One-shot functional photoacoustic microscopy for monitoring traumatic brain injury

Photoacoustic Microscopy (PAM) is a novel medical imaging technique developed rapidly in recent years with the advantages of high resolution, high contrast, and no ionizing radiation. In this study, we developed a One-Shot functional Photoacoustic Microscopy (OS-fPAM) system for assessing Traumatic Brain Injury (TBI). The OS-fPAM system only employed a single 532 nm nanosecond pulse laser with Raman delay optical path control, which can produce both 532 nm and 553 nm laser beams. The dual-wavelength beams were then coupled via a dichroic mirror and focused on the surface of the experimental sample. Then, the photoacoustic signal was collected and amplified in the ultrasonic signal acquisition module, and the blood oxygen saturation (sO₂) image was calculated by two wavelength photoacoustic images. The feasibility of the OS-fPAM system was performed through the calibration experiments with different ratios of red ink and blue ink. Meanwhile, the OS-fPAM system can monitor microvascular structures and sO₂ in the TBI model on mice for 96 hours in vivo with a spatial resolution of ~40 μm, demonstrating the potential to evaluate rehabilitation and cerebral vascular damage.