EVALUATION OF BLOOD-FLOW SIGNAL IN SMALL HEPATIC NODULES BY COLOR DOPPLER ULTRASONOGRAPHY

Small hepatic nodular lesions are frequently detected by ultrasonograp hy in patients with liver cirrhosis during follow-up. However, hepatoc ellular carcinomas (HCCs) and non-HCC nodules are difficult to differe ntiate by ultrasonography because they have a similar appearance. We u sed color Doppler ultrasonography (CDU) to examine 29 HCCs and 26 non- HCC nodules less than 2 cm in diameter to determine whether CDU can be used to differentiate small hepatic nodules. There were no significan t differences between the examined HCCs and non-HCC nodules with regar d to ultrasonographic appearance, i.e., hypoechoicity or hyperechoicit y. Blood flow signals were detected in a significantly higher percenta ge of HCCs (13 of 29, 44.8%) than in non-HCC nodules (2 of 26, 7.7%; P <0.005), although the sensitivity was low. Therefore, we classified no dules as hypoechoic or hyperechoic by B-mode ultrasonography and exami ned their blood flow signals. Among nodules that were hypoechoic, sign als were detected in a significantly higher percentage of HCCs (12 of 18, 66.7%) than in non-HCC nodules (2 of 13, 15.4%; P<0.005). In contr ast, among hyperechoic nodules, signals were detected in only 1 of 11 (9.1%) HCCs and in 0 of 13 non-HCC nodules. Our results suggest that e xamination of blood flow by CDU is useful for differentiating small he patic nodules, especially hypoechoic nodules.