Ultrafast MR imaging of the pelvic floor

OBJECTIVE. The aim of this study was to compare pelvic floor anatomy and la xity at rest and on straining (Valsalva's maneuver) using dynamic ultrafast MR imaging in women who were continent versus those with stress incontinen ce differing in obstetric history. MATERIALS AND METHODS. Thirty continent women were divided into three equal groups (nulliparous. previous cesarean delivery, previous vaginal delivery ) and compared with 10 women with stress-incontinence with a history of at least one vaginal delivery. MR imaging of the pelvic floor at rest and on m aximal strain was performed, using axial T2 weighted fast spin-echo images followed by sagittal ultrafast T2-weighted single-shot fast spin-echo seque nces, Mean population age (age range, 22-45 years: mean +/- SD. 36 +/- 5.4 years), was similar in the four groups, as was parity in the three parous g roups, RESULTS. Mean distances between the bladder floor and pubococcygeal line at rest did not differ between the four groups. On straining, bladder floor d escent was 1.1 +/- 0.9, 1.0 +/- 1.1, and 1.9 +/- 0.9 cm in continent nullip arous, cesarean delivery. and vaginal delivery women, respectively, versus 3.2 +/- 1.0 cm in incontinent women (p = 0.0005). Cervical descent was grea ter in incontinent versus nulliparous women (p = 0.0019). Bladder floor des cent was greater in the continent vaginal delivery group than in continent cesarean delivery control patients (p = 0.04). In patients with stress inco ntinence. symptoms did not correlate with amplitude of descent. The right l evator muscle was thinner overall than the left, regardless of frequency di rection (p = 0,001). CONCLUSION. Ultrafast MR imaging using the T2-weighted single-shot fast spi n-echo sequence allows dynamic evaluation of the pelvic compartments at max imal strain with no need for contrast medium. Pelvic door laxity and suppor ting fascia abnormalities were most common in patients with stress incontin ence followed by continent women with a history of vaginal delivery. The re sults are therefore compatible with the hypothesis of vaginal delivery as a contributory factor to stress incontinence in older parous women.