Raman and infrared spectroscopic mapping of human primary intracranial tumors: a comparative study

Intracranial tumors are neoplasias of brain tissue or other tissue inside the skull. Cryosections of the three most frequent primary intracranial tumors - gliomas, meningeomas and schwannomas - were prepared on calcium fluoride windows and studied by both Raman spectroscopy and infrared (IR) spectroscopy. Spectroscopic maps were recorded by sequential acquisition of spectra in a raster pattern. Cluster analyses on selected wavenumber regions were applied for evaluation of these data sets. Raman spectroscopic contributions of proteins including collagen and hemoglobin were identified in cluster centroids, as were nucleic acids and lipids including cholesterol, cholesterol ester (CE) and phosphatidylcholine (PC). Moreover, hydroxyapatite and tricalciumphosphate could be identified as markers for calcification. The spatial distributions of these spectral properties were visualized in pseudocolor Raman and IR maps representing the cluster memberships. The prospects of both methods are discussed. Copyright (C) 2006 John Wiley & Sons, Ltd.