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MRI markers for mild cognitive impairment: comparisons between white matter integrity and gray matter volume measurements.

Zhang Y, Schuff N, Camacho M, Chao LL, Fletcher TP, Yaffe K, Woolley SC, Madison C, Rosen HJ, Miller BL, Weiner MW - PLoS ONE (2013)

Bottom Line: Significant group differences between MCI and CN were detected by each MRI modality: In particular, reduced FA was found in splenium, left isthmus cingulum and fornix; increased DR was found in splenium, left isthmus cingulum and bilateral uncinate fasciculi; reduced GM volume was found in bilateral hippocampi, left entorhinal cortex, right amygdala and bilateral thalamus; and thinner cortex was found in the left entorhinal cortex.Group classifications based on FA or DR was significant and better than classifications based on GM volume.Using either DR or FA together with GM volume improved classification accuracy.

View Article: PubMed Central - PubMed

Affiliation: Center for Imaging of Neurodegenerative Diseases, San Francisco VA Medical Center, San Francisco, California, United States of America. Yu.Zhang@ucsf.edu

ABSTRACT
The aim of the study was to evaluate the value of assessing white matter integrity using diffusion tensor imaging (DTI) for classification of mild cognitive impairment (MCI) and prediction of cognitive impairments in comparison to brain atrophy measurements using structural MRI. Fifty-one patients with MCI and 66 cognitive normal controls (CN) underwent DTI and T1-weighted structural MRI. DTI measures included fractional anisotropy (FA) and radial diffusivity (DR) from 20 predetermined regions-of-interest (ROIs) in the commissural, limbic and association tracts, which are thought to be involved in Alzheimer's disease; measures of regional gray matter (GM) volume included 21 ROIs in medial temporal lobe, parietal cortex, and subcortical regions. Significant group differences between MCI and CN were detected by each MRI modality: In particular, reduced FA was found in splenium, left isthmus cingulum and fornix; increased DR was found in splenium, left isthmus cingulum and bilateral uncinate fasciculi; reduced GM volume was found in bilateral hippocampi, left entorhinal cortex, right amygdala and bilateral thalamus; and thinner cortex was found in the left entorhinal cortex. Group classifications based on FA or DR was significant and better than classifications based on GM volume. Using either DR or FA together with GM volume improved classification accuracy. Furthermore, all three measures, FA, DR and GM volume were similarly accurate in predicting cognitive performance in MCI patients. Taken together, the results imply that DTI measures are as accurate as measures of GM volume in detecting brain alterations that are associated with cognitive impairment. Furthermore, a combination of DTI and structural MRI measurements improves classification accuracy.

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Related in: MedlinePlus

GM and WM parcellations.A. Automated parcellation of 21 cortical and subcortical ROIs for GM measurement, performed by Freesurfer software. B. Automated parcellation of 20 deep WM ROIs for DTI measurement, performed by SPM8.
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pone-0066367-g001: GM and WM parcellations.A. Automated parcellation of 21 cortical and subcortical ROIs for GM measurement, performed by Freesurfer software. B. Automated parcellation of 20 deep WM ROIs for DTI measurement, performed by SPM8.

Mentions: Based on previous MRI reports of prominent brain alterations in AD and MCI [46]–[48], GM volumes were evaluated in 21 anatomical ROIs, including 3 callosal regions (anterior, middle and posterior corpus callosum), 8 medial temporal regions (bilateral hippocampus, entorhinal cortex, parahippocampal cortex and amygdala), 6 parietal regions (bilateral precuneus, posterior and isthmus cingulate gyrus) and 4 subcortical regions (bilateral thalamus and putamen) (Figure 1A). Although several other ROIs, such as inferior, middle and superior temporal cortex as well as inferior parietal cortex have been reported in the literature, we were unable to obtain reliable values from these regions across all subjects with the automated Freesurfer procedure due to limited image quality. Thus the study was limited in the above 21 ROIs in which FreeSurfer measurements were available for all participants. Regional values of the GM volume were normalized to total intracranial volume (ICV), to account for variations in head size.


MRI markers for mild cognitive impairment: comparisons between white matter integrity and gray matter volume measurements.

Zhang Y, Schuff N, Camacho M, Chao LL, Fletcher TP, Yaffe K, Woolley SC, Madison C, Rosen HJ, Miller BL, Weiner MW - PLoS ONE (2013)

GM and WM parcellations.A. Automated parcellation of 21 cortical and subcortical ROIs for GM measurement, performed by Freesurfer software. B. Automated parcellation of 20 deep WM ROIs for DTI measurement, performed by SPM8.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3675142&req=5

pone-0066367-g001: GM and WM parcellations.A. Automated parcellation of 21 cortical and subcortical ROIs for GM measurement, performed by Freesurfer software. B. Automated parcellation of 20 deep WM ROIs for DTI measurement, performed by SPM8.
Mentions: Based on previous MRI reports of prominent brain alterations in AD and MCI [46]–[48], GM volumes were evaluated in 21 anatomical ROIs, including 3 callosal regions (anterior, middle and posterior corpus callosum), 8 medial temporal regions (bilateral hippocampus, entorhinal cortex, parahippocampal cortex and amygdala), 6 parietal regions (bilateral precuneus, posterior and isthmus cingulate gyrus) and 4 subcortical regions (bilateral thalamus and putamen) (Figure 1A). Although several other ROIs, such as inferior, middle and superior temporal cortex as well as inferior parietal cortex have been reported in the literature, we were unable to obtain reliable values from these regions across all subjects with the automated Freesurfer procedure due to limited image quality. Thus the study was limited in the above 21 ROIs in which FreeSurfer measurements were available for all participants. Regional values of the GM volume were normalized to total intracranial volume (ICV), to account for variations in head size.

Bottom Line: Significant group differences between MCI and CN were detected by each MRI modality: In particular, reduced FA was found in splenium, left isthmus cingulum and fornix; increased DR was found in splenium, left isthmus cingulum and bilateral uncinate fasciculi; reduced GM volume was found in bilateral hippocampi, left entorhinal cortex, right amygdala and bilateral thalamus; and thinner cortex was found in the left entorhinal cortex.Group classifications based on FA or DR was significant and better than classifications based on GM volume.Using either DR or FA together with GM volume improved classification accuracy.

View Article: PubMed Central - PubMed

Affiliation: Center for Imaging of Neurodegenerative Diseases, San Francisco VA Medical Center, San Francisco, California, United States of America. Yu.Zhang@ucsf.edu

ABSTRACT
The aim of the study was to evaluate the value of assessing white matter integrity using diffusion tensor imaging (DTI) for classification of mild cognitive impairment (MCI) and prediction of cognitive impairments in comparison to brain atrophy measurements using structural MRI. Fifty-one patients with MCI and 66 cognitive normal controls (CN) underwent DTI and T1-weighted structural MRI. DTI measures included fractional anisotropy (FA) and radial diffusivity (DR) from 20 predetermined regions-of-interest (ROIs) in the commissural, limbic and association tracts, which are thought to be involved in Alzheimer's disease; measures of regional gray matter (GM) volume included 21 ROIs in medial temporal lobe, parietal cortex, and subcortical regions. Significant group differences between MCI and CN were detected by each MRI modality: In particular, reduced FA was found in splenium, left isthmus cingulum and fornix; increased DR was found in splenium, left isthmus cingulum and bilateral uncinate fasciculi; reduced GM volume was found in bilateral hippocampi, left entorhinal cortex, right amygdala and bilateral thalamus; and thinner cortex was found in the left entorhinal cortex. Group classifications based on FA or DR was significant and better than classifications based on GM volume. Using either DR or FA together with GM volume improved classification accuracy. Furthermore, all three measures, FA, DR and GM volume were similarly accurate in predicting cognitive performance in MCI patients. Taken together, the results imply that DTI measures are as accurate as measures of GM volume in detecting brain alterations that are associated with cognitive impairment. Furthermore, a combination of DTI and structural MRI measurements improves classification accuracy.

Show MeSH
Related in: MedlinePlus