Limitations of characterization of hepatic hemangiomas using a sonographic contrast agent (Levovist) and power Doppler ultrasonography

Power Doppler ultrasonography using a sonographic contrast agent (Levovist) was evaluated in 20 patients with hepatic hemangiomas with a 2-4 MHz convex transducer according to a standardized examination protocol (pulse repetition frequency, 1000 Hz; medium wall filter; power Doppler gain, 50 to 85%). Enhancement patterns were assessed and were compared with those on dynamic magnetic resonance imaging (n = 11) or computed tomography (n = 9). The most common enhancement pattern was dotlike or linear enhancement located predominantly at the periphery of the tumor (15 cases, 75%). Diffuse homogeneous enhancement was seen in one case (5%). No definite contrast enhancement was evident in four cases (20%). The enhanced area on ultrasonograms was smaller than that on dynamic MR images or CT scans in 18 cases (90%). A transient centripetal fill-in pattern was identified in six cases (30%). Persistent enhancement until 300 s was not seen in any case. Therefore, specific diagnosis of hemangioma with power Doppler ultrasonography and contrast agent may not be possible.