Anatomical assessment of the bladder outlet and proximal urethra using ultrasound and videocystourethrography

In a prospective blinded comparative clinical study 125 women underwent videocystourethrography and cystometry as well as transperineal ultrasound as part of their diagnostic work-up for urinary incontinence or after incontinence-correcting surgery. Comparisons between ultrasound and X-ray imaging were carried out on 117 women for whom complete data sets were available. Mean bladder neck descent was significantly greater with ultrasound compared to VCU (US: 2.1 +/- 1.2 cm vs. VCU: 1.8 +/- 0.9; P = 0.003). Rotation of the proximal urethra was not always seen on X-ray, but when it was (44 patients) there was good correlation with US (US rotation 55 +/- 27 degrees vs. VCU rotation 55 degrees +/- 29). There was also good agreement between both tests regarding visualization of funneling or opening of the proximal urethra, with both tests showing equivalent results in 95 out of 117 patients (Cohen's kappa 0.58). On comparing extensive funneling to the midurethra on US with frank leakage on VCU the methods were in agreement for 90 out of 117 patients (kappa 0.54). Overall a good correlation between ultrasound and radiological findings was observed. Both methods allow anatomic assessment of the bladder neck and have different strengths and weaknesses. Ultrasound imaging may be preferable as it is cheaper, requires less technological back-up and avoids the risks of radiation exposure and allergic reactions to contrast medium.