Hepatobiliary & Gastrointestinal
Click on to view the abstract pdf. Click on to view the recorded presentation.
Wednesday 9 May 2012
Room 219-220  10:00 - 12:00 Moderators: Shahid M. Hussain, Shreyas S. Vasanawala

10:00 0398.   
Complex and Magnitude MRI for Quantification of Hepatic Steatosis – Correlation with MR Spectroscopy and Biopsy
Alejandro Roldán-Alzate1, Catherine Hines1,2, Rashmi M. Agni3, Diego Hernando1, Karl K Vigen1,4, Gavin Hamilton5, Mark Bydder5, Claude Sirlin5, and Scott B Reeder1,4
1Radiology, University of Wisconsin, Madison, Wisconsin, United States, 2MERK, 3Department of Pathology, University of Wisconsin - Madison, Madison, WI, United States, 4Medical Physics, University of Wisconsin, Madison, Wisconsin, United States, 5University of California San Diego

Synopsis (100 words maximum): NAFLD is the most common type of chronic liver disease affecting an estimated 90-100 million people in the US alone, including 10% of children. Liver biopsy is the current gold standard for diagnosis of NAFLD, but is limited due to sampling variability, cost and risk. The purpose of this study is to validate two quantitative MRI methods (complex, magnitude) for accurate diagnosis and grading of NAFLD using MRI. Single voxel MR spectroscopy and non-targeted liver biopsy are used as reference standards in this study. Excellent correlation between both MRI methods and MRS, and very good correlation with biopsy was found.

10:12 0399.   Fully automated, user-independent "screening" of the liver for diffuse steatosis/iron overload using a two-point Dixon pulse sequence
Mustafa Rifaat Bashir1, Xiaodong Zhong2, Brian Marshall Dale3, Daniel Tobias Boll1, and Elmar Max Merkle1
1Radiology, Duke University Medical Center, Durham, NC, United States, 2Siemens Medical Solutions, Atlanta, GA, United States, 3Siemens Medical Solutions, Cary, NC, United States

MRI-based liver fat and iron quantification are becoming increasingly well-validated. A major barrier to using these techniques on a wide-scale basis is that they require prior knowledge of the presence of disease, or running quantification on all patients having a liver MRI. We have implemented a technique which "screens" the liver for fat/iron based on a clinical two-point Dixon pulse sequences, which can be used in routine clinical liver MRI as the in/opposed phase acquisition. This identifies patients with disease and advises the MR operator to perform quantification only when necessary. This study compares the performance of the automated algorithm with the performance of expert readers in the detection and characterization of diffuse liver disease by MRI.

10:24 0400.   
Accelerated Liver Fat Quantitation Using Parallel Imaging and Compressed Sensing
Samir D Sharma1, Houchun H Hu2, and Krishna S Nayak1
1Electrical Engineering, University of Southern California, Los Angeles, CA, United States, 2Radiology, Children's Hospital Los Angeles, Los Angeles, CA, United States

Chemical shift-encoded water-fat imaging has recently shown considerable promise as a safe and noninvasive alternative to tissue biopsy for in-vivo liver fat quantitation. However, this technique requires measurements at multiple echo-times; this limits the spatial resolution and/or volume coverage that can be achieved in one breath-held scan. In this work, we present a combined parallel imaging and compressed sensing framework for liver fat quantitation. The proposed approach is compared to an existing parallel imaging and water-fat quantitation method. We demonstrate more accurate liver fat quantitation at 2.5x 1D acceleration using the proposed approach than with the existing method.

10:36 0401.   
Optimizing Liver 3D Arterial Phase Imaging with Gadoxetate Disodium
Nanda Deepa Thimmappa1, Pascal Spincemaille2, Bo Xu2, Sarah Eskreis-Winkler2,3, Yi Wang2, and Martin R. Prince1
1Radiology, Weill Cornell Medical College, New York, NY, United States, 2Weill Cornell Medical College, New York, NY, United States, 3New York Hospital Queens, Flushing, NY, United States

Dynamic contrast enhanced imaging of the liver using 3D spiral offers a greatly increased ability to visualize the different enhancement sub-phases. In this abstract, we propose to use a high frame rate reconstruction using the same data to derive signal enhancement curves of the aorta, portal vein and other territories. These are used to obtain optimal temporal windows for a second reconstruction of particular sub-phases.

10:48 0402.   
Differences in hepatic lipid composition linked to histological evidence of inflammation in the liver: A 1H MRS study investigating omega-3 fatty acid supplementation
Mary Charlotte Stephenson1, Richard D Johnston2,3, Guruprasad P Aithal2, Philip Kaye2, Ian A MacDonald3, and Peter G Morris1
1SPMMRC, School of Physics and Astronomy, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom, 2National Institute for Health Research, Nottingham Digestive Diseases Centre, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom, 3School of Biomedical Sciences, University of Nottingham, Nottingham, Nottinghamshire, United Kingdom

Previous studies, investigating the effects of n-3 polyunsaturated fatty acid (PUFA) supplementation on liver steatosis have shown reduced hepatic lipid levels and inflammation using ultrasound and biochemical markers. This study aims to investigate the effects of n-3 PUFA supplementation on the lipid composition and content in patients with non alcoholic fatty liver disease (NAFLD). MRS measurement of the liver lipid composition suggests an increase in lipid chain length in steatohepatitis (compared to steatosis) which is predictive of the NAFLD Activity Score. However, no reduction in steatosis was found following 3 months of n-3 PUFA supplementation.

11:00 0403.   Accuracy and reproducibility of T2* measurement of liver iron overload in pediatric patients
Hai-Ling Margaret Cheng1,2, Stephanie Holowka3, Rahim Moineddin4, and Isaac Odame5
1Medical Biophysics, University of Toronto, Toronto, ON, Canada, 2Physiology & Experimental Medicine, The Hospital for Sick Children, Toronto, ON, Canada, 3Diagnostic Imaging, The Hospital for Sick Children, 4Family and Community Medicine, University of Toronto, 5Haematology/Oncology, The Hospital for Sick Children

A rapid T2*-based method for liver iron measurement is desirable, particularly in children to avoid sedation. Although liver iron concentration equations based on T2* have been calibrated, there has been little independent validation in a clinical setting. In our ongoing study of pediatric patients with liver iron overload, we assess the accuracy and reproducibility of the T2* method and use FerriScan, a T2-based service that has regulatory approval, as our reference standard for liver iron measurement. Our results in 99 patients to date show high accuracy and reproducibility of our T2*-based technique for absolute liver iron quantification.

11:12 0404.   Increasing diffusion time improves in vivo DWI sensitivity to liver fibrosis
Darwin S. Gao1,2, Jian Yang1,3, Matthew M. Cheung1,2, April M. Chow1,2, Shujuan Fan1,2, Kwan Man4, and Ed X. Wu1,2
1Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China, 2Department of Electrical and Electronic Engineering, The University of Hong Kong, Hong Kong SAR, China, 3Department of Radiology, The First Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, China, 4Department of Surgery, The University of Hong Kong, Hong Kong SAR, China

In liver fibrosis, the structural damage on cellular scale may modify the restricted diffusion behavior of water molecules in the intra- and extracellular space. In this study, we examined whether different diffusion times would yield different sensitivities in detecting the pathological alterations in tissue microstructure during liver fibrogenesis in an experimental rat model. Our results demonstrated that true diffusion coefficient (DTrue) measured with long diffusion time was highly sensitive in detecting and accessing subtle changes in tissue microstructure during liver fibrogenesis.

11:24 0405.   
Noninvasive Liver Stiffness Assessment with Tagged MRI in Cirrhotic Patients with Child-Pugh scores
Sohae Chung1, Kyung-Eun Kim2, Mi-Suk Park2, and Leon Axel1
1Center for Biomedical Imaging, Radiology Department, NYU Langone Medical Center, New York, NY, United States, 2Department of Diagnostic Radiology, Severance Hospital, Yonsei University College of Medicine, Seoul, Korea, Republic of

Liver fibrosis is an important prognostic factor in patients with liver disease, and its assessment can be used to guide therapy. It is known to result in increased mechanical stiffness, so that the assessment of liver stiffness is a key feature of current noninvasive approaches, for example, by detecting the motion of the liver with ultrasound or MRI. In our previous study, we described a new noninvasive approach for the assessment of liver stiffness by using magnetization-tagged MRI (tMRI) to measure the cardiac-induced motion and deformation in the liver. In this work, we applied our method to 45 cirrhotic patients with Child-Pugh scores.

11:36 0406.   Magnetic Resonance Elastography of the Anal Sphincter
Scott A Kruse1, David S Lake2, Armando Manduca1,2, Phillip J Rossman1, Jessica R Edge3, Joel G Fletcher1, Joel P Felmlee1, Richard L Ehman1, and Adil E Bharucha3
1Radiology, Mayo Clinic, Rochester, MN, United States, 2Physiology & Biomedical Engineering, Mayo Clinic, Rochester, MN, United States, 3Clinical and Enteric Neuroscience Translational and Epidemiological Research Program (C.E.N.T.E.R.), Mayo Clinic, Rochester, MN, United States

The relationship between imaging findings and function of the anal sphincter in fecal incontinence is not well understood. Anal sphincter stiffness has not been assessed by any technique, including magnetic resonance elastography (MRE), in humans. We performed MRE exams on six patients at 120 Hz with a customized driver and an endorectal coil. The median shear stiffness value of the internal sphincter for all patients was 3.7 kPa. Although further work is necessary to assess reproducibility and establish normal stiffness values and their variation with disease, it is possible to quantify anal sphincter stiffness with MRE.

11:48 0407.   Small Bowel Strictures in Crohn’s Disease: a quantitative investigation of intestinal motility using MR enterography
Alex Menys1, Emma Helbren2, Jesica Makanyanga2, Steve Halligan2, David Atkinson2, and Stuart Taylor2
1Centre for Medical Imaging, University College London, UCLH, London, United Kingdom, 2Centre for Medical Imaging, University College London

Small bowel strictures are common in Crohn’s disease (CD) and often present a therapeutic dilemma with a poorly understood natural history. Dynamic motility sequences are increasingly used in MR Enterography (MRE) and may provide insights into the functional significance of stricturing disease. We aimed to quantify intestinal motility in 24 patients with CD related strictures and investigate potential differences in upstream (dilated/non-dilated) bowel. We found reduced motility within the stricture and significantly decreased motility in dilated pre-strictured bowel compared to non-dilated. These data provide new insights into the effect on bowel motility by stricturing Crohn’s disease.