HAI Book 2025 - Flipbook - Page 186
Dhaynaut, Maeva
35
Cerebral perfusion indices from early-phase [18F]-MK6240 dynamic
Tau PET imaging in brain regions associated with Alzheimer9s disease
progression in an aging population.
Maeva Dhaynaut1, Cristina Lois3, Amal Tiss3, Emma Thibault3, Jessie Fanglu Fu4, Jinsong
Ouyang1, Keith A. Johnson3, Georges El Fakhri1,2, Marc D. Normandin1, Nicolas J. Guehl1
1
Yale PET Center, Department of Radiology & Biomedical Imaging, Yale University School of Medicine, New Haven,
CT, US
2
Yale PET Center, Department of Bioinformatics & Data Science, Yale University School of Medicine, New Haven, CT,
US
3
Gordon Center for Medical Imaging, Department of Radiology, Massachusetts General Hospital, Harvard Medical
School, Boston, MA, US
4
Athinoula A. Martinos Center for Biomedical Imaging, Department of Radiology, Massachusetts General Hospital,
Harvard Medical School, Boston, MA, US
Background: Radiotracers with sufficient extraction fraction can provide insights into cerebral blood flow (CBF).
Recent findings highlight the utility of early-phase [18F]-MK6240 PET in deriving quantitative perfusion indices,
providing information on Tau load and perfusion from the same dynamic scan. Since the relationship between
CBF changes and Alzheimer9s disease (AD) remains unclear, this study examines cerebral perfusion indices across
brain regions mapping AD progression and their relationships with A´ and Tau.
Methods: Ninety-five aging adults (twenty-four cognitively unimpaired with PIB positive status (CU PIB+), fiftyfive with PIB negative status (CU PIB-), sixteen MCI/AD) underwent dynamic [11C]-PiB and [18F]-MK6240 PET scans
on a Discovery MI-5, with structural MRI on a 3T Tim Trio. Braak regions (I3VI) were segmented using FreeSurfer to
extract regional brain time3activity curves. Early [18F]-MK6240 frames were analyzed with the simplified reference
tissue model 2 to estimate the relative delivery rate R1. A´ and Tau burdens were quantified using distribution
volume ratios (DVR) with Logan method. A´ burden was defined in a large neocortical aggregate (FLR). All analyses
used the cerebellum grey matter as reference. Correlation analyses explored relationships between R1, age, A´,
and Tau.
Results: R1 parameter distribution followed the regional advancement of Braak stages (n=95, p
