Power Doppler sonography for hepatocellular carcinoma: factors affecting the power Doppler signals of the tumors

Aims/Background: A recent advancement in Doppler ultrasonography (US) is po wer Doppler for detecting low-velocity blood flow at the microvascular leve l with angle independence. The present study was performed to characterize the factors contributing to the power Doppler signals of hepatocellular car cinoma (HCC). Method: Correlation of Doppler signals of HCC in 114 patients with 178 HCC nodules was analyzed in relation to the findings of CT and an giography, tumor characteristics (size, echo pattern, and histological diff erentiation of tumor), viral markers and severity of liver disease. Results : The sensitivity of power Doppler US was superior to that of CT and angiog raphy teach p<0.05; McNemar's test). The detection rate of power Doppler si gnal was significantly higher in tumors with diameter greater than or equal to 2 cm (vs <2 cm in diameter), and with low/mixed echo pattern (vs high e cho appearance), and with moderately/poorly differentiated HCC (vs well-dif ferentiated HCC). Univariate analysis revealed that echo pattern, tumor siz e and histological differentiation of HCC in addition to CT and angiographi c findings were significant. Multivariate analysis showed that tumor size a nd differentiation were significant. Conclusion: These results indicate tha t tumor characteristics play an important role in power Doppler signals and that these could be assessed by the presence or absence of power Doppler s ignals.