SPECTROSCOPIC MEASUREMENT OF DIFFUSE-REFLECTANCE FOR ENHANCED DETECTION OF BLADDER-CARCINOMA

Objectives. To assess the diagnostic potential of diffuse reflectance spectroscopy for the detection of bladder carcinoma during cystoscopy. Our hypothesis is that neovasculature in neoplastic (dysplastic and m alignant) regions will lead to a blood absorption ''signature'' that i s different from that of normal tissue. Methods. Diffuse reflectance m easurements have been performed in 14 patients undergoing mucosal biop sies or transurethral resection of a bladder tumor. A quartz optical f iber was advanced through the working channel of a cystoscope and plac ed in gentle contact with the bladder surface. A standard cystoscopy x enon light source was used for illumination and the reflectance spectr a were recorded using an optical multichannel analyzer (OMA) system. F rom the spectra, the relative concentrations of hemoglobin (Hb), oxyhe moglobin (HbO(2)), oxygen saturation (HbO(2)%), and the total amount o f blood (arbitrary units) were calculated to assess their usefulness i n differentiating between neoplastic and benign bladder areas. Results . The spectra of 26 bladder areas (9 malignant areas including 4 carci nomata in situ, 2 dysplastic lesions, and 15 benign areas) have been a nalyzed. Only the total amount of blood was a useful parameter for the differentiation between neoplastic and benign bladder areas. The sens itivity, specificity, and positive and negative predictive values of t his method for neoplastic tissue were found to be 91%, 60%, 63%, and 9 0%, respectively. Conclusions. The measurement of diffuse reflectance is a fast, simple, and noninvasive method which allows in vivo determi nation of bladder blood perfusion. The total blood concentration was i ncreased in neoplastic bladder tissue, making it a tool for tissue dia gnosis. The relatively low specificity is a result of inflammatory are as also exhibiting an increased total blood concentration. This pilot study encourages further studies to assess the usefulness of reflectan ce measurements for enhanced detection of bladder cancer. (C) 1998, El sevier Science Inc. All rights reserved.