Intravascular Polarimetry: Clinical Translation and Future Applications of Catheter-Based Polarization Sensitive Optical Frequency Domain Imaging

Abstract

Optical coherence tomography (OCT) and optical frequency domain imaging (OFDI) \nvisualize the coronary artery wall and plaque morphology in great detail. The advent of \nthese high-resolution intracoronary imaging modalities has propelled our understanding \nof coronary atherosclerosis and provided enhanced guidance for percutaneous coronary \nintervention. Yet, the lack of contrast between distinct tissue types and plaque \ncompositions impedes further elucidation of the complex mechanisms that contribute \nto acute coronary syndrome (ACS) and hinders the prospective identification of \nplaques susceptible to rupture. Intravascular polarimetry with polarization-sensitive \nOFDI measures polarization properties of the coronary arterial wall using conventional \nintravascular imaging catheters. The quantitative polarization metrics display notable \nimage contrast between several relevant coronary plaque microstructures that are difficult \nto identify with conventional OCT and OFDI. Tissues rich in collagen and smooth \nmuscle cells exhibit birefringence, while lipid and macrophages cause depolarization. \nIn this review, we describe the basic principles of intravascular polarimetry, discuss the \ninterpretation of the polarization signatures, and outline promising avenues for future \nresearch and clinical implications