Liver Fibrosis
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Wednesday May 11th
Room 518-A-C  10:30 - 12:30 Moderators: Bachir Taouli and Bernard Van Beers

10:30 388.   Introduction
Claude B. Sirlin
10:42 389.   Magnetic resonance elastography measurements of viscosity: a novel biomarker for human hepatic tumor malignancy? 
Sabrina Doblas1, Philippe Garteiser1, Nathalie Haddad1,2, Jean-Luc Daire1,2, Mathilde Wagner1,2, Helena Leitao2,3, Valérie Vilgrain1,2, Ralph Sinkus1, and Bernard E Van Beers1,2
1Centre de Recherche Biomédicale Bichat-Beaujon, INSERM U773, Clichy, France, 2Department of Radiology, Beaujon University Hospital, University Paris Diderot, Clichy, France, 3Department of Radiology, Hospitais de Universidade de Coimbra, Coimbra, Portugal
The accurate and non-invasive determination of the degree of malignancy of a tumor remains a clinical challenge. To determine if magnetic resonance elastography (MRE) could represent a novel non-invasive diagnosis tool, tissue elasticity and viscosity measurements were conducted in a cohort of 76 patients with histologically confirmed hepatic lesions (42 benign and 37 malignant). Malignant tumors, especially HCC, were found to be more viscous than benign lesions. This study shows that MRE measurements of viscosity could be a promising tool for tumor malignancy detection, and can help characterizing some tumor types.

10:54 390.   MR Elastography of the Liver: Observations from a Review of 1,377 Exams 
Meng Yin1, Jayant A Talwalkar2, Kevin J Glaser1, and Richard L Ehman1
1Department of Radiology, Mayo Clinic, Rochester, MN, United States, 2Division of Gastroenterology, Mayo Clinic, Rochester, MN, United States

A retrospective review of 1,377 clinical hepatic MRE examinations was performed. The technical success rate in this broad spectrum of patients was over 94%. The analysis also indicated that MRE-assessed hepatic stiffness correlates with many histological and physiological parameters besides the well-established fibrosis extent, including blood pressure and serum liver enzyme tests. The use of MRE to assess changes in tissue mechanics associated with these parameters could provide new insights into the natural history of hepatic diseases and may have significant diagnostic value in the future.

11:06 391.   Paradoxical correlation between mrp2 expression and fibrosis 
Natsuko Tsuda1, and Osamu Matsui2
1Medical Affairs, Bayer Yakuhin, Ltd., Osaka, Osaka, Japan, 2Department of Radiology, Kanazawa University Graduate School of Medical Science, Kanazawa, Ishikawa, Japan

We compared the transporter (oatp1 and mrp2) expression and signal profile on the Gd-EOB-DTPA-enhanced MRI between NASH and cirrhotic liver induced in rats, and investigated the correlation of the transporter expression and fibrosis rate in both diseases. There was no significant difference in the oatp1 expression between the cirrhosis and NASH groups; whereas, the mrp2 expression in the TAA group increased in comparison with the NASH and control groups. In addition, there was a paradoxical correlation between the fibrosis rate and mrp2 expression. The signal enhancement on Gd-EOB-DTPA-enhanced MRI would reflect the transporter expression in NASH and cirrhosis.

11:18 392.   Macromolecular proton fraction mapping of the human liver in vivo: technical feasibility and preliminary observations in hepatic fibrosis 
Vasily L. Yarnykh1, and George N. Ioannou2
1Department of Radiology, University of Washington, Seattle, WA, United States, 2Department of Medicine, University of Washington, Seattle, WA, United States

Cross-relaxation imaging (CRI) method has been adapted for fast 3D parametric mapping of the macromolecular proton fraction (MPF) in the human liver. The entire protocol requires four breath-hold intervals and provides four magnetization transfer images, variable flip angle T1 mapping, and sequences for correction of B0 and B1 inhomogeneities. Preliminary data were obtained from 6 patients with chronic HCV infection and histologically confirmed presence (stages F1, F3, and F4) or absence (stage F0) of hepatic fibrosis. Analysis of MPF histograms of the liver parenchyma indicated that MPF increases in liver fibrosis, and this increase is associated with the fibrosis stage.

11:30 393.   Gadoxetic Acid-Enhanced Magnetic Resonance Imaging for Evaluation of Borderline Hepatocellular Nodules in Cirrhotic Livers  -permission withheld
Jeong Min Lee1, Hyun Kyung Yang1, joon koo han1, and Byung Ihn Choi1
1Radiology, Seoul National University Hospital, Seoul, Seoul, Korea, Republic of

Our study results demonstrate that a significant proportion of hypovascular and hypointense nodules (ˇĂ1 cm in diameter) seen on HBPI of gadoxetic, acid-enhanced MRI in patients with liver cirrhosis, showed either malignant features on pathology (85.7%) or imaging features suggesting malignant changes (77.5%). Therefore, these are clinically significant lesions which must be closely followed or which require local ablation treatment.

11:42 394.   Quantitative MRI of Liver Fibrosis in an Experimental Mouse Model 
April M. Chow1,2, Darwin S. Gao1,3, Shu Juan Fan1,3, Gladys G. Lo4, Siu Ki Yu2, and Ed X. Wu1,3
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Pokfulam, Hong Kong SAR, China, People's Republic of, 2Medical Physics & Research Department, Hong Kong Sanatorium & Hospital, Happy Valley, Hong Kong SAR, China, People's Republic of, 3Department of Electrical and Electronic Engineering, The University of Hong Kong, Pokfulam, Hong Kong SAR, China, People's Republic of, 4Department of Diagnostic and Interventional Radiology, Hong Kong Sanatorium & Hospital, Happy Valley, Hong Kong SAR, China, People's Republic of

Liver fibrosis is a common response to chronic liver injury. Early diagnosis of liver fibrosis could facilitate early interventions and treatments, thus prevent its progression to cirrhosis. Clinical utility of advanced MRI techniques for staging liver fibrosis has yet to be established. Recently, a preliminary human study has reported that liver T2 value increases monotonically with increasing fibrosis stage. Quantitative mapping of relaxation times can be routinely and reliably performed in standard scanners with rapid imaging capability and breath-holding/triggering techniques and hence may be valuable and robust in clinical settings. In this study, we characterized the change in relaxation times longitudinally in a well controlled experimental mouse model of liver fibrosis. Increased T1 and T2 values were observed after CCl4 insult, suggesting that both relaxation times may serve as sensitive markers for liver fibrosis.

11:54 395.   T2 relaxation time as a surrogate marker of liver fibrosis 
Alexander R Guimaraes1,2, Luiz Siqueira2, Giles Boland2, Deborah Gervais2, Michael Chew2, and Peter Hahn2
1Radiology/Massachusetts General Hospital, Martinos Center for Biomedical Imaging, Charlestown, MA, United States, 2Radiology/Massachusetts General Hospital, Division of Abdominal Imaging and Interventional Radiology, Boston, MA, United States

The diagnosis, staging and quantification of fibrosis relies on liver biopsy, which is invasive with significant risks. We studied retrospectively in 123 patients with either Hepatitis B or C, having recent random liver biopsy, whether T2 correlated to liver fibrosis stage. Our retrospective analysis demonstrates that there is a monotonically increasing T2 value with increasing fibrosis stage. We validated our quantitative approach with phantom data, which demonstrate, that there is close agreement in absolute T2 values when comparing a 2 point fit from TSE data to multi-echo CPMG. Furthermore, our results in a rat model corroborate our human studies.

12:06 396.   Analysis of Radially Undersampled 4D Velocity Mapping (PC VIPR) for Comprehensive Imaging in Portal Hypertension. 
Alex Frydrychowicz1, Alejandro Roldán-Alzate2, Ben R Landgraf1, Eric Niespodzany2, Rakhee Wadhwa Verma1, Oliver Wieben2, and Scott B Reeder1
1Department of Radiology, University of Wisconsin - Madison, Madison, WI, United States, 2Departments of Radiology, Medical Physics, University of Wisconsin - Madison, Madison, WI, United States

Comprehensive 4D flow imaging encompassing the entire upper abdominal vasculature would facilitate diagnosis of complex disease processes in the hepatic and splanchnic vasculature. An efficient 4D velocity mapping approach using 5-point PC-VIPR was applied to assess the splanchnic and hepatic vasculature in 24 participants, many with portal hypertension. This approach may be advantageous in the assessment of liver disease because hepatic and splanchnic flow can change dramatically in the presence of portal hypertension. Comparison with contrast-enhanced imaging and analysis of complex flow patterns analysis will be presented.

12:18 397.   MRI-based detection of the extracellular matrix surrounding the hepatic sinusoid 
Scott Charles Beeman1, Lawrence Mandarino2,3, Jorge Rakela4, and Kevin Bennett1,5
1School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona, United States, 2Department of Medicine, Mayo Clinic in Arizona, Scottsdale, Arizona, United States, 3School of Life Sciences, Arizona State University, Tempe, Arizona, United States, 4Department of Gastroenterology and Hepatology, Mayo Clinic in Arizona, Scottsdale, Arizona, United States, 5Keller Center for Imaging Innovation, Barrow Neurological Institute, Phoenix, Arizona, United States

A technique is demonstrated to detect changes in the extracellular matrix (ECM) surrounding the hepatic sinusoid (HS). ECM changes are detected via specific binding of the cationic form of the superparamagnetic endogenous protein ferritin (CF) to the ECM. Confocal microscopy shows colocalization of CF with ECM surrounding the HS. Electron microscopy confirms the presence of CF in the ECM. The specific binding of CF to the ECM surrounding the HS is observable in vivo using MRI, raising the possibility of detecting ECM changes associated with the development of liver disease.