HAI Book 2025 - Flipbook - Page 726
Feizpour, Azadeh
Positive plasma Aβ42/40 despite negative Amyloid PET: A harbinger of
progression to amyloid PET positivity?
Azadeh Feizpour1,2, Vincent Doré2,3, James D. Doecke4, Rodrigo Canovas3, Pierrick Bourgeat4, Simon M.
Laws5,6,7, Tenielle Porter5,6,7, Kun Huang2, Christopher Fowler1, Michael W. Weiner8, John C. Morris9,10,
Tammie L. S. Benzinger10,11, Suzanne E. Schindler9,10, Randall J. Bateman9,10,12, Larry Ward1, Jurgen Fripp4,
Colin L. Masters1, Victor L. Villemagne13, Christopher C. Rowe1,2,14
1
Florey Institute of Neuroscience and Mental Health, Melbourne, AU
Department of Molecular Imaging & Therapy, Austin Health, Melbourne, AU
3
The Australian e-Health Research Centre, CSIRO, Melbourne, Melbourne, AU
4
The Australian e-Health Research Centre, CSIRO, Brisbane, Brisbane, AU
5
Centre for Precision Health, Edith Cowan University, Joondalup, Western Australia, AU
6
Collaborative Genomics and Translation Group, Edith Cowan University, Joondalup, Western Australia, AU
7
Curtin Medical School, Curtin University, Bentley, Western Australia, AU
8
Department of Radiology, University of California at San Francisco, San Francisco, CA, US
9
Department of Neurology, Washington University School of Medicine, St. Louis, MO, US
10
Charles F. and Joanne Knight Alzheimer Disease Research Center (Knight ADRC), Washington University School of
Medicine, St. Louis, MO, US
11
Department of Radiology, Washington University in St. Louis, St. Louis, Missouri, St. Louis, MO, US
12
Tracy Family SILQ Center, Washington University School of Medicine, St. Louis, MO, US
13
Department of Psychiatry, University of Pittsburgh, Pittsburgh, PA, US
14
Florey Department of Neuroscience and Mental Health, The University of Melbourne, Melbourne, AU
2
Background: The agreement between plasma A´42/40 and A´-PET is approximately 75%, with a large portion of
the discrepancies attributed to false positive (Plasma+/PET-) cases. It remains unclear whether these false
positives reflect A´ changes in plasma before PET-detectable A´ buildup. Our aim was to examine these cases
over 7 years to assess their risk and rate of progressing to A´-PET positivity.
Method: Cognitively unimpaired participants from AIBL, OASIS, and ADNI underwent A´-PET and plasma A´42/40
(IPMS) analysis at baseline and one to five additional PET scans, every 1.5-3 years. Individuals with baseline A´ PET
20CL).
Results: Plasma+/PET- group (n=87) had a higher percentage of APOE ε4 carriers than Plasma-/PET- group
(n=294) (30% vs. 16%, p
