Investigation Of Perfusion-weighted Imaging Before And After High Intensity Focused Ultrasound Treantment In VX2 Hepatic Tumors Of Rabbit

Objective To Compare the MR perfusion-weighted imaging (PWI) characteristics and parameters changes in both before and after High Intensity Focused Ultrasound ( HIFU),supposed to provide experimental basis for evaluation of PWI in clinic diagnoses and measurement of effect on rabbit models of hepatic VX2 tumors.Methods 40 rabbit models of hepatic VX2 tumors were implated successfully, two weeks later, after routine scans were performed on 1.5T MR scanner,using EPI-SE series, 40 New Zealand white rabbits with VX2 carcinoma were divided randomly into treatment group 20, control group 20, HIFU with treatment group. MR perfusion-weighted imaging and enhanced scan were performed 14d before and after HIFU for the two groups.Select the ROI of the VX2 tumor center, tumor border and paratumor parenchyma. Maximal signal reduction slope(SRSmax) of the signal intensity versus time curves were created as quantitative variable. Analyze the SRSmax change degrees and regularities of different ROI. The results of PWI were compared with that of pathology. Results 48 lesions were detected in 40 rabbit models,and 36 lesions in 33 rabbit models were statistical analysis finally. At original map on perfusion, tumor showed heterogeneous were mixed with high signal, normal signal and low signal; the degrees and intensity of blood perfusion in different ROI were different at blood perfusion maps. The results of SRSmax value in tumor parenchyma and normal liver tissue were statistical difference (F = 5.870, P = 0.023). The SRSmax value of tumor border were higher than tumor center and paratumor parenchyma in treatment group and control group,it is different of SRSmax value in tumor center, tumor border and paratumor parenchyma. (F = 8.625, P = 0.013 ). No significant difference in tumor central of treatment group (HIFU treatment area) with the control group (t = 0.624, P = 0.732). The degrees of blood perfusion of different ROI were consistented with the results of MVD and VEGF. The SRSmax,MVD and VEGF correlation analysis showed that they were positively correlated in tumor border of both groups(P﹤0.05).Conclusion The findings of VX2 carcinomas on PWI are matched with the levels and scopes of necrosis , and PWI can be used in evaluating the liver tumor angiogenesis and angioruin with the treatment of HIFU. It will be possible for qualitative analysis of rabbit models of hepatic VX2 tumors by different treatments.