High-resolution near-infrared tomographic imaging simulations of the rat cranium by use of a priori magnetic resonance imaging structural information.

Near-infrared (NIR) optical image reconstruction that incorporates magnetic resonance image (MRI) structural data was tested in a series of simulated reconstructions. NIR diffuse tomography generally suffers from comparatively low spatial resolution. By using the fine structural detail that is available with MRI, combined with the functional information of NIR spectroscopy, it is possible to design a new image-reconstruction methodology that provides high-resolution images that are correlated with hemoglobin concentration and oxygen saturation. To test this concept a MRI spin-echo image of a rat cranium was used to obtain an outline of the bone, brain, and muscle tissues, and this information was incorporated into an iterative-based diffuse tomography reconstruction. These simulations represent what is believed to be the first attempt at evaluating a spatially constrained iterative-reconstruction MRI-NIR imaging modality for brain tissue.