Hepatic steatosis is a common finding encountered during cross-sectional im
aging examinations. This article reviews the imaging findings of hepatic st
eatosis as revealed by sonography, computed tomography, magnetic resonance
imaging, and magnetic resonance spectroscopy. Focal fatty sparing and focal
hepatic steatosis are conditions that can create potential diagnostic chal
lenges for the radiologist. The typical findings, distribution, and etiolog
y of these focal processes are presented. In the setting of diffuse hepatic
steatosis, hepatic mass lesions can be difficult to discern on both comput
ed tomography and sonography, with reported decreased sensitivity and speci
ficity of lesion detection. In such cases, magnetic resonance imaging may b
e the imaging procedure of choice for the detection and characterization of
both hepatic steatosis and coexistent hepatic masses. Some hepatocellular
neoplasms, particularly hepatic adenoma and well-differentiated hepatocellu
lar carcinoma, can have intratumoral lipid. By demonstrating the lipid cont
ent of these masses, imaging can add specificity in characterizing them as
hepatocellular in origin because nonhepatocellular neoplasms in general do
not contain intracellular lipid.