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Time-resolved fluorescence of human aortic wall: use for improved identification of atherosclerotic lesions
J M Maarek1, L Marcu, M C Fishbein
1Department of Biomedical Engineering, University of Southern California, Los Angeles, California 90089, USA. jmaarek@bmsrs.usc.edu
Background And Objective:
This study characterized aortic time-resolved fluorescence spectra for stratified levels of atherosclerosis and proposed interpretation of spectrotemporal variations in terms of histologic changes.
Study Design/Materials And Methods:
Fluorescence emission transients were measured at 370-510 nm (337 nm excitation) on 94 excised human aortic samples, ranging from normal to advanced fibrous atherosclerotic lesion. Global analysis yielded a three-exponential approximation of the time-resolved spectra from which average lifetime and decay-associated spectra were derived.
Results:
Average lifetime at 390 nm gradually increased from 2.4+/-0.1 nsec (normal aorta) to 3.9+/-0.1 nsec (advanced lesion). Fluorescence intensity was markedly decreased above 430 nm in intermediate and advanced lesions. Spectral intensity associated with the intermediate decay increased at 470-490 nm for early and intermediate lipid-rich lesions.
Conclusion:
Time-resolved fluorescence spectra of aortic samples presented distinctive features for each atherosclerotic lesion type, which could serve as characteristic markers for optical analysis of the aortic wall.