Cardiac‐gated spectroscopic photoacoustic imaging for ablation‐induced necrotic lesion visualization

Abstract Radiofrequency (RF) ablation is a minimally invasive therapy for atrial fibrillation. Conventional RF procedures lack intraoperative monitoring of ablation‐induced necrosis, complicating assessment of completeness. While spectroscopic photoacoustic (sPA) imaging shows promise in distinguishing ablated tissue, multi‐spectral imaging is challenging in vivo due to low imaging quality caused by motion. Here, we introduce a cardiac‐gated sPA imaging (CG‐sPA) framework to enhance image quality using a motion‐gated averaging filter, relying on image similarity. Necrotic extent was calculated based on the ratio between spectral unmixed ablated tissue contrast and total tissue contrast, visualizing as a continuous color map to highlight necrotic area. The validation of the concept was conducted in both ex vivo and in vivo swine models. The ablation‐induced necrotic lesion was successfully detected throughout the cardiac cycle through CG‐sPA imaging. The results suggest the CG‐sPA imaging framework has great potential to be incorporated into clinical workflow to guide ablation procedures intraoperatively.