Diffusion‐weighted MRI: Role in detecting abdominopelvic internal fistulas and sinus tracts

Abstract

To retrospectively determine the incremental value of diffusion-weighted MR-imaging (DW-MRI) to T2-weighted (T2w) images in diagnosis of internal fistulas (IFs) and sinus tracts (STs). Fourteen patients with 25 IFs and STs arising from the small bowel (20), colon (4) and biliary tract (1) were included. Two independent observers reviewed T2w images, T2w+DW-MRI images and T2w+contrast enhanced T1-weighted (CE T1w) images at three sessions to detect IF/ST based on a confidence scale of five. Sensitivity and confidence score of each session was compared. 10/25 (40%) and 9/25 (36%) IFs and STs were detected on T2w images by observer 1 and 2, respectively. Both observers detected 19/25 (76%) and 24/25(96%) IFs and STs on T2w+DW-MRI and T2w+CE T1w images, respectively. Detection rate and confidence score improved significantly by combining T2w images with DW-MRI or CE T1w images (reader 1 + 2: P ≤ 0.01). There was no significant difference between the IF/ST detection rate of T2w+DW-MRI and T2w+CE T1 image combinations. Confidence scores with T2w+CE T1w images were significantly greater than DW-MRI+T2w images (reader 1:P = 0.01; reader 2: P = 0.03). DW-MRI showed additional value to T2w imaging for diagnosis of IF and ST. DW-MRI can be a useful adjunct, especially for patients with renal failure.