Hepatic Hemangioma with Atypical Sonographic Features: Value of Two-Phase Spiral CT

PURPOSE: 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) MATERIALS AND METHODS: 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 (150 ml, 5 ml/sec). Enhancement patterns of hemangiomas during each phase were classified as homogeneous high, peripheral high, or low attenuation, and were retrospectively analyzed. RESULTS: 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. CONCLUSION: 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.

Spiral CT of Hepatocellular Carcinoma: Value of Dynamic Fast Infusion of Contrast Material

PURPOSE: To assess the value of dynamic fast infusion of contrast material in the detection and diagnosis of hepatocellular carcinoma(HCC) with spiral CT. MATERIALS AND METHODS: Two-phase dynamic spiral CT was performed in 59 patients with 104 HCCs. 150ml of nonionic contrast material was injected with an automatic injector at the rateof 5 ml/sec. Two-phase images were obtained at 20-45 sec(arterial dominant phase) and 2-5 min(equilibrium phase)after the initiation of bolus injection of contrast material. The tumors were divided into three groups(5cm) according to the size and the enhancement patterns on two-phase images were compared. RESULTS: Inthe arterial phase, HCCs showed total or partial hyperattenuation in 79% of cases(82/104), isoattenuation in 12%,and hypoattenuation in 9%. In the equilibrium phase, HCCs showed hypoattenuation in 86%(89/104) and isoattenuationin 14%. The most common and characteristic enhancement patterns of HCCs were hyperattenuation in the arterialphase and hypoattenuataion in the equilibrium phase ; in the latter, capsules were demonstrated in 45% of cases. Invasions of the portal and/or hepatic vein were demonstrated in 34% of cases. CONCLUSION: Dynamic fastinfusion(5ml/sec) of contrast material(150ml) is useful in the detection and diagnosis of HCCs with spiral CT.