Dye-free, on-demand visualization of blood flow during cerebrovascular surgery

ABSTRACT Cerebrovascular surgeons performing delicate surgeries such as aneurysm clipping, arteriovenous malformation resections, or revascularization procedures could benefit if quantitative information pertaining to the blood flow status of vessels in their surgical field was made available to them. Current technologies that can monitor blood flow at high resolution either use complex dedicated equipment or rely on administration of contrast agents, both of which are disruptive to the surgical procedure and hence, undesired. Dye-based techniques like ICG video- angiography may not be used frequently and often used only for post-surgical confirmation of surgical success. We propose a novel method that can noninvasively provide real-time information about blood flow in the neurosurgeon’s field of view at the spatial scale of microvessels. This modular optical imaging system (called the CVSurgeONTM) will integrate with existing neurosurgical microscopes in operating rooms providing the neurosurgeon-user an on-demand video feed of blood flow information to assist in surgical decision-making. This complementary blood flow information will be obtained using proprietary and licensed laser speckle contrast imaging technology, and optionally presented to the neurosurgeon in his/her visual field overlaid on the region of interest. We have previously built a prototype of the system and validated its function in small and large animal models of reversible and irreversible occlusion of vessels in the brain. Our proposed Phase II project aims to adapt our technology for clinical use in neurosurgery and then conduct first-in-human studies to validate the system performance and usefulness in three important types of cerebrovascular surgeries – aneurysm clipping, cauterization of arteriovenous malformations, and cerebrovascular bypass surgery for moyamoya disease.