without significant differences.

15:00         3722.     Evaluation of Superparamagnetic Iron Oxide (SPIO) Particles for MR Imaging of Nonalcoholic Steatohepatitis (NASH)
[Not Available]

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Akihiro Tanimoto¹, Kengo Tomita¹, Rie Irie¹, Koichi Oshio¹, Sachio Kuribay¹

¹Keio University School of Medicine, Tokyo, Japan

To determine whether SPIO-enhanced MRI can help to detect NASH, we evaluated 19 patients with nonalcoholic fatty liver disease (NAFLD). Liver biopsy proved ten of 19 patients were definitive NASH.  MRI consisting of T2-FSE, T2*-GRE, and EPI was performed prior to biopsy.  Relative signal decrease [%T2 and %T2*] caused by SPIO were smaller in NASH group than in not NASH group.  The time constant &[tau] from exponential approximation of signal decay on EPI was larger in NASH group than in not NASH group.  SPIO-enhanced MRI would be a reliable tool to identify NASH patients among the patients having NAFLD.

13:30         3723.     Depiction of Non-Dilated Intrahepatic Bile Duct by High Spatial Resolution 3D MR Cholangiography Using SPACE at 3 T; Comparison with 1.5 T in Healthy Volunteers [Not Available]

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Shigeki Arizono¹, Hiroyoshi Isoda¹, Yoji Maetani¹, Yuusuke Hirokawa¹, Kotaro Shimada¹, Yuji Nakamoto¹, Kaori Togashi¹

¹Kyoto University Graduate School of Medicine, Kyoto, Japan

SPACE is a new technique that could overcome SAR problem on 3D TSE sequence at 3T by using variable refocusing FA, while maintaining better SNR. Applying the SPACE technique at 3T, high spatial resolution 3D MRC can be obtained without running into SAR problem. In this presentation, we described the superiority of 3D MRC with SPACE at 3 T over MRC with conventional constant FA at 3T or MRC at 1.5T. In addition, we showed that high resolution 3D MRC with SPACE at 3T allows high-quality images of biliary tract, and has the ability to depict non-dilated intrahepatic bile ducts.

14:00         3724.     Navigator-Triggered Prospective Acquisition Correction (PACE) Technique vs. Conventional Respiratory-Triggered Technique for Free-Breathing 3D MRCP: Prospective Comparative Study Using Healthy Volunteers

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Satoru Morita¹, Eiko Ueno¹, Kazufumi Suzuki¹, Haruhiko Machida¹, Mikihiko Fujimura¹, Shinya Kojima¹, Masami Hirata¹, Takahiro Ohnishi², Chiaki Imura²

¹Tokyo Women's Medical University Medical Center East, Tokyo, Japan; ²Siemens-Asahi Medical Technologies, Tokyo, Japan

This study sought to confirm the superiority of navigator-triggered prospective acquisition correction (PACE) technique over the conventional respiratory-triggered (RESP) technique. This has been perceived experimentally, but  without definite evidence, for free-breathing 3D MRCP. Images from free-breathing 3D turbo spin-echo MRCP using both PACE and RESP techniques were prospectively performed on 25 healthy volunteers. Qualitative and quantitative analyses of contour sharpness index both revealed the image quality of PACE technique to be significantly better than RESP. The superiority of PACE to conventional RESP for free-breathing 3D MRCP with regard to the image quality was confirmed.

14:30         3725.     Respiratory Triggered High-Spatial Resolution T1-Weighted MR Imaging of Liver and Biliary Tree in the Hepatobiliary Phase

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Patrick Asbach¹, Carsten Warmuth², Matthias Rief¹, Matthias Taupitz¹, Bernd Hamm¹, Christian Klessen¹

¹Charité - Universitaetsmedizin Berlin, Berlin, Germany; ²Siemens Medical Solutions, Erlangen, Germany

Hepatobiliary contrast media have the potential to increase the diagnostic performance of magnetic resonance imaging of the liver. The hypothesis for this study was that respiratory triggered high-spatial resolution images acquired in the hepatobiliary phase provide significantly increased image quality compared to breath-hold images. A quantitative and qualitative analysis was performed in 20 patients comparing a respiratory triggered T1w inversion prepared spoiled gradient echo sequence to a breath-hold T1w spoiled gradient echo sequence. The respiratory triggered high-spatial resolution images provide a significantly increased image quality in comparison to breath-hold images on the expense of extended acquisition time.

15:00         3726.     Biliary Anatomy on 3D MRCP Using Free-Breathing Navigator-Triggered Prospective Acquisition Correction: Comparison of Volume-Rendering and Maximum-Intensity-Projection Algorithm

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Satoru Morita¹,², Naoko Saito³, Kazufumi Suzuki¹, Haruhiko Machida¹, Mikihiko Fujimura¹, Eiko Ueno¹, Norio Mitsuhashi⁴, Takahiro Ohnishi⁵, Chiaki Imura⁵

¹Tokyo Women's Medical University Medical Center East, Tokyo, Japan; ²Saiseikai Kurihashi Hospital, Saitama, Japan; ³Boston Medical Center, Boston University School of Medicine, MA, USA; ⁴Tokyo Women's Medical U

This study sought to compare VR and MIP as postprocessing techniques of 3D MRCP to define biliary anatomies. VR and MIP images of 3D MRCP using a prospective acquisition correction technique for 102 patients were retrospectively evaluated by two radiologists in a blinded fashion independently. Interpretation confidence and the accuracies of each reformation with the reference standard were compared. VR findings agreed with the reference standard findings more often than MIP with regard to cystic duct variation. Mean confidence score was significantly higher with VR than MIP with regard to both cystic duct variation and biliary branching patterns. VR reformation of 3D MRCP defines biliary anatomies more accurately than MIP.

13:30         3727.     k-TE GRAPPA for Rapid Abdominal R2* Mapping

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Xiaoming Yin¹,², Andrew C. Larson¹,²

¹Northwestern University, Chicago, Illinois, USA; ²Evanston, Illinois, USA

R2* measurements have proven useful for abdominal imaging applications. The commonly used multiple-GRE (MGRE) sequence collects a train of echoes thereby permitting the reconstruction of images at each TE and subsequent derivation of R2* maps. However, spatial resolution remains to be a challenge to breath-hold requirements. Based upon an extension of k-t GRAPPA parallel imaging methods we recently developed a k-TE GRAPPA approach to reduce MGRE scan times. It has been found that k-TE GRAPPA is an effective parallel imaging method to accelerate MGRE R2*-mapping. It reduced artifact levels and provided more accurate R2* measurements compared to VS and GRAPPA approaches. k-TE GRAPPA offers the potential to reduce breath-hold times and/or increase spatial resolution or coverage.

14:00         3728.     Safety of MR Imaging of the Liver with Ferucarbotran: Multicenter Investigation Using Questionnaire Before and After an Examination

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Hiromitsu Onishi¹, Takamichi Murakami², Tonsok Kim¹, Masatoshi Hori¹, Mitsuru Matsuki, Shinji Hirohashi, Yasuharu Imai, Kousuke Sakurai, Yoshifumi Narumi, Hironobu Nakamura¹

¹Osaka University Graduate School of Medicine, Suita, Japan; ²Kinki University, Osakasayama, Japan

We prospectively investigated the incidence of adverse reactions of ferucarbotran, a superparamagnetic iron oxide contrast agent, using a questionnaire style. Three hundred fifteen patients who underwent ferucarbotran-enhanced magnetic resonance imaging were given a questionnaire asking about the symptoms over a period of 7 days before and after injection of ferucarbotran in order to estimate the false positive adverse reactions. The adverse events to ferucarbotran which were classified as possibly or definitely ferucarbotran related occurred in 14.3%. All of adverse reactions were mild of intensity. Ferucarbotran was considered to be safe in the clinical use at MR imaging of the liver.

14:30         3729.     Discrimination of Pancreaticohepatobiliary Cancer and Benign Patients in Presence and Absence of Jaundice and Cholangitis: 1H and 31P NMR Studies of Bile

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Lakshmi Bala¹, Pratima Tripathi¹, Raja Roy¹, Gourdas Choudhuri², Chunni Lal Khetrapal¹

¹Sanjay Gandhi Post-Graduate Institute of Medical Sciences Campus, LUCKNOW, India; ²Sanjay Gandhi Post-Graduate Institute of Medical Sciences, LUCKNOW, India

1H and 31P NMR quantitative analysis of bile specimens from pancreaticohepatobiliary cancer (n=28) and benign patients (n=20) (with/without jaundice and cholangitis) were carried out for chief biliary constituents viz. total bile acids (TBA), cholesterol (Chol.), phosphatidylcholine (PtC) and inorganic phosphate (Pi). Presence of jaundice and cholangitis significantly lowered biliary constituents (p<0.05 for all) in both benign and malignant patients, possibly due to the down regulation of function of tranporters located at the canalicular side of hepatocytes. Hence, presence of jaundice and cholangitis reduces biliary constituents in bile in benign resulting them indiscriminant with malignant without jaundice and cholangitis.

15:00         3730.     Respiratory Self-Gated Phase-Contrast MRI for Free-Breathing Flow Measurements in the Portal Venous System

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Ning Jin¹, Andrew C. Larson¹,²

¹Northwestern University, Chicago, Illinois, USA; ²Robert H. Lurie Comprehensive Cancer Center, Chicago, Illinois, USA

Breath hold is commomly needed for abdominal phase contrast (PC) flow measurement to remove the respiratory motion. However, the scan times may be prohibitive for cardiac-gated high-resolution imaging. Also for some ill patients, they may be unable to comply with breath hold commands. Some alternative free-breathing methods may be beneficial. Self-gating approaches with additional central k-space lines sampled to track respiratory motion have been applied in cardiovascular and abdominal imaging with free breathing. In this abstract we developed a respiratory self-gated imaging strategy for free breathing abdominal PC flow measurements and compared this technique to conventional breath-hold PC flow measurement in the portal venous system.

Advances in GI & Hepatobiliary Imaging

13:30         3731.     Diffusion Weighted MR Imaging of Gastric Cancer: Comparison with Conventional MRI Sequences

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Lei Tang¹, Xiao Peng Zhang¹, Ying Shi Sun¹, Kun Cao¹, Jie Li¹, Ning Wang¹, Fei Sun²

¹Beijing Cancer Hospital & Peking University School of Oncology, Beijing, People's Republic of China; ²GE healthcare China, Beijing, People's Republic of China

MRI examinations were performed on 31 patients with gastric cancer. Three diffusion-weighted sequences were designed with different b values. Free water grade was used to evaluate the suppression of content signal in gastric lumen. SNR and SIR of high b-value DWI and conventional MRI sequences were calculated and compared. High b-value DWI could demonstrate signal differences better. The ADCs of gastric cancer were decreased following the increase of b-value. The CNR and SIR of high b-value DWI were higher than that of T1WI and T2WI. DWI can be a supplementary method for conventional MRI examinations to demonstrate gastric cancer better.

14:00         3732.     Utility of Ferucarbotran-Enhanced T1-Weighted Spoiled Gradient Recalled Echo MR Images for Hepatic Metastases: A Prospective Comparison with 3.0 T and 1.5T

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Masakatsu Tsurusaki¹, Keitaro Sofue¹, Mototaka Miyake¹, Aine Sakurada¹, Ukihide Tateishi¹, Yasuaki Arai¹, Kazuro Sugimura²

¹National cancer center, Tokyo, Japan; ²Kobe University, Graduate school of medicine, Kobe, Japan

To prospectively compare the frequency and qualitative efficacy of �gring enhancement�h on ferucarbotran-enhanced T1-weighted GRE images using 3.0 T to 1.5T for the detection of hepatic metastases. A total of 25 patients with 70 hepatic metastases underwent ferucarbotran-enhanced MR imaging using both 3.0T and 1.5T scanner. The frequency of �gring enhancement�h in hepatic metastases at 3.0T (74.2%) was significantly (p<0.05) higher than at 1.5T (55.7%) on ferucarbotran-enhanced T1-weighted GRE images. On T1-weighted GRE images, �gring enhancement�h is shown more frequent at 3.0T than 1.5T. Therefore, it is also helpful sign for characterizing hepatic metastases in ferucarbotran-enhanced MR images.

14:30         3733.     Ferucarbotran-Enhanced Magnetic Resonance Imaging in Patients with Hepatic Metastases: Prospective Quantitative and Qualitative Comparison of 3.0 T and 1.5T [Not Available]

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Keitaro Sofue¹, Masakatsu Tsurusaki¹, Mototaka Miyake¹, Aine Sakurada¹, Ukihide Tateishi¹, Yasuaki Arai¹, Kazuro Sugimura²

¹National Cancer Center Hospital, Tokyo, Japan; ²Kobe University, Graduate School of Medicine, Kobe, Japan

To prospectively compare quantitative and qualitative efficacy of ferucarbotran-enhanced MR imaging using 3.0 T to 1.5T for the detection of hepatic metastases. Using 3.0T, ferucarbotran-enhanced MRI showed higher sensitivity than the images using 1.5T for the detection of hepatic metastases. On ferucarbotran-enhanced MRI using 3.0T, higher SNR and lesion-to-liver CNR were achieved than 1.5T, moreover, the decreasing of motion artifact and the improvement of overall image quality on T2*-weighted GRE images using 3.0T might contribute the higher sensitivity.

15:00         3734.     Evaluation of Quantitative Dynamic Contrast Enhanced Pharmacokinetic Parameters with and Without Postprocessing Alignment

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Keiko Miyazaki¹, David J. Collins¹, Dow-Mu Koh¹, David Atkinson², David J. Hawkes², Martin O. Leach¹

¹Institute of Cancer Research, Sutton, UK; ²University College London, London, UK

Dynamic imaging in the liver is a major challenge particularly in accounting for mis-alignments and deformation of the liver. In this paper, the effects of mis-alignment effects in a clinical DCE-MRI liver protocol which involved successive full-exhale breath-holds was evaluated by analyzing the pharmacokinetic (PK) parameters with and without post-processing alignment. DCE-MR protocols which are robust to mis-alignments in the organs would assist accurate derivation of quantitative PK parameters which are increasingly used in several clinical setting to monitor disease progression and regression.

13:30         3735.     Diagnosis of Liver Metastatic Lesions: Performance of Diffusion-Weighted Imaging Compared to Contrast-Enhanced T1-Weighted Imaging

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Andrew D. Hardie¹, Mohit Naik¹, Elizabeth M. Hecht¹, Hersh Chandarana¹, Vivian S. Lee¹, Bachir Taouli¹

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

With the recently described risks of gadolinium exposure in patients with poor renal function, optimization of non-gadolinium enhanced sequences is essential. This study compares the accuracy of diffusion-weighted imaging (DWI) compared to Gadolinium-enhanced T1 sequence for diagnosis of liver metastases in patients with primary cancer. Sensitivity of the DWI and Gd-enhanced datasets were both 81% while the specificity was 78% for DWI and 89% for Gd-enhanced T1. This preliminary study demonstrates the potential role of DWI as an alternate method for the assessment of focal liver lesions in oncology patients in whom gadolinium is contraindicated.

14:00         3736.     ¹H MRS of Human Bile in the Differential Diagnosis of Cholangiocarcinoma and Pancreatic Cancer

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Tedros Bezabeh¹, Omkar B. Ijare¹, Nils Albiin², Urban Arnelo², Bo Lindberg², Ian C.P. Smith¹

¹National Research Council Institute for Biodiagnostics, Winnipeg, Canada; ²Karolinska Institutet, Stockholm, Sweden

Bile is a biofluid of choice for the study of pancreaticobiliary malignancies such as cholangiocarcinoma, gallbladder cancer and pancreatic cancer. In the course of these malignancies, the biochemical composition of bile alters as a result of increased cell turnover. In the present study, the biochemical composition of bile was compared in two pancreaticobiliary malignancies – cholangiocarcinoma and pancreatic cancer, making use of ¹H MRS. The study revealed that cholangiocarcinoma patients showed a decrease in biliary biochemicals such as bile salts, phosphatidylcholine and cholesterol compared to the normal reference patients. Furthermore, most of the bile samples showed the absence of some conjugated bile salts and phosphatidylcholine. On the contrary, in pancreatic cancer, biliary lipid components were intact, but a carbohydrate moiety, D-glucuronate, was predominantly observed in the bile.

14:30         3737.     Effect of Intravenous Superparamagnetic Iron Oxide on Diffusion-Weighted Imaging

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Nagaaki Marugami¹, Satoru Kitano¹, Shinji Hirohashi², Megumi Takewa¹, Junko Takahama¹, Aki Takahashi¹, Kimihiko Kichikawa¹

¹Nara Medical University, Kashihara, Japan; ²Osaka Gyoumeikan Hospital, Osaka, Japan

Superparamagnetic iron oxide injection had significant effects on ADC values. Therefore, only pre-contrast diffusion-weighted images should be used on quantitative ADC studies.

15:00         3738.     ROC Comparison Between Diffusion-Weighted MR and PET/CT Imaging to Detect Lymph Node Metastasis from Gastrointestinal Cancer

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Hitoshi Kubo¹, Masafumi Harada¹, Tatsuro Goto¹, Masaaki Ikeguchi¹, Mayumi Takeuchi¹, Hiromu Nishitani¹

¹University of Tokushima, Tokushima, Japan

The usefulness of diffusion-weighted MR imaging (DWI) to detect lymph node metastasis from the gastrointestinal cancer was evaluated by ROC analysis in comparison with ¹⁸F-FDG imaging (PET). We analyzed 21 patients examined both DWI and PET in our Hospital. The sensitivity of DWI was higher but the specificity was lower than those of PET. The ROC analysis showed higher accuracy on DWI than PET, though the variation of individual evaluation on DWI was larger than that on PET depending on the experience of imaging diagnosis by observers.

13:30         3739.     Comparison in Functional and Metabolic MR Imaging Findings Between Targeted and Non-Targeted Unresectable Hepatic Tumors Treated with TACE

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Ihab R. Kamel¹, Josephina A. Vossen, Manon Buijs, Nouha Salibi, David A. Bluemke, Jean-Francois H. Geschwind

¹Johns Hopkins Hospital, Baltimore, Maryland, USA

The objective of this study was to compare functional (tumor enhancement and ADC value) and metabolic (Choline concentration) findings in patients with unresectable hepatic tumors treated with TACE. MR Imaging studies were obtained before and after a single TACE treatment in 19 patients with primary or metastatic liver lesions. All targeted tumors had complete loss of the Choline peak, a significant increase in tumor ADC value, and a significant decrease in tumor arterial and venous enhancement, without change in tumor size.  These functional findings precede tumor regression in size, and may be utilized to detect early therapeutic response.

14:00         3740.     Characterization of Gastric Cancer with Diffusion-Weighted MR Imaging: Prospective Study in 101 Patients

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Xiao Peng Zhang¹, Lei Tang¹, Ying Shi Sun¹, Kun Cao¹, Jie Li¹, Ning Wang¹

¹Beijing Cancer Hospital & Peking University School of Oncology, Beijing, People's Republic of China

MRI examinations were performed on 101 patients with gastric cancer. Diffusion-weighted single-shot echo-planar sequences were performed combined with sensitivity encoding technique. Forty-four gastric cancers displayed uniformly high signal; and 46 displayed nonuniform signal on DWI. Ten Borrmann-4 gastric cancers displayed ¡°sandwich¡± sign on DWI, which appeared high signal on mucosa and serosa layers, with a low signal band mediately which indicate muscularis propria. The ADCs of diffuse-type gastric cancers were lower than that of confining-type with statistical significances.

14:30         3741.     Hepatocellular Carcinoma: Assessment of Tumor Oxygenation with BOLD MRI

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Mohit Naik¹, Lorenzo Mannelli¹, Hersh Chandarana¹, Vivian Lee¹, Bachir Taouli¹

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

In this study we prospectively evaluated the ability of BOLD MRI to assess tumor hypoxia for treated and untreated hepatocellular carcinoma (HCC). Untreated HCC demonstrates significantly higher oxygen uptake (ÄR2*) compared to HCCs post transarterial chemoembolization (TACE) and liver parenchyma. These preliminary results demonstrate the potential utility of BOLD in quantifying tumor hypoxia and evaluating patients prior to and following therapy with TACE.

15:00         3742.     Detection of Focal Malignant Liver Lesions: Comparison of T2-Weighted and Diffusion-Weighted Imaging at 1.5T or 3.0T

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Hua Wang¹, Xiaoying Wang, Xuexiang Jiang

¹Tianjin Medical University Cancer Institute and Hospital, Tianjin, People's Republic of China

Thirty-three consecutive patients with focal malignant liver lesions on MR images were included in the study. Among them, nineteen patients were examined at 1.5T and 14 patients at 3.0T. Both T2W and DW imaging were performed on each patient. Two observers interpreted images independently and separately. The signal intensity (SI) of tumors and liver were measured at workstation. The ratio of SI of tumor/liver was calculated on tumors more than 1 cm in diameter and without interference of artifacts. There were no significant differences between the performance of 1.5T and 3T. T2W and DW imaging was similar in detection of focal malignant liver lesions. Combined with T2WI, the detection rate on DWI can be improved.

Perfusion of the Liver & Pancreas

13:30         3743.     Geometry and Flow in the Portal Vein of Normal Subjects and Patients Using Magnetic Resonance Imaging

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Stephanie M. George¹, Puneet Sharma², Diego R. Martin², Don P. Giddens¹

¹Georgia Institute of Technology and Emory University, Atlanta, USA; ²Emory University School of Medicine, Atlanta, USA

Cirrhosis is a leading cause of death in the United States.  Previous studies, using ultrasound, have shown varying differences in portal flow in cirrhosis as compared to normal subjects.  However, the flow was significantly affected by the degree of cirrhosis.  This study evaluates the use of PC-MRI to characterize normal and patient portal hemodynamics as a first step towards non-invasive classification and monitoring of cirrhosis in patients with chronic liver disease.  Image post- processing was performed using MATLAB programs to segment the vessel and acquire the velocity values.  Preliminary results show the feasibility of PC-MRI determination of detailed normal portal vein hemodynamics with future work to include more subjects and subject-specific modeling.

14:00         3744.     MR Evaluation of Portal Hypertensive Collateral Shunting Vessels for Prediction of Outcomes After Transjugular Intrahepatic Portosystemic Shunt

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Takeshi Yoshikawa¹,², Donald G. Mitchell², David Eschelman²

¹Kobe University Graduate School of Medicine, Kobe, Japan; ²Thomas Jefferson University, Philadelphia, Pennsylvania, USA

TIPS is an interventional radiologic minimal invasive procedures and leads to portal decompression. However, selection of patients is still a controversial issue. In addition, various complications after TIPS, such as shunt dysfunction, onset or worsening of hepatic encephalopathy can worsen patients�f QOL. Also, technical difficulty in TIPS procedure differs from patient to patient. We found that patients with pre-existing large portosystemic shunt showed the trends toward higher initial technical failure and tract stenosis rates, and toward lower onset or worsening rates of hepatic encephalopathy. Our results suggest gadolinium-enhanced MRI has the potential to predict therapeutic effectiveness and complications after TIPS.

14:30         3745.     Contrast-Enhanced MR Angiography at 3 Tesla for the Assessment of Vascular Complications of Pancreas Transplantation

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