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