Accuracy of Gray-Scale and Color Doppler Sonography in Diagnosis of Hepatic Hemangioma, Hepatocellular Carcinoma and Liver Metastasis

Background/ Distinguishing cavernous hemangioma from malignant neoplasmsrepresents a diagnostic challenge. Knowledge of the entire spectrum of gray-scaleultrasonography (US) and color Doppler appearances of these tumors is important. The objective of this study was to determine the diagnostic accuracy of gray-scale US and color Doppler appearances of liver tumors. Patients and 88 patients with 93 focal hepatic lesions were prospectivelystudied with gray-scale and color Doppler US. The final diagnoses of the liver lesions as confirmed by pathology or 99mTc-red blood cell scintigraphy were 41 hemangiomas, 15 hepatocellular carcinomas (HCCs) and 37 metastases. 87.8% of hemangiomas and 66.7% of HCCs were hyperechoic, while 54.1% of metastases were hypoechoic. In lesions < 3 cm in diameter, the sensitivity and specificity of the hyperechoic pattern for differentiation of hemangioma from metastasis and HCC were 94.1% and 80.0%, respectively. They were higher than the lesions with a diameter ≥3 cm (83.3% and 45.9%, respectively, both P=0.001). Posterior acoustic enhancement was seen in 78% of hemangiomas (P<0.001), as compared to 24.4% in metastases and 13.3% in HCCs. 10 hemangiomas had an echogenic rim. The peripheral hypoechoic rim, named as the target sign, was seen in 37.8% of metastases, 26.7% of HCCs and 2.4% of hemangiomas (P<0.001). Most hemangiomas (85.4%) showed no lesional blood flow, while most HCCs (80%) had both intraand peri-lesional vascularity (P<0.001). There was intratumoral blood flow in 86.7% of HCCs.Lesional flow, whether intratumoral or peritumoral or both, was seen in all 14 patients with HCC while absence of the lesional flow was not noted in any of the HCCs. Most hemangiomas had no detectable blood flow in color Doppler US. Almostall HCCs had intra- and/or peri-tumoral vascularity in color Doppler sonography, so the probability of hepatocellular carcinoma is low in a hepatic mass without intra- or peri-lesional vascular blood flow. So these findings together with morphological criteria may help narrow down the differential diagnosis in certain clinical conditions.