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P2‐001: Spatial smoothing impacts effect size of ADNI florbetapir and FDG PET data
Author(s) -
Klein Gregory,
Sampat Mehul,
Staewen Davis,
Scott David,
Suhy Joyce
Publication year - 2015
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2015.06.537
Subject(s) - nuclear medicine , white matter , smoothing , magnetic resonance imaging , mathematics , medicine , statistics , radiology
Background: We compare results of differing PET scanner spatial resolution on effect size of standard uptake value ratio (SUVR) measurements in Florbetapir and FDG images from the ADNI database. Most reported ADNI analyses use “Level 4” preprocessed data [Koeppe] smoothed to a uniform isotropic resolution of 8mm FWHM, but there is the potential that the unsmoothed data contains more sensitive information. Methods:Freesurfer was used to obtain an ROI parcellation on T1 MRI data from 458 subjects (175 Normal, 92 EMCI, 153 LMCI, 39AD). Florbetapir and FDG data from two time points approximately 24 months apart were registered to the MRI data in T1 native space, and SUVR’s were computed at each time point. Results were obtained from both ADNI level 4 smoothed data, and from unsmoothed images (ADNI level 3). Cross sectional effect sizes between AD, EMCI, LMCI and Normal groups were evaluated using Cohen’s d. Effect size of longitudinal change in each group was also compared. Eight reference regions including whole cerebellum, brainstem and subcortical white matter were evaluated for the Florbetapir data, and FDG data were evaluated using whole brain and whole cerebellar reference regions. Results: Unsmoothed data consistently showed slightly higher effect size in both the cross sectional and