MR扩散加权成像评估回结肠克罗恩病活动性的价值

The diagnostic value of diffusion-weighted MR for inflammatory activity in ileocolonic Crohn disease

目的 探讨DWI信号及ADC值评估回结肠克罗恩病（CD）活动性的价值.方法 回顾性分析经内镜和病理检查确诊为CD,同时行MR肠道成像（MRE）和DWI检查的42例患者.根据CD简化内镜活动评分（SES-CD）标准对每个病变肠段评分,将患者分为缓解期、轻度活动期和中重度活动期.观察MRE表现,分别进行肠壁厚度、T2WI信号和肠壁强化程度评分;观察DWI表现,进行DWI信号评分,并测量ADC值.3组不同活动性CD肠段间MRE评分、DWI信号评分和ADC值的比较采用Kruskal-Wallis秩和检验或单因素方差分析,采用ROC分析MRE、DWI各征象评价CD活动性的效能,采用Spearman相关分析评价各MRI指标和SES-CD的相关性.结果 114个病变肠段纳入研究,其中缓解期、轻度活动期和中重度活动期分别为15、72、27个,SES-CD评分为1.0-10.0分,平均（4.6±2.3）分.3组间ADC值和DWI信号评分的差异均有统计学意义（P均〈0.01）.114个肠段的SES-CD与ADC值为负相关（r=-0.642,P〈0.05）,与强化程度评分（r=0.679,P〈0.05）,肠壁厚度（r=0.573,P〈0.05）、DWI（r=0.568,P〈0.05）和T2WI信号（r=0.500,P〈0.05）评分正相关.采用ADC和DWI信号评分鉴别缓解期和活动期CD的ROC下面积（AUC）分别为0.914、0.904,高于或等效于T2WI信号评分、肠壁厚度评分和强化程度评分的AUC（分别为0.812、0.876和0.928）;ADC值鉴别诊断中重度活动期CD的AUC为0.853,仍高于或等效于DWI信号评分、肠壁厚度评分、T2WI信号评分和强化程度评分的AUC（分别为0.715、0.792、0.762、0.856）.结论 DWI可准确评估回结肠CD的活动性.

Objective To evaluate the diagnostic value of DWI signal intensity （SI） and ADC for inflammatory activity in ileocolonic Crohn disease （CD）. Methods The MR enterography （MRE） and DWI data were retrospectively analyzing in 42 patients with CD confirmed by endoscopic and pathological examination. The segment disease activity was scored by a simplified endoscopic score for Crohn disease （SES-CD） and was graded as inactive （1 to 2）, mild （3 to 6） or moderate-severe inflammation （≥7）. On MRE, wall thickness, contrast enhancement and T2WI SI were scored respectively. On DWI and ADC map, DWI SI was scored and ADC value was measured in bowel wall. The differences in MRE findings scores, DWI SI scores and ADC values among three groups with different activity were analyzed by Kruskal-Wallis test or one-way ANOVA. The efficacy of MRE and DWI for CD activity was evaluated by area under curve （AUC） of ROC analysis. The correlations between MRI findings and SES-CD were analyzed by using Spearman rank correlation. Results One hundred and fourteen bowel segments were enrolled, including inactive （n=15）, mild （n=72）, and moderate-severe （n=27） inflammation. The mean SES-CD was （4.6±2.3） with a range of 1 to 10. There were significant differences in ADC and DWI SI among three groups （all P〈0.01）. Negative correlation of ADC values with SES-CD was shown in total 114 segments （r=-0.642, P〈0.05）, which was similar to that of contrast enhancement scores （r=0.679, P〈0.05） and higher than those of mural thickness （r=0.573, P〈0.05）, DWI SI scores （r=0.568, P〈0.05） and T2WI SI scores （r=0.500, P〈0.05）.The diagnostic accuracy of ADC values （AUC=0.914） and DWI SI （AUC=0.904） to differentiate active from inactive CD was higher or similar to MRE findings （AUC=0.812, 0.876, 0.928, respectively）. Higher or similar accuracy of ADC values （AUC=0.853） for differentiating inactive-mild from moderate-severe CD was also shown when compared with DWI SI scores and MRE findings （AUC=0.715, 0.792, 0.762, 0.856, respectively）. Conclusion DWI enables to accurate evaluate inflammatory activity in ileocolonic CD.