AUTHOR=Li Cheng-Hsuan , Chen Ta-Fu , Chiu Ming-Jang , Yen Ruoh-Fang , Shih Ming-Chieh , Lin Chin-Hsien 

TITLE=Integrated 18F-T807 Tau PET, Structural MRI, and Plasma Tau in Tauopathy Neurodegenerative Disorders

JOURNAL=Frontiers in Aging Neuroscience

VOLUME=13

YEAR=2021

URL=https://www.frontiersin.org/journals/aging-neuroscience/articles/10.3389/fnagi.2021.646440

DOI=10.3389/fnagi.2021.646440

ISSN=1663-4365

ABSTRACT=<p><bold>Background and Objective:</bold> Tau-specific positron emission topography (PET) imaging enables <italic>in vivo</italic> assessment of Alzheimer's disease (AD). We aimed to investigate its performance in combination with plasma tau levels in patients with non-AD tauopathy.</p><p><bold>Methods:</bold> A total of 47 participants were enrolled, including 10 healthy controls, 16 with tauopathy parkinsonism syndromes (9 with corticobasal syndrome [CBS], 7 with progressive supranuclear palsy [PSP]), 9 with frontotemporal dementia (FTD), 4 with AD, and 8 with Parkinson's disease (PD). All participants underwent clinical assessments, <sup>18</sup>F-T807 tau PET, brain MRI, and plasma tau assay.</p><p><bold>Results:</bold> The global cortical standard uptake value ratio (SUVR) of <sup>18</sup>F-T807 PET was comparable between PD and control (<italic>p</italic> = 0.088). The cortical SUVR was significantly higher in AD group (<italic>p</italic> = 0.002) but was modestly increased in PSP group compared to the PD group (<italic>p</italic> = 0.044), especially in parietal and pallidal regions. Asymmetric <sup>18</sup>F-T807 uptake at the pallidum was noted in patients with CBS and FTD. Cortical tau tracer uptake was associated with increased plasma total tau level (<italic>p</italic> = 0.016), especially in frontal and parietal regions. Regional tracer uptake was correlated with cortical thinning in patients with CBS and PSP (CBS: <italic>r</italic> = −0.092, <italic>p</italic> = 0.025; PSP: <italic>r</italic> = −0.114, <italic>p</italic> = 0.015).</p><p><bold>Conclusions:</bold> The <sup>18</sup>F-T807 tau tracer uptake was only modestly increased in patients with PSP. Although the cortical tau tracer uptake correlated with regional cortical atrophy and plasma tau levels, a four-repeated tau-specific tracer is needed for future classifying tauopathy parkinsonism syndromes.</p>