Hepatic fat fraction and visceral adipose tissue fatty acid composition in mice: Quantification with 7.0T MRI

Abstract

Purpose: To develop an MRI method for quantifying hepatic fat content and visceral adipose tissue fatty acid composition in mice on a 7.0T preclinical system. Methods: MR acquisitions were performed with a multiple echo spoiled gradient echo with bipolar readout gradients. After phase correction, the number of double bounds (ndb) and the number of methylene interrupted double bounds (nmidb) were quantified with a model including eight fat components, and parametric maps of saturated, monounsaturated, and polyunsaturated fatty acids were derived. The model included a complex error map to correct for the phase errors and the amplitude modulation caused by the bipolar acquisition. Validations were performed in fat-water emulsions and vegetable oils. In vivo, the feasibility was evaluated in mice receiving a high-fat diet containing primarily saturated fatty acids and a low-fat diet containing primarily unsaturated fatty acids. Results: Linear regressions showed strong agreements between ndb and nmidb quantified with MRI and the theoretical values calculated using oil compositions, as well as between the proton density and the fat fractions in the emulsions. At MRI, the mouse liver fat fraction was smaller in mice fed the low-fat diet compared with mice fed the high-fat diet. In visceral adipose tissue, saturated fatty acids were significantly higher, whereas monounsaturated and polyunsaturated fatty acids were significantly lower in mice fed the low-fat diet compared with mice fed the high-fat diet. Conclusion: It is feasible to simultaneously quantify hepatic fat content and visceral adipose tissue fatty acid composition with 7.0T MRI in mice. Magn Reson Med 76:510-518, 2016.

Accurate fatty acid composition estimation of adipose tissue in the abdomen based on bipolar multi‐echo MRI

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Simultaneous MR quantification of hepatic fat content, fatty acid composition, transverse relaxation time and magnetic susceptibility for the diagnosis of non‐alcoholic steatohepatitis

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In vivo MRS for the assessment of mouse colon using a dedicated endorectal coil: initial findings

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