Magnetic Resonance Fistulography for the Demonstration of Anovaginal Fistula: An Alternative Imaging Technique? Fatma Bilge Ergen, MD, E. Bengi Arslan, MD, Ulku Kerimoglu, MD, and Deniz Akata, MD Abstract: Anovaginal fistulae (AVF) are frequently seen in patients with inflammatory bowel disease, especially in Crohn disease with active colonic inflammation. Herein, we report a 21-year-old woman with Crohn disease suffering from vaginal discharge and anal pain. Although clinical presentation was very suggestive of AVF, physical examination and colonoscopy were inconclusive. We used an alternative technique and performed magnetic resonance fistulo- graphy by applying rectal contrast for the demonstration of AVF. Key Words: rectovaginal fistula, anovaginal fistula, MRI, phased array coil (J Comput Assist Tomogr 2007;31:243Y246) A novaginal fistulae (AVF) and rectovaginal fistulae (RVF) are epithelial-lined communications between the anus or rectum and the vagina. They account for approximately 5% of all anorectal fistulae 1 and are often results from obstetric and surgical trauma, inflammatory bowel disease, and radiation therapy. 2 The most common cause of AVF is inflammatory bowel disease. Specifically, the rate of perianal fistulae approaches 100% in patients with Crohn disease. 3 Patients with active distal colonic inflammation have the greatest risk for fistula formation. 4,5 Rectovaginal fistulae cause distressing clinical symp- toms, including recurrent vaginitis, vaginal discharge, and passage of flatus and feces through the vagina. Although findings based on patient’s clinical history are helpful for the establishment of the diagnosis, proper evaluation of the course of the fistula and the presence of associated findings are crucial for presurgical evaluation and prevention of possible complications. 6 Currently, magnetic resonance imaging (MRI) has become a promising imaging modality for demonstration of the complex anatomy of the pelvic floor and related structures. Several techniques with phased array or endorectal coils were used, and successful results were achieved with MRI in the demonstration of AVF and RVF. 7Y10 In this report, we performed an alternative MR technique using phased array coil and by applying rectal contrast for the demon- stration of AVF. CASE REPORT A 21-year-old woman who has a history of Crohn disease for a year presented with vaginal discharge and pain around the anus which started 5 months ago. In the later days, she complained of the passage of flatus and stool from the vagina. On physical examination of the anus, there were suspicious internal openings at the 1-o’clock position. The mucosa of the rectum was thickened, and vaginal examination revealed a fistula opening in the left lower third of the vagina. Conventional colonoscopy was planned for the determination of internal opening of the fistula in the rectum and evaluation of the colonic mucosa. There was no fistulous opening in the rectum that can be demonstrated with conventional colonoscopy. Multiple ulcers in the cecum and a vegetative, fragile lesion around the ileocecal valve were seen. Biopsy from these vegetative lesions revealed inflam- matory cellular reaction and lymphoid aggregates suggestive of patchy colitis. The rest of the colonic mucosa was unremarkable. In small-bowel follow through, there were thumbprinting lesions in the terminal ileum that correlates with colonoscopic findings. No fistulous tract was determined in the small bowel. The clinical presentation and physical examination were confirmatory for AVF. For further evaluation of the extent of the disease, endorectal MR examination was planned. The patient has refused endorectal examination because of severe pain in the anal region. Preoperative MRI using phased array coil was performed to define the location and the course of the fistula. Images were acquired with a 1.5 T MR scanner (Siemens, Symphony, Erlangen, Germany). Bowel preparation was not performed. Before the examination, 20 mg/mL hyoscine-n butyl- bromide (Buscopan, Boehringer Ingelheim, Ingelheim, Germany) was administered intravenously to reduce bowel peristalsis. No intra- venous contrast agent was given. Transverse (TR/TE 3500/99, imaging matrix 294 Â 512, slice thickness 3 mm, interslice gap 20%, signal average 4) and sagittal (TR/TE 3630/98, imaging matrix 329 Â 512, slice thickness 4 mm, interslice gap 20%, signal average 3) T2-weighted turbo spin-echo sequences were obtained first and revealed 2 focal hyperintense areas in the 11- and 1-o’clock positions of the distal rectum that are suggestive of internal openings (Fig. 1), but the rest of the fistulous tract cannot be visualized. Afterwards, 30 mL of gadolinium-based rectal enema (5 mL gadoterate meglumine [Dotarem, Guerbet, France] and 25 mL saline) was administrated rectally via a 14-F foley catheter. The catheter was deployed, and the patient was sent for defecation. We aimed to force contrast transition through the fistulous tract by increasing rectal pressure. Before and after defecation, axial 2-dimensional, fat- saturated Fast Low Angle Shot (TR/TE 133/2.8, imaging matrix CASE REPORT J Comput Assist Tomogr & Volume 31, Number 2, March/April 2007 243 From the Department of Radiology, Hacettepe University School of Medicine, Ankara, Turkey. Received for publication June 9, 2006; accepted June 26, 2006. Reprints: Fatma Bilge Ergen, MD, Hacettepe University School of Medicine, Department of Radiology, Adnan Saygun Cad. Sihhiye, Ankara 06100, Turkey (e-mail: bergen@delta-eur.com, bergen@hacettepe.edu.tr). Copyright * 2007 by Lippincott Williams & Wilkins Copyr ight © Lippincott Williams & Wilkins. Unauthor iz ed reproduction of this article is prohibited.