In vivo Raman spectroscopy for bladder cancer detection using a superficial Raman probe compared to a nonsuperficial Raman probe.

Raman spectroscopy is promising as a noninvasive tool for cancer diagnosis. A superficial Raman probe might improve the classification of bladder cancer, because information is gained solely from the diseased tissue and irrelevant information from deeper layers is omitted. We compared Raman measurements of a superficial to a nonsuperficial probe, in bladder cancer diagnosis. Two-hundred sixteen Raman measurements and biopsies were taken in vivo from at least one suspicious and one unsuspicious bladder location in 104 patients. A Raman classification model was constructed based on histopathology, using a principal-component fed linear-discriminant-analysis and leave-one-person-out cross-validation. The diagnostic ability measured in area under the receiver operating characteristics curve was 0.95 and 0.80, the sensitivity was 90% and 85% and the specificity was 87% and 88% for the superficial and the nonsuperficial probe, respectively. We found inflammation to be a confounder and additionally we found a gradual transition from benign to low-grade to high-grade urothelial carcinoma. Raman spectroscopy provides additional information to histopathology and the diagnostic value using a superficial probe.

Clinical superficial Raman probe aimed for epithelial tumor detection: Phantom model results.

A novel clinical Raman probe for sampling superficial tissue to improve in vivo detection of epithelial malignancies is compared to a non-superficial probe regarding depth response function and signal-to-noise ratio. Depth response measurements were performed in a phantom tissue model consisting of a polyethylene terephthalate disc in an 20%-Intralipid(®) solution. Sampling ranges of 0-200 and 0-300 µm were obtained for the superficial and non-superficial probe, respectively. The mean signal-to-noise ratio of the superficial probe increased by a factor of 2 compared with the non-superficial probe. This newly developed superficial Raman probe is expected to improve epithelial cancer detection in vivo.

Real-time bladder lesion registration and navigation: a phantom study.

BACKGROUND: Bladder cancer is the fourth most common malignancy in men, with a recurrence rate of 33-64%. Tumor documentation during cystoscopy of the bladder is suboptimal and might play a role in these high recurrence rates. OBJECTIVE: In this project, a bladder registration and navigation system was developed to improve bladder tumor documentation and consequently increase reproducibility of the cystoscopy. MATERIALS/METHODS: The bladder registration and navigation system consists of a stereo-tracker that tracks the location of a newly developed target, which is attached to the endoscope during cystoscopy. With this information the urology registration and navigation software is able to register the 3D position of a lesion of interest. Simultaneously, the endoscopic image is captured in order to combine it with this 3D position. To enable navigation, navigational cues are displayed on the monitor, which subsequently direct the cystoscopist to the previously registered lesion. To test the system, a rigid and a flexible bladder phantom was developed. The system's robustness was tested by measuring the accuracy of registering and navigating the lesions. Different calibration procedures were compared. It was also tested whether system accuracy is limited by using a previously saved calibration, to avoid surgical delay due to calibration. Urological application was tested by comparing a rotational camera (fixed to the rotating endoscope) to a non-rotational camera (dangling by gravity) used in standard urologic practice. Finally, the influence of volume differences on registering and navigating was tested. RESULTS/CONCLUSION: The bladder registration and navigation system has an acceptable accuracy for bladder lesion registration and navigation. Limitations for patient determinants included changes in bladder volume and bladder deformation. In vivo studies are required to measure the effect of these limitations and functionality in urological practice as a tool to increase reproducibility of the cystoscopy.