Abstract P2018: In Vivo Imaging Of The Coronary Microcirculation Throughout The Contractile Cycle With Optical Coherence Tomography Angiography

Abstract

Introduction: Studying coronary microvascular disease (CMD) warrants in vivo high-resolution microcirculation imaging, which requires advanced motion correction and gating strategies. We hypothesized that cardiac and respiratory gating and custom angiogram reconstruction algorithms may enable label-free optical coherence tomography angiography (OCTA) of the coronary microcirculation in vivo in mice throughout the cardiac cycle. Methods: C57BL/6 male mice (n=20) were imaged through a sternotomy while anesthetized and ventilated. OCTA was performed using a custom tissue stabilizer and a Thorlabs TEL 321 OCT system, which was synchronized to physiologic signals using custom hardware and software and cardiac pacing protocols (Fig. 1A). Angiograms were created by calculating speckle variance between images with one of two strategies: 1. Images within the same cardiac cycle (AB method); or 2. Images in two different cardiac cycles (AC method). Angiograms were formed during both diastole and systole (Fig. 1C and E). Data were processed in MATLAB and ImageJ. Results: Without gating or stabilization, angiograms cannot be produced (Fig. 1B). Using stabilization with custom gating and reconstruction strategies significantly improved image registration (Fig. 1G) and allowed creation of widefield capillary angiograms without exogenous contrast agent during both diastole and systole (Fig. 1D and F). Conclusion: In vivo OCTA can image the coronary microcirculation in the heart throughout the cardiac cycle and will provide a powerful new tool for investigating coronary microvascular dysfunction in mouse models of heart disease.