Dynamic MR imaging of the pelvic floor in asymptomatic subjects

OBJECTIVE. Dynamic MR imaging may be used as an alternative to dynamic cyst oproctography for the evaluation of pelvic floor prolapse and configuration . MR criteria for normality are derived from proctographic studies because no large MR study of asymptomatic individuals has been performed. Our study aimed to define the normal range of dynamic pelvic MR appearances in a lar ge group of asymptomatic individuals. SUBJECTS AND METHODS. Fifty healthy adult volunteers (25 men and 25 women; age range, 20-66 years; mean age, 34 years) were prospectively recruited an d examined using dynamic MR imaging. All subjects were interviewed and esta blished as healthy using a validated questionnaire. Axial, coronal, and sag ittal MR imaging was performed at rest and during maximum pelvic strain usi ng a static 1.0-T unit and a fast-field-echo sequence, providing 10 slices in 31 sec. Standardized measurements of pelvic configuration were taken, an d rest and strain imaging were compared to determine the range of normal ap pearances. RESULTS. Three women developed a cystocele during maximum pelvic strain, tw o of whom also showed grade 1 uterocervical prolapse, which was also seen i n another woman. Three men showed posterior pelvic floor descent in excess of 3 cm during straining. No rectocele, enterocele, rectal prolapse, or per ineal hernia was seen in any subject. CONCLUSION. The normal range of pelvic organ descent in asymptomatic subjec ts seen on dynamic MR imaging included cystocele, uterocervical prolapse, a nd excessive anorectal junction descent. Although we encountered pelvic pro lapse in seven volunteers, it was infrequent and low grade, suggesting that criteria for abnormality derived from proctography art generally applicabl e to MR imaging.