Quantitative multivoxel proton MR spectroscopy study of brain metabolites in patients with amnestic mild cognitive
Zhong-Xian Yang1, Shan-Shan Huo, Xiao-Fang Cheng
1Department of Medical Imaging, The Second Affiliated Hospital, Medical College of Shantou University, Shantou, China.
Introduction:
The purpose of this study is to investigate brain metabolic changes in patients with amnestic mild cognitive impairment (aMCI) using multivoxel proton MR spectroscopy ((1)H-MVS).
Methods:
Fourteen aMCI patients and fifteen healthy control subjects participated in this experiment. All MR measurements were acquired using a 1.5-T GE scanner. (1)H-MVS point resolved spectroscopy (2D PROBE-CSI PRESS) pulse sequence (TE = 35 ms; TR = 1,500 ms; phase × frequency, 18 × 18) was used for acquiring MRS data. All data were post-processed using Spectroscopy Analysis by General Electric software and linear combination of model (LCModel). The absolute concentrations of N-acetylaspartate (NAA), choline (Cho), myoinositol (MI), creatine (Cr), and the metabolite ratios of NAA/Cr, Cho/Cr, MI/Cr, and NAA/MI were measured bilaterally in the posterior cingulate gyrus (PCG), inferior precuneus (Pr), paratrigonal white matter (PWM), dorsal thalamus (DT), and lentiform nucleus (LN).
Results:
Patients with aMCI displayed significantly lower NAA levels in the bilateral PCG (p < 0.01), PWM (p < 0.05), and left inferior Pr (p < 0.05). The metabolite ratio of NAA/MI was decreased in the bilateral PCG (p < 0.01) and PWM (p < 0.05) and in the left DT (p < 0.01). NAA/Cr was decreased in the left PCG (p < 0.01), DT (p < 0.05), right PWM (p < 0.05), and LN (p < 0.05). However, MI/Cr was elevated in the right PCG (p < 0.01) and left PWM (p < 0.05). Significantly increased Cho level was also evident in the left PWM (p < 0.05).
Conclusions:
Our observations of decreased NAA, NAA/Cr, and NAA/MI, in parallel with increased Cho and MI/Cr might be characteristic of aMCI patients.
Insights
Brain metabolic changes, including reduced N-acetylaspartate (NAA) and altered choline (Cho) and myoinositol (MI) levels, characterize amnestic mild cognitive impairment (aMCI). These findings may serve as biomarkers for aMCI detection.
Area of Science:
- Neuroimaging and Spectroscopy
- Biomarkers for Neurodegenerative Diseases
Background:
- Amnestic mild cognitive impairment (aMCI) represents a transitional stage between normal aging and Alzheimer's disease.
- Understanding brain metabolic alterations in aMCI is crucial for early diagnosis and intervention.
- Multivoxel proton magnetic resonance spectroscopy ((1)H-MVS) offers a non-invasive method to assess brain metabolites.
Purpose of the Study:
- To investigate and characterize specific brain metabolic changes in patients diagnosed with aMCI.
- To utilize multivoxel proton MR spectroscopy ((1)H-MVS) for quantifying metabolite concentrations and ratios in key brain regions.
- To identify potential spectroscopic biomarkers indicative of aMCI.
Main Methods:
- Study included 14 aMCI patients and 15 healthy controls, with all MR measurements acquired on a 1.5-T GE scanner.
- Proton MR spectroscopy data were acquired using a 2D PROBE-CSI PRESS pulse sequence.
- Absolute concentrations and ratios of key metabolites (NAA, Cho, MI, Cr) were measured in multiple brain regions including the posterior cingulate gyrus (PCG) and dorsal thalamus (DT).
Main Results:
- Significantly decreased levels of N-acetylaspartate (NAA) were observed in aMCI patients in the bilateral posterior cingulate gyrus (PCG) and paratrigonal white matter (PWM).
- Reduced NAA/MI and NAA/Cr ratios were found in multiple brain regions, including PCG, PWM, and dorsal thalamus (DT), in aMCI patients.
- Elevated myoinositol/creatine (MI/Cr) ratios and increased choline (Cho) levels were noted in specific regions like the right PCG and left PWM in the aMCI group.
Conclusions:
- The observed metabolic profile in aMCI patients, characterized by decreased NAA and altered NAA/Cr and NAA/MI ratios, alongside increased Cho and MI/Cr, may be a distinct feature of the condition.
- These metabolic alterations identified through (1)H-MVS could serve as potential neuroimaging biomarkers for diagnosing aMCI.
- Further research is warranted to validate these findings and explore their clinical utility in distinguishing aMCI from other cognitive disorders.
