Spectral region optimization for Raman-based optical diagnosis of inflammatory lesions

FT-Raman Spectroscopy was applied to identify biochemical alterations existing between inflammatory fibrous hyperplasia (IFH) and normal tissues of buccal mucosa. One important implication of this study is related to the cancer lesion border. In fact, the cancerous normal border line is characterized by the presence of inflammation and its correct discrimination would increase the accuracy in delimiting the lesion frontier. Seventy spectra of IFH from 14 patients were compared to 30 spectra of normal tissue from 6 patients. The statistical analysis was performed with Principal Components Analysis and Soft Independent Modeling Class Analogy methodologies. After studying several spectral ranges it was concluded that the best discrimination capability (sensibility of 95% and specificity of 100%) was found using the 530 to 580 cm$^{-1}$ wavenumbers. The bands in this region are related to vibrational modes of Collagen aminoacids Cistine, Cysteine, and Proline and their relevant contribution to the classification probably relies on the extracellular matrix degeneration process occurring in the inflammatory tissues.