Remy Klaassen^1,2, Anne Steins^1,2, Oliver J. Gurney-Champion³, Maarten F. Bijlsma², Hessel Wijkstra⁴, Geertjan van Tienhoven⁵, Marc G.H. Besselink⁶, Johanna W. Wilmink¹, Mark J. van de Vijver⁷, Jaap Stoker³, Aart J. Nederveen³, and Hanneke W.M. van Laarhoven^1
1Department of Medical Oncology, Academic Medical Center, Amsterdam, Netherlands, ²Laboratory for Experimental Oncology and Radiobiology, Academic Medical Center, Amsterdam, Netherlands, ³Department of Radiology, Academic Medical Center, Amsterdam, Netherlands, ⁴Department of Urology, Academic Medical Center, Amsterdam, Netherlands, ⁵Department of Radiation Oncology, Academic Medical Center, Amsterdam, Netherlands,⁶Department of Surgery, Academic Medical Center, Amsterdam, Netherlands, ⁷Department of Pathology, Academic Medical Center, Amsterdam, Netherlands

Magnetic Resonance Imaging (MRI) enables the non-invasive characterization of the pancreas tumor microenvironment. Using diffusion weighted imaging, water diffusivity can be used as measure for stromal deposition and dynamic contrast enhanced MRI provides further insight on tumor vascularization. Although these sequences provide valuable information on macro scale, interpretation of the underlying biological processes is not unambiguous. In this pilot study we show the feasibility of matching post-operative axial tissue slices to in vivo MRI of the pancreas. Matching immunohistochemically stained whole mount tissue slices provides direct information on localization and local tumor heterogeneity for biological correlation of functional MRI parameters.

Lorenzo Mannelli¹, Maggie M Fung², Gregory Nyman¹, Sabrina Lopez¹, and Richard Kinh Gian Do^1
1Radiology, Memorial Sloan Kettering Cancer Center, New York, NY, United States, ²Global MR Applications and Workflow, GE Healthcare, New York, NY, United States

Our preliminary results show that navigator echo respiratory triggering restricted FOV (rFOV) ss-DW imaging is feasible with similar SNR compared to large FOV DWI, and also demonstrates higher overall image quality with reduced artifacts. Furthermore, measurements from ADC maps derived from rFOV DWI show significantly lower ADC values in the body and trends towards lower ADCs in the head and tail, a finding that merits further investigation.

Tess Armstrong^1,2, Isabel Dregely¹, Fei Han¹, Ziwu Zhou¹, Kyung Sung^1,2, Peng Hu^1,2, and Holden Wu^1,2
1Radiological Sciences, University of California Los Angeles, Los Angeles, CA, United States, ²Biomedical Physics, University of California Los Angeles, Los Angeles, CA, United States

Non-alcoholic fatty liver disease affects about 30% of the general population and is the leading cause of chronic liver disease in the United States. The gold standard for diagnosis and monitoring is by an invasive biopsy, which has several limitations. MRI methods based on multi-echo fat-water separation can provide non-invasive quantification of fat in the entire liver. In this work, we have developed a free-breathing multi-echo 3D stack-of-stars MRI technique that can produce fat-water separated images of the liver with quality comparable to a breath-held multi-echo Cartesian technique. Our new technique has potential for free-breathing characterization of liver fat content.

Harald Kramer^1,2, Mark A Kliewer², Perry J Pickardt², Diego Hernando², Guang-Hong Chen², and Scott B Reeder^2
1Department of Clinical Radiology, University of Munich, Munich, Bavaria, Germany, ²Department of Radiology, University of Wisconsin - Madison, Madison, Wisconsin, United States

Fatty infiltration of hepatocytes is the hallmark feature of non-alcoholic fatty liver disease (NAFLD) and potentially leads to inflammation, fibrosis and cirrhosis. Since the currently accepted diagnostic standard biopsy represents an invasive procedure and samples only very circumscribed regions within the liver, there is a need for a comprehensive, accurate and non-invasive quantitative biomarker.

Kim Nhien Vu¹, Guillaume Gilbert^1,2, Marianne Chalut¹, Miguel Chagnon³, Gabriel Chartrand⁴, Jacques de Guise⁴, and An Tang^1
1Radiology, University of Montreal, Montreal, Qc, Canada, ²Philips Healthcare Canada, Montreal, Qc, Canada, ³Mathematics and Statistics, University of Montreal, Montreal, Qc, Canada, ⁴Imaging and Orthopaedics Research Laboratory (LIO), École de technologie supérieure, Montreal, Qc, Canada

Magnetic resonance spectroscopy (MRS) is widely accepted as the noninvasive reference standard for liver fat quantification. MRI-proton density fat fraction (PDFF) is an emerging biomarker of liver fat that offers the possibility to cover the entire liver volume. Conventionally, MRI-PDFF is calculated by sampling regions of interest (ROI). However, it is unclear how various ROI sampling methods reported in the literature would agree with the liver mean PDFF. In this study, we assessed the fat distribution heterogeneity across segments. We also examined the agreement between various ROI sampling methods reported in the literature.

Anna Orzylowska¹, Krzysztof Jasinski¹, Pawel T. Jochym², Edyta Maslak³, and Tomasz Skorka^1
1Department of Magnetic Resonance Imaging, Institute of Nuclear Physics Polish Academy of Sciences, Krakow, Poland, ²Department of Materials Research by Computers, Institute of Nuclear Physics Polish Academy of Sciences, Krakow, Poland, ³Department of Endothelium Experimental Pharmacology, Jagiellonian Center for Experimental Therapeutics (JCET), Krakow, Poland

The purpose was to develop MR tagging (MRt) based cardiac-induced liver deformation analysis for the assessment of liver elasticity in mouse model of non-alcoholic fatty liver disease (NAFLD). The deformation was computed from MRt images as the maps of principal strains, fractional volume changes, and absolute strain magnitude, and quantified using two-dimensional central and invariant image moments. In NAFLD, the deformed area within all maps was more irregular in comparison to Controls. The central and invariant moments revealed decreased strain area and level. The proposed method provided a routine suitable for in-vivo measurements of the liver elasticity impairement in NAFLD.

Temel Kaya Yasar¹, Octavia Bane¹, Cecilia Besa¹, Stephan Kannengiesser², and Bachir Taouli^1
1Icahn School of Medicine at Mount Sinai, New York, NY, United States, ²Siemens Healthcare, Germany

There is insufficient knowledge on variability of MR Elastography (MRE) between different platforms. In this study, 6 underwent MRE on 1.5T Siemens and 3.0T GE systems using a 2D-GRE sequence. Liver and spleen stiffness values obtained from the 2 scanners were compared. Excellent concordance was observed between scanners (CV of 9.8% and 12.0% for liver and spleen, respectively). It remains to be seen whether different sequences on different platforms will provide similar results.

Jing Guo¹, Christian Althoff², Carsten Büning³, Eckart Schott⁴, Thomas Kröncke⁵, Jürgen Braun⁶, and Ingolf Sack^2
1Radiology, Charité - Universitätsmedizin Berlin, Berlin, Berlin, Germany, ²Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany,³Krankenhaus Waldfriede,Akademisches Lehrkrankenhaus der Charité, Berlin, Germany, ⁴Department of Hepatology and Gastroenterology, Charité - Universitätsmedizin Berlin, Berlin, Germany, ⁵Clinic for Diagnostic Radiology and Neuroradiology, Klinikum Augsburg, Bavaria, Germany, ⁶Department of Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany

High-resolution multifrequency MRE based on MDEV inversion was applied to patients with portal hypertension before and after TIPS placement. The magnitude shear moduli |G^*|of liver and spleen were both sensitive to the portal decompression following TIPS. The observed linear correlation between spleen viscoelasticity and HVPG raises the prospect of an image-based and noninvasive assessment of portal pressure by MR elastography in the follow-up of TIPS placements.

Tomohiro Takamura¹, Utaroh Motosugi¹, Shintaro Ichikawa¹, Katsuhiro Sano¹, Hiroyuki Morisaka¹, Tomoaki Ichikawa¹, Nobuyuki Enomoto², and Hiroshi Onishi^1
1Department of Radiology, University of Yamanashi, Kofu, Yamanashi, Japan, ²First Department of Internal Medicine, University of Yamanashi, Yamanashi, Japan

It is important to identify the cirrhotic patients at a high risk of progression to the decompensated stage. Liver stiffness measurement with magnetic resonance elastography (MRE) is a recently developed method for non-invasively measuring liver stiffness. The purpose of this study was to evaluate the usefulness of MRE in predicting the progression of cirrhosis in patients with type C chronic viral hepatitis as assessed with the Child-Pugh classification system. In this study, we elucidate the stiffness measurement with MRE was the strongest indicator of cirrhosis progression from Child-Pugh class A to B among known risk factors.

Utaroh Motosugi^1,2, Peter Bannas^1,3, Alejandro Roldan-Alzate¹, Sean G. Kelly⁴, Adnan Said⁴, Oliver Wieben⁵, and Scott B. Reeder^1,5
1Radiology, University of Wisconsin, Madison, WI, United States, ²Radiology, University of Yamanashi, Chuo-shi, Yamanashi, Japan, ³Radiology, University Hospital Hamburg-Eppendorf, Humburg, Germany, ⁴Gastroenterology and Hepatology, University of Wisconsin, Madison, WI, United States,⁵Medical Physics, University of Wisconsin, Madison, WI, United States