<title>Spectral reflectance of atherosclerotic tissue versus normal arterial tissue</title>

Abstract

Laser angioplasty as a method of removal of atherosclerotic plaque from arterial walls is still being developed as a reliable medical procedure. Problems encountered are thermal damage to surrounding tissue, perforation of the arterial wall, and identification of the atherosclerotic plaque that is to be removed. This study concentrates on the problem of distinguishing between the atherosclerotic and normal arterial tissue. Spectral optical characteristics, such as reflectance and fluorescence of the atherosclerotic tissue, could provide useful information to be implemented for identification purposes. The total reflected light (specular and diffuse reflectance plus fluorescence) of atherosclerotic arterial tissue and unaffected arterial tissue were measured between the wavelengths of 250 nm and 800 nm, using a double beam spectrophotometer, Hitachi U3400. The results show significant differences between the affected and unaffected aorta samples in the ultraviolet region, especially at the wavelengths 315 nm and 400 nm. These differences can be used as criteria to identify atherosclerotic plaque from normal arterial tissue. An instrument can be developed to be used with laser angioplasty. This instrument can combine the identification and ablation processes by using a 308 nm excimer laser, which emits light close enough to the 315 nm identification criteria and removes atherosclerotic plaque successfully.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.