Quantitative assessment of bladder neck compliance by using transvaginal real-time elastography of women

To assess the feasibility of using ultrasound real-time elastography (RTE) to measure bladder neck compliance, we performed real-time elastography measurements by manually applying repetitive compression with the transducer on the scan position of the bladder neck. Instant elastography index (EI) and mean EI of anterior and posterior lips of the bladder neck were calculated. The EI values of anterior and posterior lips of the bladder neck were analyzed in relation to age, body surface area, body mass index, detrusor wall thickness and length, width and thickness of the bladder neck in healthy women. The intra-observer and inter-observer repeatability of measurements in different parts of the bladder neck were assessed using intra-class correlation coefficients with 95% confidence intervals and Bland-Altman analysis. There were no statistically significant differences between elastography measurements made by the same or two different observers in each area measured. There was no significant difference between anterior and posterior lip thickness of the bladder neck. The distribution of the elastography measurements indicated that the anterior lip of the bladder neck was slightly harder than the posterior lip. On the whole, from the results of the study, it was clear that EIs of the bladder neck were related to age in healthy women. Stepwise multiple regression analysis results revealed that age was the only independent factor modulating compliance of the bladder neck in healthy women. It is possible to provide a reproducible semi-quantification of real-time elastography in bladder neck compliance.