PET biomarkers in behavioral variant Frontotemporal dementia: analysis of an Argentine cohort.

Abstract

AbstractBackgroundBehavioral variant frontotemporal dementia (bvFTD) is a neurodegenerative disorder characterized by early and progressive changes in behavior, emotional processing and executive control. This entity represents a diagnostic challenge in which positron emission tomography (PET) may play a key role in the diagnosis and follow‐up in vivo with a minimally invasive method. The aim of this work is to evaluate PET biomarkers in a cohort of patients with a clinical diagnosis of bvFTD.Method21 normal controls (NC: 64 ± 9 years) and 20 patients with a diagnosis of probable bvFTD (65 ± 7 years) were evaluated by: neurological, neuropsychological, neuropsychiatric evaluation and PET imaging biomarkers: [18F]‐FDG, [18F]‐AV1451 (TAU), [11C]‐PIB. For neuroimaging processing and analysis, they were spatially normalized to an FDG template. Group comparisons (voxel‐based) of each biomarker were performed by t‐test (SPM12) using cerebellar gray matter as reference tissue, and for inter‐biomarker uncoupling comparison a covariate of uptake in total cortex was used.ResultIn the statistical comparison between NC vs. bvFTD groups (p<0.05), hypometabolism is observed at the frontotemporal level and hypermetabolism in the precentral region (FDG). Amyloid marker (PIB) uptake shows no significant difference between groups in much of the cortex, except in the precentral region. TAU uptake shows a significant difference, greater in bvFTD, at frontal, parietal and precuneus levels. In the uncoupling between FDG and TAU biomarkers, it is observed that hypometabolism is related to an increase in TAU uptake in medial and inferior temporal regions. Differences between PIB and TAU are mainly observed in frontotemporal regions. There was an association between clinical symptoms (mainly apathy) and the anatomical distribution of [18F]‐FDG, [18F]‐AV1451 radiotracers (TAU).ConclusionPET biomarkers are a valuable tool in the diagnosis of bvFTD. The [11C]‐PIB may be of paramount importance in the differential diagnosis of FTvc FTD with Alzheimer’s disease. FDG is a very sensitive biomarker of neuronal metabolism and its variations, sometimes losing specificity. Advances in tracers such as [18F]‐AV1451 (TAU) can provide important information on the underlying neuropathological process. The combined use of these tools brings us closer to understanding the biological phenomena behind the cardinal symptoms of bvFTD.