高分辨率MRI-DWI鉴别肛瘘并发脓肿及炎性肿块的应用价值

Differential Diagnosis of Anal Fistula Complicated with Abscess and Inflammatory Mass by High Resolution MRI-DWI

目的:讨论高分辨率MRI-DWI在鉴别肛瘘并发脓肿及炎性肿块中的应用价值。方法:对2018年6月至2020年12月37例经证实的肛瘘并发的脓肿及炎性肿块患者的临床及影像学资料进行分析,ADC值的测量是将ROI放置在最大可疑区域并记录最低ADC值。结果:37例患者中,肛瘘并发脓肿25例,炎性肿块12例。ADC值在脓肿较炎性肿块低(t=-6.106,P<0.001),ROC曲线下面积为0.953和ADC最佳阈值为1.1305×10^(-3)mm^(2)/s,最佳ADC阈值对脓肿诊断的敏感性、特异性、阳性预测值及阴性预测值分别为100%[95%CI:56%-100%]、83%[95%CI:65%-94%]、58%[95%CI:29%-84%]及100%[95%CI:83%-100%]。高分辨率MRI-T2WI及DWI对瘘管的敏感性分别为90.70%(39/43)及95.35%(41/43)。结论:MRI-DWI对肛周脓肿的诊断敏感性高且有助于鉴别脓肿和炎性肿块,肛瘘在MRI-DWI上较T2WI显示更为清晰。

Objective:To discuss the application of high-resolution MRI-DWI in the differential diagnosis of anal fistula complicated with abscess and infalmmatory mass.Methods:Clinical data and image findings of 37 patients had confirmed anal fistula complicated with abscess and infalmmatory mass were analyzed retrospectively,the measurement of ADC value by placing a region of interest(ROI)in the maximum suspicious area and the lowest ADC value was recorded.Results:Of all 37 patients,anal fistula complicated with abscess and infalmmatory mass were 25 and 12 patients,respectively.ADC values were lower in abscesses than in inflammatory masses(t=-6.106,P<0.001).The area under the ROC curve was 0.953 and the optimal cut-off ADC value was 1.1305×10^(-3)×10^(-3)mm^(2)/s,yielding a sensitivity of 100%[95%CI:56%-100%],a specificity of 83%[95%CI:65%-94%],a positive predictive value of 58%[95%CI:29%-84%]and a negative predictive value of 100%[95%CI:83%-100%]for an abscess diagnosis.The sensitivity of high resolution MRI fat suppression T2 WI and DWI for detecting anal fistula were 90.70%(39/43)and 95.35%(41/43).Conclusion:MRI-DWI shows high sensitivity for the diagnosis of perianal abscesses and helps discriminate between an abscess and inflammatory mass.Conspicuity of fistulas-in-ano is greater with MRI-DWI than with T2-weighted.