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Abstract #1079

Diffusion Weighted Spectroscopy of NAA in Multiple Sclerosis: Studying the Microstructure, Macrostructure and Organization of Axonal Tracts in the Corpus Callosum

Emily T. Wood1, 2, Itamar Ronen3, Aranee Techawiboonwong4, Pascal Sati1, Daniel Reich1, 5

1National Institute of Neurological Disease and Stroke, National Institutes of Health, Bethesda, MD, United States; 2Dept of Neuroscience, Johns Hopkins University, Baltimore, MD, United States; 3C.J. Gorter Center for High Field MRI, Department of Radiology, Leiden University Medical Center, Leiden, Netherlands; 4Dept of Electrical Engineering, Mahidol University, Salaya, Nakhon Pathom, Thailand; 5Depts of Neurology & Radiology, Johns Hopkins University School of Medicine, Baltimore, MD, United States

Previous work comparing multiple sclerosis (MS) patients to healthy controls demonstrated lower N-acetylaspartate (NAA) diffusion parallel to axon tracts in the corpus callosum (CC). In order to better characterize axonal damage in the CC in MS and improve the reliability of diffusion weighted spectroscopy (DWS) for longitudinal follow-up, we applied a modeled analysis of NAA diffusion in the CC. By modeling the CC as a cluster of cylinders with macroscopic curvature and microscopic angular dispersion distribution, DWS measurements made parallel and perpendicular to axon tracts can yield NAA diffusion values that more accurately reflect the fiber organization and integrity.