Hepatic infections include pyogenic and amebic abscesses and fungal and parasitic diseases. Entry of the infectious organisms into the liver can occur by hematogenous spread via the portal vein or hepatic artery, ascension of the infection from the biliary tract, or from trauma. Worldwide, liver abscess is most often caused by Entamoeba histolytica, but in the developed world, pyogenic liver abscess is more common. Fungal infection is most often seen in immunosuppressed chemotherapy patients, whereas parasitic infections are seen in patients with recent travel to endemic areas of Asia, Africa, and South America. Imaging, and in particular ultrasound, plays a crucial role in following patients from treatment to resolution of disease.
We review the ultrasound and computed tomographic findings and the clinical features that are characteristic of hepatic pyogenic abscess, amebic abscess, fungal infection, and parasitic infection.