Near-infrared diffuse tomography with apriori MRI structural information: testing a hybrid image reconstruction methodology with functional imaging of the rat cranium

The ability to combine MRI and NIR information into a single imaging modality can potentially provide high-resolution images of absolute hemoglobin concentration and oxygen saturation from non-invasive simultaneous measurement. In order to take advantage of the MRT information, a finite element based imaging algorithm has been used to include both a priori structural information and spatial constraints during NIR image reconstruction. A case study of the optical changes in a rat cranium in response to variations in the inhaled oxygen supply has been used to test this imaging algorithm. The ability to introduce structure from MRI into NIR image reconstruction resulted in significant improvements in the discrimination of hemoglobin concentration changes from oxygen saturation changes in the brain and muscle tissues.