Triglycerides have lower x-ray absorption than normal liver parenchyma,
leading to decreased CT attenuation (measured in Hounsfield units) with
increasing liver fat content. Shown are three example noncontrast CT
images in patients with increasing degrees of fat content. Images were
obtained in (A) a patient with normal liver and (B,
C) patients with moderate-to-severe (B) and
severe (C) hepatic steatosis. The MRI proton density fat
fraction equivalent values to 65 HU, 23 HU, and –3 HU are
approximately 0.5%, 25%, and 40%, respectively.