多模态磁共振成像鉴别诊断直肠子宫内膜异位症和直肠癌的价值

Differential Diagnosis of Rectum Endometriosis and Rectal Carcinoma Based on Multimodal Magnetic Resonance Imaging

目的 探讨多模态磁共振成像(MRI)在直肠子宫内膜异位症和直肠癌鉴别诊断中的价值。方法 回顾性分析经临床及病理确诊的16例直肠子宫内膜异位症和18例直肠癌患者的MRI平扫、MRI多期动态增强及弥散加权成像(DWI)图像,对比分析MRI表现,测量基于动态增强的时间-信号强度曲线(TIC)类型、最大对比增强率(MCER),以及基于DWI的表观弥散系数(ADC)和相对表观弥散系数(rADC)。应用受试者工作特征(ROC)曲线、Youden指数和Cohen’s d效应量分析定量指标(MCER、ADC值和rADC值)对直肠子宫内膜异位症与直肠癌的鉴别诊断效能。结果 直肠子宫内膜异位和直肠癌均可表现为肠腔狭窄、肠壁不均匀增厚、周围组织受累等,两者间不同之处为约50%的直肠子宫内膜异位病灶内可见短T_(2)信号及特征性的“蘑菇帽征”和“黏膜下水肿征”。直肠子宫内膜异位症患者TIC最常见的类型为Ⅰ型流入型,而直肠癌患者中最常见的为Ⅱ型平台型。两组病灶MCER值、ADC值、rADC值差异有统计学意义(P<0.001),直肠子宫内膜异位症MCER值低于直肠癌,但ADC值、rADC值高于直肠癌。ADC值显示出最佳的鉴别诊断效能,其次是rADC值和MCER值。结论 多模态MRI的联合应用能够有效鉴别直肠子宫内膜异位症与直肠癌,有助于避免临床误诊。

Objective To explore the application value of multimodal magnetic resonance imaging(MRI)in the differentiation of rectal endometriosis and rectal carcinoma.Methods Sixteen patients with pathologically proven rectal endometriosis and eighteen patients with rectal carcinoma underwent MRI,diffusion weighted imaging(DWI)and dynamic contrast-enhanced MRI,which were retrospectively reviewed.The MR signals,time-signal intensity curve(TIC)type,maximum contrast enhancement ratio(MCER),mean apparent diffusion coefficient(ADC)values,and relative ADC(rADC)values of each case were analyzed and calculated.Receiver operating characteristic(ROC)curve analysis,Cohen’s d effect size,and the Youden index were used to assess the differential diagnostic ability of the quantitative indicators(MCER,ADC,and rADC).Results Both rectal endometriosis and rectal carcinoma showed stenosis of the intestinal lumen,heterogeneous thickening of the intestinal wall,and involvement of adjacent structures.The difference was that short T_(2) signals were seen within almost half of the rectal endometriosis lesions,accompanied by the characteristic“mushroom cap”sign and“submucosal edema”sign.The most common TIC curve was typeⅠin patients with rectal endometriosis,while the majority of the curves were typesⅡin patients with rectal carcinoma.MCER,ADC,and rADC were statistically significantly different between groups(P<0.001).The MCER values of rectal endometriosis were significantly lower than those in rectal carcinoma,but the ADC and rADC values were significantly higher.Among these factors,ADC revealed the most reliable diagnostic performance,followed by rADC and MCER.Conclusion The combination of multimodal MRI could effectively distinguish rectal endometriosis from rectal cancer and help to avoid clinical misdiagnosis.