MR-IMAGING OF PELVIC FLOOR CONTINENCE MECHANISMS IN THE SUPINE AND SITTING POSITIONS

OBJECTIVE. Our goal was to determine the anatomic differences in pelvi c floor anatomy for continent women and women with stress incontinence using MR imaging and to assess whether these anatomic differences dep end on the position of the subject during imaging. SUBJECTS AND METHOD S. Eight continent volunteers and eight women with stress incontinence underwent MR imaging in the supine and sitting positions. For imaging , we used an open-configuration 0.5-T magnet. T2-weighted images were obtained in the midline sagittal plane with subjects at rest and at ma ximal pelvic floor strain in 5 sec using a modified fast spin-echo seq uence. In the axial plane, thin-section T2-weighted images were obtain ed with subjects at rest using a standard fast spin-echo technique. Im ages were evaluated for mobility of the urethra and bladder neck and f or integrity of the vagina, levator ani, and supporting fascia, RESULT S. Pelvic floor laxity and abnormalities of the supporting fascia were more common in incontinent women than in continent women. Both descen t of the bladder neck when subjects strained and the posterior urethro vesical angle were not significantly greater when subjects were measur ed in the sitting position (p < .1), CONCLUSION. Changes of pelvic flo or laxity related to incontinence can be seen with subjects in both th e supine and the sitting positions but are increased in the sitting po sition.