SG179311A1 - Methods and apparatus relating to integrated nir fluorescence and reflectance imaging and spectroscopy with polarization for improving tissue diagnosis and characterization - Google Patents

Abstract

Methods and apparatus relating to integrated NIR fluorescence and reflectanceimaging and spectroscopy with polarization for improving tissue diagnosis andcharacterizationAbstractWe report on the development of the near-infrared (NIR) autofluorescence (AF)spectroscopy technique for in vivo identification of neoplastic polyps in the colon atcolonoscopy. In vivo NIR AF spectra from colonic tissue can be acquired within 1 secondusing the 785 nm laser excitation power of 1.0 W/cm2. Significant differences in in vivoNIR AF spectra are observed among normal (n=116), hyperplastic polyp (n=48) andadenomatous polyp (n=34) colonic tissue from 96 patients. The multivariate analysis [i.e.,principal components analysis (PCA) and linear discriminate analysis (LDA)], togetherwith the leave-one tissue site-out, cross validation on in vivo NIR AF spectra yields apredictive accuracies of 90%, 82.6% and 90.2%, respectively, for differentiation amongnormal, hyperplastic and adenomatous polyps in the colon. This work demonstrates for thefirst time that NIR AF spectroscopy associated with PCA-LDA diagnostic algorithms haspotential for the noninvasive, in vivo diagnosis of neoplastic polyps in the colon duringclinical colonoscopy screening. In the mean time, we have further evaluated the diagnosticfeasibility of the integrated near-infrared (NIR) autofluorescence (AF) and NIR diffusereflectance (DR) imaging technique developed for colonic cancer detection. A total of 48paired colonic tissue specimens (normal vs. cancer) were measured using the integratedNIR DR (850-1100 nm) and NIR AF imaging at the 785 nm laser excitation. The resultsshowed that NIR AF intensities of cancer tissues are significantly lower than those ofnormal tissues (p<0.001, paired 2-sided Student's t-test, n=48). NIR AF imaging underpolarization conditions gives a higher diagnostic accuracy (of -92-94%) compared to non-polarized NIR AF imaging or NIR DR imaging. Further, the ratio imaging of NIR DR toNIR AF with polarization provides the best diagnostic accuracy (of -96%) among the NIRAF and NIR DR imaging techniques. This work suggests that the integrated NIR AFspectroscopy and NIR AF/DR imaging under polarization condition has the potential togreatly improve the early diagnosis and detection of malignant lesions in the colon.Figure 1.