High-resolution magnetic resonance imaging of the anorectal region withoutan endocoil

Background: To evaluate the feasibility of a high-resolution magnetic reson ance imaging (MRI) technique in detailed imaging of the anal sphincter and lower pelvic region without the use of an endoluminal coil. Methods: MRIs with an external phased array coil (T1- and T2-weighted turbo spin echo) were performed in 22 volunteers and 12 patients with an anal fi stula, an anal sphincter defect, or a rectal tumor. The normal scans were e valuated by three independent observers. The scans of the patients were com pared with surgical and/or histologic findings. Results: The anal sphincter was visualized with detail. In the anal canal, hemorrhoidal tissue and the submucosae ani muscle could be seen. The MRI te chnique also allowed detailed imaging of anatomical structures above the pe lvic floor. The MR findings in the 12 patients showed exact correlation wit h surgery and/or histology. Conclusions: High-resolution MRI of the anorectal region without an endolum inal coil is feasible. The MR technique with an external phased array coil allows detailed imaging of the anal sphincter at rest, the rectum, and the surrounding pelvic structures with one single investigation. The results ar e promising and suggest useful applications in the management of anorectal diseases.