Usefulness of Preoperative MRI in Recurrent Anorectal Fistula

ABSTRACT

PURPOSE: To evaluate the usefulness of preoperative MRI in the patient with recurrent anorectal fistula. MATERIALS AND METHODS: Fourteen patients with recurrent anorectal fistula underwent non-contrast MRI. In eight patients, T1-, T2- and proton-weighted images were taken in the axial, coronal and sagittal planes, and T1- andT2-weighted images taken in the axial and coronal planes were obtained from the other six. RESULTS: Fourteen cases of anorectal fistula and eight cases in which there was a combined abscess were detected. Preoperative MRI clearly showed the exact anatomical relationship with the anal sphincter, levator ani and surrounding soft tissue. In two cases in which there was fibrous scarring of the fistula tract, low signal intensities were seen on all MRI sequences. Preoperative information in the group in which only axial and coronal T1- and T2-weighted images were obtained was sufficient. CONCLUSION: Preoperative MRI in patients with recurrent anorectal fistula or suspected multiple fistulous tracts provide objective information concerning the anatomical location and extension of a fistula and combined abscess and could thus reduce the reoperation rate. An understanding of pathologic state through MRI signal intensity can help decide the most appropriate course of treatment.