Hypervascular liver lesions are findings that enhance more or similarly to the background hepatic parenchyma in the late arterial phase on contrast-enhanced CT or MRI.

Differential diagnosis

Non-neoplastic

• focal nodular hyperplasia (FNH)

  • bright arterial phase enhancement except central scar

  • isodense/isointense to liver on portal venous phase

  • central scar enhancement on delayed phase

• haemangioma

  • benign; most common liver tumour overall

  • discontinuous, nodular, peripheral enhancement starting in the late arterial phase

  • gradual central filling in

  • enhancement must match blood pool in each phase, or not a haemangioma (i.e. similar to the aorta in arterial, portal vein in portal phase, etc)

  • small haemangiomas (<1.5 cm) may demonstrate "flash filling" - complete homogeneous enhancement in arterial phase (no gradual filling in)

• vascular shunts / fistulas

  • intrahepatic arterioportal shunt - arterioportal fistula ⁸

  • intrahepatic arteriovenous shunt - arteriovenous fistula

• focal hepatic hot spot sign

• hepatic artery aneurysm

• failing Fontan circulation ³

• hepatic peliosis ⁷

• background liver disease (cirrhosis) ⁶​

  • regenerative nodules

  • dysplastic nodules

Neoplastic

• hepatocellular carcinoma (HCC)

  • most common hypervascular primary liver malignancy

  • early arterial phase enhancement and then rapid wash out

  • rim enhancement of capsule may persist

• hepatic adenoma

  • arterial phase: transient homogeneous enhancement

  • returns to near isodensity on portal venous and delayed phase image

• primary hepatic neuroendocrine tumour (carcinoid)

Metastases

Although the majority of liver metastases are hypodense and enhance less than the surrounding liver, metastases from certain primaries demonstrate an increase in the number of vessels, resulting in a hyperechoic ultrasound appearance, and arterial phase hyperenhancement on CT or MRI which washes out on delayed scan (cf. haemangioma which does not show washout). The primaries typically include:

• renal cell carcinoma (RCC)

• thyroid carcinoma

• neuroendocrine tumour (NETs)

  • gastrointestinal NETs

  • islet cell tumours

  • phaeochromocytoma

• leiomyosarcoma

• choriocarcinoma

• melanoma

• breast cancer

• colonic carcinoma ⁵

• ovarian cystadenocarcinoma ⁵

See also

• liver lesions