Intraoperative Laser Speckle Contrast Imaging to Assess Blood Flow During Neurosurgery

Cerebral blood flow (CBF) is of paramount importance to human brain function, as the brain relies on a continuous blood supply to meet its energy needs. Blockage of a cerebral blood vessel during neurosurgery, even if transient and short-lived, may result in irreversible brain tissue damage (i.e. stroke) and loss of cortical function, if not identified quickly enough. Laser speckle contrast imaging (LSCI) has been demonstrated to provide the ability to visualize flow in vessels in real time and continuously without the need for contrast agents. In LSCI, the tissue of interest is illuminated with low power laser light at red or near infrared wavelengths and the light reflected from the tissue surface is imaged onto a camera. The resulting images are laser speckle patterns and a computer processes the images to produce speckle contrast images, which are images of the motion within the field of view (ie, blood flow). The purpose of this clinical investigation is to assess the usefulness and accuracy of LSCI compared to ICGA and/or FA during neurovascular surgery. LSCI videos will be recorded automatically intraoperatively in each patient before, during, and after ICGA and/or FA in the same surgical field of view to guarantee comparability of the methods.