Double-helix optical point spread function enables real-time mesoscopic 3D functional microangiography in the living...

Quantitative, volumetric imaging of cerebrovascular networks and microcirculation is essential for understanding brain function. However, rapid mesoscopic 3D imaging remains challenging because of fundamental trade-offs between spatiotemporal resolution, field of view, and sensitivity to functional parameters. Here we present a mesoscopic fluorescence imaging platform featuring a double-helix phase mask for real-time, depth-resolved measurements through the intact mouse skull. The compact phase-mask design is compatible with both laser-scanning and widefield microscopy. Using multifocal laser scanning, we demonstrate real-time volumetric in vivo imaging while discriminating calvarial from cerebral vasculature across 6.6×6.6×0.8 mm³ volume. Beyond high-resolution structural imaging, perfusion time-to-peak values are extracted from the laser-scanning configuration while accurate flow velocity/direction information is provided via widefield tracking of fluorescently labeled cells. We demonstrate the platform's capabilities by analyzing brain-layer-specific perfusion dynamics and vascular topology in glioma-bearing mouse brains, offering unprecedented views for probing cerebrovascular alterations in both physiological and pathological contexts.