Colour Doppler ultrasonography of female urethral vascularization in normal young volunteers: a preliminary report

OBJECTIVE: To assess urethral vascularization in healthy young women, using colour Doppler ultrasonography. SUBJECTS AND METHODS: Eleven healthy young women volunteers (mean age 33.6 years, range 24-46) with no pelvic floor disorders and no history of incontinence were assessed. The subjects underwent colour Doppler ultrasonography using a 4-7 MHz convex broadband transducer. Translabial sagittal scans of the urethra were taken when the subjects had a full bladder, both during the oestrogenic and progestogenic phases. The colour Doppler ultrasonography parameters were optimized to detect slow flows in the anterior and posterior distal, middle and proximal urethra. A rank-sum nonparametric test was used to assess differences between the resistive indices. RESULTS: The statistical evaluation showed a significant difference in the resistive index only in the anterior urethra, between the distal and middle plus proximal urethra, in both the progestogenic (P = 0.002) and oestrogenic (P = 0.0127) phases. CONCLUSIONS: This study confirmed that the vascularization of the urethra plays an important role in the 'seal' effect, which is considered one of the most important factors in urethral closure. There was a significantly greater resistive index in the anterior proximal urethra than in the middle and distal urethra. These findings suggest that the seal effect is related to the existence of a rich venous urethral vascularization, involved in the mechanism of urethral closure. Colour Doppler ultrasonography of the urethra seems to be feasible and useful for understanding the mechanism of the vascular component in female continence.