On dynamic contrast-enhanced CT, a hepatic lesion in a cirrhotic patient shows arterial phase enhancement with washout (hypodensity) in the portal venous phase. This enhancement pattern is diagnostic of:

• A Hepatic metastasis with peripheral rim enhancement
• B Focal nodular hyperplasia with central scar enhancement
• C Hepatic hemangioma with peripheral nodular fill-in
• D Hepatocellular carcinoma (HCC) — arterial enhancement with portal-venous washout ✓

Explanation

The hallmark imaging signature of HCC on dynamic multiphasic CT or MRI is arterial phase hyperenhancement followed by washout appearance in the portal venous or delayed phase — this reflects the tumor's neovascularity from hepatic arterial supply (unlike the dual blood supply of normal liver) and relatively faster contrast clearance. This pattern, known as the 'HCC hallmark,' meets LI-RADS-5 criteria and is diagnostic of HCC in cirrhotic livers without biopsy. Hemangioma shows peripheral nodular fill-in with progressive centripetal enhancement. FNH shows uniform arterial enhancement with central stellate scar and delayed scar enhancement.

Reference: Grainger & Allison's Diagnostic Radiology, 7th ed.

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