Association between urethral funneling in stress urinary incontinence and the biological properties of the urethral rhabdosphincter muscle based on shear wave elastography.

OBJECTIVES: To apply shear wave elastography (SWE) combined with transperineal ultrasonography (TPUS) to study the association between urethral funneling in stress urinary incontinence (SUI) and the biological properties of the urethral rhabdosphincter muscle in women. METHODS: This single-center retrospective study included 166 women with SUI (SUI group) and 185 women who underwent a routine physical examination (control group). The control group and SUI group were divided into nonfunneling and funneling groups according to the presence or absence of urethral funneling, respectively, and their ultrasound findings were compared to analyze the association between funneling and ultrasound measurements. RESULTS: The SUI group had a lower mean E than the control group (15.54 vs. 20.82 kPa, p < 0.001). The SUI-funneling group had a lower mean E than the SUI-nonfunneling group (15.50 vs. 17.21 kPa, p < 0.001). The area under the (AUC) receiver operating characteristic (ROC) curve of the mean E for predicting SUI was 0.864, with a cutoff value of 19.19 kPa. The AUC of the mean E for predicting urethral funneling was 0.832, with a cutoff value of 17.15 kPa. The stiffness of the urethral rhabdosphincter was an independent factor related to SUI and urethral funneling in SUI. CONCLUSIONS: SWE can be used to assess the biological properties of the urethral rhabdosphincter, and reduced stiffness of the rhabdosphincter was significantly correlated with SUI and funneling in SUI. Thus, women with urethral funneling in SUI may have a weak urethral rhabdosphincter.