DYNAMIC MR DEFECOGRAPHY WITH A SUPERCONDUCTING, OPEN-CONFIGURATION MRSYSTEM

PURPOSE: To evaluate dynamic magnetic resonance (MR) defecography perf ormed with a superconducting, open-configuration system in diagnosis o f defecation disorders. MATERIALS AND METHODS: Five healthy volunteers and 15 patients with defecation disorders were studied with MR defeco graphy performed with a superconducting, open-configuration system; th e patients also underwent fluoroscopic defecography. Before MR imaging , the rectum was filled with 300 mL of mashed potatoes mixed with 1.5 mL of gadopentetate dimeglumine. T1-weighted gradient-echo images were acquired every 2 seconds in the midsagittal plane with the patient at rest, at maximal contraction of the anal sphincter, during straining, and during defecation. RESULTS: MR defecography permitted analysis of the anorectal angle, anal canal, puborectal muscle, and descent of th e pelvic floor. Owing to the high signal intensity of the intraluminal contrast material, the rectal walls were well demonstrated on the MR images, permitting visualization of intussusception nad rectocele. Con comitant demonstration of structures surrounding the anorectal canal w as helpful in assessment of spastic pelvic floor syndrome and descendi ng perineum syndrome. MR defecography was superior to fluoroscopic def ecography and allowed detection of all clinically relevant pathologic conditions except for one. CONCLUSION: Dynamic MR defecography is an a ttractive alternative for evaluation of defecation disorders.