Hyperintense benign liver lesions on spin-echo T1-weighted MR images: pathologic correlations.

Abstract

To determine the incidence of hyperintensity on T1-weighted spin echo (SE) images in benign liver lesions, value of fat-suppressed magnetic resonance (MR) imaging for the detection of fat within these lesions, and the causes of hyperintensity by correlation to pathologic examinations. Five hundred forty-nine patients with 805 benign liver lesions including 585 hemangiomas, 188 focal nodular hyperplasias (FNHs), 14 hepatic adenomas (HAs), 14 focal fatty infiltrations (FFIs), two biliary cystadenomas, and two hemorrhagic cysts were examined by T2-weighted and T1-weighted SE MR imaging. For hyperintense lesions on T1-weighted SE images, fat-suppressed images were obtained by selective presaturation of fat. Thirty-two lesions (four FNHs, 10 HAs, 14 FFIs, two biliary cystadenomas, and two hemorrhagic cysts) appeared hyperintense on T1-weighted SE images; 21 of these became hypointense on the fat-suppressed T1 weighted SE images (one FNH, six HAs, and 14 FFIs) and contained fat at pathological examination. The other 11 lesions remained hyperintense on fat-suppressed T1-weighted SE images and had no fat deposition. Causes of hyperintensity in these cases were sinusoidal dilatation, copper deposition, hemorrhage, and high protein content. Among benign liver lesions, hyperintensity on T1-weighted SE images is rare (3.9%). Causes of this hyperintensity are fat deposition, copper accumulation, sinusoidal dilatation, bemorrhage, and high protein content. Fat-suppressed imaging can distinguish fat deposition from other causes of hyperintensity.