Ex-vivo evaluation of miniaturized probes for endoscopic optical coherence tomography in urothelial cancer diagnostics

BACKGROUND: The gold standard for detecting bladder cancer is white light cystoscopy (WLC) and resection of suspicious lesions. In this study, we evaluate two miniaturized Optical Coherence Tomography (OCT) probes for endoscopic use, regarding their applicability in diagnosing urothelial cancer. MATERIALS AND METHODS: In total, 33 patients who underwent a radical cystectomy were included. Preoperative oncological staging and determining the indication for the surgical intervention were done following the latest European Association of Urology (EAU) guidelines. Samples were taken from bladder tissue after bladder removal and prepared for OCT measurement. Additionally, porcine bladder samples were used as reference tissue. We took measurements using two miniaturized probes: a bimodal probe and a single modality OCT probe. A non-miniaturized standard OCT scanner was used as a reference. RESULTS: Histopathological examination revealed urothelial cancer in all but three patients. Measurements on porcine tissue revealed a clear distinction between the urothelial layers for all probes. Furthermore, we detected improved image quality thanks to the stretching of the tissue. We took 271 measurements in human samples. While the urothelial layers were well delineated in healthy tissue, all the probes revealed a loss of these structures in cancerous regions. While the single-modality probe delivered an image quality equaling the reference images, it was possible to detect cancerous areas with the bimodal probe. CONCLUSION: We demonstrate that endoscopic probes for OCT imaging are technologically feasible and deliver acceptable image quality. A distinction between healthy and abnormal tissue is possible. We propose combining different endoscopic imaging modalities as a promising approach for urothelial cancer diagnostics.