Laser-induced autofluorescence of human arteries

A new technique for imaging the intimal surface of arteries through optic fibers has been devised. With the aid of an optical multichannel analyzer, we recorded in real time fluorescence spectra during excitation of the arterial surface with an argon ion laser. Spectral parameters were used to detect atherosclerotic plaques and to discriminate normal tissue from lipid rich and calcified atheromas. By digitizing relative intensity values and the ratios of the peak at 550 nm to that at 520 nm into a gray scale, we generated pseudocolor maps of the arterial wall of 10 human aortas. Specific color distributions were congruent with the distribution of calcified tissue visualized by soft x-ray radiography and the distribution of lipid delineated by staining with Sudan IV. Thus, bidimensional maps obtained by laser spectroscopy can be used to identify the presence and composition of atherosclerotic lesions. Fluorescence imaging may prove to be an important application of laser techniques for the diagnosis and treatment of atherosclerosis.