Data from: 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 greater than right precentral, dorsolateral and
dorsomedial prefrontal cortex. In svPPA, baseline atrophy/hypometabolism
encompassed the anterior temporal and medial prefrontal cortex and
longitudinal changes were found in temporal, orbitofrontal and lateral
parietal cortex. Across syndromes, there was substantial overlap in the
brain regions showing volume and metabolism loss. Even though the pattern
of metabolic decline was more extensive, metabolic changes were also more
variable and sample size estimates were similar or higher for 18FDG-PET
compared to MRI. Conclusion: Our findings demonstrated the sensitivity of
18FDG-PET and structural MRI for tracking disease progression in FTD. Both
modalities showed highly overlapping patterns of longitudinal change and
comparable sample size estimates to detect longitudinal changes in future
clinical trials.