Ultrafast photoacoustic endomicroscopy with a dynamic-static decoupled catheter for 3D volumetric imaging of intracavitary blood perfusion

The inability to capture dynamic blood perfusion in deep cavities with high spatiotemporal resolution has long been a major obstacle in photoacoustic endoscopy (PAE). Herein, we develop an ultrafast photoacoustic endoscopy ultrasonic (UF-PAEUS) system with a dynamic-static decoupled coaxial core (DSCC) design, featuring high-resolution and high-speed wide-area 3D volume imaging. This design separates the rotating scanning element from the stationary optical and acoustic transmission core, eliminating proximal slip-rings or distal micromotors while enabling stable scanning at 100 revolutions per second (rps). The system achieves 30 mm length dual-modality colorectal imaging in 6 s, with 22 μm lateral and 79 μm axial resolutions, and quantifies perfusion loss in vivo within 1 min. This technology provides a powerful platform for studying microvascular dynamics and diagnosing intracavitary diseases.