title: Discrimination of human coronary artery atherosclerotic lipid-rich lesions by time-resolved laser-induced fluorescence spectroscopy.
abstract: Lesion composition plays a significant role in atherosclerotic lesion instability and rupture. Current clinical techniques cannot fully characterize lesion composition or accurately identify unstable lesions. This study investigates the use of time-resolved fluorescence spectroscopy for unstable atherosclerotic lesion diagnosis. The fluorescence of human coronary artery samples was induced with nitrogen laser and detected in the 360- to 510-nm wavelength range. The samples were sorted into 7 groups according to the AHA classification: normal wall and types I, II(a) (fatty streaks), III (preatheroma), IV (atheroma), V(a) (fibrous), and V(b) (calcified) lesions. Spectral intensities and time-dependent parameters [average lifetime tau(f); decay constants: tau(1) (fast-term), tau(2) (slow-term), A(1) (fast-term amplitude contribution)] derived from the time-resolved spectra of coronary samples were used for tissue characterization. We determined that a few intensity values at longer wavelengths (>430 nm) and time-dependent parameters at peak emission region (390 nm) discriminate between all types of arterial samples except between normal wall and type I lesions. The lipid-rich lesions (more unstable) can be discriminated from fibrous lesions (more stable) on the basis of time-dependent parameters (lifetime and fast-term decay). We inferred that features of lipid fluorescence are reflected on lipid-rich lesion emission. Our results demonstrate that analysis of the time-resolved spectra may be used to enhance the discrimination between different grades of atherosclerotic lesions and provide a means of discrimination between lipid-rich and fibrous lesions.
authors.affiliation: Laser Research and Technology Development, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA. lmarcu@bmsrs.usc.edu
authors.forename: L
authors.initials: L
authors.lastname: Marcu
authors.forename: M C
authors.initials: MC
authors.lastname: Fishbein
authors.forename: J M
authors.initials: JM
authors.lastname: Maarek
authors.forename: W S
authors.initials: WS
authors.lastname: Grundfest
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001011:Aorta / Q000473:pathology; D002648:Child; D003324:Coronary Artery Disease / Q000473:pathology*; D003331:Coronary Vessels / Q000473:pathology; D006801:Humans; D007834:Lasers; D050356:Lipid Metabolism; D008875:Middle Aged; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013997:Time Factors