Diagnostic value of MRI for diabetic perianorectal infection

Objective 　To investigate the diagnostic value of magnetic resonance imaging (MRI) for diabetic perianal lesion. Methods 　Imaging images of 350 patients undergoing anorectal MRI scan for perianal discomfort with a history of diabetes in the Department of Radiology from September 2009 to April 2018 were analyzed retrospectively by two associate chief physicians, and the items recorded and analyzed included perianal inflammation, perianal abscess, hip subcutaneous fat space inflammation and adeno-anal fistula (anorectal fistula typing, main fistula position, location of the main fistula internal opening, number of branch fistula, external fistula conditions, distance from the external opening to the anal vertical line), sinus tract, dynamic enhanced signal change, and the non-adenoid fistula. Results 　Abnormal changes in pelvic floor signal were found in 271(77.43%) of the 350 cases, including anal canal inflammation, thickening of mucosa, vascular enlargement, hemorrhoid formation, perianal abscess, perineal cellulitis or abscess, hip cellulitis or abscess, adeno-anal fistula (Parks type), nonadeno-anal fistula (atypical), or coexistence of the above signs. There were 72(46.45%) cases of labial abscess in females, 17(8.72%) cases of prostate, seminal vesicle or penis abscess in males. There were 227(83.76%) cases of perianal vascular thickening, hemorrhoids or anal canal inflammation, including 162(59.78%) cases of subcutaneous fat space inflammation in the buttocks and 141(52.03%) cases of perianal space abscess. There were 154 cases of anal fistula, of whom 108(70.13%) were simple anal fistula and 46(29.87%) complex anal fistula; 89 main fistulas, 150 branch fistulas and 43 patients had external fistula (detailed findings); There were 92 single internal fistulas, 41 multiple internal fistula and 89 main internal fistulas (specific internal fistula). The image morphology showed that early obvious enhancement of the fistula and internal fistula after dynamic enhancement, the slight high signal of the abscess on diffusion weighted imaging (DWI), significant enhancement of the abscess accompanied by peripheral infection, and delayed enhancement of the fistula wall and opening of fibrous internal fistula. Conclusions 　Perianal infection is very common in diabetic patients. MRI can provide accurate diagnosis of perianal lesions in diabetic patients. DOI: 10.11855/j.issn.0577-7402.2018.09.09