Longitudinal structural and metabolic changes in frontotemporal dementia

Objective: To compare the sensitivity of structural MRI and 18F-Fludeoxyglucose PET (18FDG-PET) to detect longitudinal changes in frontotemporal dementia (FTD).
Methods: Thirty patients with behavioral-variant FTD (bvFTD), 7 with non-fluent/agrammatic variant primary progressive aphasia (nfvPPA), 16 with semantic variant PPA (svPPA) and 43 cognitively normal controls underwent 2-4 MRI and 18FDG-PET scans (total scan/visit=270) as part of the Frontotemporal Lobar Degeneration Neuroimaging Initiative study. Linear mixed-effects models were carried out voxel-wise and in regions of interest to identify areas showing decreased volume or metabolism over time in patients as compared to controls.
Results: At baseline, patients with bvFTD showed bilateral temporal, dorsolateral and medial prefrontal atrophy/hypometabolism that extended with time into adjacent structures and parietal lobe. In nfvPPA, baseline atrophy/hypometabolism in supplementary motor cortex extended with time into left greate...