Region-specific changes of cerebral white matter during normal aging: A diffusion-tensor analysis

doi:10.1016/j.archger.2007.07.004

Archives of Gerontology and Geriatrics

Volume 47, Issue 1, July–August 2008, Pages 129-138

https://doi.org/10.1016/j.archger.2007.07.004 Get rights and content

Abstract

With aging, the human brain tissue undergoes degeneration and a decline in cognitive function. Diffusion tensor imaging (DTI) is a sensitive method for detecting microstructural changes of the brain white matter (WM). We examined the age-dependent, region-specific, changing patterns in microstructures of the brain. This was preformed by DTI analysis of 58 healthy volunteers from Korea. The fractional anisotropy (FA) and apparent diffusion coefficient (ADC) were measured for each region of interest (ROI) in 22 areas. The FA and ADC values of all 22 ROIs were, respectively, compared among the age groups, by linear regression analysis and analysis of variance. With aging, the ADC values tended to increase and the FA values tended to decrease. Patterns of regional changes of the FA were divided into three subgroups. The cingulum was affected earliest with aging and the age-related WM changes show an anterior to posterior gradient acceleration throughout the decades tested. This study suggests that DTI is sensitive enough a diagnostic tool to detect subtle microstructural changes. These results show that the WM has a region-specific vulnerability to the aging process.

Introduction

The brain displays an assortment of microscopic and macroscopic changes as it ages. Ultimately, the result is some degree of cognitive and functional decline. Many histological studies have demonstrated that WM changes are more prominent than cortical changes with aging (Meier-Ruge et al., 1992, Christiansen et al., 1994, Guttmann et al., 1998, Salat et al., 1999, Good et al., 2001, Jernigan et al., 2001, Bronge et al., 2002, Ge et al., 2002). These changes occur disproportionate to each other.

DTI is a new magnetic resonance imaging (MRI) method that is sensitive to water diffusion. This is a non-invasive tool, which provides more pertinent insights into tissue structure and orientation. These observations are not accessible with the conventional MRI, since the DTI measurements detecting abnormal WM appear as normal from conventional MRI scans. The recent use of DTI has remarkably forwarded the understanding of age-related brain changes. It allows investigators to perform in vivo studies of normally aging individuals at multiple time points. Previous DTI studies have demonstrated age-related changes in the alignment of cellular structures and structural integrity (Courchesne et al., 2000, Nusbaum et al., 2001, Abe et al., 2002, Armstrong et al., 2004, Inglese and Ge, 2004, Salat et al., 2005). However, the regional patterns of age-related changes in brain WM may not be so apparent.

In the current study, we assessed the patterns of microstructural changes of the cerebral WM during the life span of healthy adult Koreans, ranging from their third decade to their eighth decade. This study also evaluated whether these age-related alterations have specific regional patterns in the WM of the brain.

Section snippets

Participants

We enrolled 58 healthy volunteers; 28 males and 30 females, with an age range of 22–78 years. The subjects represented six decade groups, with the following number of subjects in each group: third decade n = 8, fourth decade n = 11, fifth decade n = 10, sixth decade n = 10, seventh decade n = 11, and the eighth decade n = 8. A conventional brain MRI was performed on all of the subjects. The scans were examined by a neuroradiologist to exclude the subjects with morphologic and signal change abnormalities.

Results

Except for the education characteristic, gender and K-MMSE scores were not significantly different among the six age groups (Table 1). ADC values tended to increase with advanced aging, but this was not statistically significant in all the ROIs (p > 0.05). The FA values showed a decreasing trend with aging (Table 2). The regional analysis by linear regression showed a statistically significant decrease in FA with aging in the bilateral hippocampus, the temporal and frontal lobes, centrum

Discussion and conclusions

In this study, the ADC values tend to increase and the FA values tend to decrease with aging. Anatomically speaking, an anterior to posterior gradient acceleration was shown and the cingulum was affected earliest. In previous studies, an increased ADC and a decreased FA value was observed with aging (Courchesne et al., 2000, Nusbaum et al., 2001, Abe et al., 2002, Armstrong et al., 2004, Inglese and Ge, 2004, Salat et al., 2005). However, any statistical correlation of the FA and ADC changes

Acknowledgements

This study was supported by a grant from the Korea Health 21 R&D Project, Ministry of Health & Welfare, and the Republic of Korea (A050079).

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View full text

Region-specific changes of cerebral white matter during normal aging: A diffusion-tensor analysis

Abstract

Introduction

Section snippets

Participants

Results

Discussion and conclusions

Acknowledgements

Neurobiol. Aging

Neurobiol. Aging

Neuroimage

Neurobiol. Aging

Neuroimage

Neurobiol. Aging

Age-related, regional, hemispheric, and medial-lateral differences in myelin integrity in vivo in the normal adult brain

Am. J. Neuroradiol.

Postmortem MRI and histopathology of white matter changes in Alzheimer brains. A quantitative, comparative study

Dement. Geriatr. Cogn. Disord.

Age dependent white matter lesions and brain volume changes in healthy volunteers

Acta Radiol.

Normal brain development and aging: quantitative analysis at in vivo MR imaging in healthy volunteers

Neuroradiology