Hepatic infarction

Hepatic infarction is an extremely rare situation because of the liver's dual blood supply by the hepatic artery and portal vein. Hepatic infarction can occur when there is both hepatic arterial and portal vein flow compromise but most cases are due to acute portal venous flow compromise ¹¹.

Epidemiology

Most cases are seen after liver transplantation or hepatobiliary surgery. Non-transplant cases are mostly caused by ^1-2:

• hepatic artery occlusion due to
  • arteriosclerosis
  • thrombosis or emboli
  • hepatic artery aneurysm
  • polyarteritis nodosa
  • sickle-cell disease
• infarction without hepatic artery occlusion is mainly caused by
  • acute shock state
  • trauma
  • hypercoagulable state
  • preeclampsia, eclampsia and post-partum HELLP syndrome ^4-10.
  • complication of anaesthesia

Clinical presentation

Clinically, these patients present with abdominal pain, nausea, vomiting and abnormal liver function tests ². Most of the time, infarction is a peripherally located wedge-shaped area, however it can be centrally or round or oval shape ².

Radiographic features

Ultrasound

• acute stage
  • anill-defineddan ill-defined hypoechoic area with indistinct border
  • gas within sterile infarcted zone can be seen ^2-3
• chronic stage
  • infarcted area becomes anechoic and cystic with distinct borders.

Differentiation between gas within sterile infarcted area and abcessabscess formation by imaging is impossible and fine needle aspiration is needed ².

CT

Typically infarction presents as an ill-defined wedge-shaped area of hypoattenuation which is mostly peripheral without mass-effect on adjacent structures in post-contrast images ^4-5. 

MRI

On MRI imaging, regions of hepatic infarction appears as hypointense lesion on T1 imaging, with hyperintensity on T2 imaging ⁶.

Differential diagnosis

General imaging differential considerations include:

• focal fatty infiltration: focal fatty infiltration also lacks mass-effect, however vessels are seen crossing troughthrough the lesion
• hepatic abscess: typically shows mass-effect on adjacent structures and ring-enhancement while hepatic infarction lacks mass-effect and any enhancement
• true hepatic masses: both mass-effect and enhancement differentiatesdifferentiate from hepatic infarction. The, and the clinical scenario is different