Jiahui Li¹, Marzanna Obrzut¹, Xin Lu¹, Alina Allen², Sudhakar K. Venkatesh¹, Taofic Mounajjed³, Jun Chen¹, Kevin J. Glaser¹, Armando Manduca¹, Vijay Shah², Richard L. Ehman¹, and Meng Yin^1
1Radiology, Mayo Clinic, Rochester, MN, United States, ²Gastroenterology, Mayo Clinic, Rochester, MN, United States, ³Mayo Clinic, Rochester, MN, United States

We performed multiparametric 3D MR Elastography (MRE) in 37 obese patients who underwent bariatric surgeries. MRI/MRE, anthropometrics, and liver biopsy were obtained within three months of bariatric surgery and one year later. 12/37 (32%) patients have biopsy-proven non-alcoholic fatty liver disease (NAFLD) at the time of surgery. The MRE-assessed shear stiffness (SS) and loss modulus (LM) of subcutaneous adipose tissue decreased significantly after the surgery, as well as the liver tissue.  MRE-assessed SS and LM have potential in distinguishing the obesity-induced metabolic disorder in the adipose tissues. The mechanical change may correlate with the therapeutic response in these obese patients.

Yang Zhou^1,2, Peter C.M. van Zijl^1,2, Xiang Xu^1,2, Jiadi Xu^1,2, Yuguo Li^1,2, and Nirbhay N. Yadav^1,2
1The Russell H. Morgan Department of Radiology, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, ²F.M. Kirby Research Center for Functional, Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States

We recently reported a method for the enhanced detection of glycogen using the nuclear Overhauser enhancement (NOE) between glycogen and water (glycoNOE). Here we show that the glycoNOE signal is linearly dependent on glycogen concentration both in vitro and in mouse liver in vivo. The glycoNOE signal is affected by glycogen particle size, but not pH or temperature. glycoNOE MRI can non-invasively quantify liver glycogen levels in vivo and thus has the potential to assess disease where glycogen metabolism is altered.  

Stephen Bawden^1,2, Prarthana Thiagarajan¹, Elizabeth Simpson¹, Olivier Mougin², Paul Greenhaff³, Penny Gowland², and Guruprasad P Aithal^1
1NIHR Nottingham Biomedical Research Centre, University of Nottingham, Nottingham University Hospitals NHS Trust and the University of Nottingham, Nottingham, United Kingdom, ²Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom, ³School of Life Sciences, University of Nottingham, Nottingham, United Kingdom

Advanced MRI techniques such as 1H MRS at 7T and saturation transfer 31P MRS offer unique capabilities to map metabolic conditions and complement current physiological methodologies. The aim of this study was to build a metabolic profile for NAFLD v healthy volunteers by measuring physiological metabolic markers alongside 1H MRS measurement of liver lipid, intra- (IMCL) and extra- (EMCL) myocellular lipid fraction, and dynamic 31P MRS measurements of ATP flux rates, and to investigate the effect of a 24 week L-carnitine intervention. Interim analysis shows metabolic inflexibility in NAFLD patients compared with HV and a potential benefit of L-carnitine supplementation

Xinya Zhao¹, Xianshun Yuan¹, Xiang Feng², Mengxiao Liu³, Xiangtao Lin¹, and Ximing Wang^1
1Department of Radiology, Shandong Provincial Hospital, Jinan, China, ²MR Scientific Marketing, Siemens Healthcare, Beijing, China, ³MR Scientific Marketing, Siemens Healthcare, Shanghai, China

The purpose of this study was to determine whether B1 inhomogeneity-corrected volumetric T1 mapping of Gd-BOPTA enhanced liver MR imaging are able to evaluate the degree of liver cirrhosis and to investigate their relationship with the histological grading.  Our study found that B1 inhomogeneity-corrected T1 mapping using Gd-BOPTA enhanced MR imaging could be used in the quantitative evaluation of liver fibrosis. 

Iris Y. Zhou¹, Chuantao Tu², Veronica Clavijo Jordan¹, Nicholas J. Rotile¹, Mozhdeh Sojoodi³, Bryan C. Fuchs³, Kenneth K. Tanabe³, and Peter Caravan^1
1Athinoula A. Martinos Center for Biomedical Imaging, Institute for Innovation in Imaging (i3), Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA, United States, ²Department of Gastroenterology and Hepatology, Zhongshan Hospital, Fudan University, Shanghai, China, ³Division of Surgical Oncology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, United States

Nonalcoholic steatohepatitis (NASH) promotes fibrotic remodeling of the liver parenchyma, which may lead to cirrhosis, liver failure, or hepatocellular carcinoma. Gd-EOB-DTPA is a hepatobiliary T1 MRI contrast agent, receiving increasing attention as a tool for detecting and staging liver fibrosis. Here, using a choline-deficient high-fat diet (CDAHFD) for different durations we modeled NASH disease progression in rats and performed  Gd-EOB-DTPA-enhanced MRI at different disease stages, correlating imaging histological measures of fibrosis as well as liver function tests.  Gd-EOB-DTPA-enhanced MRI correlated well with liver function tests but not with liver fibrosis.

Stefanie Hectors^1,2,3, Octavia Bane^1,2, Daniel Stocker^1,2, Paul Kennedy^1,2, Thomas Schiano⁴, Swan Thung⁵, Aaron Fischman², and Bachir Taouli^1,2
1BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, ²Department of Diagnostic, Molecular and Interventional Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, ³Department of Radiology, Weill Cornell Medicine, New York, NY, United States, ⁴Recanati/Miller Transplantation Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, ⁵Department of Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, United States

In this study we explored the used of liver and spleen T1 and T1ρ parameters for noninvasive assessment of portal hypertension (PH) and compared the performance of the MRI relaxation parameters with that of radiological assessment. Spleen T1ρ showed a strong significant positive correlation with quantitative portal pressure measurements (r=0.613, P=0.001), while the other relaxation parameters did not. Spleen T1ρ also outperformed other relaxation parameters and radiological assessment for prediction of (clinically significant) PH (AUC 0.778 – 0.817). Our results indicate that spleen T1ρ may be a suitable noninvasive biomarker for prediction of PH.

Manil D Chouhan¹, Naomi Sakai¹, Francisco Torrealdea², Kelly White³, Juan Carlos Lopez Talavera³, Alan Bainbridge², and Stuart A Taylor^1
1UCL Centre for Medical Imaging, University College London, London, United Kingdom, ²Department of Medical Physics, University College London Hospitals NHS Trust, London, United Kingdom, ³Fractyl Laboratories Inc., Lexington, MA, United States

R2* derived liver iron concentration (LIC) measurements from proton density fat fraction (PDFF) data obtained in patients with normal LIC levels may be useful.  Here we present data from the Revita-2 trial demonstrating strong significant positive correlations between baseline liver fat fraction (FF) and LIC.  Significant and stronger correlations between relative % change in liver FF and LIC in the treatment arms of the trial raise the possibility of treatment-related mechanistic effects on hepatic iron metabolism.

Shintaro Ichikawa¹, Daiki Tamada¹, Tetsuya Wakayama², Sagar Mandava³, Ty A Cashen⁴, Hiroshi Onishi¹, and Utaroh Motosugi^1
1Department of Radiology, University of Yamanashi, Chuo, Japan, ²MR Collaboration and Development, GE Healthcare, Hino, Japan, ³MR Collaboration and Development, GE Healthcare, Tucson, AZ, United States, ⁴MR Collaboration and Development, GE Healthcare, Madison, WI, United States

We compared arterial phase (AP) images using conventional (Cartesian) breath-hold liver acquisition with volume acceleration (LAVA) and stack-of-stars acquisition without breath-holding (LAVA-Star) on hepatic dynamic MRI. In Cartesian breath-hold LAVA group, 8.7% of patients showed inadequate scan timing of AP, while only 1 patient (4.0%) in LAVA-Star group (12 s/phase) showed inadequate scan timing. One advantage of LAVA-Star was that the adequate scan timing of AP can be obtained by using additional high frame rate reconstruction (3 s/phase) in the patient with inadequate scan timing in routine reconstruction. LAVA-Star was useful to obtain adequate scan timing in all patients.

Chris R Bradley^1,2, Rob A Scott², Eleanor F Cox^1,2, Naaventhan Palaniyappan², I Neil Guha², Guruprasad P Aithal², and Susan T Francis^1,2
1Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom, ²NIHR Nottingham Biomedical Research Centre, Nottingham University Hospitals NHS Trust and University of Nottingham, Nottingham, United Kingdom

Hepatic venous pressure gradient (HVPG) is the gold standard method for the assessment of portal pressure, but highly invasive. We scanned patients with portal hypertension at both 1.5T and 3T to assess MRI parameters related to portal pressure as defined by HVPG. Iron-corrected liver T₁ highly correlated over the full range of HVPG (3T p<0.0002, 1.5T p<0.0001), spleen T₁ and superior mesenteric artery velocity correlated up to HVPG of 15 mmHg (spleen T₁: 3T p<0.0003, 1.5T p<0.0006; SMA velocity: p<<0.00001), after which at HVPG >15 mmHg no correlation was observed. 

Henk M. De Feyter¹, Monique A. Thomas¹, Kevin L. Behar², and Robin A. de Graaf^1
1Dept. of Radiology and Biomedical Imaging, Yale University, New Haven, CT, United States, ²Dept. of Psychiatry, Yale University, New Haven, CT, United States

Deuterium metabolic imaging (DMI) is a novel technique for mapping metabolism in vivo, that combines ²H MRSI with administration of a ²H-labeled substrate.  DMI combined with [6,6'-²H₂]-glucose has the potential to detect glycogen synthesis in the liver. However, the similar ²H chemical shifts of glucose and glycogen make unambiguous detection and separation difficult in vivo. Here we investigate the NMR-detectability of glycogen using high resolution ²H NMR of ²H-labeled glycogen isolated from mouse liver, and show that ²H-labeled glycogen is not detectable with DMI under in vivo conditions.