Introduction and hypothesis: To explore the feasibility of three-dimensional (3D) transperineal tomographic ultrasound in evaluating pelvic floor support of the urethra in women.
Methods: Three-dimensional transperineal ultrasound volume data sets of 50 women with stress urinary incontinence (SUI) and 25 women without SUI were obtained for analysis. Pelvic floor support of the urethra was evaluated by studying the relationship between the urethra and vagina in vaginal cross section and quantified by estimating the urethral depression (UD) rate. The extent of paravaginal support at level II was also evaluated in tomographic ultrasound imaging (TUI) mode in all participants. Two-sample t-test and Mann-Whitney U test were used for statistical analysis.
Results: The extent of paravaginal support at level II showed no difference between the two groups. Posterior depression of the urethra into the anterior vaginal wall was increased in SUI (P < 0.05). When the UD rate value was 0.53 (CI 85%) combined with three continuous "abnormal slices," the maximum Youden Index value (sensitivity 0.82, specificity 0.88) was obtained to screen dysfunctional support of the urethra.
Conclusions: The pelvic floor support of the urethra can be evaluated indirectly by studying the relationship between the urethra and anterior vaginal wall in the vaginal cross section by TUI. The obvious posterior depression of the urethra into the anterior vaginal wall could be indirect evidence of a defect in the support of the urethra.
Keywords: Paravaginal support; Pelvic floor; Stress urinary incontinence; Ultrasound; Urethral support.