Hypervascular liver lesions on MRI.

T he superb liver-to-lesion contrast of MRI and its ability to display the same lesion enhancement patterns as CT combined with its lack of ionizing radiation have led to this modality being widely accepted for assessing the broad spectrum of hepatic abnormalities. Moreover, hepatocyte-specific contrast agents are now available. The differential diagnosis of hypervascular hepatic lesions depends on the status of the remainder of the organ. If the liver is normal, the most common causes of hypervascular liver lesions are hemangioma, focal nodular hyperplasia (FNH), adenoma, and hypervascular metastasis. In the presence of chronic liver disease, the likely causes include vascular shunts (transient hepatic enhancement difference [THED]), regenerative nodules, dysplastic nodules, and hepatocellular carcinoma (HCC) (Table 1).