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P3‐249: Magnetic Resonance Spectroscopy Based Metabolite Measurement Differentiates Alzheimer's From Healthy Brain
Author(s) -
Sheikh-Bahaei Nasim,
Sajjadi Seyed Ahmad,
Manavaki Roido,
McLean Mary,
O'Brien John T.,
Gillard Jonathan H.
Publication year - 2016
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2016.06.1912
Subject(s) - metabolite , glutamine , pittsburgh compound b , choline , nuclear medicine , medicine , biomarker , in vivo magnetic resonance spectroscopy , magnetic resonance imaging , inositol , endocrinology , chemistry , alzheimer's disease , disease , biochemistry , radiology , amino acid , receptor
Background:Magnetic resonance spectroscopy (MRS) is a feasible technique and a potential valuable biomarker for AD. There is, however, a lack of translation from research to clinical practice and previous studies have reported conflicting results. This could, in part, be secondary to variable methods used for selection of regions of interest for MRS analysis. The aim of this study was to compare the levels of various brain metabolites across normal and hypo-metabolic and amyloid positive and negative brain regions identified using fluoro-deoxy-glucose (FDG) and Pittsburgh compound B (PiB) PET scans respectively. Methods: The study comprised five patients with a clinical diagnosis of either mild probable AD (n1⁄42) or amnestic MCI (n1⁄43) and five healthy volunteers. The participants underwent MRI and MRS following 90-minute dynamic PiBand 30-minute static FDG-PET scans as part of a study conducted at the University of Cambridge, UK. After co-registration of PET scans on MRI images, two areas each of maximum amyloid uptake and minimum glucose metabolism (4 in total) were identified in each patient and corresponding regions of interests (ROI) were selected in controls. The levels of metabolites myo-inositol, total N-acetyl (tNA) groups, choline, and glutamine and glutamate (glx) were compared across normal and abnormal regions.Results:Pairwise comparison of metabolite levels showed significantly higher levels of myo-inositol (p<0.0001), and choline (p1⁄40.005) and lower level of tNA (p1⁄40.007) in the FDGPET identified hypo-metabolic areas. Glx level was not significantly different. Moreover, compared to corresponding normal areas, there was significant reduction in tNA (p1⁄40.003) and increase in myo-inositol (p1⁄40.05) levels in the amyloid positive brain regions. Choline and glx levels were not significantly different. Conclusions:Given the relatively small samples size, these significant findings signal the importance of a uniform and pathophysiologically relevant selection of MRS voxels. To our knowledge, this study is the first to have utilised both PiBand FDG-PET data for this purpose. Adopting such an approach might lead to resolution of inconsistencies in the MRS literature.