Magnetic resonance spectroscopy quantitative research of changes in bifrontal metabolite concentration and cognitive dysfunction

Jie CHEN; Yeyu XIAO; Meilian WU; Xiaoying LIANG; Xuewen XIA

ABSTRACT

Objective:

To study the change of bifrontal metabolite concentration in patients with mild cognitive impairment (MCI) and its relationship with substantia alba demyelination using magnetic resonance spectroscopy (MRS) combined with linear combination of model (LCModel) quantitative technique.

Methods:

From May 2016 to December 2018, 25 patients with MCI (group A; 12 males, 13 females, age (60.5±5.2) years) and 15 healthy control subjects (group B; 6 males, 9 females, age (59.5±3.5) years) in the Second Affiliated Hospital of Shantou University Medical College were prospectively enrolled. The MCI patients were classified into 2 subgroups according to MRI

results:

group A1 with substantia alba demyelination (7 males, 4 females, age (62.1±3.9) years) and group A2 without substantia alba demyelination (5 males, 9 females, age (59.2±5.8) years). Software LCModel was used to quantitatively analyze the MRS original data and measure the absolute concentration of N-acetylaspartate compound (NAA), creatine compound (Cr), choline-containing compound (Cho), myoinositol (mI) and ratios of NAA/Cr, Cho/Cr, mI/Cr, NAA/mI in bilateral frontal lobe. Independent-sample t test was used to analyze the inter-group differences of the above parameters, while Pearson correlation analysis was performed to analyze correlations between the above parameters and cognitive function scores.

Results:

Compared with group B, group A had higher mI of both left and right frontal lobes (left (5.19±1.28) vs (4.32±0.83), right (4.87±1.11) vs (3.85±0.98); t values 2.34, 2.93, both P<0.05); the mI/Cr of right frontal lobe in group A was also higher (1.19±0.31 vs 0.98±0.25; t=2.21, P<0.05), while the NAA/mI of right frontal lobe was lower (1.37±0.34 vs 1.78±0.47; t=-3.16, P<0.01). Differences of other parameters between group A and group B, and those between group A1 and group A2 were not significantly different ( t values -1.70 to 1.35, all P>0.05). The mI of right frontal lobe was negatively correlated with Montreal Cognitive Assessment (MoCA) score and Mini-Mental State Examination (MMSE) score( r values -0.35, -0.38, both P<0.05), on the contrary, NAA/mI of right frontal lobe was positively correlated with the cognitive function scores ( r values 0.43, 0.40, both P<0.05).

Conclusion:

MCI may be related to the loss or dysfunction of neurons in the right frontal lobe, and MRS can provide theoretical basis for early recognition of MCI to some extent.