Laser-excited autofluorescence for discrimination of atherosclerosis

Experiments on atherosclerotic plaque diagnosis were carried out using laser induced fluorescence (LIF) spectroscopy on carotid plaque specimens. The excitation laser was a nitrogen laser, emitting pulses at a wavelength of 337 nm. Over 10 samples were examined in vitro and several spectra were obtained from each sample. Results were compared with conventional clinical techniques, such as histopathological diagnosis, which showed three areas of different composition on the pathological samples: fibrous tissue, lipid constituents and calcified plaque. An effort was made to distinguish the composition of the sample from the obtained spectra. Also, the results were compared with our previous work using longer excitation wavelengths. Spectral morphology of UV excited fluorescence reveals multi-peaks lineshapes, as a result of the superposition of different tissue chromophore signals. However, there was no observed specific wavelength where spectra corresponding to fibrous tissue, calcified tissue and lipid constituents have peaks.