Reshaping the Amyloid Buildup Curve in Alzheimer Disease? Partial-Volume Effect Correction of Longitudinal Amyloid PET Data

• Published in: Journal of Nuclear Medicine Vol. 61; no. 12; pp. 1820 - 1824
• Main Authors: Rullmann, Michael, McLeod, Anke, Grothe, Michel J, Sabri, Osama, Barthel, Henryk
• Format: Journal Article
• Language: English
• Published: United States Society of Nuclear Medicine 01.12.2020
• Subjects: Aged; Alzheimer Disease - diagnostic imaging; Alzheimer Disease - metabolism; Alzheimer's disease; Amyloid - metabolism; Atrophy; Cognitive ability; Dementia disorders; Female; Humans; Image Processing, Computer-Assisted; Imaging techniques; Longitudinal Studies; Magnetic resonance imaging; Male; Medical imaging; Neurodegenerative diseases; Neuroimaging; Neurology; Plateaus; Positron emission; Positron emission tomography; Regression analysis; Shape effects; Time dependence; Tomography; Tracers; β-Amyloid; partial-volume effect correction; amyloid; longitudinal; PET
• ISSN: 0161-5505; 1535-5667; 2159-662X
• DOI: 10.2967/jnumed.119.238477

It was hypothesized that the brain β-amyloid buildup curve plateaus at an early symptomatic stage of Alzheimer disease (AD). Atrophy-related partial-volume effects (PVEs) degrade signal in hot-spot imaging techniques such as amyloid PET. The current study, a longitudinal analysis of amyloid-sensitive PET data, investigated the effect on the shape of the β-amyloid curve in AD when PVE correction (PVEC) is applied. We analyzed baseline and 2-y follow-up data for 216 symptomatic individuals on the AD continuum (positive amyloid status) enrolled in the Alzheimer's Disease Neuroimaging Initiative (17 with AD dementia and 199 with mild cognitive impairment), including F-florbetapir PET, MRI, and Mini Mental State Examination scores. For PVEC, the modified Müller-Gärtner method was performed. Compared with non-PVE-corrected data, PVE-corrected data yielded significantly higher changes in regional and composite SUV ratio (SUVR) over time ( = 0.0002 for composite SUVRs). Longitudinal SUVR changes in relation to Mini Mental State Examination decreases showed a significantly higher slope for the regression line in the PVE-corrected than in the non-PVE-corrected PET data ( = 7.1, = 0.008). These PVEC results indicate that the β-amyloid buildup curve does not plateau at an early symptomatic disease stage. A further evaluation of the impact of PVEC on the in vivo characterization of time-dependent AD pathology, including the reliable assessment and comparison of other amyloid tracers, is warranted.