Comprehensive intravascular imaging of atherosclerotic plaque in vivo using optical coherence tomography and fluorescence lifetime imaging

Abstract

Comprehensive imaging of both the structural and biochemical characteristics of atherosclerotic plaque is essential for the diagnosis and study of coronary artery disease because both a plaque’s morphology and its biochemical composition affect the level of risk it poses. Optical coherence tomography (OCT) and fluorescence lifetime imaging (FLIm) are promising optical imaging methods for characterizing coronary artery plaques morphologically and biochemically, respectively. In this study, we present a hybrid intravascular imaging device, including a custom-built OCT/FLIm system, a hybrid optical rotary joint, and an imaging catheter, to visualize the structure and biochemical composition of the plaque in an atherosclerotic rabbit artery in vivo. Especially, the autofluorescence lifetime of the endogenous tissue molecules can be used to characterize the biochemical composition; thus no exogenous contrast agent is required. Also, the physical properties of the imaging catheter and the imaging procedures are similar to those already used clinically, facilitating rapid translation into clinical use. This new intravascular imaging catheter can open up new opportunities for clinicians and researchers to investigate and diagnose coronary artery disease by simultaneously providing tissue microstructure and biochemical composition data in vivo without the use of exogenous contrast agent.

Vulnerable plaques and patients: state-of-the-art

“…It can reportedly identify compositional characteristics of superficial plaque. 32 Intravascular photoacoustics, a natural extension of IVUS that adds depth-resolved tissue to the IVUS images, relies on the analysis of the sound produced by the thermal expansion of tissues after irradiation with pulsed light. The photoacoustic response of each plaque depends on the absorption characteristics of its components, which permits IVPA to provide information about plaque composition.…”

Inflammation and atherosclerosis: what is on the horizon?

“…In experimental models, this has been used to target protease activity, plaque macrophages and fibrin deposition. OCT/near-infrared autofluorescence (NIRAF) and OCT/fluorescence lifetime imaging32 have also shown promise with the additional benefits of providing biochemical data without the requirement of exogenous contrast administration. NIRAF has recently been conducted in a clinical study and provided additional information with regard to high-risk plaque features with the use of a dedicated imaging catheter 33…”

Dual-modality optical coherence tomography and frequency-domain fluorescence lifetime imaging microscope system for intravascular imaging

“…There has been growing interest in the development of dual-modality imaging systems for characterizing atherosclerotic plaques. Dual-modality intravascular OCT/FLIM 15 , 16 systems have been developed based on swept-source OCT and time-domain FLIM. Here, we describe a dual-modality intravascular OCT/FLIM system based on swept-source OCT and frequency-domain FD-FLIM.…”