Neurometabolites and associations with cognitive deficits in mild cognitive impairment: a magnetic resonance spectroscopy study at 7 Tesla

Abstract

The levels of several brain metabolites were investigated in the anterior (ACC) and posterior cingulate cortex (PCC) in 13 healthy controls (HC) and 13 patients with mild cognitive impairment (MCI) using single-voxel magnetic resonance spectroscopy (MRS) at 7T. Levels of γ-aminobutyric acid (GABA), glutamate (Glu), glutathione (GSH), N-acetylaspartylglutamate (NAAG), N-acetylaspartate (NAA), and myo-inositol (mI) were quantified relative to total creatine (tCr). The effect of diagnosis on metabolite levels, and relationships between metabolite levels and memory and executive function, correcting for age, were investigated. MCI patients showed significantly decreased GABA/tCr (ACC, PCC), Glu/tCr (PCC), and NAA/tCr (PCC), and significantly increased mI/tCr (ACC). In the combined group, worse episodic verbal memory performance was correlated with lower Glu/tCr (PCC), lower NAA/tCr (PCC), and higher mI/tCr (ACC, PCC). Worse verbal fluency performance was correlated with lower GSH/tCr (PCC). In summary, MCI is associated with decreased GABA and glutamate, most consistently in the PCC. Further studies in larger patient samples should be undertaken to determine the utility of 7T MRS in detecting MCI-related neurochemical changes.

Quantitation of in vivo brain glutathione conformers in cingulate cortex among age‐matched control, MCI, and AD patients using MEGA‐PRESS

“…Recently, a 1 H-MRS study on 7 T using PRESS sequence among HC and MCI patients reported significant changes of GABA (p < .005), mI (p < .001) in ACC and GABA (p < .009), Glu (p < .024), and mI (p < .010) in PCC regions and no significant change in GSH was observed in either of these regions (Oeltzschner et al, 2019). On the contrary, the reduced glutamate (Glu), glutamine (Gln), and GSH, and an increase in Cr levels of PCC region have been reported as agerelated changes (Suri et al, 2017).…”

Advances in multimodal data fusion in neuroimaging: Overview, challenges, and novel orientation

“…In recent years, with advances in the technical development of MR hardware and pulse sequences, the roles of glutamate, the excitatory neurotransmitter, and GABA, the inhibitory neurotransmitter, in MCI patients became the main focus [79] , [80] , [81] . For example, with ultra-high field 7 Tesla MR scanner, abnormal concentrations of GABA, glutamate, NAA, glutathione, and myo-inositol (mI) in different brain regions were detected [82] . The manifestations of 1 HMRS in MCI patients were mainly shown in decreased NAA/Cr ratio and increased mI/Cr ratio.…”

Relationship of Parieto-Occipital Brain Energy Phosphate Metabolism and Cognition Using 31P MRS at 7-Tesla in Amnestic Mild Cognitive Impairment

“…Building on this prior evidence, the current work expands the knowledge by going one step further in measuring phosphorus metabolites, an indicator of BEM directly using 31 P MRS at 7T, followed by exploring the relationship of these phosphorus metabolites with cognition in aMCI. To date, research in MCI has focused largely on the macroscopic pathological contributing factors associated with neurodegeneration, such as the accumulation of amyloid and structural alteration (Mufson et al, 2012;Oeltzschner et al, 2019). However, there is a desire to better understand the microscopic biological mechanisms taking place inside the cells of the in vivo human brain, now that researchers have access to more advanced imaging technology and analytics.…”

“…However, recent advancements in MRI technology to use UHF magnets have enabled the robust application of the 31 P MRS technique (Godlewska et al, 2017). UHF increases the SNR with a higher spectral resolution with enhanced sensitivity of neurochemicals and neurometabolites, which are present in minute concentrations (Mekle et al, 2009;Pradhan et al, 2015;Oeltzschner et al, 2019). To date, no study has used the UHF methodology of 31 P MRS in understanding the relationship of high-energy phosphate and membrane phospholipid metabolites relationship with cognition in an aMCI group.…”