Comparison of resolution, contrast, and color differentiation among fiberoptic and digital flexible cystoscopes

Advances in electro-optics continue to improve the urologist's ability to perform minimally invasive procedures. While the development of flexible fiberoptic cystoscopes more than 20 years ago greatly impacted the practice of urology, distal-sensor digital technology may represent the next step in the evolution of endoscopy. We compared a new distal-sensor digital flexible cystoscope with two standard fiberoptic flexible cystoscopes.

We evaluated the resolution, contrast, and color discrimination of a new ACMIICN distal-sensor digital cystoscope with >165,000 effective pixels in its clear aperture (viewing area), a new ACMI-ACN II fiberoptic cystoscope with <15,000 pixels in its clear aperture, and a Storz 1127 office fiberoptic cystoscope. Five subjects compared each cystoscope across 13 test parameters.

There was no difference in the performance of the two fiberoptic cystoscopes. The ICN cystoscope was statistically superior to one or both fiberoptic cystoscopes across 12 of the 13 tests, including color differentiation between shades of dark red (P < 0.05), contrast discrimination along a 15-step grayscale gradient (P < 0.001 compared with the 1127 fiberoptic cystoscope only), resolution at 10 mm (7.52 line pairs/mm [lp/mm] (ICN) nu 3.58 lp/mm for both fiberoptic cystoscopes; (P < 0.001), and clear resolution of a 1-mm target at a distance of 6.1 cm (ICN) nu 3.3 cm (1127) and 3.8 cm (ACN II) (P < 0.001).

The ICM distal-sensor all-digital cystoscope was clearly superior to two representative fiberoptic cystoscopes in vitro in terms of resolution, contrast discrimination, and red color differentiation. In-vivo performance remains to be assessed.