Whole-Brain N-Acetylaspartate Quantification: Performance Comparison of NAA Versus Lipid Nulling

Background and Purpose N-acetylaspartate (NAA), the second most abundant amino acid derivative in the mammalian brain, is almost exclusive to neurons and their processes and, therefore, is regarded, as a marker for their health and density. Due to its unique specificity, NAA is the most frequently examined neuro-metabolite and its concentration has been reported to decline in all other central nervous system (CNS) diseases. Since many neurological disorders are diffuse throughout the CNS, it is frequently desired to gauge their global load through their surogate whole-brain NAA (WBNAA) loss. Although the NAA yields the most prominant peak in brain proton MR-spectroscopy (HMRS), it resonates at or near and is, consequently, obscured by, the much more intense skull bone marrow and subcateneous lipids signals. As a result, the cortex, i.e., most of the brains gray matter, is, unfortunately inaccessible to standard localized H-MRS. To address the lipid contamination problem as well