Evaluating the effect of high-intensity focused ultrasound therapy on liver tumors using multislice CT perfusion

The aim of this study was to investigate the changes of the multislice computed tomography (MSCT) perfusion parameters and histopathology of the liver in rabbits with VX2 tumors before and after high-intensity focused ultrasound (HIFU) therapy. VX2 carcinoma cells were implanted into the livers of eight New Zealand white rabbits 3 weeks prior to the treatment. MSCT perfusion was performed one week before and one and six weeks after the treatment. These CT perfusion (CTP) data, including hepatic blood flow (HBF), hepatic blood volume (HBV), mean transit time (MTT) and permeability-surface area product (PS), were analyzed semi-quantitatively and qualitatively. Furthermore, the histopathological features of the liver tissues were also assessed semi-quantitatively before and after the treatment. Six weeks after HIFU therapy, MTT increased noticeably from 5.45 +/- 0.27 to 10.38 +/- 2.22 sec (P<0.05) and PS decreased significantly from 79.03 +/- 3.41 to 68.13 +/- 0.21 ml/100 g/min (P<0.05), while no significant differences in HBF and HBV were found. Furthermore, more CD3(+) T cells were observed at the rim and center of the liver tumors six weeks after treatment. Therefore, HIFU therapy may be a simple and effective method for the treatment of liver tumors. CTP, as an effective method to obtain functional information about HBF, is able to quantify tumor vascularity and angiogenesis in liver tumors.