Nikolaos Panagiotopoulos^1,2, Danielle Batakis³, Tanya Wolfson⁴, Rashmi Agni⁵, Xiaofei Zhang⁵, Thekla Helene Oechtering^1,2, Daiki Tamada¹, David T. Harris¹, Claude B. Sirlin³, and Scott B. Reeder^1,6,7,8,9
1Department of Radiology, University of Wisconsin - Madison, Madison, WI, United States, ²Department of Radiology and Nuclear Medicine, Universität zu Lübeck, Lübeck, Germany, ³Department of Radiology, University of California San Diego, San Diego, CA, United States, ⁴Computational and Applied Statistics Laboratory, San Diego Supercomputer Center, University of California San Diego, La Jolla, CA, United States, ⁵Department of Pathology and Laboratory Medicine, University of Wisconsin - Madison, Madison, WI, United States, ⁶Department of Medical Physics, University of Wisconsin - Madison, Madison, WI, United States, ⁷Department of Medicine, University of Wisconsin - Madison, Madison, WI, United States, ⁸Department of Biomedical Engineering, University of Wisconsin - Madison, Madison, WI, United States, ⁹Department of Emergency Medicine, University of Wisconsin - Madison, Madison, WI, United States

Proton density fat fraction (PDFF) is not recognized as a discriminator between nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH). However, considering the two-hit theory on the pathogenesis of NASH, we hypothesize that in high-risk individuals without known liver disease, MRI-PDFF may predict the presence of NASH. There is a paucity of data to support this hypothesis. Therefore, we examined the predictive value of MRI-PDFF in 29 obese adults without suspected liver disease. We observed excellent diagnostic performance of MRI-PDFF for detecting NASH (AUC=1). If confirmed during this ongoing study, this would constitute a paradigm change in diagnosis of NASH.

Véronique Fortier^1,2, Evan McNabb¹, Ahmed Mohamed¹, Rita Zakarian³, Ives R. Levesque^2,3, and Caroline Reinhold^1,3,4,5
1Medical Imaging, McGill University Health Center, Montreal, QC, Canada, ²Medical Physics Unit, McGill University, Montreal, QC, Canada, ³Research Institute of McGill University Health Center, Montreal, QC, Canada, ⁴Diagnostic Radiology, McGill University, Montreal, QC, Canada, ⁵Montreal Imaging Experts, Inc., Montreal, QC, Canada

Commercial methods for single breath-hold proton density fat fraction (PDFF) quantification in liver can suffer from bias due to the presence of iron. In this work, the PDFF accuracy of a high-speed T₂-corrected multi-echo (HISTO) sequence was evaluated at 3T in phantoms at variable R₂^*, mimicking different iron levels. PDFF errors up to 70% for R₂^* larger than 150 s^-1 were obtained, suggesting that HISTO is unreliable at large liver R₂^*, as seen with moderate to high iron overload. A Dixon sequence was more accurate at large R₂^*. Both techniques agreed in patients and phantoms at low PDFF and R₂^*.

Christopher Ball^1,2, Zun Siong Low³, Jadegoud Yaligar¹, Sanjay Kumar Verma¹, Norliza Binte Esmail Sahib³, Hong Sheng Cheng³, Yun Sheng Yip³, Justin Yin Hao Lee³, Debbie Lim³, Walter Wahli³, Harish Poptani², Nguan Soon Tan^3,4, and S. Sendhil Velan^1
1Laboratory of Molecular Imaging, Agency for Science Technology and Research (A*STAR), Singapore, Singapore, ²University of Liverpool, Liverpool, United Kingdom, ³Lee Kong Chian School of Medicine, Singapore, Singapore, ⁴Nanyang Technological University, Singapore, Singapore

Nikolaos Panagiotopoulos^1,2, Danielle Batakis³, Tanya Wolfson⁴, Thekla Helene Oechtering^1,2, David T. Harris¹, Alan McMillan^1,5,6,7, Claude B. Sirlin³, and Scott B. Reeder^1,5,6,8,9
1Department of Radiology, University of Wisconsin - Madison, Madison, WI, United States, ²Department of Radiology and Nuclear Medicine, Universität zu Lübeck, Lübeck, Germany, ³Department of Radiology, University of California San Diego, San Diego, CA, United States, ⁴Computational and Applied Statistics Laboratory, San Diego Supercomputer Center, University of California San Diego, La Jolla, CA, United States, ⁵Department of Medical Physics, University of Wisconsin - Madison, Madison, WI, United States, ⁶Department of Biomedical Engineering, University of Wisconsin - Madison, Madison, WI, United States, ⁷Department of Electrical and Computer Engineering, University of Wisconsin - Madison, Madison, WI, United States, ⁸Department of Medicine, University of Wisconsin - Madison, Madison, WI, United States, ⁹Department of Emergency Medicine, University of Wisconsin - Madison, Madison, WI, United States

MR elastography (MRE) allows for the quantification of liver stiffness as a quantitative biomarker of liver fibrosis. Between field strength reproducibility has been shown to be high in non-obese populations. Data in obese individuals are limited, however, and obese patients may benefit from early diagnosis as they have an increased risk of liver fibrosis. Therefore, in this work we examined the reproducibility of MRE measurements across field strength in a cohort of 34 obese adults. MRE based liver stiffness measurements were highly reproducible between field strengths. Technical success rate was nearly 100% in this challenging, but relevant population.

Suraj D Serai¹, Adarsh Ghosh¹, Benjamin J Wilkins², Anne Marie Cahill¹, David M Biko¹, Elizabeth Rand³, Jack Rychik⁴, and David J Goldberg^4
1Radiology, The Children's Hospital of Philadelphia, Philadelphia, PA, United States, ²Pathology, The Children's Hospital of Philadelphia, Philadelphia, PA, United States, ³Hepatology, The Children's Hospital of Philadelphia, Philadelphia, PA, United States, ⁴Cardiology, The Children's Hospital of Philadelphia, Philadelphia, PA, United States

In patients with Fontan, although liver stiffness has been found to increase significantly with age and has been directly correlated with diminished cardiac function, the increased liver stiffness could be influenced by underlying conditions of vascular congestion. The purpose of this study was to compare stiffness as measured by MRE localized by liver biopsy with histological results from biopsy, and to determine the change in MRE defined liver stiffness over time. Our findings have important implications for how liver MRE might be a useful tool in following the progression of liver stiffness longitudinally in patients with Fontan associated liver disease.  

Alex Goodall¹, Stephen Powell¹, Jasmine Lister¹, and Andrew Fry^1
1Medical Imaging and Medical Physics, Sheffield Teaching Hospitals NHS Foundation Trust, Sheffield, United Kingdom

T2* relaxometry measurements of Liver Iron Concentration are demonstrated to be reliable and reproducible in publications. However, no suitable phantom exists for individual hospitals to validate the accuracy, reliability or precision of their methods. We demonstrate a novel phantom mimicking physiological T2* liver values for this purpose. The accuracy of 2 clinical sequences, reproducibility between 2 scanners and reliability of the phantom was investigated.

Rui V Simoes¹, Andreia Otake¹, Silvia Batista¹, Rafael N Henriques¹, Bruno Costa-Silva¹, and Noam V Shemesh^1
1Champalimaud Research, Champalimaud Centre for the Unknown, Lisbon, Portugal

Despite the recent interest in diffusion kurtosis imaging (DKI) for assessing liver pathologies, its added value over more standard diffusion-weighted or diffusion tensor imaging techniques remains to be established. Importantly, mean diffusivity (MD) and mean kurtosis (MK) estimations are strongly dependent on the diffusion time (DT), a parameter generally overlooked in liver DKI studies. Here, we demonstrate ex vivo the relevance of short DT – namely 10 ms rather than 40 ms – for MK detection of liver disease, using two well-described mouse models of liver metastasis and fibrosis.