Comparison of Superb Microvascular Imaging With Color Flow and Power Doppler Imaging of Small Hepatocellular Carcinomas

Objectives The purpose of this study was to compare Superb Microvascular Imaging (SMI; Toshiba America Medical Systems, Tustin, CA) with conventional color flow Doppler (CFD) and power Doppler (PD) imaging in the liver to distinguish between malignant and benign liver neoplasms. Methods After Institutional Review Board approval (number 449984-ED), patients undergoing routine pre-radiofrequency ablation planning ultrasound examinations for suspected hepatocellular carcinomas (HCCs) of less than 2 cm in diameter between January 1, 2015, and July 1, 2016, were prospectively identified. Four readers reviewed the ultrasound images independently for the presence or absence of flow centrally and along the periphery of the lesion. Results Higher peripheral vessel grades were found on SMI than CFD (P < .001) and PD (P < .001) imaging: in particular, more grade 2 (39% versus 16% and 11%, respectively) and grade 3 (8% versus 0% and 0%). Overall, more central and peripheral vessels were found on SMI than CFD and PD imaging for both HCC lesions (P < .001) and benign lesions (P < .001). Vascular grades were significantly higher in HCC lesions than benign lesions in nearly all cases, although the corresponding area under the curve values were relatively low, at 0.54 to 0.59 for the central vessel grades and 0.63 to 0.64 for the peripheral vessel grades. Conclusions More central and peripheral vessels were found around liver lesions on SMI than on CFD and PD imaging. Although there was significantly more vascularity on the periphery of malignant liver lesions than benign lesions, the overall diagnostic performance based on this criterion alone was relatively low, with an area under the curve of 0.64.