Correlation of fluorescence emission with the plaque content and intimal thickness of atherosclerotic coronary arteries.

The use of fluorescence emission for guidance during laser angioplasty may be limited by the complexity of the emission from the broad range of atherosclerotic plaques normally encountered in disease coronary arteries. Fatty, fibrous, and calcific plaque content as well as maximal intimal thickness were measured and correlated with fluorescence intensity ratios from the emission spectra for a broad cross-section of atherosclerotic plaques from human necropsy specimens. Multiple and stepwise regression analysis was used to analyze intensity ratios of 13 wavelengths between 390 and 600 nm corresponding to regions of observed spectral structure. The level of correlation of the intensity ratios with fatty and calcific plaque content was found to be dependent on the complexity of the atherosclerotic lesion. The fluorescence emission was found to correlate well with both fibrous plaque content and intimal thickness, allowing the differentiation between normal and atherosclerotic samples. In conclusion, plaque characteristics can be assessed by fluorescence emission, although the successful implementation of spectroscopic guidance is dependent on the level of prediction error which may vary with tissue type.