Contrast Enhancement of Hepatic Hemangiomas on Multiphase MDCT: Can We Diagnose Hepatic Hemangiomas by Comparing Enhancement With Blood Pool?

OBJECTIVE. The purpose of this article is to determine whether enhancement of nodular foci within hemangiomas is homogeneous and matches blood vessels at different phases on contrast-enhanced MDCT. MATERIALS AND METHODS. Multiphase (unenhanced, arterial, portal venous, and delayed phases) MDCT images of 58 hemangiomas were reviewed by two radiologists. Nodular-enhancing foci within hemangiomas were evaluated for enhancement pattern and were subjectively compared with enhancement of the aorta, inferior vena cava, hepatic vein, and portal vein for each contrast-enhanced phase. Both readers measured CT attenuation of enhancing nodules and vessels at each phase, and enhancement of nodules and vessels was compared. RESULTS. Qualitative analysis showed heterogeneously enhancing nodules in 79.3% and 65.5% of hemangiomas in the arterial phase and in 74.1% and 53.4% of hemangiomas in the portal venous phase, according to readers 1 and 2, respectively. In the arterial phase, 3.8% and 12.3% of nodules showed enhancement similar to that in the aorta. In the portal venous phase, 15.4% and 21.7%, 16.8% and 18.2%, 14.1% and 23.8%, and 19.5% and 25.9% of nodules were scored with enhancement similar to that in the aorta, inferior vena cava, hepatic vein, and portal vein by readers 1 and 2, respectively. Differences between attenuation of nodules and all vessels in the arterial, portal venous, and delayed phases were statistically significant. Statistically significant differences were also noted between attenuation among blood vessels in the arterial and portal venous phases but not in the delayed phase. CONCLUSION. Attenuation of enhancing foci within hemangiomas does not match vessel density qualitatively or quantitatively. No common blood pool density exists in the arterial or portal venous phase. Although persistent enhancement without washout is a useful CT criterion, specific criteria to match the blood pool cannot be used to confirm a diagnosis of hemangioma.