Early detection of liver steatosis by magnetic resonance imaging in rats infused with glucose and Intralipid solutions and correlation to insulin levels

Abstract Objective Magnetic resonance (MR) techniques allow noninvasive fat quantification. We aimed to investigate the accuracy of MR imaging (MRI), MR spectroscopy (MRS) and histological techniques to detect early-onset liver steatosis in three rat phenotypes assigned to an experimental glucolipotoxic model or a control group. Materials and Methods This study was approved by the institutional committee for the protection of animals. Thirty-two rats (13 young Wistar, 6 old Wistar and 13 diabetic Goto–Kakizaki rats) fed a standard diet were assigned to a 72 h intravenous infusion of glucose and Intralipid fat emulsion or a saline infusion. Plasma insulin levels were measured. Steatosis was quantified in ex vivo livers with gradient-recalled multi-echo MRI, MRS and histology as fat fractions (FF). Results A significant correlation was found between multi-echo MRI-FF and MRS-FF (r = 0.81, p < 0.01) and a weaker correlation was found between histology and MRS-FF (r = 0.60, p < 0.01). MRS and MRI accurately distinguished young Wistar and Goto–Kakizaki rats receiving the glucose + Intralipid infusion from those receiving the saline control whereas histology did not. Significant correlations were found between MRI or MRS and insulin plasma level (r = 0.63, p < 0.01; r = 0.57, p < 0.01), and between MRI or MRS and C-peptide concentration (r = 0.54, p < 0.01; r = 0.44, p < 0.02). Conclusions Multi-echo MRI and MRS may be more sensitive to measure early-onset liver steatosis than histology in an experimental glucolipotoxic rat model.