DWI在直肠癌术前同步放化疗疗效预测中的作用

 目的 探讨DWI在局部进展期直肠癌（LARC）术前同步放化疗疗效预测中的作用。方法 将经内镜活检病理证实的LARC患者44例纳入分析。将患者术后病理分期与治疗前临床分期作比较，分为T-降期组和T-未降期组，比较放化疗前后以及组间ADC值、组间ADC变化量（ΔADC）以及变化率（ADC%）之间的差异，并根据ROC曲线得出疗效预测的最佳临界ADC值。结果 44例患者中7例（15.9%）获得pCR。患者同步放化疗前后ADC值差异有统计学意义（P=0.000）。同步放化疗前T-降期组ADC值明显低于T-未降期组，差异有统计学意义（P=0.007）。同步放化疗后T-降期组ADC值明显高于T-未降期组，差异有统计学意义（P=0.005）。T-降期组同步放化疗后ΔADC及ADC%均高于T-未降期组，差异有统计学意义（Z=-5.53, P=0.000; P=-5.09, P=0.000）。取治疗前ADC值0.87×10^-3 mm²/s作为预测T分期是否降期的临界值，ROC曲线下面积为0.697（95%CI: 0.539~0.855），预测疗效的敏感度为87.5%，特异性为55.0%。结论 通过对ADC的定量分析可早期预测直肠癌患者对术前同步放化疗的敏感度，对术前同步放化疗疗效的判断也有一定的价值。

Role of Diffusion-weighted Magnetic Resonance Imaging in Forecasting Curative Effect of Preoperative Chemoradiotherapy on Locally Advanced Rectal Cancer

Objective To explore the role of diffusion-weighted magnetic resonance imaging(DWI) in forecasting curative effect of preoperative chemoradiotherapy(CRT) on locally advanced rectal cancer (LARC). Methods We collected 44 cases of LARC patients confirmed by colonoscope biopsy pathology from June 2016 to December 2017. The patients were divided into T-downstaged group(n=24) and T-nondownstaged group(n=20), according to postoperative pathological stage and pretherapeutic clinical stage. We compared ADC value before and after chemoradiotherapy, ADC value between two groups, the ADC variation between groups (ΔADC) and the change rate of ADC (ADC%). According to the ROC curve, we obtained the optimal critical value of ADC for forecasting curative effect. Results Among 44 cases of LARC patients, 7(15.9%) patients achieved pathological complete response. There was statistically significant difference in ADCs before and after CRT (P=0.000); before CRT, the ADC value in T-downstaged group was significantly lower than that in the T-non-downstaged group (P=0.007); after CRT, the ADC value in T-downstaged group was significantly higher than that in T-non-downstaged group (P=0.005); after CRT, ΔADC and ADC% in T-downstaged group were both significantly higher than those in T-non-downstaged group (Z=-5.53, P=0.000; P=-5.09, P=0.000). We defined the ADC value 0.87×10^-3mm²/s before the treatment as the critical value for forecasting whether the T stage would be reduced or not. The area of the ROC curve was 0.697 (95%CI: 0.539-0.855), the sensitivity of the curative effect forecasting was 87.5%, and the specificity was 55.0%. Conclusion The quantitative analysis of ADC was able to forecast the sensitivity of rectal cancer patients in early stage to CRT, with certain value in the pre-CRT judgement.