Effect of observer experience in the differentiation between benign and malignant liver tumors after ultrasound contrast agent injection.

OBJECTIVE: The purpose of this study was to assess the impact of the observer level of experience on the diagnostic performance of contrast-enhanced ultrasound imaging (CEUS) for differentiation between benign and malignant liver tumors. METHODS: From a computerized search, we retrospectively identified 286 biopsy-proven liver tumors (105 hepatocellular carcinomas, 48 metastases, 7 intra-hepatic cholangiocarcinomas, 33 liver hemangiomas, and 93 nonhemangiomatous benign lesions) in 235 patients (140 male and 95 female; mean age +/- SD, 56 +/- 11 years) who underwent CEUS after sulfur hexafluoride-filled microbubble injection. The digital cine clips recorded during the arterial (10-35 seconds…