Findings: fluid collection with thick rim enhancement, well defined, consistent with hepatic abscess

• Objectives:

  • To review segmental anatomy of the liver

  • To review the classic appearance of hepatic abscesses of various etiologies

• Protocoling:

  • Contrast enhanced CT scan

• Key Points:

  • Anatomy:

    • Review segmental anatomy of the liver

  • Pyogenic abscess:

    • Etiology: biliary (ascending cholangitis), portal venous (diverticulitis, appendicitis, etc), septicemia, direct extension, traumatic.

    • Classic CT findings: hypodense mass/cluster of smaller cystic masses, enhancing capsule, gas < 20% of cases

    • Can be indistinguishable from necrotic metastasis

    • Management options: percutaneous aspiration, antibiotics

  • Hydatid cyst (echinococcal)

    • Classic CT findings: uni or multilocular, peripheral “daughter” cysts within, “water lily” sign with endocyst rupture - appears as floating membranes, can have peripheral calcifications

    • Management options: medical (anti-parasitic), aspiration, surgical

    • Aside: E. granulosus most common, E. multilocularis is rare more aggressive form

  • Amebic abscess:

    • Classic CT findings: sharply defined, round, solitary hypodense mass with thick rim/capsular enhancement.

    • Management: 90% respond to antimicrobial therapy (metronidazole). Drainage in special situations (including if unsure of diagnosis).

  • Candidiasis

    • Classic CT finding: multiple microabscesses

    • Differential:

      • Multiple hepatic cysts

      • Biliary hamartomas (von Meyenberg complexes)

      • Multiple small metastases/lymphoma

      • Caroli’s disease

    • Management: antifungal

  • Complications: Venous thrombosis, spread to subphrenic space, recurrence