CORE--MAGNETIC RESONANCE IMAGING

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This proposal is two separate Cores summed into one administrative unit, representing two research groups in Henry Ford Health Systems; the Neurology NMR laboratory, which will oversee the Magnetic Resonance Imaging (MRI) sections of the proposed Program Project, and the Radiology Image Analysis Laboratory, which will oversee the visualization and combination of MRI (and other) images. It is the focus of Neurology NMR, and its responsibility in this Core, to parameterize MRI data in animal models of cerebral ischemia, and in humans with acute and chronic stroke. Neurology NMR is charged with data acquisition and data processing to produce maps of such parameters as proton density, T1, T2, cerebral blood flow (CBF), the apparent diffusion coefficient of water (ADC/W), the apparent forward magnetization transfer rate, K(fa), etcetera, in order to construct physical and physiological models of cerebral tissue across the phases of cerebral ischemia. To this end, the practices and principles of the MRI image acquisition and data processing used in the various Projects of the Program Project Proposal are presented in this Core, Section A. It has been the focus of the Radiology Image Analysis Laboratory to combine MRI (and other image data) in humans and animal models. In large part, because of the signal-to-noise advantage gained, image intensities alone (e.g., a set of spin-echo images, rather than a T2 map) are input to the algorithms employed by this group. Given an identified pure tissue signal, it has been possible to employ image processing algorithms in the identification of regions of irreversible tissue damage versus borderline regions, versus undamaged regions, versus regions with partial-volume effects. These techniques particularly the Eigenimage and ISODATA filters, are valuable because they employ all the information in an image set and, with experience, they allow the non-invasive identification of different tissue types. The practices and principles of Image Processing used in the various Projects of this Program Project proposal are presented in this Core, Section B. Finally, it is the purpose of this core to apply the work of both groups to the MRI study of cerebral infarction in animals and humans, and to combine their work so that the results of the image processing approaches can be mapped across field strengths and species.