弥散加权成像在活动期溃疡性结肠炎定量评估中的应用

目的  探究弥散加权成像（DWI）对活动期溃疡性结肠炎（UC）的诊断价值。方法  回顾性分析2018年至今于本院就诊治疗的80例UC患者的临床资料及影像学资料，以肠内镜诊断结果为“金标准”，将患者分为活动组（活动期UC，n=73）和非活动组（非活动期UC，n=7）。所有患者均接受CT、MRI检查，分析两组CT和MRI图像特征、表观弥散系数（ADC）值，采用ROC曲线评估ADC值对活动期UC的诊断价值。结果  MRI检查显示，UC患者以结直肠粘膜及粘膜下层T1WI高信号或稍高信号、T2WI高信或等信号为主要MRI特征，所有病变肠段在DWI上信号不同程度增高。活动组ADC值小于非活动组（P < 0.05）；ROC曲线分析结果显示，ADC值诊断活动期UC的AUC值为0.795（95% CI：0.691~0.878，P < 0.05），具有较高的诊断效能。以肠内镜诊断结果为“金标准”，DWI诊断活动期UC的敏感度、准确率和阴性预测值均高于CT（P < 0.05）。结论  UC的CT、MRI图像具有一定特征，DWI在活动期UC的鉴别诊断中具有良好的应用价值，可作为诊断UC病变时期的有效方法。

Application of diffusion weighted imaging in quantitative evaluation of active ulcerative colitis

  Objective  To investigate the diagnostic value of diffusion weighted imaging (DWI) in active ulcerative colitis (UC).  Methods  The clinical and imaging data of 80 patients with UC who were treated in the hospital from 2018 to the present were retrospectively analyzed. With the diagnostic results of intestinal endoscopy as the golden standard, the patients were divided into active group (UC in active phase, n=73) and inactive group (UC in inactive phase, n=7). All patients underwent CT and MRI examinations. The CT and MRI image features, apparent diffusion coefficient (ADC) values of the two groups were analyzed. ROC curve was used to evaluate the diagnostic value of ADC value in active UC.  Results  MRI findings mainly included colorectal mucosa and submucosa with high signal or slightly higher signal on T1WI, high signal or isointensity on T2WI. All diseased intestinal segments showed different degrees of increased signals on DWI. The ADC value of active group was significantly lower than that of inactive group (P < 0.05). The ROC curve analysis results showed that the AUC value of ADC value for diagnosing active UC was 0.795 (95% CI: 0.691-0.878, P < 0.05), indicating high diagnostic performance. With the diagnostic results of intestinal endoscopy as the golden standard, the sensitivity, accuracy and negative predictive value of DWI for diagnosing active UC were higher than those of CT (P < 0.05).  Conclusion  CT and MRI findings of UC are characteristic. DWI is helpful for differential diagnosis of active UC, and it can be used as an effective method for diagnosing the stage of UC.