Diagnosis of fatty liver with MR imaging

The diagnosis of fatty liver with magnetic resonance (MR) imaging was evaluated in experimental rat models of simple fatty infiltration and fatty liver with hepatocellular injury. T1 and T2 were measured ex vivo and correlated with the histologic degree of fatty infiltration. Enhancement of fatty liver with four different cells-specific contrast agents was studied with ex vivo relaxometry and in vivo MR imaging. Quantitative analysis of conventional and chemical shift MR images was correlated with biochemically determined fat content of the liver. Diet-induced simple fatty infiltration of the liver caused a decrease in T1 of 15%, whereas the T1 of L-ethionine-induced fatty liver with hepatocellular injury increased by 12%. T2 showed a positive correlation with the degree of fatty infiltration in both models. Cell-specific hepatobiliary contrast agents showed the same liver uptake and relaxation enhancement in fatty livers as in normal livers. Conventional T1-weighted images and chemical shift images showed good correlation (r = .83 and .80, respectively) between signal intensity and the degree of fatty infiltration. However, only chemical shift imaging was reliable in the diagnosis of fatty liver.