Diagnostic potential of near-infrared Raman spectroscopy in the colon: differentiating adenomatous from hyperplastic polyps

Background: Near-infrared Raman spectroscopy is a promising optical technique for GI tissue diagnosis. This study assessed the diagnostic potential of near-infrared Raman spectroscopy in the colon by evaluating its ability to distinguish between adenomatous and hyperplastic polyps. Methods: Ex vivo and in vivo Raman spectra of colon polyps were collected by using a custom-built, fiber-optic, near-infrared Raman spectroscopic system. Multivariate statistical techniques, including principal component analysis and linear discriminant analysis, were used to develop diagnostic algorithms for classifying colon polyps based on their spectral characteristics. With the number of samples available, spectral classification of polyps was tested by using a leave-one-out, cross-validation method. Results: Fifty-four ex vivo Raman spectra were analyzed (20 hyperplastic, 34 adenomatous). The spectral-based diagnostic algorithms identified adenomatous polyps with 91% sensitivity, 95% specificity, and 93% accuracy. In vivo, adenomas (n = 10) were distinguished from hyperplastic polyps (n = 9) with 100% sensitivity, 89% specificity, and 95% accuracy. Conclusions: Near-infrared Raman spectroscopy differentiated adenomatous from hyperplastic polyps with high diagnostic accuracy. To our knowledge, this is the first demonstration of the potential of near-infrared Raman spectroscopy for differentiation of colonic polyps during GI endoscopy.