Acquisition of fluorescence and reflectance spectra during routine bronchoscopy examinations using the ClearVu Elite...

Fluorescence flexible bronchoscopy (FFB) has proved to be very useful for detecting carcinoma in situ (CIS) and pre-cancerous lesions of the lung that are generally occult to white light reflectance bronchoscopy (WLRB). However, the increased sensitivity has caused a significant decrease of specificity, resulting in a large number of false positive signals that lead to a significant number of unnecessary biopsies. We have been planning to test a hypothesis that reflectance spectra and fluorescence spectra could be used to distinguish the true positive lesions from the false positive ones. To properly test such hypothesis, several thousand patients will need to be examined to obtain sufficient data from different lung lesions. Towards this goal, we have developed and have been testing a special system (ClearVu Elite ) that facilitates acquisition of both WLRB and FFB spectra during routine bronchoscopy examinations. In this pilot study we examined (1) if such could be used in a practical, routine clinical conditions without affecting commonly used bronchoscopy procedures; (2) if the spectral data obtained from the images are identical to those obtained with fiber-optic probes; and (3) if the few malignant and early neoplastic lesions available for this pilot study show any differences from normal lung tissue.

The study population consisted of 63 patients that were suspicious for presence of lung cancer (19 female and 44 male, smokers and non-smokers). All were examined by diagnostic bronchoscopy using ClearVu Elite during a period of 8 weeks.

The experimental system provides excellent real time WLRB and FFB that can be switched from one to another mode instantaneously. Acquisition of both white light reflectance spectra and fluorescence spectra is acquired in real time through the images and does not prolong the routine WLRB and FFB procedures. The experimental bronchoscopy procedure is as simple as conventional bronchoscopy, adding on average less than 5 min to the 20 min procedure. The acquired spectra are identical to those obtained by fiber-optic probes. In all of the limited number of malignant and early neoplastic lesions, there were differences found which are sufficiently pronounced to warrant initiation of a large, multicenter study for development of differentiating algorithms of statistical validity.