Correlates of cognitive impairment in patients with leukoaraiosis by magnetic resonance spectroscopy

Abstract

To explore the pathological changes in patients with leukoaraiosis (LA) by magnetic resonance spectroscopy (MRS) and examine its relationship with cognitive function. Twenty-three LA patients and 23 age and gender-matched healthy subjects were recruited from the Department of Neurology, Beijing Chaoyang Hospital, Capital Medical University between August 2010 and November 2010. All participants underwent the neuropsychological tests. Multi-voxel chemical shift imaging was performed and the regions of interest were positioned in bilateral frontal white matter. The relative metabolite ratios, involving N-acetyl aspartate/choline ratio (NAA/Cho), N-acetyl aspartate/creatine (NAA/Cr) and choline/creatine (Cho/Cr), were estimated. The correlation of the MRS data and the performance of cognitive function was analyzed. The LA patients were associated with a worse performance of mini mental state examination (MMSE) versus the healthy controls (24 ± 3 vs 28 ± 1, P < 0.05). Univariate analysis of the MRS data revealed the ratios of NAA/Cho and NAA/Cr significantly decreased in bilateral frontal white matter lesions in the LA group versus the control group (1.72 ± 0.20 vs 1.96 ± 0.36, 1.67 ± 0.17 vs 1.85 ± 0.21, P < 0.05). The values of NAA/Cr and NAA/Cho in normal appearing white matter increased versus the LA group (1.83 ± 0.24 vs 1.72 ± 0.20, 1.78 ± 0.28 vs 1.67 ± 0.17) and decreased versus the control group (1.83 ± 0.24 vs 1.96 ± 0.36, 1.78 ± 0.28 vs 1.85 ± 0.21). But no significant differences were found (P > 0.05). The ratio of Cho/Cr did not differ among 3 groups (P > 0.05). The pathological change of NAA/Cr in white matter lesion in LA patients was markedly correlated with the performance of MMSE (r = 0.47, P < 0.05). NAA may be a marker of axonal loss/dysfunction in LA patients. And the changes of NAA/Cr have a positive correlation with cognitive impairment.