Imaging of amyloid plaques and cerebral glucose metabolism in semantic dementia and Alzheimer’s disease

摘要: Semantic dementia (SD) is a rare clinical syndrome, assigned to the group of frontotemporal lobar degenerations (FTLD). Histopathological analysis has not revealed deposition amyloid plaques in majority SD cases, contrast Alzheimer type (AD). However, based on examination alone reliable differentiation underlying pathology cannot be guaranteed, i.e. AD and may confused some cases. Our aim was determine, whether can differentiated vivo by means plaque PET imaging. In groups patients, matched for gender, age overall degree cognitive impairment, cerebral glucose metabolism examined with [(18)F]Fluorodeoxyglucose (FDG)-PET density assessed using [(11)C]6-OH-BTA-1 (PIB)-PET. A volume-of-interest (VOI), cerebellum as reference region, voxel-based statistical comparisons (SPM2) were carried out between patient healthy controls. To control potential influence atrophy findings, correction partial volume effects performed. Characteristic patterns hypometabolism could demonstrated both clinically defined regional overlap subtle differences (AD: bilateral posterior cingulate, temporoparietal frontal cortex; SD: left>right polar temporal, mesial cortex). Compared controls, significant [(11)C]PIB tracer binding observed only patients (in temporoparietal, cingulate cortex precuneus) but SD. This difference reproduced direct comparison clearly extended metabolic groups. These findings support notion that diagnosed separate entity from general, complement neuropsychological assessment regarding differential diagnosis FTLD dementias characterization improve definition individual prognosis selection scientific trials.