[18F]FDG-PET in a case of right temporal lobe variant of frontotemporal dementia

[18F] FDG-PET EM UM CASO DE VARIANTE DO LOBO TEMPORAL DIREITO DE DEMÊNCIA FRONTOTEMPORAL

Key words:
positron-emission tomography; fluorodeoxyglucose F18; frontotemporal dementia

Palavras-chave:
tomografia por emissão de pósitrons; fluordeoxiglicose F18; demência frontotemporal

A 61-year-old woman presented with a 4-year history of slowly progressive amnestic and topographical disorientation symptoms, followed by an early onset of apathy, hyperorality, ritualistic behaviors, prosopagnosia, and phonagnosia. Due to diagnostic uncertainty between Frontotemporal Dementia (FTD) and Alzheimer's Disease (AD) pathology, CSF biomarker analysis and brain [18F]FDG-PET were ordered. The first proved negative for AD profile, and the latter demonstrated marked hypometabolism in the right temporal and frontal lobes, areas that also had asymmetric atrophy on brain MRI. These findings, together with the clinical picture, were compatible with the hypothesis of a right temporal lobe variant of FTD.^1,2

Figure
Upper row - A1, A2: [18F]FDG-PET transaxial images showing prominent hypometabolism in the right temporal lobe and, to a lesser degree, in the right frontal and parietal lobes, particularly orbitofrontal areas. B - transaxial T2 FLAIR MRI image showing selective right temporal atrophy. Lower row - C1: a 3D-SSP reconstruction (inferior view) showing prominent hypometabolism in the right temporal lobe and right orbitofrontal cortex. C2 - 3D-SSP projection of comparison with a group of healthy age-matched individuals. Red areas indicate areas of lower metabolism than expected 423x423mm (72 x 72 DPI).

• This study was conducted at Hospital das Clínicas, University of Sao Paulo School of Medicine, São Paulo, SP, Brazil.

REFERENCES

• ¹
  Foster NL, Heidebrink JL, Clark CM, et al. FDG-PET improves accuracy in distinguishing frontotemporal dementia and Alzheimer's disease. Brain 2007;130(Pt 10):2616-35.
• ²
  Seeley WW, Bauer AM, Miller BL, et al. The natural history of temporal variant frontotemporal dementia. Neurology 2005;64:1384-90.

Publication Dates

• Publication in this collection
  23 Sept 2019
• Date of issue
  Jul-Sep 2019

History

• Received
  27 Mar 2019
• Accepted
  13 June 2019