A239 Particle image velocimetry (PIV) for cerebrovascular applications

<h3>Introduction</h3> Particle Image Velocimetry (PIV) is an optical technique used to visualize and quantify fluid flow by tracking the movement of tracer particles within the fluid. High-frequency optical coherence tomography (HF-OCT), with its ~10 μm resolution, offers high-resolution intravascular or intrathecal imaging and may serve as a novel platform for in-situ PIV. <h3>Aim of Study</h3> To evaluate the use of HF-OCT for conducting PIV of cerebrospinal fluid (CSF) and aneurysmal flow patterns in large animal models, both in vivo and in vitro. <h3>Method</h3> In a porcine model, a low-profile OCT catheter was inserted intrathecally, and the CSF was seeded with diluted homologous blood to act as tracer. The catheter was held in position, and a 2–4 second acquisition captured real-time CSF flow, with red blood cells serving as tracers. Separately, a silicone replica of a rabbit aneurysm was integrated into an in-vitro circulatory system operating under physiological conditions. The aneurysm model was filled with saline seeded with diluted bovine blood, and OCT imaging was performed at the aneurysm neck. <h3>Results</h3> Accurate PIV was achieved using HF-OCT data. In vivo imaging of the porcine thecal canal revealed strong lateral CSF motion synchronized with the cardiac cycle and coherent flow structures shaped by surrounding anatomy. In the aneurysm model, flow visualization revealed a distinct recirculation zone resembling a vortex near the aneurysm neck. <h3>Conclusion</h3> In-vivo PIV using HF-OCT is possible and provides a promising experimental approach for exploring in-situ cerebrovascular and CSF flow dynamics with high resolution. <h3>Conflict of Interest</h3> No