Objective This 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. Methods A 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. Results At 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%). Conclusion Three-dimensional pelvic ultrasound is a reproducible and accurate method for determining the type of fistula and detecting internal openings and anal fistulas.

Objective In this study, we investigated the diagnostic value of pelvic floor three-dimensional ultrasound for anal fistula. Methods Sixty-seven patients (62 males) with anal fistula were included in the study. All patients underwent pelvic floor three-dimensional ultrasound and magnetic resonance imaging before the operation.. The type of fistula and the number of internal openings were documented. These parameters were compared with the postoperative outcomes. Results At surgery, 11(14%) were intersphincteric, 55(68%) transsphincteric, 10(12%) suprasphincteric and 5(6%) extrasphincteric. There were no significant differences(P > 0.05) in the accuracy rates of pelvic three-dimensional ultrasound and MRI, in terms of anal fistulas (97.01%, 94.03%), internal openings (97.92%, 94.79%) and those under Parks classification (97.53%, 93.83%). Conclusion Three-dimensional pelvic floor ultrasound is an accurate and reproducible method for detecting anal fistulas and internal openings, as well as determining the type of fistula.