Combined fluorescence lifetime imaging-optical coherence tomography for in vivo label-free assessment of high-risk atherosclerotic plaque

摘要

Multimodal optical coherence tomography (OCT) techniques are promising diagnostic tools to accurately assess highriskatherosclerotic plaques. For rapid translation into clinical practice, the techniques should be performed through anintravascular imaging catheter without exogenous contrast agents under the same procedures as conventional imaging. Inthis study, we developed a label-free, multispectral, and catheter-based imaging system to simultaneously visualize themorphological and compositional information of coronary plaques by combining fluorescence lifetime imaging (FLIm)and OCT. Using a broadband hybrid optical rotary joint and a dual-modal imaging catheter, intravascular combinedFLIm-OCT imaging was safely performed in an in vivo atherosclerotic coronary artery of atherosclerotic swine modelswithout any imaging agent. Along with detailed coronary microstructure by OCT, the multispectral FLIm couldaccurately visualize fluorescence lifetime signature of key biochemical components of plaque in vivo (lipid, macrophage,and fibrous tissue) when comparing the corresponding histopathological stained-sections and ex vivo FLIm microscopyimages. Especially, significant differences in fluorescence lifetime distribution were noted between lipid andmacrophage (p < 0.0001), which were mostly indistinguishable with standalone OCT. Also, fluorescence lifetimedistributions were significantly different according to plaque types (normal, fibrous vs. lipid-rich inflamed plaque, p <0.0001). With these statistical differences in plaque types and components, lipid distribution characterization andinflammation level estimation were provided in a pixel-by-pixel manner for the further assessment of the high-riskatherosclerotic plaque. This highly translatable imaging strategy can offer new opportunity for clinical intracoronarydetection of high-risk plaques and will be a promising next-generation multimodal OCT technique.