NEAR-INFRARED DIFFUSE REFLECTION AND LASER-INDUCED FLUORESCENCE SPECTROSCOPY FOR MYOCARDIAL TISSUE CHARACTERIZATION

In order to evaluate the potential of cardiovascular tissue characteri sation using near-infrared (NIR) spectroscopy, spectra in a previously unexplored wavelength region 0.8-2.3 mu m were recorded from various pig heart tissue samples in vitro: normal myocardium (with and without endo/epicardium), aorta; fatty and fibrous heart tissue. The spectra were analysed with principal component analysis (PCA), revealing sever al spectroscopically characteristic features enabling tissue classific ation. Several of the identified spectral features could be attributed to specific tissue constituents by comparing the tissue signals with spectra obtained from water, elastin, collagen and cholesterol as well as with published data. The results obtained with the NIR spectroscop y technique in terms of its potential to classify different tissue typ es were compared with those from laser-induced fluorescence (LIF) usin g 337 nm excitation. LIF and NIR spectroscopy can in combination with PCA be used to discriminate between all previously mentioned tissue gr oups, apart from fatty versus fibrous tissue (LIF) and aorta versus fi brous tissue (NIR), respectively. The NIR analysis was improved by foc using the PCA to the wavelength segment 2.0-2.3 mu m, resulting in suc cessful spectral characterisation of all cardiovascular tissue groups. (C) 1997 Elsevier Science B.V.