Imaging cortical absorption, scattering, and hemodynamic response during ischemic stroke using spatially modulated near-infrared illumination

Abstract

Stroke occurs when arteries supplying blood to the brain burst (hemorrhagic stroke) or are obstructed¹ (ischemic stroke). About 90% of all strokes are ischemic, occurring from occlusion of one of the main arteries supplying the brain. Under these conditions brain cells undergo a series of pathophysiologic changes, but ultimately die from lack of oxygen supply.² Cerebral ischemia results in changes in regional concentrations of oxyhemoglobin, deoxyhemoglobin, and water.³ Because these molecules absorb specific wavelengths of light, ischemia alters the optical properties of brain tissue. Since the most commonly involved artery in ischemic strokes is the middle cerebral artery (MCA) we chose to focus our experiments on MCA occlusion^{4, 5} (MCAo).