Review of the emerging role of optical polarimetry in characterization of pathological myocardium

Abstract

Abstract. Myocardial infarction (MI), a cause of significant morbidity and mortality, is typically followed by microstructural alterations where the necrotic myocardium is steadily replaced with a collagen scar. Engineered remodeling of the fibrotic scar via stem cell regeneration has been shown to improve/restore the myocardium function after MI. Nevertheless, the heterogeneous nature of the scar patch may impair the myocardial electrical integrity, leading to the formation of arrhythmogenesis. Radiofrequency ablation (RFA) offers an effective treatment for focal arrhythmias where local heating generated via electric current at specific spots in the myocardium ablate the arrhythmogenic foci. Characterization of these myocardial pathologies (i.e., infarcted, stem cell regenerated, and RFA-ablated myocardial tissues) is of potential clinical importance. Optical polarimetry, the use of light to map and characterize the polarization signatures of a sample, has emerged as a powerful imaging tool for structural characterization of myocardial tissues, exploiting the underlying highly fibrous tissue nature. This study aims to review the recent progress in optical polarimetry pertaining to the characterization of myocardial pathologies while describing the underlying biological rationales that give rise to the optical imaging contrast in various pathologies of the myocardium. Future possibilities of and challenges to optical polarimetry in cardiac imaging clinics are also discussed.

Mecanismos Fisiopatológicos do Infarto Agudo do Miocárdio: Uma Revisão Atualizada

“…Outra área promissora é o desenvolvimento de terapias dirigidas que modulam a resposta inflamatória e promovem a cicatrização e a regeneração do tecido de forma mais eficaz, minimizando ao mesmo tempo os efeitos colaterais negativos (Dutta, P. & Nahrendorf, M., 2015;Cebova, M. & Pechanova, O., 2020). A exploração de novos biomarcadores e técnicas de imagem avançadas também pode melhorar a capacidade de diagnosticar o IAM de forma mais precisa e prever os desfechos, permitindo intervenções mais oportunas e personalizadas (Ahmad, I., 2017).…”

Toward the development of a polarimetric tool to diagnose the fibrotic human ventricular myocardium

“…10 Cardiac tissue is composed of fibrous components (such as cardiomyocytes and collagen fibers) that are highly anisotropic, which is significant for assessing cardiac disorders using optical polarimetry. 11 The healthy zones of heart tissues are predominantly constituted of well-organized arrays of cardiomyocytes [Fig. 1(b)], resulting in higher linear birefringence values than the pathological zones, where severe disruption of the normally well-ordered architecture leads to a commensurate loss of cardiac tissue anisotropy.…”

“…1(b)], resulting in higher linear birefringence values than the pathological zones, where severe disruption of the normally well-ordered architecture leads to a commensurate loss of cardiac tissue anisotropy. 11 In diseased cardiac tissues [Fig. 1(c)], the rise in collagen concentration (i.e., fibrosis) is the most common and significant contribution of ECM proteins to CVD.…”

“…5 Depolarization directly correlates with the anisotropic structure of the constituents of heart tissue, which is considered a prominent metric in tissue optical polarimetry (e.g., myocardium). 11 Bickel et al 12 demonstrated that polarization in light scattering could be used as an effective tool in biological study. Various biological tissues, including tissues from cardiac muscle, brain, liver, kidney cortex, loin muscle, and tendon of pigs, [13][14][15][16] tissues from heart, brain, retina, kidney, and spleen of rats, 17 cardiac tissues of Lewis rats, 18,19 human breast cancer tissues, [20][21][22] and invasive breast cancer specimens, [23][24][25] have been characterized using a wide variety of optical modalities such as polarimetric light microscopy (PLM), [23][24][25] linear polarization spectroscopy, [23][24][25] Mueller polarimetry, 26 near-infrared spectroscopy (NIRS), [20][21][22]27 and optical coherence tomography (OCT).…”

“…Optical polarimetry of cardiac tissues has been shown to effectively assess the impacts of disease development and monitor treatment efficacy. 11 Ahmad et al 16 quantified factors, such as depolarization and retardance, to characterize myocardial disease such as myocardial infarction and monitored stem cell treatment in radiofrequency ablated (RFA) myocardium. The RFA lesion showed lower depolarization when compared to neighboring healthy tissue.…”