Presented by: Jia-Lun Kwok MBBS, FRCS(Urol)(Glasg)
Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland ; Department of Urology, Tan Tock Seng Hospital Singapore, Singapore

Introduction

Imaging properties of flexible ureteroscopes have been extensively evaluated – mostly in air. No study to date evaluated the effects of varying brightness settings on image quality from ureteroscopes submerged in saline. The aim of the study was to evaluate blackout and whiteout occurrences in an in-vitro kidney model.

Materials

We evaluated a series of contemporary flexible ureteroscopes including the Storz Flex-Xc and Flex-X2s, Olympus V3 and P7, Pusen 7.5F and 9.2F, as well as OTU Wiscope using a 3D printed pink in-vitro kidney model consisting of a closed spherical cavity with 20mm diameter submerged in saline. Endoscopic images were captured with the tip of the ureteroscope at 5mm,10mm and 20mm distance from the inner surface of the sphere – mimicking situations frequently found in clinical routine. The complete range of brightness settings and video capture modes were evaluated for each scope – where available. Images were analysed for their histogram on the distribution of brightness values (scale range 0 to 255). Blackout and whiteout were defined as median histogram ranges from 0 to 30 and 225 to 255, respectively (image on monitor too dark or too bright for the human eye, respectively).

Results

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Blackout occurred with the P7, Pusen 7.5F and WiScope at all evaluated distance settings – mostly with lowest brightness settings. Whiteout occurred with the Flex-X2s, V3 and P7 at 5mm and 10mm distance, as well as with the V3 and P7 for the 20mm distance setting – mostly with highest brightness settings. Scopes that had neither blackout nor whiteout over all brightness settings and video capture modes were the Flex-Xc and Pusen 9.2F at 5mm and at 10mm, as well as the Flex-Xc, Flex-X2s and Pusen 9.2F at 20mm distance.

Conclusion

Blackout or whiteout of images is an undesirable property that was found for several scopes, possibly impacting diagnostic and therapeutic purposes during ureteroscopy. These observations form a guide for urologists which may impact their choice of instruments and corresponding settings.

Funding

None

Co-Authors

Vincent De Coninck, MD, FEBU
Department of Urology, AZ Klina, Brasschaat, Belgium ; Young Academic Urologists (YAU), Endourology & Urolithiasis Working Group, Arnhem, The Netherlands ; Progressive Endourological Association for Research and Leading Solutions (PEARLS)

Hatem Kamkoum, MD
Hamad Medical Corporation, Doha, Qatar ; Progressive Endourological Association for Research and Leading Solutions (PEARLS)

Felipe Pauchard, MD
Urology Department, Hospital Naval Almirante Nef, Viña del Mar 2520000, Chile ; Progressive Endourological Association for Research and Leading Solutions (PEARLS)

Anil Shrestha, MD
Department of Urology, National Academy of Medical Sciences, Bir Hospital and B&B Hospital, Gwarko Lalitpur, Nepal ; Progressive Endourological Association for Research and Leading Solutions (PEARLS)

Vineet Gauhar, MD
Department of Urology, Ng Teng Fong General Hospital, Singapore, Singapore; Progressive Endourological Association for Research and Leading Solutions (PEARLS)

Jan Brachlow, MD
Zentrum für Urologie Winterthur, Winterthur, Switzerland ; Progressive Endourological Association for Research and Leading Solutions (PEARLS)

Florian Schmid, MD, FEBU
Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland

Manuela Hunziker, MD, FEBU
Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland

Cédric Poyet, MD, FEBU
Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland

Olivier Traxer, MD
Sorbonne Université, GRC n°20, Groupe de Recherche Clinique sur la Lithiase Urinaire, Hôpital Tenon, F-75020 Paris, France ; Progressive Endourological Association for Research and Leading Solutions (PEARLS)

Daniel Eberli, MD, FEBU
Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland

Etienne Xavier Keller, MD, FEBU
Department of Urology, University Hospital Zurich, University of Zurich, Zurich, Switzerland ; Young Academic Urologists (YAU), Endourology & Urolithiasis Working Group, Arnhem, The Netherlands ; Progressive Endourological Association for Research and Leading Solutions (PEARLS)