Evaluation of superficial bladder transitional-cell carcinoma by optical coherence tomography

Optical coherence tomography (OCT) is a new modality that allows noninvasive examination of the internal structure of biological tissue in vivo with a spatial resolution of 10 to 15 microm. This study evaluated the clinical application of OCT to determine epithelial and subepithelial anatomic structure and invasiveness of bladder epithelial lesions.

The OCT examination was performed with a 980-nm 10 mW superluminescent diode using a 2.7-mm-diameter optical fiber positioned cystoscopically. A total of 261 scans of 1.5 seconds' duration, which generated 200 x 200-pixel images, were performed on 87 areas in 24 patients at high risk of having transitional-cell carcinoma (TCC). Lesions, visually suspect, and normal areas were photographed, scanned, and biopsied. The scans were evaluated independently before comparison with histopathology findings.

Of the 87 areas, 29 of 36 visually suspect areas and 35 of 35 normal areas, were correctly diagnosed with OCT. Of the 16 areas with papillary TCC, all 16 were diagnosed correctly as tumor, and 9 of 10 were diagnosed correctly as invasive, including 6 with lamina propria invasion only. Papillary and flat tumors, carcinoma in situ, inflammation, chronic cystitis, and von Brunn's nests were scanned. Overall, OCT had a sensitivity of 100%, overall specificity of 89%, positive predictive value of 75%, and negative predictive value of 100%. The accuracy was 92%. The positive predictive value for invasion was 90%.

Optical coherence tomography is a simple, portable, promising modality for evaluation of bladder lesions and depth of tumor penetration. Further refinement of this technology may lead to the development of an optical surrogate for biopsy.