Characteristic Findings of Hepatic Malignancy on Triphasic CT

Primary Enhancement Pattern for Malignancy

The American Association for the Study of Liver Diseases recommends that arterial phase hyperenhancement with subsequent portal venous phase washout is considered the "typical characteristic" for hepatocellular carcinoma (HCC) and is incorporated into major diagnostic guidelines, with a sensitivity of 72% and specificity of 81% for malignancy 1, 2, 3
The European Association for the Study of the Liver suggests that for HCC specifically, this arterial hypervascularity with washout allows diagnosis without biopsy in cirrhotic patients with lesions ≥2 cm, with a high degree of confidence 2

The American College of Radiology recommends that rim enhancement during arterial and portal venous phases is characteristic of cholangiocarcinoma and some metastases, with a moderate level of evidence 1, 4
The Society of Abdominal Radiology states that combining hypervascularity with any hypoattenuation on any phase increases sensitivity for malignancy, although the exact percentage is not specified 1, 4

The American Hepato-Pancreato-Biliary Association notes that hemangiomas show peripheral nodular enhancement with progressive centripetal fill-in, remaining hyperenhancing through venous and delayed phases, which is distinct from the washout pattern seen in malignancies 1, 3
The European Society of Gastrointestinal and Abdominal Radiology recommends that focal nodular hyperplasia (FNH) demonstrates intense arterial enhancement becoming isoattenuating in portal venous phase, without washout, which is a key differentiator from HCC 1, 3
The Radiological Society of North America suggests that adenomas may mimic HCC but typically show transient arterial enhancement with rapid washout, making them difficult to distinguish from malignancy 1

The American College of Radiology recommends that hypovascular metastases are best detected on portal venous phase as hypoattenuating lesions, with a high degree of sensitivity 4
The Society of Abdominal Radiology states that hypervascular metastases show arterial enhancement with washout, mimicking HCC, with a moderate level of evidence 1, 4

The American College of Radiology recommends that single-phase CT is inadequate and multiphasic imaging is mandatory when malignancy is suspected, with a high level of evidence 3, 5
The European Society of Gastrointestinal and Abdominal Radiology suggests that correlation with clinical context is essential, as 30% of liver lesions in patients with known malignancy are benign 5