Fluorescence lifetime imaging for the characterization of the biochemical composition of atherosclerotic plaques

Abstract

Abstract. This study investigates the ability of a flexible fiberoptic-based fluorescence lifetime imaging microscopy (FLIM) technique to resolve biochemical features in plaque fibrotic cap associated with plaque instability and based solely on fluorescence decay characteristics. Autofluorescence of atherosclerotic human aorta (11 autopsy samples) was measured at 48 locations through two filters, F377: 377/50 and F460: 460/60 nm (center wavelength/bandwidth). The fluorescence decay dynamic was described by average lifetime (τ ) and four Laguerre coefficients (LECs) retrieved through a Laguerre deconvolution technique. FLIM-derived parameters discriminated between four groups [elastin-rich (ER), elastin and macrophage-rich (E+M), collagenrich (CR), and lipid-rich (LR)]. For example, τ F377 discriminated ER from CR (R = 0.84); τ F460 discriminated E+M from CR and ER (R = 0.60 and 0.54, respectively); LEC-1 F377 discriminated CR from LR and E+M (R = 0.69 and 0.77, respectively); P < 0.05 for all correlations. Linear discriminant analysis was used to classify this data set with specificity >87% (all cases) and sensitivity as high as 86%. Current results demonstrate for the first time that clinically relevant features (e.g., ratios of lipid versus collagen versus elastin) can be evaluated with a flexible-fiber based FLIM technique without the need for fluorescence intensity information or contrast agents. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE).

Fluorescence Lifetime Imaging Combined with Conventional Intravascular Ultrasound for Enhanced Assessment of Atherosclerotic Plaques: an Ex Vivo Study in Human Coronary Arteries

“…Previous work has shown the potential of endogenous fluorescence lifetime measurements for atherosclerotic plaque characterization in open arteries [6, 7]. This paper reports the first results from human coronary arteries interrogated with such a bimodal rotational catheter that serves as an important feasibility step prior to studying plaques in an in vivo animal model as well as future human studies.…”

Biochemical characterization of atherosclerotic plaques by endogenous multispectral fluorescence lifetime imaging microscopy

“…Both spatial resolution and acquisition speed can be significantly improved by implementing time-resolved fluorescence spectroscopy in imaging-mode, most commonly known as fluorescence lifetime imaging (FLIM) (19). Two recent studies have shown some of the potential of FLIM for biochemical imaging of atherosclerotic plaques; however, its ability to distinguish intimal-thickening, fibrotic and fibro-lipid plaques (as in point-spectroscopy) has not yet been established (20, 21). …”

Design, construction, and validation of a rotary multifunctional intravascular diagnostic catheter combining multispectral fluorescence lifetime imaging and intravascular ultrasound

“…Elastin, in particular, is known to be the dominant contributor of fluorescence signal in the normal coronary artery upon UV excitation. 27,28 The capability of IVUS to display real-time images played initially an important role in the localization of the area of interest (i.e., stent covered area) for bimodal interrogation of the coronary vessel. Subsequently, this information was used for guiding and triggering the data acquisition.…”