Hypoechoic focal liver lesions:: Characterization with contrast enhanced ultrasonography

Purpose. To evaluate the late sinusoidal phase of contrast enhancement with a 2nd-generation ultrasound contrast enhanced medium in the characterization of hypoechoic focal liver lesions. Methods. We studied 88 hypoechoic liver lesions (diameter range, 1-18 cm; with 18 lesions 2 cm or less) found on conventional grayscale sonography (US) with contrast-enhanced ultrasonography (CEUS). Final diagnosis was made using contrast enhanced helical CT, contrast enhanced MR, angiography (DSA), and/or histopathic confirmation or clinical imaging follow-up. Results. There were 37/88 benign lesions demonstrated: 17 cavernous hemangiomas, 3 capillary hemangiomas, 11 focal nodular hyperplasias (FNH), 3 focal areas of sparing in hepatic steatosis, 2 adenomas, and 1 intrahepatic necrotic area. Malignant lesions demonstrated included 51/88: 27 hepatocellular carcinomas (HCC) in cirrhosis, 11 metastatic carcinomas, 10 metastatic endocrine tumors, 2 cholangiocellular carcinomas (CCC) and 1 non-Hodgkin's lymphoma (NHL). CEUS characterized 30/37 (81%) benign lesions and 45/51 (88%) malignant lesions. On the basis of the results obtained during the sinusoidal contrast enhanced phase of CEUS, diagnosis of benignancy was possible in 35/37 (95%) of benign liver lesions and diagnosis of malignancy in 49/51 (96%) of malignant liver lesions. The enhancement pattern of 13 small (< or = 2 cm in diameter) hypervascular liver lesions (3 capillary hemangiomas, 2 FNHs, 4 HCCs, 4 metastatic endocrine tumors) was better demonstrated on CEUS than on helical CT. In these cases the hyper vascularization of the lesions shown on CEUS was not confirmed on CT. Conclusions. CEUS distinguished malignant from benign hypoechoic liver lesions with an accuracy of 95%. (c) 2005 Wiley Periodicals, Inc.