COMPARISON OF ILLUMINATION WAVELENGTHS FOR DETECTION OF ATHEROSCLEROSIS BY OPTICAL FLUORESCENCE SPECTROSCOPY

Illumination wavelengths between 270 and 470 nm are evaluated to deter mine which wavelength produces the greatest difference between the flu orescence emission spectra of normal and atheromatous arterial tissues . Atherosclerotic plaques are considered as a diseased class and are f urther subdivided into three diseased subclasses-fibrous plaques, comp licated plaques, and hard calcified plaques. The Mahalanobis distance squared, a statistical figure of merit describing class separability, is used to compare the illumination wavelengths. Classification accura cies are also estimated and used for comparison. Optimum classificatio n performance is found to occur with illumination in the wavelength ra nge 314 to 334 nm, except for hard calcified plaques, which are more a ccurately classified with illumination wavelengths longer than 380 nm. The issue of how much information is required from the fluorescence e mission spectra to accurately classify tissue is also investigated.