Terra Maaike P, Beets-Tan Regina G H, van der Hulst Victor P M, Deutekom Marije, Dijkgraaf Marcel G W, Bossuyt Patrick M M, Dobben Annette C, Baeten Cor G M I, Stoker Jaap
Department of Radiology, Academic Medical Center, Meibergdreef 9, Amsterdam, The Netherlands 1105 AZ.
AJR Am J Roentgenol. 2006 Oct;187(4):991-9. doi: 10.2214/AJR.05.0386.
External anal sphincter atrophy seen at endoanal MRI may predict poor outcome of surgical anal sphincter repair for an external anal sphincter defect. The purposes of this study were to compare external phased-array MRI to endoanal MRI for depicting external anal sphincter atrophy in patients with fecal incontinence and to evaluate observer reproducibility in detecting external anal sphincter atrophy with these techniques.
Thirty patients with fecal incontinence (23 women, seven men; mean age, 58.7 years; age range, 37-78 years) underwent both endoanal and external phased-array MRI. Images were evaluated for external anal sphincter atrophy by three radiologists. Measures of differences and agreement between both MRI techniques and of interobserver and intraobserver agreement of both techniques were calculated.
The MRI techniques did not significantly differ in their ability to depict external anal sphincter atrophy (p = 0.63) with good agreement (kappa = 0.72). Interobserver agreement was moderate (kappa = 0.53-0.56) for endoanal MRI and moderate to good (kappa = 0.55-0.8) for external phased-array MRI. Intraobserver agreement was moderate to very good (kappa = 0.57-0.86) for endoanal MRI and fair to very good (kappa = 0.31-0.86) for external phased-array MRI.
External phased-array MRI is comparable to endoanal MRI in depicting external anal sphincter atrophy and, thereby, in selecting patients for anal sphincter repair. Because results among interpreters varied considerably depending on the experience level, both techniques can be recommended in the diagnostic workup of fecal incontinence only if sufficient experience is available.
肛管内磁共振成像（endoanal MRI）显示的肛门外括约肌萎缩可能预示着肛门外括约肌缺损的手术修复效果不佳。本研究的目的是比较经腹相控阵磁共振成像（external phased - array MRI）与肛管内磁共振成像在描绘大便失禁患者肛门外括约肌萎缩方面的差异，并评估使用这些技术检测肛门外括约肌萎缩时观察者间的可重复性。
30例大便失禁患者（23例女性，7例男性；平均年龄58.7岁；年龄范围37 - 78岁）接受了肛管内和经腹相控阵磁共振成像检查。三名放射科医生对图像进行肛门外括约肌萎缩评估。计算了两种磁共振成像技术之间的差异和一致性测量值，以及两种技术的观察者间和观察者内一致性。
两种磁共振成像技术在描绘肛门外括约肌萎缩的能力上无显著差异（p = 0.63），一致性良好（kappa = 0.72）。肛管内磁共振成像的观察者间一致性为中等（kappa = 0.53 - 0.56），经腹相控阵磁共振成像的观察者间一致性为中等至良好（kappa = 0.55 - 0.8）。肛管内磁共振成像的观察者内一致性为中等至非常好（kappa = 0.57 - 0.86），经腹相控阵磁共振成像的观察者内一致性为一般至非常好（kappa = 0.31 - 0.86）。
经腹相控阵磁共振成像在描绘肛门外括约肌萎缩方面与肛管内磁共振成像相当，因此在选择肛门括约肌修复患者方面也相当。由于不同解释者的结果根据经验水平差异很大，只有在有足够经验的情况下，这两种技术才可以推荐用于大便失禁的诊断检查。
