ABSTRACT
The widely used intraoperative neurosurgical brain mapping techniques include electrical stimulation mapping (ESM), electrocorticography (ECoG), microelectrode recordings, and also, less commonly, intraoperative magnetic resonance imaging. This chapter reviews intraoperative optical imaging and spectroscopy (iOIS), which allows mapping of perfusion and oxygenation changes. iOIS shows potential for precise, cost-effective delineation of epileptic foci, gliomas, and cerebral arteriovenous malformations and functional mapping of language and sensorimotor cortices. Intraoperative brain imaging techniques have revolutionized neurosurgery by allowing surgeons to update real-time information for navigational systems, to monitor tumor resections, to adjust the approach to intracranial lesions, and to guide functional and drug or cell delivery procedures. ESM is performed in different stages. The surgeon must open the skull and expose the brain; then a small electrical probe is used to correlate specific tissues with the systemic functions. ECoG records spectral changes in various frequency bands due to normal cortical function during overt or imagined motor activity.
