Correlations between MRS and DTI in cerebral small vessel disease

Abstract

Cerebral small vessel disease results in lacunar infarcts and cognitive impairment. Diffusion tensor imaging (DTI) demonstrates a reduction in fractional anisotropy and increase in mean diffusivity, which correlates more strongly with cognition than conventional MRI. The underlying pathological basis for these DTI changes is not known. In this study magnetic resonance spectroscopy was used to determine the biochemical basis of these DTI alterations. Twenty-five patients with lacunar stroke and radiological leukoaraiosis were recruited. Chemical shift imaging (CSI) and DTI were performed on a 1.5 T MRI scanner. A region of interest was positioned in the white matter of the centrum semiovale. Multivoxel CSI data were processed and the metabolite ratios estimated. DTI parameters corresponding to the exact region of tissue excited by CSI were obtained. Mean spectroscopy data and DTI values for each subject were correlated. Univariate analysis revealed a positive correlation between N-acetyl aspartate-creatine (NAA/Cr) and fractional anisotropy (r = 0.52, p = 0.008), and a negative correlation with mean diffusivity (r = -0.51, p = 0.009). Results remained little changed after controlling for mean percentage lesion and mean percentage white matter per voxel (with fractional anisotropy r = 0.54, p = 0.008, and with mean diffusivity r = -0.52, p = 0.01). These findings are consistent with axonal loss or dysfunction, or both, accounting for at least part of the DTI abnormalities found in patients with small vessel disease. It provides evidence that DTI identifies axonal disruption in white matter tracts.

Imaging age‐related cognitive decline: A comparison of diffusion tensor and magnetization transfer MRI

“…FA provides information on the main direction of diffusion and is therefore likely to be a better indicator of white matter tract disruption (24). Studies in which DTI has been correlated with magnetic resonance spectroscopy have found FA correlated most strongly with N-acetyl aspartate, a marker of neuronal and axonal integrity, consistent with DTI being a measure of axonal damage (9,25). Therefore, this stronger correlation is consistent with white matter tract disruption and secondary corticalsubcortical and cortical-cortical disconnection playing a role in age-related cognitive decline (5).…”

Multimodal MRI in Cerebral Small Vessel Disease

“…15 Percentage lesion volume was determined as a ratio of lesion volume to nonnormalized brain volume.…”

Abnormalities of magnetic resonance spectroscopy and diffusion tensor imaging are correlated with executive dysfunction in patients with ischemic leukoaraiosis

“…[6][7][8] This technique allows non-invasive imaging of metabolic changes within brain tissue. Evidence of neuronal or axonal loss and damage can be obtained by measuring N-acetylaspartate (NAA), a marker of neuronal and axonal integrity, viability, activity, and function.…”