PT  - JOURNAL ARTICLE
AU  - Aliaga, Antonio
AU  - Therriault, Joseph
AU  - Quispialaya, Kely Monica
AU  - Aliaga, Arturo
AU  - Hopewell, Robert
AU  - Rahmouni, Nesrine
AU  - Macedo, Arthur C.
AU  - Kunach, Peter
AU  - Soucy, Jean-Paul
AU  - Massarweh, Gassan
AU  - Diaz, Aida Abreu
AU  - Pascoal, Tharick A.
AU  - Rocha, Andreia
AU  - Guiot, Marie-Christine
AU  - Machado, Luiza S.
AU  - De Bastiani, Marco Antônio
AU  - de Souza, Débora Guerini
AU  - Souza, Diogo O.
AU  - Gauthier, Serge
AU  - Zimmer, Eduardo R.
AU  - Rosa-Neto, Pedro
TI  - Comparison Between Brain and Cerebellar Autoradiography Using [<sup>18</sup>F]Flortaucipir, [<sup>18</sup>F]MK6240, and [<sup>18</sup>F]PI2620 in Postmortem Human Brain Tissue
AID  - 10.2967/jnumed.124.267539
DP  - 2025 Jan 01
TA  - Journal of Nuclear Medicine
PG  - 123--129
VI  - 66
IP  - 1
4099  - http://jnm.snmjournals.org/content/66/1/123.short
4100  - http://jnm.snmjournals.org/content/66/1/123.full
SO  - J Nucl Med2025 Jan 01; 66
AB  - Our objective was to evaluate the in vitro binding properties of [18F]flortaucipir, 6-(fluoro-18F)-3-(1H-pyrrolo[2,3-c]pyridin-1-yl)isoquinolin-5-amine ([18F]MK6240), and 2-(2-([18F]fluoro)pyridin-4-yl)-9H-pyrrolo[2,3-b:4,5c′]dipyridine ([18F]PI2620) head-to-head in postmortem human brain tissue. Methods: Autoradiography was used to assess uptake of [18F]flortaucipir, [18F]MK6240, and [18F]PI2620 in control and Alzheimer disease (AD) autopsy-confirmed brain tissues. The study focused on the analysis of the prefrontal cortex, hippocampus, and cerebellum sections in 12 controls and 12 AD cases, as well as whole-brain hemisphere in 1 control and 1 AD sample, for each radiotracer. The binding values of [18F]flortaucipir, [18F]MK6240, and [18F]PI2620 were calculated from regions of interest manually drawn in the prefrontal, hippocampal, and cerebellar cortices. Results: For all 3 radioligands investigated, we observed significant tracer binding differences between control and AD tissues in the whole-brain hemisphere, prefrontal cortex, and hippocampus but not in the cerebellar cortex. [18F]MK6240 and [18F]PI2620 had higher effect sizes to differentiate control and AD cases than did [18F]flortaucipir. Bland–Altman analyses revealed strong correlations between [18F]MK6240, [18F]PI2620, and [18F]flortaucipir, with the highest agreement found for [18F]MK6240 versus [18F]PI2620. Conclusion: The 3 radioligands showed comparable diagnostic properties to assess tau aggregates in vitro. Binding to AD brain tissues was higher for [18F]MK6240 and [18F]PI2620 than for [18F]flortaucipir. Additionally, [18F]MK6240 and [18F]PI2620 had greater selectivity, displaying decreased uptake in control brain tissue compared with [18F]flortaucipir. These results might provide insights on ongoing initiatives to create a universal scale for tau imaging studies.