Dynamic Magnetic Resonance Imaging of the Behavior of the Mid-Urethra in Healthy and Stress Incontinent Women

Abstract

ABSTRACT

Previous studies have shown that the new minimally invasive mid-urethral tape procedures are as effective or even more effective in curing female stress urinary incontinence (SUI) than the traditional methods. An essential mechanism involved in maintenance of continence in the female is believed to be sufficient support of the middle portion of the urethra (mid-urethra). Dynamic magnetic resonance imaging (MRI) has been used to assess the function of the pelvic floor organs among both continent and incontinent women.

This prospective study compared the behavior of the mid-urethra in 40 women with SUI and in 15 healthy continent volunteers analyzed with dynamic MRI. All participants underwent dynamic MRI at rest and during coughing, voiding, and pelvic floor muscle contraction and had a bladder volume of 200 mL at assessment. The precise coordinate location and movement of the mid-urethra was determined.

Dynamic MRI showed that the continent volunteers were able to elevate their mid-urethra significantly higher than the SUI women (P = 0.002). Moreover, during straining and coughing, the mid-urethra in SUI women rotated significantly more downward compared to the continent healthy volunteers (P = 0.002).

These findings suggest that elevation of the mid-urethra may provide better support and may be indicative of continence, whereas downward rotation of the mid-urethra may be indicative of SUI.