Three-dimensional optical tomographic imaging of vascular reactivity in the brain

We report on the first three-dimensional, volumetric, tomographic localization of changes in the concentration of oxyhemoglobin and deoxyhemoglobin in the brain. To this end we have developed a model-based iterative image reconstruction scheme that employs adjoint differentiation methods to minimize the difference between measured and predicted data. To illustrate the performance of the technique, the three-dimensional distribution of changes in the concentration of oxyhemoglobin and deoxyhemoglobin during a Valsalva maneuver are visualized. The observed results are consistent with previously reported effects concerning optical responses to hemodynamic perturbations.