Hepatic attenuation on CT

Hepatic attenuation on CT, reflected by Hounsfield values, depends on a combination of factors including the presence or absence, as well as the phase, of IV contrast administration.

Allowing for all these factors, the mean unenhanced attenuation value is around 55 HU ⁴.

Pathology

Several intrinsic liver pathologies can cause a diffuse change in liver attenuation with increased hepatic fat being the most prevalent.

Etiology

Diffusely increased attenuation

• iron deposition

  • hemosiderosis

    • thalassemia

  • hemochromatosis: one paper suggests investigation for iron overload if unenhanced liver density is >75 HU ⁹

• copper deposition

  • Wilson disease

• glycogen storage diseases

• medications/drugs

  • amiodarone hepatotoxicity: long-term amiodarone administration ^7,8,10

  • gold therapy ⁶

• previous Thorotrast administration

Diffusely decreased attenuation

• diffuse hepatic steatosis (diffuse fatty liver)

• diffuse malignant infiltration

• diffuse non-malignant infiltrative disease (e.g. hepatic amyloidosis)