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© 2014. This work is licensed under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.

Abstract

In neurodegeneration research, normalization of regional volumes by intracranial volume (ICV) is important to estimate the extent of disease-driven atrophy. There is little agreement as to whether raw volumes, volume-to-ICV fractions or regional volumes from which the ICV factor has been regressed out should be used for volumetric brain imaging studies. Using multiple regional cortical and subcortical volumetric measures generated by Freesurfer (51 in total), the main aim of this study was to elucidate the implications of these adjustment approaches. Magnetic resonance imaging (MRI) data were analyzed from two large cohorts, the population-based PIVUS cohort (N=406, all subjects age 75) and the Alzheimer disease Neuroimaging Initiative (ADNI) cohort (N=724). Further, we studied whether the chosen ICV normalization approach influenced the relationship between hippocampus and cognition in the three diagnostic groups of the ADNI cohort (Alzheimer’s disease, mild cognitive impairment and healthy individuals). The ability of raw vs adjusted hippocampal volumes to predict diagnostic status was also assessed. In both cohorts raw volumes correlate positively with ICV, but do not scale directly proportionally with it. The correlation direction is reversed for all volume-to-ICV fractions, except the lateral and third ventricles. Most grey matter fractions are larger in females, while lateral ventricle fractions are greater in males. Residual correction effectively eliminated the correlation between the regional volumes and ICV and removed gender differences. The association between hippocampal volumes and cognition was not altered by ICV normalization. Comparing prediction of diagnostic status using the different approaches, small but significant differences were found. The choice of normalization approach should be carefully considered when designing a volumetric brain imaging study.

Details

Title
The effects of intracranial volume adjustment approaches on multiple regional MRI volumes in healthy aging and Alzheimer's disease
Author
Voevodskaya, Olga; Simmons, Andrew; Nordenskjöld, Richard; Kullberg, Joel; Ahlström, Håkan; Lind, Lars; Wahlund, Lars-Olof; Larsson, Elna-Marie; Westman, Eric; Alzheimer's Disease Neuroimaging Initiative 1 

 Alzheimer's Disease Neuroimaging Initiative 
Section
Original Research ARTICLE
Publication year
2014
Publication date
Oct 7, 2014
Publisher
Frontiers Research Foundation
ISSN
16634365
e-ISSN
16634365
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2301888326
Copyright
© 2014. This work is licensed under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.