Purpose: Optical coherence tomography is a new imaging modality capable of imaging luminal surface of biological tissue in the near infrared range with a spatial resolution close to the cellular level. We identified characteristic optical coherence tomography patterns for nonproliferative and proliferative inflammation, and malignant alterations of the bladder.
Materials and methods: Optical coherence tomography was performed to image the bladder of 66 patients. The probe passed through the operating channel of a cystoscope and was pressed onto the mucosal site of interest. A mucosal biopsy of the image site was obtained. Optical coherence tomography was used to construct 680 images of the bladder and the images were compared with histology slides.
Results: Optical coherence tomography images of normal bladder showed 3 layers, namely the mucosa or transitional epithelium, submucosa and smooth muscle. In exudative processes there were poor light scattering areas in the connective tissue layer. Images of bladders with proliferative cystitis revealed nonuniform thickening of the epithelium or hyperplasia. Squamous metaplasia appeared as thicker and less transparent epithelium with a jagged boundary. Images of transitional cell carcinoma were characterized by the complete loss of a regular layered structure of the bladder wall and the penetration depth of optical imaging was slight.
Conclusions: This study provides the characteristic optical coherence tomography pattern of nonproliferative and proliferative inflammation, and the characteristic appearance of severe dysplasia and transitional cell carcinoma. This technique may be useful as a guide for biopsy and for assisting in establishing resection margins.