PS-OCT local optic axis measurement of quail embryonic hearts

Congenital heart defects (CHDs) remain the most common birth anomalies, and prenatal alcohol exposure (PAE) is a well-established teratogen related to high CHD risk. A key determinant of normal cardiac development is the precise alignment of myocardial fibers, which guides chamber morphogenesis and coordinated contraction. Yet, the impact of PAE on this critical aspect of heart architecture remains poorly understood. Polarization-sensitive optical coherence tomography (PS-OCT) is a label-free imaging modality that enables high-resolution, depth-resolved visualization of myocardial fiber organization in intact embryonic hearts. Unlike conventional techniques such as diffusion tensor imaging (DTI), polarized light imaging (PLI), or second harmonic generation (SHG) microscopy, PS-OCT can non-invasively map local optic axis orientation throughout the myocardial wall without requiring extensive sample preparation. In this study, we used PS-OCT to image and quantify birefringence and local optic axis orientation in embryonic quail hearts (n = 7 per group) from embryonic day 7 to day 13.