High Throughput Detection of Capillary Stalling Events with Bessel Beam Two-Photon Microscopy

Disruptions in capillary flow have the potential to drive pathology across numerous diseases. But our understanding of the temporal and spatial dynamics of these events are hindered by slow volumetric imaging rates and the reliance on laborious manual analysis to process data. To address the challenges of increasing volumetric imaging speed, we use a custom-built Bessel beam two-photon microscope for efficient volumetric imaging of the capillary network. We demonstrate its ability to continuously monitor roughly 200 capillaries for capillary flow stoppages (i.e. stalling events) at a frame rate of approximately 0.5 Hz and develop a semi-automated correlation-based approach for identifying these stalling events. We applied our system and algorithm in a photothrombotic model of stroke and show elevated levels of stalling 1-week post-stroke in regions both within and outside of the stroke region, demonstrating that stalling may have impacts on stroke recovery that extend past the acute stage.