Dynamic magnetic resonance defecography in 10 asymptomatic volunteers

Abstract

Evaluation of the wide range of normal findings in asymptomatic women undergoing dynamic magnetic resonance (MR) defecography. MR defecography of 10 healthy female volunteers (median age: 31 years) without previous pregnancies or history of surgery were evaluated. The rectum was filled with 180 mL gadolinium ultrasound gel mixture. MR defecography was performed in the supine position. The pelvic floor was visualized with a dynamic T2-weighted sagittal plane where all relevant pelvic floor organs were acquired during defecation. The volunteers were instructed to relax and then to perform straining maneuvers to empty the rectum. The pubococcygeal line (PCGL) was used as the line of reference. The movement of pelvic floor organs was measured as the vertical distance to this reference line. Data were recorded in the resting position as well as during the defecation process with maximal straining. Examinations were performed and evaluated by two experienced abdominal radiologists without knowledge of patient history. Average position of the anorectal junction was located at -5.3 mm at rest and -29.9 mm during straining. The anorectal angle widened significantly from 93° at rest to 109° during defecation. A rectocele was diagnosed in eight out of 10 volunteers showing an average diameter of 25.9 mm. The bladder base was located at a position of +23 mm at rest and descended to -8.1 mm during defecation in relation to the PCGL. The bladder base moved below the PCGL in six out of 10 volunteers, which was formally defined as a cystocele. The uterocervical junction was located at an average level of +43.1 mm at rest and at +7.9 mm during straining. The uterocervical junction of three volunteers fell below the PCGL; described formally as uterocervical prolapse. Based on the range of standard values in asymptomatic volunteers, MR defecography values for pathological changes have to be re-evaluated.