RT Journal Article SR Electronic T1 In Vivo 18F-Flortaucipir PET Does Not Accurately Support the Staging of Progressive Supranuclear Palsy JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP 1052 OP 1057 DO 10.2967/jnumed.121.262985 VO 63 IS 7 A1 Maura Malpetti A1 Sanne S. Kaalund A1 Kamen A. Tsvetanov A1 Timothy Rittman A1 Mayen Briggs A1 Kieren S.J. Allinson A1 Luca Passamonti A1 Negin Holland A1 P. Simon Jones A1 Tim D. Fryer A1 Young T. Hong A1 Antonina Kouli A1 W. Richard Bevan-Jones A1 Elijah Mak A1 George Savulich A1 Maria Grazia Spillantini A1 Franklin I. Aigbirhio A1 Caroline H. Williams-Gray A1 John T. O’Brien A1 James B. Rowe YR 2022 UL http://jnm.snmjournals.org/content/63/7/1052.abstract AB Progressive supranuclear palsy (PSP) is a neurodegenerative disorder characterized by neuroglial tau pathology. A new staging system for PSP pathology postmortem has been described and validated. We used a data-driven approach to test whether postmortem pathologic staging in PSP can be reproduced in vivo with 18F-flortaucipir PET. Methods: Forty-two patients with probable PSP and 39 controls underwent 18F-flortaucipir PET. Conditional inference tree analyses on regional binding potential values identified absent/present pathology thresholds to define in vivo staging. Following the postmortem staging approach for PSP pathology, we evaluated the combinations of absent/present pathology (or abnormal/normal PET signal) across all regions to assign each participant to in vivo stages. ANOVA was applied to analyze differences among means of disease severity between stages. In vivo staging was compared with postmortem staging in 9 patients who also had postmortem confirmation of the diagnosis and stage. Results: Stage assignment was estimable in 41 patients: 10, 26, and 5 patients were classified in stage I/II, stage III/IV, and stage V/VI, respectively, whereas 1 patient was not classifiable. Explorative substaging identified 2 patients in stage I, 8 in stage II, 9 in stage III, 17 in stage IV, and 5 in stage V. However, the nominal 18F-flortaucipir--derived stage was not associated with clinical severity and was not indicative of pathology staging postmortem. Conclusion: 18F-flortaucipir PET in vivo does not correspond to neuropathologic staging in PSP. This analytic approach, seeking to mirror in vivo neuropathology staging with PET-to-autopsy correlational analyses, might enable in vivo staging with next-generation tau PET tracers; however, further evidence and comparisons with postmortem data are needed.