Multiparametric transcranial photoacoustic imaging after photothrombotic stroke

Stroke requires rapid and accurate diagnosis due to its high mortality and limited treatment chances. Therefore, an imaging modality capable of assessing early-stage stroke is needed. Photoacoustic imaging (PAI) offers real-time, non-invasive, and high-resolution cerebrovascular imaging with multiparametric information, making it suitable for the assessment of early-stage stroke. This study presents the development and application of a PAI system for rat brains to in vivo monitor photothrombosis stroke. The imaging system employs a 1024-element hemispherical transducer, a 3-axis gantry system, and a rotational motor system. We combined rotary and raster scans to obtain three-dimensional vascular images, achieving high-resolution angiograms and multiparametric images. With this system, we assessed cerebral hemodynamic changes in a photothrombotic stroke rat model. Our results highlight the PAI’s capability to provide detailed morphological and functional assessments of the brain’s vasculature. We observed neovascularization and an increase in vessel density in the stroke-induced region one day after induction. Moreover, we precisely monitored oxygen saturation (SO₂) levels in specific vessel regions. The stroke-induced region displayed significantly lower SO₂ levels, while newly formed vessels exhibited higher SO₂, indicating the recovery response to ischemia. These findings demonstrate the potential of PAI to monitor pathophysiological changes following photothrombotic stroke, providing multiparametric data for early diagnosis and therapeutic decision-making.