Intraoperative Hyperspectral Imaging for Mapping Brain Motor and Sensory Functions With the Measurements of Changes in Hemoglobin Oxygenation and Oxidation of Cytochrome-C-Oxidase

A neuroimaging technique during surgery can further complement preoperative fMRI and electrical brain stimulation (EBS) to optimize the localization of eloquent areas during glioma resection and could improve dramatically the surgical procedure and patient care. Hyperspectral optical imaging is a non-invasive technique that is able to monitor hemodynamic and metabolic responses during neurosurgery. This technique can be used to complement the cortical functional mapping during neurosurgical procedures. However, a robust quantification of biomarkers of brain functionality is required to assist neurosurgeons. It is also essential to calibrate acquisition devices with robust optical phantoms to test instrument reliability. In this work, we explore the possibility to use a combined liquid blood phantom with cytochrome contained yeast to evaluate the reliability of hyperspectral imaging to measure oxygenation and metabolic changes. We also used hyperspectral imaging for identifying motor and sensory areas of human patients during neurosurgery. The results showed that a blood phantom and commercial yeast can be used to validate the measurement of hemodynamic and metabolic changes. This homogeneous phantom provides an excellent means to verify the reliability of intraoperative optical setups before moving on to clinical application. We showed that a commercial hyperspectral camera combined with a white light illumination could be used for identifying functional brain areas using hemodynamic and metabolic biomarkers. We also observed significant changes of the oxidative state of cytochrome-c-oxidase in periarterial tissue which seems to give an indication of the metabolism of the tissue during cerebral activity.