In Vivo Assessment of Cardiac Radiofrequency Ablation in a Large-Animal Model Using Photoacoustic-Ultrasound Imaging.

Despite advancements in catheter technology, intraoperative assessment of radiofrequency ablation (RFA) lesions remains elusive. Prior ex vivo data suggest photoacoustic imaging (PAI) can provide RFA lesion characteristics, but in vivo data are lacking. PAI involves delivering near-infrared light to tissue, leading to transient acoustic waves that can be detected by clinically available ultrasound transducers, providing optically based tissue characterization at depth. Three epicardial RFA lesions were delivered in an open-chest porcine model. In vivo PAI-based measurements of RFA lesion dimensions matched (<0.7-mm error) gross pathologic assessment, yielding in vivo feasibility data of PAI to provide intraoperative RFA lesion dimensions.