磁共振扩散加权成像预测、监测直肠癌放化疗效果的价值

The Clinical Value of DWI in Predicting and Monitoring Radiochemotherapy Effect in Rectal Cancer

目的探讨MR扩散加权成像（diffusion-weighted imaging,DWI）在预测、监测直肠癌放、化疗效果中的应用价值。资料与方法动态监测15例行放、化疗的直肠癌患者,于放化疗前、放化疗结束和放化疗后4-5周行3次常规MRI及DWI。测量直肠癌的长度、肿瘤侵犯直肠壁厚度和表观扩散系数（apparent diffusion coefficient,ADC）值在放化疗前、后各时间点的变化,并分别进行比较;依据实体瘤疗效评价标准（RECIST）分组,比较各组在放化疗前ADC值之间的差异。结果直肠癌放化疗结束时,肿瘤侵犯肠壁的厚度较放化疗前差异有统计学意义（0.010.05）;而对于放化疗结束与放化疗后4~5周,三者的变化差异均无统计学意义。放化疗前部分缓解（PR）与病灶稳定（SD）组之间的ADC值差异无统计学意义（P=0.222〉0.05）。结论 DWI可优先、准确评价直肠癌放化疗的疗效相对于肿瘤形态学变化;而放化疗前ADC值对于预测直肠癌放化疗的疗效无明显意义。

Objective To investigate the clinical value of diffusion weighted imaging（DWI） in predicting and monitoring radiochemotherapy effect in rectal cancer.Materials and Methods Fifteen patients with rectal cancer underwent conventional MRI and DWI examination at 3 time points： before radiochemotherapy（1st time point）,radiochemotherapy completed（2nd time point）,4-5 weeks after radiochemotherapy（3rd time point）.The parameters,including the length of tumors,the thickness of rectal wall and apparent diffusion coefficient（ADC） at different time points were measured and compared.The patients were classified into SD and PD subgroups according to RECIST standard.ADC values measured before radiochemotherapy were compared between subgroups.Results Compared the 1st and 2nd time points,there were differences in the thickness of rectal wall（0.01P=0.0230.05） and ADC values（P=0.0000.01）.There were no difference in the length of tumors between the 1st and 2nd time piont（P=0.1180.05）.There were no differences in.the length of tumor,the thickness of rectal wall and ADC between the 2nd and 3rd time point.There were no differences in ADC values between PD and SD subgroups before radiochemotherapy（P=0.2220.05）.Conclusion DWI can monitor the therapeutic effect of rectal cancer accurately by comparison of the length of tumors and the thickness of rectal wall.ADC values measured before radiochemotherapy may be no value in predicting the therapeutic effect.