Intraoperative Identification of Cranial Nerves in Skull Base Surgery Using Polarization Sensitive Optical Coherence Tomography

Project summary/abstract Identification of cranial nerves during skull base surgery is critical to avoid iatrogenic injury. Even the slightest damage to any one of these nerves can hugely affect patient outcomes. Despite the importance of cranial nerve identification, preoperative imaging struggles to provide the needed information. During

the surgical procedure, electrostimulation techniques are often utilized to provide a point-based analysis of a nerve and its functional capability, but they remain unable to picture the whole field. In fact, there is no current clinical tool capable of mapping nerve fibers and displaying their location back to the surgeon

in real time. In this project, we propose to develop an imaging tool that can fill this obvious gap in current technology and place it directly into the hands of skull base surgeons. This tool will be based on polarization sensitive optical coherence tomography (OCT), an optical imaging modality that shows exquisite contrast

for myelinated nerves. Recent advances in laser technology (known as circular ranging, invented by Mentor Dr. Vakoc) have brought OCT lasers to a point where their use is compatible with the motion induced by standard surgical workflow. This two-aim project seeks to bring circular ranging into the operating theater during skull base surgery and assess its capability to enhance cranial nerve visualization,

uniquely combining both surgical and technical expertise. This work will take place between two NIH- funded P41-holding institutions: the Wellman Center for Photomedicine at Massachusetts General Hospital (MGH), home to the Center for Biomedical OCT Research (CBORT), and Brigham and Women’s Hospital

(BWH), home of the National Center for Image-Guided Therapy (NCIGT) where the resources of the Advanced Multi-modality Image Guided Operating suite (AMIGO), both in terms of equipment and experience, will provide the perfect environment to conduct such a study. The candidate for this award is Dr. Danielle J. Harper, a postdoctoral fellow at MGH and Harvard Medical School. Dr. Harper has been

well trained in the field of biophotonics. Her area of expertise is OCT and its functional extensions, including polarization mapping and depth-resolved spectroscopy. Her long-term career goal is to reach academic independence and lead a research group focused on intraoperative optical neuroimaging. To help her

achieve this, Dr. Harper has built a strong team to guide her in all aspects of research and career development. Dr. Benjamin J. Vakoc at MGH/HMS, an expert in optical imaging, will serve as the primary mentor. Neurosurgeons Dr. Alexandra J. Golby and Dr. Michael Mooney at BWH will provide mentoring,

guidance, and assistance with all clinical aspects. Dr. Lei Tian of Boston University will provide supervision and guidance for the deep learning aspects of the project, and Dr. Tayyaba Hasan at MGH/HMS will provide general career development advice. Supported by this team, this career development award will

give Dr. Harper the remaining skills and training she requires to make the transition to full independence.