MR弥散加权成像评估兔肝VX2肿瘤放疗后再增殖  

MR diffusion weighted imaging in evaluation on cancer cell repopulation for rabbit models of hepatic VX2 tumor after radiotherapy

作　　者：古杰洪[1] 黄云海[1] 江新青[1] 丁汉军[1] 吴红珍[1] 吴梅[1] 

机构地区：[1]广州市第一人民医院放射科,广东广州510180

出　　处：《中国医学影像技术》2011年第9期1761-1765,共5页Chinese Journal of Medical Imaging Technology

摘　　要：目的探讨磁共振弥散加权成像评估兔肝VX2肿瘤放疗后肿瘤细胞再增殖的可行性。方法以经腹腔瘤块种植法建立32只兔肝VX2肿瘤模型,瘤体直径≥1 cm时行单次三维立体适形放疗,放疗剂量15 Gy。将兔平均分为4组,于术后第1、5、10、15天进行MR检查,取b值300、500、600 s/mm2分别进行DWI,测量VX2肿瘤、肝脏ROI的ADC值,计算两者比值,并与病理结果对照。结果 DWI图上VX2肿瘤信号高于肝实质。放疗后VX2肿瘤T2WI信号不均,DWI图上肿瘤实性部分信号不均匀减低,坏死液化部分呈明显低信号,ADC图则相反;放疗后不同b值下不同时间组ADC均值及比值均有显著差异,不同时间组的ADC均值及比值两两比较差异均有统计学意义,肿瘤ADC值及比值放疗后第5天组高于第1天组,第10天组低于第5天组,第15天组低于第10天组。VX2肿瘤ADC值及比值的变化与病理所示肿瘤细胞变化相符。结论 DWI能反映肿瘤组织内微观改变,可用于监测兔肝VX2肿瘤放疗后不同时间点肿瘤细胞的再增殖变化。Objective To observe the feasibility of DWI in evaluating cancer cell repopulation for rabbit models of hepatic VX2 tumor after radiotherapy.Methods VX2 liver cancer models were established in 32 rabbits using celiac tumor block planting method.Three-dimensional stereotactic conformal radiation therapy was performed in each rabbit when the diameter of tumor is equal or greater than 1 cm（single radiation,dose 15 Gy）.After radiotherapy,32 rabbits were randomly averagely divided into four groups,and MRI was performed on 1st,5th,10th,15th day,respectively with EPI-SE sequence and SENSE technology.DWI was performed with different b values（300,500 and 600 s/mm2）.ROIs of VX2 tumor and normal liver tissue were selected,the ADC values of ROI as well as ADCtumor/ADCliver ratios were calculated,statistically analyzed and compared with pathology findings.Results Signal intensity of VX2 tumor on DWI was higher than that of liver tissue.After radiotherapy,signal intensity of VX2 tumor became heterogeneous on T2WI.The signal of solid part decreased unevenly,while the necrotic cystic part showed very low signal on DWI,while ADC images behaved in the opposite way.Significant differences were found in ADC value and ADCtumor/ADCliver among different time groups with different b value.There were significant differences in ADC value and ADCtumor/ADCliver between every two groups.ADCtumor value and ADCtumor/ADCliver on the 5th day after operation were higher than that on 1st day,on the 10th day after operation were lower than that on the 5th day,on the 15th day after operation were lower than those on the 10th day.Changes of ADC values and ADCtumor/ADCliver accorded with cellular changes in pathological samples.Conclusion Micro changes of tumor tissue can be reflected with DWI images through changes of ADCtumor images,ADCtumor values and ADCtumor/ADCliver.DWI can be used to monitor cancer cell repopulation of rabbit VX2 liver cancer at different time after radiotherapy.

关 键 词：扩散磁共振成像 癌 肝细胞 放射治疗 模型 动物 

分 类 号：R445.2[医药卫生—影像医学与核医学] R-332[医药卫生—诊断学]