Get 20M+ Full-Text Papers For Less Than $1.50/day. Start a 14-Day Trial for You and Your Team.

Learn More →

Whither the Hippocampus? FDG-PET Hippocampal Hypometabolism in Alzheimer Disease Revisited

Whither the Hippocampus? FDG-PET Hippocampal Hypometabolism in Alzheimer Disease Revisited BACKGROUND AND PURPOSE: The hippocampus is a widely recognized area of early change in AD, yet voxelwise analyses of FDG-PET activity differences between AD and CN controls have consistently failed to identify hippocampal hypometabolism. In this article, we propose a high-dimensional PET-specific analysis framework to determine whether important hippocampal metabolic FDG-PET activity differences between patients with AD and CN subjects are embedded in the Jacobian information generated during spatial normalization. MATERIALS AND METHODS: Resting FDG-PET data were obtained from 102 CN and 92 participants with AD from the ADNI data base. A PET-study-specific template was constructed using symmetric diffeomorphic registration. Spatially normalized raw FDG maps, Jacobian determinant maps, and modulated maps were generated for all subjects. Statistical parametric mapping and tensor-based morphometry were performed, comparing patients with AD with CN subjects. RESULTS: Whole-brain spatially normalized raw FDG maps demonstrated robust hypometabolism in cingulate gyrus and bilateral parietal areas. No hippocampal differences were present, except on ROI-based analyses with a hippocampal mask. Whole-brain modulated maps demonstrated robust bilateral hippocampal hypometabolism, and some hypometabolism in the posterior cingulate. Tensor-based morphometry demonstrated robust hippocampal differences only. CONCLUSIONS: These results demonstrate that hippocampal metabolic differences are embedded in the Jacobian information from the spatial normalization procedure. We introduce a voxelwise PET-specific analysis framework based on the use of a PET-population-specific template, high-dimensional symmetric diffeomorphic normalization, and the use of Jacobian information, which can provide substantially increased statistical power and an order of magnitude decrease in imaging costs. ABBREVIATIONS: AD Alzheimer disease ADNI Alzheimer's Disease Neuroimaging Initiative CN cognitively normal FWE family-wise error hpa hippocampal/parahippocampal/amygdala MCI mild cognitive impairment SyN symmetric diffeomorphic registration VBM voxel-based morphometry http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png American Journal of Neuroradiology American Journal of Neuroradiology

Whither the Hippocampus? FDG-PET Hippocampal Hypometabolism in Alzheimer Disease Revisited

American Journal of Neuroradiology , Volume 33 (10): 1975 – Nov 1, 2012

Loading next page...
 
/lp/american-journal-of-neuroradiology/whither-the-hippocampus-fdg-pet-hippocampal-hypometabolism-in-zhk4M6SGYr
Publisher
American Journal of Neuroradiology
Copyright
Copyright © 2012 by the American Society of Neuroradiology.
ISSN
0195-6108
eISSN
1936-959X
DOI
10.3174/ajnr.A3113
pmid
22700745
Publisher site
See Article on Publisher Site

Abstract

BACKGROUND AND PURPOSE: The hippocampus is a widely recognized area of early change in AD, yet voxelwise analyses of FDG-PET activity differences between AD and CN controls have consistently failed to identify hippocampal hypometabolism. In this article, we propose a high-dimensional PET-specific analysis framework to determine whether important hippocampal metabolic FDG-PET activity differences between patients with AD and CN subjects are embedded in the Jacobian information generated during spatial normalization. MATERIALS AND METHODS: Resting FDG-PET data were obtained from 102 CN and 92 participants with AD from the ADNI data base. A PET-study-specific template was constructed using symmetric diffeomorphic registration. Spatially normalized raw FDG maps, Jacobian determinant maps, and modulated maps were generated for all subjects. Statistical parametric mapping and tensor-based morphometry were performed, comparing patients with AD with CN subjects. RESULTS: Whole-brain spatially normalized raw FDG maps demonstrated robust hypometabolism in cingulate gyrus and bilateral parietal areas. No hippocampal differences were present, except on ROI-based analyses with a hippocampal mask. Whole-brain modulated maps demonstrated robust bilateral hippocampal hypometabolism, and some hypometabolism in the posterior cingulate. Tensor-based morphometry demonstrated robust hippocampal differences only. CONCLUSIONS: These results demonstrate that hippocampal metabolic differences are embedded in the Jacobian information from the spatial normalization procedure. We introduce a voxelwise PET-specific analysis framework based on the use of a PET-population-specific template, high-dimensional symmetric diffeomorphic normalization, and the use of Jacobian information, which can provide substantially increased statistical power and an order of magnitude decrease in imaging costs. ABBREVIATIONS: AD Alzheimer disease ADNI Alzheimer's Disease Neuroimaging Initiative CN cognitively normal FWE family-wise error hpa hippocampal/parahippocampal/amygdala MCI mild cognitive impairment SyN symmetric diffeomorphic registration VBM voxel-based morphometry

Journal

American Journal of NeuroradiologyAmerican Journal of Neuroradiology

Published: Nov 1, 2012

There are no references for this article.