Background/aims: The study was to utilize both color Doppler sonography and power Doppler sonography to analyze the enhancement characteristics of hepatic tumors known to have a clinical or histologically confirmed diagnosis of hepatocellular carcinoma, hemangioma, or focal nodular hyperplasia.
Methodology: Twenty-two hepatocellular carcinomas, 6 hemangiomas, and 2 focal nodular hyperplasias were observed with color Doppler sonography and power Doppler sonography before and after contrast agent (Levovist) administration. Color Doppler sonography and power Doppler sonography were used to detect the intratumoral vasculature and their sensitivity would be evaluated.
Results: Significant improvement in the detection of color flow signals was obtained in hepatocellular carcinomas after administering Levovist (32% (7/22) vs. 91% (20/22); p = 0.0002), but it was not significant in hemangiomas (0% (0/6) vs. 33% (2/6); p = 0.454). Power Doppler sonography was more sensitive than color Doppler sonography in the detection of flow signals in hepatocellular carcinomas after administering Levovist (91% (20/22) vs. 50% (11/22); p = 0.008). Eighty percent (16/20) of hepatocellular carcinomas had signals of curvilinear type versus spotty type (p = 0.0005), the detected signal in both hemangiomas was iris diaphragm phenomenon. The typical spoke-wheel appearance of focal nodular hyperplasia was more easily demonstrated after administering Levovist. The hepatocellular carcinomas with absent baseline flow (1.2-5.6 cm, mean: 3.1 +/- 1.0 cm) tended to be smaller than the hepatocellular carcinomas with baseline flows (2.3-8.3 cm, mean: 4.9 +/- 2.2 cm) (p = 0.06). The 9 hepatocellular carcinomas (largest diameter: 1.2-3.8 cm, mean: 2.6 +/- 0.8 cm) with enhanced flows only observed by power Doppler sonography was smaller than the 11 hepatocellular carcinomas (largest diameter: 2.3-8.3 cm, mean: 4.5 +/- 1.8 cm) with enhanced flows observed by color Doppler sonography and power Doppler sonography (p = 0.01).
Conclusions: Enhanced color flow study may aid in the detection of flow signals or sonographic differentiation of hepatic tumors.