Three-dimensional pelvic ultrasound is a practical tool for the assessment of anal fistula

Abstract

ObjectiveThis study aims to investigate the diagnostic value of three-dimensional pelvic ultrasound in the preoperative assessment of anal fistula compared with findings of MRI and surgery.MethodsA total of 67 patients (62 males) with suspected anal fistula were analyzed retrospectively. Preoperative three-dimensional pelvic ultrasound and magnetic resonance imaging were performed in all patients. The number of internal openings and the type of fistula were recorded. The accuracy of three-dimensional pelvic ultrasound was determined by comparing these parameters with surgical outcomes.ResultsAt surgery, 5 (6%) were extrasphincteric, 10 (12%) were suprasphincteric, 11 (14%) were intersphincteric, and 55 (68%) were transsphincteric. There was no significant difference in the accuracy of pelvic 3D US and MRI, based on internal openings (97.92%, 94.79%), anal fistulas (97.01%, 94.03%), and those under Parks classification (97.53%, 93.83%).ConclusionThree-dimensional pelvic ultrasound is a reproducible and accurate method for determining the type of fistula and detecting internal openings and anal fistulas.