Probe-based confocal laser endomicroscopy (pCLE) is an emerging technology for in vivo optical imaging of the urinary
tract. Particularly for bladder cancer, real time optical biopsy of suspected lesions will likely lead to improved
management of bladder cancer. With pCLE, micron scale resolution is achieved with sterilizable imaging probes (1.4 or
2.6 mm diameter), which are compatible with standard cystoscopes and resectoscopes. Based on our initial experience
to date (n = 66 patients), we have demonstrated the safety profile of intravesical fluorescein administration and
established objective diagnostic criteria to differentiate between normal, benign, and neoplastic urothelium. Confocal
images of normal bladder showed organized layers of umbrella cells, intermediate cells, and lamina propria. Low grade
bladder cancer is characterized by densely packed monomorphic cells with central fibrovascular cores, whereas high
grade cancer consists of highly disorganized microarchitecture and pleomorphic cells with indistinct cell borders.
Currently, we are conducting a diagnostic accuracy study of pCLE for bladder cancer diagnosis. Patients scheduled to
undergo transurethral resection of bladder tumor are recruited. Patients undergo first white light cystocopy (WLC),
followed by pCLE, and finally histologic confirmation of the resected tissues. The diagnostic accuracy is determined
both in real time by the operative surgeon and offline after additional image processing. Using histology as the standard,
the sensitivity, specificity, positive and negative predictive value of WLC and WLC + pCLE are calculated. With
additional validation, pCLE may prove to be a valuable adjunct to WLC for real time diagnosis of bladder cancer.