Multichannel urethral pressure profiles: reproducibility and three-dimensional representation.

Urethral pressure profilometry (UPP) is used to investigate the pressure distribution in the urethra. Single UPP is dependent on the orientation of the catheter during the study. To circumvent this problem, we developed a system for multichannel profilometry (MCUPP) that can be used in daily clinical practice. In the study reported in this article, 29 healthy female volunteers (mean age 34.6 years) underwent MCUPP. The mean time needed to make five pressure profiles ranged from 4 to 12 minutes (mean 7.6). The system is patient- and user-friendly. The volunteers scored the discomfort on a 1 to 10 scale, with 10 meaning no discomfort at all, rendering a mean score of 7.6. The Symmetry Index (SI) is a calculated variable expressing the asymmetry in the pressure profiles. An SI of 1 means a completely symmetrical pattern of pressure distribution. The mean SI for the whole group was 0.7 (range 0.407-0.930). The standard deviation was 0.109. Within-subject SI was highly reproducible (Greenhouse-Geisser epsilon = 0.98292).

Endoluminal ultrasound of the urethra: a new modality for cross-sectional imaging of the urethra?

Endoluminal ultrasound (ELUS) with high-frequency transducers is a new technique for imaging tubular structures. In combination with a rotating mirror, 360 degrees cross-sectional images of the wall can be obtained. Because of the high frequency, the axial resolution is much higher and thus more detail can be seen. In the study reported in this article, ELUS was performed to image the wall of the female pig urethra to see whether cross-sectional images obtained by ELUS could be correlated with anatomic cross sections of the urethra. Commercially available transducers with a frequency of 30 and 20 MHz were used, the latter having the best suitable frequency for this procedure. The images were of high quality and the different anatomic layers could be clearly visualized. The mucosa/submucosa, the external sphincter, and the surrounding serosa were all identifiable. The correct interpretation was also confirmed by histological cross-section study. We believe that endoluminal ultrasound is a very promising technique for imaging the urethra. Further studies need to be conducted to improve the catheters for urological use and to develop the clinical usefulness of this technique.