Mieke Bus

80 Chapter 5 been discovered if a measurement of the complete upper urinary tract would have been performed. Current grading is obtained by offline analysis using in-house developed software. Incorporation of this software on the OCT console would allow immediate analysis of atten- uation values. The fast acquisition time of the current available endoscopic OCT systems does allow imaging of a 54 mm long segment in 5.4 seconds and visualization of a full 3D dataset can be done immediately after acquisition and makes real time intra-operatively tumor grading and -staging possible. Grading of thin layers using µ oct has not been incor- porated so far because current methods require at least 5-10 data points in depth which accounts for 50-100 µm of layer thickness. Most normal urothelium however, does not have this required thickness. Recently published novel attenuation analysis methods for thin layers by Vermeer et al. could solve this limitation. (18) We recommend a prospective observational study with a long-term follow-up to confirm the cut-off value for UTUC grading using OCT. This study should be conducted strictly according to the STARD initiative criteria and/or IDEAL stages. Since UTUC is rare, preferably this study design should be conducted in a multicenter approach. Conclusion We confirmed the ability of OCT to visualize, grade and stage low, high-grade and CIS lesions in the upper urinary tract. OCT as a diagnostic tool resulted in a sensitivity of 86.7% and specificity of 78.6% for UTUC grading. For UTUC staging, OCT had a sensitivity of 91.7% and a specificity of 78.6%. Project Support This study is funded with a grant provided by the Cure for Cancer foundation and Urology 1973 foundation, which are gratefully acknowledged.