Nuklearmedizin 2020; 59(02): 106
DOI: 10.1055/s-0040-1708171
Wissenschaftliche Vorträge
Kognitive Störungen
© Georg Thieme Verlag KG Stuttgart · New York

Binding characteristics of 18 F-PI-2620 differentiate the clinically predicted tau isoform in suspected 3/4-repeat and 4-repeat tauopathies

M Song
1   LMU München, Klinik und Poliklinik für Nuklearmedizin, München
,
H Barthel
2   University of Leipzig, Klinik und Poliklinik für Nuklearmedizin, Leipzig
,
T van Eimeren
3   University of Cologne, Klinik und Poliklinik für Nuklearmedizin, Köln
,
K Marek
4   InviCRO, LLC, Boston
,
L Beyer
1   LMU München, Klinik und Poliklinik für Nuklearmedizin, München
,
J Sauerbeck
1   LMU München, Klinik und Poliklinik für Nuklearmedizin, München
,
M Barbe
5   University of Cologne, Köln
,
ML Schroeter
6   University of Leipzig, Clinic for Cognitive Neurology, Leipzig
,
DS Russell
7   Molecular Neuroimaging, New Haven
,
A Stephens
8   Piramal Imaging GmbH, Berlin
,
J Herms
9   LMU München, Center for Neuropathology and Prion Research, München
,
J Levin
10   LMU München, Neurologische Klinik und Poliklinik, München
,
J Classen
11   University of Leipzig, Leipzig
,
G Höglinger
12   DZNE, München
,
P Bartenstein
1   LMU München, Klinik und Poliklinik für Nuklearmedizin, München
,
V Villemagne
13   University of Melbourne, The Florey Institute of Neuroscience and Mental Health, Melbourne
,
A Drzezga
14   University of Cologne, Klinik und Poliklinik für Nuklearmedizin, Köln
,
J Seibyl
7   Molecular Neuroimaging, New Haven
,
O Sabri
11   University of Leipzig, Leipzig
,
M Brendel
1   LMU München, Klinik und Poliklinik für Nuklearmedizin, München
› Author Affiliations
Further Information

Publication History

Publication Date:
08 April 2020 (online)

 

Ziel/Aim Tau proteins consist of different isoforms, characterized by the number of repeats (R) of their microtubule binding sites. Preliminary evidence suggests that the novel second-generation tau PET tracer 18F-PI-2620 is able to visualize the predominantly 3/4R-tauopathy Alzheimer’s disease (AD) and the 4R-tauopathies Corticobasal syndrome (CBS) and Progressive supranuclear palsy (PSP) by PET, but - apart from the obvious topographical differences - likely with different kinetics and magnitude of affinity among them. The aim of this study was to determine whether binding characteristics of 18F-PI-2620 are different between 3/4R- and 4R-tauopathies.

Methodik/Methods We evaluated 14 patients with suspected 3/4R tauopathy and 29 patients with suspected 4R tauopathy (14 CBS, 15 PSP) at two different centers according to current diagnosis criteria. 18F-PI-2620 PET scans were acquired 0-60min p.i. and distribution volume ratios (DVR, cerebellar reference) were calculated. Cortical und subcortical clusters exceeding 20 voxels of elevated DVR (≥ 2.5 SD vs. 10 healthy controls) per region were evaluated by non-invasive kinetic modelling. R1 (perfusion), k2 (clearance), DVR, 30-60 min standard-uptake-value-ratios (SUVr30-60) and the linear slope of SUVr between 10 and 60 min p.i. were compared between 3/4R- and 4R-tauopathies.

Ergebnisse/Results Cortical tau-positive clusters in 4R-tau cases had equal R1 but higher k2 values when compared to 3/4R-tau cases (p < 0.001). Higher mean DVR (1.35±0.19 vs. 1.17±0.60, p < 0.01), higher mean SUVr30-60(1.67±0.33 vs. 1.31±0.22, p < 0.001) and steeper slopes (0.85±0.51 vs. 0.43±0.49, p < 0.001) were observed in cortical clusters of 3/4R-tau cases when compared to 4R-tau cases. Subcortical clusters did not show significant differences.

Schlussfolgerungen/Conclusions 18F-PI-2620 binding characteristics in tau-positive cortical regions differentiate clinically suspected 3/4R-tauopathies from 4R-tauopathies. Higher tracer clearance indicates less stable binding in 4R tauopathies when compared to 3/4R-tau cases.