Alejandro Roldán-Alzate¹, Catherine Hines^1,2, Rashmi M. Agni³, Diego Hernando¹, Karl K Vigen^1,4, Gavin Hamilton⁵, Mark Bydder⁵, Claude Sirlin⁵, and Scott B Reeder^1,4
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.

Mustafa Rifaat Bashir¹, Xiaodong Zhong², Brian Marshall Dale³, Daniel Tobias Boll¹, and Elmar Max Merkle^1
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.

Samir D Sharma¹, Houchun H Hu², and Krishna S Nayak^1
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.

Nanda Deepa Thimmappa¹, Pascal Spincemaille², Bo Xu², Sarah Eskreis-Winkler^2,3, Yi Wang², and Martin R. Prince^1
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.

Mary Charlotte Stephenson¹, Richard D Johnston^2,3, Guruprasad P Aithal², Philip Kaye², Ian A MacDonald³, and Peter G Morris^1
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.

Hai-Ling Margaret Cheng^1,2, Stephanie Holowka³, Rahim Moineddin⁴, and Isaac Odame^5
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.

Darwin S. Gao^1,2, Jian Yang^1,3, Matthew M. Cheung^1,2, April M. Chow^1,2, Shujuan Fan^1,2, Kwan Man⁴, and Ed X. Wu^1,2
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.

Sohae Chung¹, Kyung-Eun Kim², Mi-Suk Park², and Leon Axel^1
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.

Scott A Kruse¹, David S Lake², Armando Manduca^1,2, Phillip J Rossman¹, Jessica R Edge³, Joel G Fletcher¹, Joel P Felmlee¹, Richard L Ehman¹, and Adil E Bharucha^3
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.

Alex Menys¹, Emma Helbren², Jesica Makanyanga², Steve Halligan², David Atkinson², and Stuart Taylor^2
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.