A near-infrared spectroscopy computational model for cerebral hemodynamics.

Near infrared spectroscopy (NIRS) is a technique used to detect and measure changes in the concentrations of oxygenated hemoglobin, deoxygenated hemoglobin, and water in tissues based on the differential absorption, scattering, and refraction of the near infrared light. In this imaging technique, the optical properties of tissues are reconstructed from the measurements obtained from the sensors located on the boundary. A computational method for the rapid noninvasive detection ∕ quantification of cerebral hemorrhage is described using the above procedure. CFD Research Corporation's finite volume computational biology code was used to numerically mimic the NIRS procedure by (i) noninvasively 'numerically penetrating' the brain tissues and (ii) reconstructing the optical properties the presence of water, oxygenated, and deoxygenated blood. These numerical noninvasive measurements are then used to predict the extent and severity of the brain hemorrhage. The paper also discusses ideas to obtain the location and the severity of a localized injury. Two-dimensional and three-dimensional simulations are performed as a proof of concept for the numerical formulation being feasible for the above mentioned detection/quantification. The results demonstrate that this numerical NIRS formulation can be used as a noninvasive technique for both qualitative and quantitative evaluation of cerebral hemodynamics.