High‐Efficiency Photoacoustic Microscopy for Ultrafast Hemodynamic Imaging

Abstract Understanding brain functions requires visualization of cerebral hemodynamics with a high spatiotemporal resolution. Recent advances utilize various scanning schemes to promote the imaging speed of photoacoustic microscopy for label‐free hemodynamic imaging. However, due to the insufficient utilization of laser pulses, recording cerebral hemodynamics with a satisfactory spatiotemporal resolution still remains a challenge. Here, a 3‐axis optical scanner is employed to develop a high‐efficiency photoacoustic microscopy (HePAM) for the investigation of hemodynamics in the cerebral cortex. The scan engine provides an ultrafast B‐scan rate of up to 1.6 kHz. Its capability in flexible imaging of specific regions of interest (ROIs) is demonstrated to capture hemodynamic responses in whole cortex, hemisphere, and arbitrary single blood vessels. In addition, HePAM has the unique advantage of integrating with widefield imaging to provide simultaneous precise photothrombosis induction and monitoring.