Hepatic hemangioma with atypical sonographic features : value of two-phase spiral CT

The purpose of this study was to evaluate enhancement patterns, as seen on two-phase spiral CT, of hepatic hemangiomas in which atypical features had been seen on sonography(US) Two-phase spiral CT scanning was performed in 18 patients in whom 24 atypical hemangiomas had been seen on US. Two-phase images were obtained at 25-45 seconds(arterial dominant phase) and 2-5 minutes(equilibrium phase) after the initiation of a bolus injection of contrast material(150ml, 5ml/sec). Enhancement patterns of hemangiomas during each phase were classified as homogeneous high, peripheral high, or low attenuation, and were retrospectively analyzed. In the arterial dominant phase of spiral CT, low attenuation was seen in nine hemangiomas (38%), globular or spotty peripheral high attenuation in 14(58%), and homogeneous high attenuation in one(4%). In the equilibrium phase, enhancement patterns were peripheral high attenuation(partial fill-in) in 18 lesions (75%), and homogeneous high attenuation(complete fill-in) in three (12.5%), In the other three(12.5%) enhancement showed no significant change;in one of these, density was slightly less than in the arterial phase, and two showed subtle peripheral high attenuation. Fourteen hemangiomas (58%) showed globular or spotty peripheral high attenuation in the arterial dominant phase and peripheral or homogeneous high attenuation with progressive centripetal enhancement in the equilibrium phase. Our results suggest that two-phase spiral CT during the arterial dominant and equilibrium phase is useful in differentiating hepatic hemangiomas with atypical features seen on US from malignant hepatic tumors