Small hypervascular hepatocellular carcinoma versus hypervascular pseudolesions: differential diagnosis on MRI

Background: We wanted to differentiate small hypervascular hepatocellular carcinoma (HCC) from hypervascular pseudolesion (HPL) on magnetic resonance imaging (MRI). Methods: We reviewed small hypervascular foci (≤2 cm in diameter) on dynamic MRI in patients with chronic liver disease, which were followed-up with serial MRI examinations. Results: Twenty of 34 hypervascular foci were larger at follow-up; 19 of 20 foci had characteristics suggesting HCC; and 14 foci did not grow or disappeared and were judged to be HPLs. There were no differences in the initial sizes and follow-up periods between HCCs and HPLs. On initial MRI, nine of 19 HCCs (47%) and one of 14 HPLs (7%) appeared hyperintense on T2-weighted images. The difference between HCCs and HPLs on T2-weighted images was statistically significant ( p = 0.039). Conclusion: HPLs are seen frequently as small hypervascular foci on dynamic MRI in patients with chronic liver disease. Hyperintensity of the foci on T2-weighted images differentiates HCCs from HPLs.