title: Quantification of blood flow-dependent component in estimates of beta-amyloid load obtained using quasi-steady-state standardized uptake value ratio.
abstract: Longitudinal positron emission tomography (PET) imaging of beta-amyloid is used in basic research and in drug efficacy trials in Alzheimer's disease (AD). However, the extent of amyloid accumulation after clinical onset is not fully known. Importantly, regional PET data are typically quantified using the standardized uptake value ratio (SUVR), which according to simulations is sensitive to changes in regional cerebral blood flow (rCBF). We aimed to better understand the potentials of longitudinal amyloid imaging by disentangling the influence of blood flow on SUVR using experimental data. [18F]AV-45 PET data from 101 subjects, ranging from cognitively normal to AD patients, in the Alzheimer's Disease Neuroimaging Initiative were extracted. The relationship between global cortical distribution volume ratio, indicator of rCBF (R1), and SUVR was examined using multilinear regression. There was a significant effect of rCBF on SUVR. The effect increased by disease severity. Results suggest that changes in rCBF can produce apparent changes in SUVR in AD. Therefore, future longitudinal studies should measure amyloid changes in a way not sensitive to this effect, ideally using quantitative PET imaging. Furthermore, the results suggest no true accumulation beyond clinical onset and highlight the risks of longitudinal amyloid imaging in drug trials in AD.
authors: Department of Clinical Neuroscience, PET Centre, Karolinska Institutet, Stockholm, Sweden.|Department of Clinical Neuroscience, AZ Translational Science Centre, Karolinska Institutet, Stockholm, Sweden.
authors: Zsolt
authors: Z
authors: Cselényi
authors: Department of Clinical Neuroscience, PET Centre, Karolinska Institutet, Stockholm, Sweden.|Department of Clinical Neuroscience, AZ Translational Science Centre, Karolinska Institutet, Stockholm, Sweden.
authors: Lars
authors: L
authors: Farde
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000097:blood / Q000000981:diagnostic imaging / Q000503:physiopathology; D016229:Amyloid beta-Peptides / Q000097:blood*; D001783:Blood Flow Velocity; D002540:Cerebral Cortex / Q000098:blood supply / Q000000981:diagnostic imaging / Q000378:metabolism / Q000503:physiopathology; D002560:Cerebrovascular Circulation; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D049268:Positron-Emission Tomography; D011859:Radiography
chemical_list: D016229:Amyloid beta-Peptides