Value of MR imaging in evaluating focal fatty infiltration of the liver: preliminary study.

Focal fatty infiltration of the liver is a well-known entity that occasionally mimics metastatic disease on ultrasonographic (US) and computed tomographic (CT) scans and requires biopsy for diagnosis. To determine if high-field-strength magnetic resonance (MR) imaging might be useful in the differential diagnosis of the lesions, the authors compared US, CT, and MR findings in three patients with biopsy-proved fatty hepatic lesions. Areas of focal fatty infiltration were hyperechoic on US scans and had low attenuation on CT scans. No mass effect of the lesions on vascular structures or liver contours was observed, particularly on contrast material-enhanced CT scans. For all three patients, MR findings suggested the correct diagnosis by demonstrating focal high signal intensity on spin-echo T1- and T2-weighted images. On the basis of these preliminary findings, it appears that focal fatty infiltration of the liver may be differentiated from metastatic disease by means of high-field-strength MR imaging.