Nonalcoholic Fatty Liver Disease: Rapid Evaluation of Liver Fat Content with In-Phase and Out-of-Phase MR Imaging

Purpose: To evaluate in-phase and out-of-phase magnetic resonance (MR) imaging in the estimation of liver fat content (LFC) in patients with nonalcoholic fatty liver disease (NAFLD), with hydrogen (H-1) MR spectroscopy as the reference standard. Materials and Methods: Written informed consent was obtained from all subjects, and the local ethics committee approved this prospective study protocol. A total of 33 patients with type 2 diabetes mellitus who were at high risk for NAFLD (23 men, 10 women; overall mean age, 62.8 years +/- .3 [standard deviation]; age range, 48-77 years) underwent 1.5-T MR imaging with H-1 MR spectroscopy and in-phase and out-of-phase imaging of the liver. Three fat indexes were calculated from the signal intensity (SI) measured on the images. Two radiologists independently graded SI changes between in-phase and out-of-phase images by means of visual inspection. The Pearson correlation coefficient was used to study the relationship between the obtained parameters of SI change and LFC measured with H-1 MR spectroscopy. Results: Fat indexes calculated from in-phase and out-of-phase images correlated linearly with LFC measured with H-1 MR spectroscopy (P Conclusion: In-phase and out-of-phase imaging can be used to rapidly estimate the LFC in patients with NAFLD. The cutoff value of 5.1% enables objective rapid and reliable discrimination of normal LFC from elevated LFC. (C) RSNA, 200

Inverse association between liver fat content and hepatic glucose uptake in patients with type 2 diabetes mellitus

The objective of this research was to study (1) the mutual relationship between liver fat content (LFC) and hepatic glucose uptake (HGU) in patients with type 2 diabetes mellitus and (2) the relationship between changes in LFC and HGU uptake induced by rosiglitazone in these patients. Liver fat was measured with proton magnetic resonance spectroscopy and insulin-stimulated HGU with [F-18]-labeled 2-fluoro-2-deoxyglucose positron emission tomography in 54 patients with type 2 diabetes mellitus and 8 healthy Subjects. Measurements were repeated in diabetic patients after a 16-week intervention period with rosiglitazone (n = 27) or placebo (n = 27). Patients with diabetes had lower HGU (24.5 +/- 14.2 vs 35.6 +/- 9.7 mu mol/[kg min], P <.01) and higher LFC (10.9% +/- 9.2% vs 2.5% +/- 1.4%, P <.001) compared with healthy subjects. Liver fat was inversely associated with HGU (r = -0.31, P <.05). but more strongly with whole-body insulin sensitivity and adiponectin levels. Rosiglitazone treatment reduced liver fat by 24.8% (P = .01 vs placebo) and increased HGU by 29.2% (P = .013 vs placebo). This decrease in LFC was best explained by the increment in suppression of nonesterified fatty acid levels during hyperinsulinemia (P <.001) and improved glycemic control (P = .034), but not by changes in HGU. A significant inverse relationship between LFC and HGU was observed, but changes were not related. This suggests that the beneficial effects of rosiglitazone on liver metabolism are indirect and can be partly explained by increased suppression of nonesterified fatty acid levels, leading to reduced liver fat. (C) 2008 Elsevier Inc. All rights reserved