Lu-Ping Li^1,2, Huan Tan¹, Jon Thacker³, Wei Li^1,2, Ying Zhou⁴, Orly Kohn⁵, Stuart Sprague^2,6, and Pottumarthi V Prasad^1,2
1Radiology, Northshore University HealthSystem, Evanston, IL, United States, ²Pritzker School of Medicine, University of Chicago, Chicago, IL, United States, ³Biomedical Engineering, Northwestern University, Evanston, IL, United States, ⁴Center for Biomedical Research & Informatics, Northshore University HealthSystem, Evanston, IL, United States, ⁵Medicine, University of Chicago, Chicago, IL, United States,⁶Medicine, Northshore University HealthSystem, Evanston, IL, United States

Renal blood flow is thought to be reduced in subjects of diabetic nephropathy (DN).  However, there is limited amount of quantitative data on renal blood flow in patients with DN. In this study, ASL MRI data was acquired in 28 patients with diabetes and stage-3 CKD along with 30 healthy controls. Renal blood flow was found to be significantly lower in subjects with DN with a large Cohen’s d value.  Renal blood flow also showed a significant correlation with eGFR and age was not found to be a significant confounder in this relationship.

Gaëlle Diserens¹, Waldo Valenzuela², Maryam Seif¹, Laila Mani³, Daniel Fuster³, Christoph Stettler⁴, Bruno Vogt³, Mauricio Reyes², Chris Boesch¹, and Peter Vermathen^1
1Depts Clinical Research and Radiology, University of Bern, Bern, Switzerland, ²Institute for Surgical Technology and Biomechanics, University of Bern, Bern, Switzerland, ³Dept. of Nephrology, Hypertension and Clinical Pharmacology, University of Bern, Bern, Switzerland, ⁴Dept. of Endocrinology, Diabetes and Clinical Nutrition, University of Bern, Bern, Switzerland

Renal ectopic lipid accumulation may lead to kidney dysfunction. The study purpose was to determine (1) renal ectopic lipid content in overweight type-2 diabetic patients compared to (a) overweight non-diabetic patients and (b) lean volunteers by 1H-MRS and (2) renal sinus fat content by DIXON-MRI in the same three patient groups. This study demonstrates that renal ectopic lipids appear to be not higher in overweight diabetic patients compared to overweight non-diabetic subjects, while ectopic lipids are higher in both groups compared to healthy subjects. Significantly higher renal sinus bulk lipids were detected for overweight diabetic patients compared to BMI-matched non-diabetics. 

Dian Liu¹, Helen Louise Parker², Jelena Curcic^1,2, Sebastian Kozerke¹, and Andreas Steingoetter^1,2
1Institute for Biomedical Engineering, University and ETH Zurich, Zurich, Switzerland, ²Division of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland

Simultaneous assessment of both intragastric secretion and fat is important in food science but has hitherto been hampered by the bi-exponential relaxation behavior of fat emulsions. In combination with IDEAL, this work introduced a fat correction for rapid T₁ mapping, which enabled the simultaneous measurement of the intragastric distribution and temporal development of gastric secretion and fat. Results revealed the interaction between these two components by dilution and mixing, making this method a promising tool to non-invasively assess the emulsification and emptying of ingested fat.

Lucas Lindeboom^1,2,3, Robin A. de Graaf⁴, Christine I. Nabuurs^1,2,3, Matthijs K.C. Hesselink², Joachim E. Wildberger¹, Patrick Schrauwen^2,3, and Vera B. Schrauwen-Hinderling^1,2,3
1Radiology, Maastricht University Medical Center, Maastricht, Netherlands, ²Human Biology and Human Movement Sciences, Maastricht University Medical Center, Maastricht, Netherlands, ³Top Institute Food and Nutrition, Wageningen, Netherlands, ⁴Diagnostic Radiology, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, CT, United States

We here show that postprandial ¹³C fatty acid tracking is feasible in the human liver using ge-HSQC. Experiments in two human volunteers revealed that intake of 5 or 7 grams of ¹³C-labeled fatty acids resulted in two- or threefold increase in hepatic ¹³C-enrichment after 3 hours. It is estimated that 3% of the oral load is stored in the liver at this time point. The ge-HSQC sequence can be used to reveal the contribution of dietary fat to the development of hepatic steatosis.

Rosa Tamara Branca^1,2, Le Zhang^3,4, Alex Burant^1,4, Laurence Katz⁵, and Andrew McCallister^1,4
1Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, ²Biomedical Research Imaging Center, Chapel Hill, NC, United States, ³Material Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, ⁴Biomedical Research Imaging Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States, ⁵Emergency Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States

Despite histological evidence that all humans have brown adipose tissue, the detection of this tissue in overweighs and obese subjects has proven to be a challenge. A recent study showed that MRI by hyperpolarized xenon gas (HP129Xe) enables the detection of this tissue in both lean and obese animal phenotype, with enhanced sensitivity in the latter with respect to the gold standard, FDG-PET. Here we demonstrate that HP129Xe gas MRI can also be used to detect human BAT with better sensitivity than FDG-PET.

Sanjay Kumar Verma¹, Kaz Nagashima¹, Swee Shean Lee¹, Tian Xianfeng¹, Jadegoud Yaligar¹, Venkatesh Gopalan¹, Bhanu Prakash KN¹, and S. Sendhil Velan^1
1Laboratory of Molecular Imaging, Singapore Bioimaging Consortium, Singapore

There are two types of fat tissues, white adipose tissue (WAT) and brown adipose tissue (BAT), which essentially perform opposite functions in whole body energy metabolism.  There is a large interest in development of MR Imaging techniques that will be suitable for separating white and brown fat.   In this work we have implemented diffusion NMR spectroscopy to differentiate these two types of tissues.  Water diffused faster than the fat in both WAT and BAT.  Fat diffusion was faster in WAT compared to BAT.  Our findings also suggest restricted behavior of fat molecules in BAT and not in WAT.

Jesper Lundbom^1,2, Alessandra Bierwagen^1,2, Kálmán Bodis^1,2, Jaakko Kaprio^3,4,5, Aila Rissanen^6,7, Nina Lundbom⁸, Michael Roden^1,2,9, and Kirsi Pietiläinen^4,6,10
1German Diabetes Center, Leibniz Center for Diabetes Research, Düsseldorf, Germany, ²German Center for Diabetes Research (DZD e.V.), Partner Düsseldorf, Düsseldorf, Germany, ³Finnish Twin Cohort Study, Department of Public Health, Hjelt Institute, Helsinki, Finland, ⁴FIMM, Institute for Molecular Medicine, University of Helsinki, Helsinki, Finland, ⁵National Institute for Health and Welfare, Helsinki, Finland,⁶Obesity Research Unit, Diabetes and Obesity, University of Helsinki, Helsinki, Finland, ⁷Department of Psychiatry, Helsinki University Central Hospital, Helsinki, Finland, ⁸HUS Medical Imaging Center, University of Helsinki, Helsinki, Finland, ⁹Department of Endocrinology and Diabetology, Medical Faculty, Heinrich-Heine University, Düsseldorf, Germany, ¹⁰Endocrinology, Abdominal Center, Helsinki University Central Hospital, Helsinki, Finland

The present study uses non-invasive MRS to examine whether MZ twins discordant for BMI display depot specific differences in adipose tissue unsaturation (DSAT and SSAT), and how the unsaturation relates to body fat distribution and ectopic fat. The main finding of the twin study is that DSAT lipid unsaturation associates with intramyocellular lipid content, which was further confirmed  in a general population study and for the repeated sampling of one volunteer. These results highlight the role of fatty acid composition in adipose tissue -  skeletal muscle crosstalk.

Jürgen Machann¹, Malte Niklas Bongers², Andreas Fritsche³, Norbert Stefan³, Hans-Ulrich Häring³, Konstantin Nikolaou⁴, and Fritz Schick^2
1Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, IDM of the Helmholtz Center Munich at the University Tübingen, German Center for Diabetes Research (DZD), Tuebingen, Germany, ²Section on Experimental Radiology, Department of Diagnostic and Interventional Radiology, University Hospital Tuebingen, Tuebingen, Germany, ³Department of Endocrinology and Diabetology, Angiology, Nephrology and Clinical Chemistry, IDM of the Helmholtz Center Munich at the University Tübingen, German Center for Diabetes Research (DZD), Tuebingen, Germany, ⁴Department of Diagnostic and Interventional Radiology, University Hospital Tuebingen, Tuebingen, Germany

MR-based phenotyping is of increasing interest for cross-sectional and interventional studies on large cohorts. Quantification of adipose tissue (AT) compartments – e.g. by T1-weighted MRI – has mainly been performed by giving the absolute amounts in litres. However, this does not directly reflect the distribution and quantity (e.g. for people with different size). Thus, the percentage of AT compartments are given as percent of total AT and new fat indices, corrected for height (comparable to BMI) are introduced and age- and gender related differences are determined in a large cohort of people at increased risk for metabolic diseases.

Ana Francisca Soares¹, João M. N. Duarte¹, Blanca Lizarbe¹, and Rolf Gruetter^1,2,3,4
1Laboratory of Functional and Metabolic Imaging (LIFMET), Swiss Federal Institute of Technology Lausanne (EPFL), Lausanne, Switzerland, ²Center for Biomedical Imaging (CIBM), Lausanne, Switzerland,³Department of Radiology, University of Geneva (UNIGE), Geneva, Switzerland, ⁴Department of Radiology, University of Lausanne (Unil), Lausanne, Switzerland

Obesity is associated with a loss of metabolic control, largely driven by alterations in whole-body lipid distribution. Impaired insulin action leads to hepatic lipid accumulation and, conversely, high levels of liver lipids also cause insulin resistance. We followed the loss of glucose homeostasis in mice fed a high-fat diet for 18 weeks. In parallel, we assessed their hepatic lipids by ¹H-MRS in vivo. In this model, glucose intolerance preceded hepatic lipid accumulation that then contributed to aggravate the phenotype. Moreover, fasting-induced hepatic lipid dynamics was hampered with high-fat diet feeding.

Jürgen Machann¹, Malte Niklas Bongers², Norbert Stefan³, Andreas Fritsche³, Konstantin Nikolaou⁴, Hans-Ulrich Häring³, and Fritz Schick^5
1Section on Experimental Radiology, IDM of the Helmholtz Center Munich at the University Tübingen, German Center for Diabetes Research (DZD), Tuebingen, Germany, ²Department of Diagnostic and Interventional Radiology, Section on Experimental Radiology, Tuebingen, Germany, ³Department of Endocrinology and Diabetology, Angiology, Nephrology and Clinical Chemistry, IDM of the Helmholtz Center Munich at the University Tübingen, German Center for Diabetes Research (DZD), Tuebingen, Germany, ⁴Department of Diagnostic and Interventional Radiology, University Hospital Tübingen, Tuebingen, Germany, ⁵Section on Experimental Radiology, University Hospital Tübingen, Tuebingen, Germany

Axial T1-weighted MRI and volume selective ¹H-MRS were performed in a cohort of almost 500 non-obese subjects at increased risk for metabolic diseases. Adipose (AT) and lean tissue (LT) compartments from different body regions were quantified and are expressed as percentage of the entire volume in order to display tissue distribution and to differentiate metabolically healthy (insulin sensitive, IS) and unhealthy (insulin resistant, IR) subgroups. Additionally, intrahepatic lipids (IHL) were quantified. It could be shown that IS subjects are characterized by lower percentage of AT in abdominal regions but higher amounts in the extremities whereas IHL are almost doubled in IR subjects.