Validation of eyelids as acoustic receiver locations for photoacoustic-guided neurosurgery

Accidental injury to underlying blood vessels and nerves during minimally invasive neurosurgery can have severe surgical complications (e.g., blindness, paralysis, and death). Transcranial photoacoustic imaging is a promising technique for real-time visualization of these structures, but it is challenged by acoustic-bone interactions which degrade image quality. We are developing patient-specific simulation methods that identify viable transcranial acoustic windows for intraoperative photoacoustic visualization of these underlying structures. Photoacoustic k-Wave simulations were performed based on a CT volume of an intact human cadaver head, which was later used to create experimental images of the internal carotid arteries. Acoustic receivers distributed across the eyelids measured pressure from intracranial photoacoustic sources. Differences in photoacoustic signal quality between the left and right eyelid receiver locations were investigated. Simulated sensors placed on the right eyelid received a 6.4 dB greater median acoustic energy than simulated sensors placed on the left eyelid, which was confirmed experimentally with a 14.5 dB greater DAS photoacoustic image amplitude with the ultrasound probe placed on the right eyelid rather than the left eyelid. Therefore, the ocular cavity is a viable acoustic window for photoacoustic-guided neurosurgeries with the potential to identify intrapatient, left-right asymmetries, supporting a new paradigm for performing patient-specific simulations prior to surgical guidance.