Fluorescence guided optical coherence tomography for the diagnosis of early bladder cancer in a rat model

Purpose: We describe the technique of fluorescence image guided optical coherence tomography (FG-OCT). We examined its ability to enhance specificity and sensitivity for the noninvasive diagnosis of early bladder cancer. Materials and Methods: Transitional cell carcinoma was developed in 54 Fisher 344 female rats by intravesical methyl-nitroso-urea instillations. Two or three rats were diagnosed sequentially by 5-ALA (5-aminolevulinic acid hydrochloride) induced fluorescence imaging, cross-sectional OCT and histological microscopy weekly during weeks 11 to 33 following initial methyl-nitroso-urea instillation to track the course of carcinogenesis. Results: The specificity of fluorescence detection was significantly enhanced by FG-OCT (53% and 93%, respectively, p <0.0001). The sensitivity of fluorescence detection and FG-OCT was 79% and 100%, respectively. Conclusions: FG-OCT cystoscopy has the potential to diagnose early bladder cancer with high sensitivity and specificity with drastically decreased imaging time compared to that of white light guided OCT cystoscopy.