A naked-eye comparison of image quality between a portable versus a fixed camera system for digital flexible...

To assess the image quality using the portable OTV-SI (Olympus, Southend, UK) light source system compared to a dedicated fixed standard stack system for flexible ureterorenoscopy (URS) as judged by the human eye.

We compared two differing flexible URS set-ups. The first was our normal completely digital fixed set-up, comprising a flexible ureteroscope and matching digital stack system (CLV-S40 PRO-6E, Olympus). The second set-up comprised the same digital ureteroscope but with a conventional non-digital stack system and the OTV-SI portable light source. Seven experienced urologists were asked to subjectively assess the quality of the video sequences with the naked eye. The image qualities assessed were as follows: colour, distortion, graininess, depth perception, contrast, and glare. Finally, they were asked to guess whether they were observing images from the normal fixed set-up or the portable set-up. Fisher's exact test was used to compare the two sets of nominal variables.

There were no significant differences in the observation ratings between the fixed and portable systems, independent of observer or image settings. Also, the surgeons were not able to correctly guess which stack system had been used.

For flexible URS imaging, the combination of a digital ureteroscope with a conventional non-digital stack system together with the OTV-SI portable light source was subjectively found not to be inferior to the completely digital fixed set-up. Thus, the cheaper and smaller portable system could be considered as an economical option without substantial loss of image quality, especially useful in developing countries.