Decline of cerebral glucose metabolism in frontotemporal dementia: a longitudinal 18F-FDG-PET-study

ObjectiveTo identify the pattern of progression of decline of cerebral glucose metabolism in frontotemporal dementia (FTD, frontal variant).Methods22 patients with mild FTD underwent 18F-FDG-positron emission tomography at baseline and at follow-up in average 19.5 months later. Patient scans were compared with scans from 15 healthy age-matched control subjects on a voxel-by-voxel basis using SPM-99.ResultsAs compared with healthy control subjects at baseline patients with FTD showed a significant symmetrical hypometabolism of the frontal lobes sparing the motor cortex, of the caudate nuclei, insula and thalamus bilaterally. At follow-up further significant reductions in glucose metabolism were observed in the parietal and temporal cortices.ConclusionsIn early stages of FTD the neurodegenerative process is limited to the frontal lobes. During the progression of the disease, the pathological changes pass over the lobar borders and spread into the parietal and temporal cortices.