磁化传递成像与扩散加权成像对克罗恩病肠壁性质的诊断价值

Diagnostic value of magnetized transfer imaging and diffusion-weighted imaging in the evaluation of bowel wall in Crohn disease

目的：探讨磁化传递成像（MTI）以及DWI对克罗恩病（CD）肠壁性质的诊断价值。方法前瞻性收集临床诊断为CD的44例患者，行MR肠道成像（MRE）平扫及增强扫描、MTI和DWI检查。根据MRE征象将患者分为急性炎症组、慢性纤维化组、炎症＋纤维化组。分别在MRE、MTI和DWI图像上进行肠壁T2WI信号评分、测量肠壁磁化传递率（MTR）和ADC值。采用单因素方差分析比较各组间MTR值及ADC值差异，采用秩和检验分析各组间T2WI评分的差异，采用配对t检验比较正常和病变肠壁MTR值及ADC值的差异，采用Spearman秩相关分析评价病变肠壁MTR值及ADC值与T2WI评分的相关性；以MRE征象为参考标准，采用ROC曲线评价MTI、DWI鉴别诊断CD肠壁纤维化和炎症的效能。结果44例中，急性炎症组11例、慢性纤维化组18例、炎症＋纤维化组15例。3组间肠壁T2WI信号评分、病变肠壁MTR值和ADC值差异均有统计学意义（P均＜0.01）。44例CD患者病变肠壁的MTR值和ADC值分别为（40.77±6.05）%、（1.04±0.18）×10-3mm2/s，邻近正常肠壁分别为（21.75±4.17）%、（1.97±0.23）×10-3mm2/s，差异均有统计学意义（t值分别为19.12、－21.80，P均＜0.01）。病变肠壁MTR值与T2WI评分呈负相关（r=－0.71，P＜0.01），ADC值与T2WI评分呈正相关（r=0.80，P＜0.01）。采用MTR值和ADC值鉴别CD肠壁急性炎症与纤维化的ROC下面积分别为0.97和0.96。结论 MTI和DWI均可用于评估CD肠壁性质，二者鉴别CD肠壁急性炎症与纤维化的效能相当。

Objective To explore the diagnostic value of magnetization transfer imaging （MTI） and DWI for detecting intestinal wall property of crohn＇s disease （CD）. Methods Forty four patients with CD were prospectively enrolled in the study, and MR enterography （MRE）, MTI and DWI were performed. According to MRE findings, patients were divided into three subgroups：acute inflammatory group, chronic fibrotic group and combined inflammatory with fibrotic group. Intestinal wall T2WI signal, magnetization transmisson rate （MTR） and ADC value were measured on MRE, MRI and DWI imagings, respectively. The differences of MTR and ADC among the three groups were analyzed by one-way ANOVA;the differences of T2WI scores were analysed by Kruskal Wallis;the differences of MTR and ADC values between normal and pathological intestinal wall were analyzed by paired t test;ROC curve were used to evaluate the CD fibrosis and inflammation diagnostic efficiency of MTI ana DWI based on MRE signs. Results Among the 44 cases, 11 cases were in the acute inflammatory group, 18 cases were in the chronic fibrotic group and other 15 cases were in the combination group. The T2WI score, MTR and ADC among the three groups showed significant differences （all P〈0.01）.The mean MTR and ADC of pathological intestinal wall of the 44 cases were （40.77±6.05）%and （1.04±0.18）× 10-3mm2/s, and the adjacent normal bowel were （21.75±4.17）%and （1.97 ± 0.23） × 10- 3mm2/s, respectively. Moreover, the difference of the above values showed significant differences （t=19.12,-21.80 respectively, all P〈0.01）. There was a negative correlation between MTR and T2WI score （r=-0.71,P〈0.01）. While ADC value was positively correlated with T2WI score （r=0.80, P〈0.01）. Using ROC curve analysis to differentiate the CD fibrosis from acute inflammation, the area under the curve （AUC） of MTR and ADC were 0.97 and 0.96 ,respectively. Conclusions Both MTI and DWI can be used to assess the properties of intestinal wall, which has the same diagnostic efficacy to identify the acute inflammation and fibrosis.