Hepatic Storage Disease
Tuesday 21 April 2009
Room 316A 10:30-12:30


Hero K. Hussain and Joachim Lotz

10:30  202. Simultaneous Estimation of Water-T2 and Fat Fraction Using a Single Breath Hold Radial GRASE Method
    Christian Graff1, Zhiqiang Li2, Eric W. Clarkson2, Chuan Huang3, Ali Bilgin4, Maria I. Altbach2
Program in Applied Mathematics, University of Arizona, Tucson, AZ, USA; 2Department of Radiology, University of Arizona, Tucson, AZ, USA; 3Department of Mathematics, University of Arizona, Tucson, AZ, USA; 4Department of Electrical and Computer Engineering, University of Arizona, Tucson, AZ, USA
    A new algorithm for processing radial GRASE data has been developed. With this algorithm one obtains both fat-water information and T2 of the water component within a breath hold. This novel method is fast and should provide valuable information for the characterization of pathologies in the clinic.
10:42 203. Breath-Hold FSE for Accurate Imaging of Myocardial and Hepatic R2
    Daniel Kim1, Jens H. Jensen1, Ed X. Wu2, Sujit S. Sheth3, Gary M. Brittenham3
Center for Biomedical Imaging and Radiology, NYU Langone Medical Center, New York, NY, USA; 2Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong; 3Pediatrics and Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA
    MRI provides a means to non-invasively assess tissue iron concentration by exploiting the paramagnetic effects of iron on T2 or T2*. The most widely used method is T2* imaging is sensitive to non-iron related magnetic field (B0) inhomogeneities, which can confound T2* measurements within the whole heart and liver. An alternative method is T2 imaging, but they are generally performed during free breathing with respiratory gating due to their low data acquisition efficiency. The purpose of this study was to develop a breath-hold fast spin echo (FSE) sequence for fast and accurate imaging of myocardial and hepatic T2.
10:54 204.

Hepatic Fat Quantification in Children Using Multi-Echo Gradient-Echo Imaging and Fat Spectral Modeling at 1.5 T

    Masoud Shiehmorteza1, Takeshi Yokoo1, Gavin Hamilton1, Mark Bydder1, Manuel Rodriguez1, Joel E. Lavine2, Jeffrey B. Schwimmer2, Claude B. Sirlin1
Radiology, University of California San Diego, San Diego, CA, USA; 2Pediatrics, University of California San Diego, San Diego, CA, USA
    Fatty liver disease is currently the most common cause of liver disease in children (12-17% prevalence). Although MR imaging has been applied to children previously, the accuracy of fat quantification has not been verified. Confirming that MR imaging is accurate in children is necessary because they may not be able or willing to cooperate with MR examinations. Also, the histological features of pediatric FLD differ from those of adult FLD, and generalization of adult study’s data may not be valid. In this dedicated pediatric study, we assessed fat estimation accuracy of MR imaging, using single-voxel MR spectroscopy as the reference.


11:06 205. Correlation of T1 and T2* Corrected Dual-Echo MRI Vs. MRS for Hepatic Fat Determination in a Multicenter Clinical Trial: Results of the Phase II Study of the MTP Inhibitor AEGR-733

Mark Rosen1, Sarah Englander1, Harish Poptani1, Evan Siegelman1, James Gimpel2, Dena Flamini2, Matthew Parris3, Bill Sasiela3, Bruce Hillman4
Radiology, University of Pennsylvania, Philadelphia, PA, USA; 2American College of Radiology Imaging Network, Philadelphia, PA, USA; 3Aegerion, Inc., Bridgewater, NJ, USA; 4Radiology, University of Virginia, Charlottesville, VA, USA

    A multisite trial of the MTP inhibitor AEGR-733 using hepatic MRI/MRS for liver fat determination was performed. Both single voxel (SV) MRS and multiple dual-echo gradient echo MRI data were used to quantify hepatic fat. A total of 1160 exams with evaluable MRI and MRS data sets were obtained. Correlation of hepatic fat by SV-MRS and several dual-echo MRI methods ranged from 0.870-0.890 for all data sets, 0.935-0.942 for protocol compliant MRI data, and 0.949-0.955 high-quality MRS data. Dual-echo MRI with correction for T1 and T2* effects outperformed other methods, with lower mean squared variation and fewer outlying data points.


11:18 206. Quantification of Abdominal Fat Accumulation During Hyperalimentation Using MRI
    Olof Dahlqvist Leinhard1,2, Andreas Johansson1, Joakim Rydell1, Johan Kihlberg2, Örjan Smedby1,2, Fredrik H. Nyström1, Peter Lundberg1,2, Magnus Borga1,2
Linköping University, Linköping, Sweden; 2Center for Medical Image Science and Visualization (CMIV), Linköping University, Linköping, Sweden
    The abdominal fat content was quantified using in- and out-of-phase imaging after phase sensitive reconstruction and an initial intensity correction procedure. Classification of all tissue as subcutaneous, intraabdominal or retroperitoneal was performed using a novel completely automatic segmentation procedure. This technique was used to determine intraabdominal fat before and after a two-fold increase in daily caloric intake. A significantly lower increase of intraabdominal fat tissue was observed in women than in men. The study highlighted the suitability of MR for accurate and user independent investigation of the compartmentalization of fat deposits in the body. 


11:30 207. Validation of Chemical Shift Based Fat-Fraction Imaging with MR Spectroscopy
    Sina Meisamy1, Catherine DG Hines1,2, Gavin Hamilton3, Karl Vigen1, Jean H. Brittain4, Charles A. McKenzie5, Huanzhou Yu6, Scott K. Nagle1, Yu Grace Zeng1, Claude B. Sirlin3, Scott B. Reeder1,2
Radiology, University of Wisconsin, Madison, WI, USA; 2Biomedical Engineering, University of Wisconsin, Madison, WI, USA; 3Liver Imaging Group, Department of Radiology, University of California, San Diego, CA, USA; 4Applied Science Laboratory, GE Healthcare, Madison, WI, USA; 5Medical Biophysics, University of Western Ontario, London, Ontario, Canada; 6Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA
    Nonalcoholic steatohepatitis is a form of liver disease, which affects nearly 30% of the US population and 75% of obese individuals. 1H-MRS is regarded by many as the non-invasive gold standard for quantification of hepatic steatosis. In this study we compare a chemical shift based fat-fraction imaging method (IDEAL) of the liver with 1H-MRS for quantification of hepatic steatosis. The results of our study show that overall, there is excellent correlation between IDEAL and MR spectroscopy with the highest correlation and excellent one-one agreement seen when both T2* correction and accurate spectral modeling of fat is applied.


11:42 208. A Dynamic Study of Changes in  Hepatic and Skeletal Muscle Lipid and Glycogen Levels, Due to 24h Starvation and Re-Feeding: A 1H and 13C MRS Study
    Mary Charlotte Stephenson1, Sherif Awad2, Elisa Placidi1, Luca Marciani2, Kenneth C. H. Fearon3, Ian A. Macdonald4, Robin C. Spiller2, Penny A. Gowland1, Peter Gordon Morris1, Dileep N. Lobo2
SPMMRC, School of Physics and Astronomy, University of Nottingham, Nottingham, UK; 2Nottingham Digestive Diseases Centre Biomedical Research Unit, University of Nottingham, Nottingham, UK; 3Department of Surgery, University of Edinburgh, Ednburgh, UK; 4School of Biomedical Sciences,, University of Nottingham, Nottingham, Nottinghamshire, UK
    Short-term starvation has been shown to induce insulin resistance in hepatic and skeletal muscle tissue although the metabolic processes involved are unknown. The aim of this study was to measure changes in hepatic and skeletal muscle glycogen and lipid content in order to understand substrate metabolism leading to an insulin resistant state following short-term starvation and re-feeding using a carbohydrate rich drink. Short-term starvation induced decreases in hepatic liver glycogen and lipid stores, with associated decreases in liver volume. Lipid levels in calf muscle increased due to starvation which may be the mechanism via which tissue becomes insulin resistant.
11:54 209.

Spectrally-Modeled Hepatic Fat Quantification by Multi-Echo Gradient-Recalled-Echo Magnetic Resonance Imaging at 3.0T

    Takeshi Yokoo1, Masoud Shiehmorteza1, Mark Bydder1, Gavin Hamilton1, Yuko Kono2, Alexander Kuo2, Joel E. Lavine3, Claude B. Sirlin1
Radiology, UCSD, San Diego, CA, USA; 2Medicine, UCSD, San Diego, CA, USA; 3Pediatrics, UCSD, San Diego, CA, USA
    Several groups recently suggested that accurate fat quantification by MR requires correction of the relaxation effects as well as modeling of multi-component fat signal. Using non-T1-weighted multi-echo GRE imaging and 3-peak fat spectral modeling, high fat estimation accuracy was demonstrated at 1.5 T in fatty liver patients. In principle, this general approach would be independent of the field strength and therefore is also applicable at 3.0 T. In this first human study on spectrally-modeled hepatic fat quantification at 3.0 T, we assessed fat estimation accuracy of MR imaging using MR spectroscopy as the reference standard.


12:06 210. Identification of Brown Adipose Tissue in Mice Using IDEAL Fat-Water MRI
    Houchun Harry Hu1, Daniel L. Smith, Jr. 2, Tim R. Nagy2, Michael I. Goran3, Krishna S. Nayak1
Ming Hsieh Department of Electrical Engineering, University of Southern California, Los Angeles, CA, USA; 2Department of Nutritional Sciences, University of Alabama, Birmingham, AL, USA; 3Department of Preventive Medicine, University of Southern California, Los Angeles, CA, USA
    The fat-signal fraction derived from IDEAL-MRI is used to discriminate white (WAT) and brown adipose tissue (BAT) depots in mice. We found in both excised tissue samples and in vivo that WAT has a fat-signal fraction range of 90-93%. In contrast, BAT exhibits a much wider and significantly lower range of 39-62%. Analysis from high-resolution (0.6 mm isotropic) 3T results in whole juvenile and adult mice clearly identified BAT in the interscapular region, as well as perirenal and intercostal sites. We thus conclude that BAT can be non-invasively identified based on MRI measurements of IDEAL fat-signal fraction.


12:18 211. On the Definition of Fat-Fraction for in Vivo Fat Quantification with Magnetic Resonance Imaging

Scott B. Reeder1,2, Catherine DG Hines1,3, Huanzhou Yu4, Charles A. McKenzie5, Jean H. Brittain6
Radiology, University of Wisconsin, Madison, WI, USA; 2Medical Physics, University of Wisconsin, Madison, WI, USA; 3Biomedical Engineering, University of Wisconsin, Madison, WI, USA; 4Applied Science Laboratory, GE Healthcare, Menlo Park, CA, USA; 5Medical Biophysics, University of Western Ontario, London, Ontario, Canada; 6Applied Science Laboratory, GE Healthcare, Madison, WI, USA


The most commonly used metric for fat quantification with MRI is “fat-signal-fraction”. After correction for confounding factors (eg. T2*-decay, etc) fat-signal-fraction is synonymous with fat-proton-density-fraction. Unfortunately, gold standard assays used to validate MRI provide estimates of fat-volume-fraction or fat-mass-fraction. The purpose of this work is to clarify fat-fraction definitions, and to estimate fat-volume-fraction and fat-mass-fraction from separated fat/water signals. Theory and experiment demonstrate that for fat, signal-fraction is equivalent to volume-fraction and mass-fraction. The same is not true, however, for other combinations of chemical species such as acetone and water, which require correction factors to determine volume or mass fraction.