IC‐P‐206: Similarities and Differences in Patterns of [F18]‐Av‐1451 And [F18]‐FDG in Frontotemporal Dementia

cohort.Methods:18 participants were included. 80-100minute [F] AV-1451 images were normalized to SUVR units by cerebellar grey matter. Measures from antecedent cross-sectional [F]FDG-PET, baseline [F]Florbetapir PET and MRI that were approximately 3yrs before the [F]AV-1451 scan (mean 1⁄4 3.2yrs; range 1⁄4 2.05.1yrs), and two-year change in florbetapir and MRI measures were explored as independent predictors of [F]AV-1451 SUVR values extracted from the whole cortex and the medial temporal lobe (MTL). [F]Florbetapir and []FDG scans were pre-processed as described [1]. [F]Florbetapir scans were intensity normalized by the whole cerebellum (baseline) and a composite of the cerebral white matter, brainstem, and whole cerebellum (longitudinal). [F]FDG intensity was normalized to the pons. Baseline global cortical [F]Florbetapir and mean parietal [F]FDG SUVR, as well as 2yr annualized percent change (APC) in global [F]Florbetapir were extracted. Baseline and 2-year hippocampal volumes (HV) were estimated using Freesurfer v5.1. Step-wise linear models predicting cortical or MTL [F]AV-1451 SUVR with the following predictors were assessed: cortical [F]Florbetapir SUVR, annual percent change (APC) in cortical [F]Florbetapir SUVR, mean parietal [F]FDG SUVR, HV, APC in HV, diagnosis (control or MCI/AD), age, gender, and time between scans. Results:Mean cortical [F]AV-1451 uptake was predicted only by diagnosis and cross-sectional mean cortical [F]Florbetapir SUVR. However, MTL [F]AV-1451 uptake was predicted by both mean cross-sectional cortical [F]Florbetapir uptake and cross-sectional HV. Conclusions: Overall, [F]AV-1451 uptake (representative of tau deposition) was predicted by the extent of cortical amyloid deposition ([F]Florbetapir uptake) approximately three years prior. Hippocampal atrophy may interact with this process. [1] Risacher et al. (2015) Alzheimer’s & Dementia, (11): 1417.