Quantification of Tumor Vascularity with Contrast-enhanced Ultrasound for Early Response of Transcatheter Arterial Chemoembolization for Hepatocellular Carcinoma: a Report of Three Cases

Many contrast-enhanced ultrasound (CE-US) studies have been conducted by qualitative analysis of blood flow, such as classification of enhancement pattern. We evaluated early response of transcatheter arterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) by quantitative analysis of intratumoral vascularity with CE-US in three patients. Three patients (one man, two women) with HCCs were treated in July 2009. CE-US with perfluorocarbon microbubbles (Sonazoid) and CT were performed serially before and 5 days after TACE. Post-processing enhancement intensity on US was analyzed to determine mean transit time (s), time to peak (s), enhancement peak intensity (dB), and "A" (scaling factor) by ultrasound quantification software after the data were fitted to a gamma variate curve. Mean transit time was prolonged by TACE in all three patients. Mean transit time rates on CE-US were 64.3, 33.8, and 65.6%, respectively, whereas the avascular rates on CT were 59.07, 31.71, and 62.25%, respectively. Mean transit time rates on CE-US approximated avascular rates on CT. Mean transit time rate may quantitatively indicate the early response of HCC to TACE.