MR imaging of the female urethra and supporting ligaments in assessment of urinary incontinence: spectrum of abnormalities.

The traditional methods for evaluation of urinary incontinence in women include urodynamics, cystourethroscopy, cystourethrography, and ultrasonography. Magnetic resonance (MR) imaging has not played a major role in the assessment of women with urinary incontinence. However, high-resolution MR imaging allows detailed visualization of the urethral sphincter and supporting ligaments in women and may contribute to the diagnosis and staging of sphincteric incompetence related to intrinsic sphincter deficiency or urethral hypermobility. Both the anatomy and the function of the female urethra can be depicted on MR images. The spectrum of abnormalities detected at MR imaging in women with stress urinary incontinence are classified as (a) findings related to the urethral sphincter deficiency and (b) defects of the urethral support ligaments and urethral hypermobility. These abnormalities include a small urethral sphincter, funneling at the bladder neck, distortion of the urethral support ligaments, cystocele, an asymmetric pubococcygeus muscle, abnormal shape of the vagina, enlargement of the retropubic space, and an increased vesicourethral angle.