Can Stress Urinary Incontinence Be Predicted by Ultrasound?

OBJECTIVE. The purpose of this study is to determine the value of translabial real-time 3D ultrasound for predicting stress urinary incontinence (SUI). SUBJECTS AND METHODS. From December 2012 to August 2016, women with or without SUI diagnosed by urologists via urodynamics were prospectively recruited. All subjects underwent translabial real-time 3D ultrasound at one institution. Volume data were analyzed offline by a radiologist who was blinded to the diagnosis and who evaluated the bladder neck position on maximal Valsalva maneuver, the levator hiatus area on maximum Valsalva maneuver, bladder neck descent, and the urethral rotation angle. Combinations of two, three, and four parameters were analyzed using Fisher linear discriminant analysis. ROC curves were constructed to determine the optimal cutoff values of the four parameters and all combinations of parameters to predict SUI. RESULTS. A total of 321 women with SUI (mean [± SD] age, 35 ± 11 years) and 90 women without SUI (mean age, 31 ± 8 years) were included. Only 337 women were included in the final study, to eliminate the confounder of age. The cutoff values for the bladder neck position on maximal Valsalva maneuver, the levator hiatus area on maximum Valsalva maneuver, bladder neck descent, and the urethral rotation angle as parameters predicting SUI were 1 mm, 19 cm², 24 mm, and 45°, respectively. For all combinations of parameters, the negative predictive values were more than 90%, although none of the combinations had a sensitivity higher than 70%. The specificities were approximately 95% when three or four parameters were included. The positive predictive value of the combinations ranged from 49.2% to 84.8%. CONCLUSION. Translabial real-time 3D ultrasound is insufficient for predicting SUI, but it can be used to identify women without the condition.