Intratumoral blood perfusion detected by quantitative contrast-enhanced ultrasonography in pazopanib-treated HCCLM3 xenograft model. Panel A shows typical images of the contrast-enhanced ultrasonography (CEUS) in subcutaneous tumor (T) and ipsilateral kidney (K) from the control (ctrl) and pazopanib-treated mice (pazo) 3 wk after the initiation of the treatment (left panels). ROIs were selected in the tumor ("T," yellow lines) and ipsilateral kidney ("K," green lines), and the time-intensity curves (right panels) were then obtained in the two regions of interest for further analyses. Tumor perfusion changed in a biphasic manner (panel B). The standardized volume-related parameters detected by CEUS in the whole tumor changed over time. As compared to the control, an increase in signal intensity, the area under the curve, and the blood flow coefficient increased 1 wk after the pazopanib treatment, but decreased afterward. Mean transit time of the contrast in the tumor was also significantly prolonged at the end of the third week of the pazopanib treatment (A). Bars, SEM. Asterisks indicate P < 0.05.