Magnetic Resonance Imaging - A road map for perianal fistulae in comparison with Contrast Fistulography

Abstract

Objective: To assess the complete details of perianal fistulae with the help of MR Imaging in comparison with contrast fistulography. Design: It is an observational and comparative study. Place and duration: This study was carried out in department of diagnostic radiology of Sir Ganga Ram and Masood Hospitals Lahore from January 2000- December 2002. Subject and methods: 15 patients with history of perianal fistulae were included in this study. Contrast fistulography was performed with the help of water soluble contrast medium and these points were noted: 1. Site of external opening, 2. Extension of primary track, 3. Any secondary track, 4. Any evidence of abscess and 5. Position of internal opening. All the patients were advised MR Imaging and again above important points were evaluated in detail. Results: 12 males (80%) and 3 females (20%) were included in our study. Age range was 20 - 60 years and mean age being 42 years. MRI clearly demonstrated fistulae in 12 patients and 3 cases were diagnosed as sinus. But only 4 patients out of 12 identified on fistulography. External opening was visible with MRI as well as with fistulography in all patients. Primary tracks were also seen with both modalities but, in 3 patients length of primary tracks was found to be rather small as compared to MRI which showed complete extension. In only two patients abscesses / cavities were seen with the help of fistulography while on MRI 4 additional cases were identified. In none of patient Park`s classification of fistulae was possible on fistulography instead this was possible only with MRI. Conclusion: MRI is an excellent examination for perianal fistulae. It showed each and every aspect of perianal fistulae which could be essential for excellent management in comparison with fistulography which is rather a invasive procedure, inconvenient for patient, radiation exposure to patient and there could be chance of exacerbation of inflammation.