Lucas Lindeboom1,2, Robin A de Graaf3. 1. Department of Radiology, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, the Netherlands. 2. Department of Human Biology/Human Movement Sciences, NUTRIM School for Nutrition and Translational Research in Metabolism, Maastricht University Medical Center, Maastricht, the Netherlands. 3. Department of Radiology and Biomedical Imaging, Magnetic Resonance Research Center, Yale University School of Medicine, New Haven, Connecticut, USA.
Abstract
PURPOSE: Accumulation of triglycerides in nonadipose tissue (e.g. ectopic lipids) is characteristic of metabolic derangements and is linked to insulin resistance and cardiovascular disease. Although the detrimental effects of the total amount of ectopic fat has been established, the role of composition of the ectopic lipid stores is unknown. In this study we used proton magnetic resonance spectroscopy (1 H-MRS) homonuclear spectral editing to characterize lipid stores in adipose tissue and skeletal muscle at 4 T. METHODS: A MEGA-sLASER sequence was used to selectively detect lipid resonances that are scalar coupled to the methine resonance at 5.31 ppm and that can be used to estimate saturated fatty acid and mono- and polyunsaturated fatty acids. Phantom experiments were performed to empirically determine correction factors for editing efficiency of the different lipid groups. RESULTS: The spectral editing approach enabled the estimation of saturated, mono-unsaturated, and polyunsaturated fatty acid contributions in phantoms and in vivo. These estimations are in the same order as reported in studies using invasive biopsies. CONCLUSIONS: In this study, we have shown the feasibility of spectral editing techniques for ectopic lipid store characterization with 1 H-MRS, regardless of spectral resolution (e.g., B0- field strength). This new approach offers the opportunity to study ectopic lipid composition in relation to metabolic diseases. Magn Reson Med 79:619-627, 2018.
PURPOSE: Accumulation of triglycerides in nonadipose tissue (e.g. ectopic lipids) is characteristic of metabolic derangements and is linked to insulin resistance and cardiovascular disease. Although the detrimental effects of the total amount of ectopic fat has been established, the role of composition of the ectopic lipid stores is unknown. In this study we used proton magnetic resonance spectroscopy (1 H-MRS) homonuclear spectral editing to characterize lipid stores in adipose tissue and skeletal muscle at 4 T. METHODS: A MEGA-sLASER sequence was used to selectively detect lipid resonances that are scalar coupled to the methine resonance at 5.31 ppm and that can be used to estimate saturated fatty acid and mono- and polyunsaturated fatty acids. Phantom experiments were performed to empirically determine correction factors for editing efficiency of the different lipid groups. RESULTS: The spectral editing approach enabled the estimation of saturated, mono-unsaturated, and polyunsaturated fatty acid contributions in phantoms and in vivo. These estimations are in the same order as reported in studies using invasive biopsies. CONCLUSIONS: In this study, we have shown the feasibility of spectral editing techniques for ectopic lipid store characterization with 1 H-MRS, regardless of spectral resolution (e.g., B0- field strength). This new approach offers the opportunity to study ectopic lipid composition in relation to metabolic diseases. Magn Reson Med 79:619-627, 2018.
Authors: Ajay Thankamony; Graham J Kemp; Albert Koulman; Vlada Bokii; David B Savage; Chris Boesch; Leanne Hodson; David B Dunger; Alison Sleigh Journal: Sci Rep Date: 2018-02-09 Impact factor: 4.379