Optimal timing of tau pathology imaging and automatic extraction of a reference region using dynamic [18F]THK5317 PET

• Published in: NeuroImage clinical Vol. 22; p. 101681
• Main Authors: Jonasson, My, Wall, Anders, Chiotis, Konstantinos, Leuzy, Antoine, Eriksson, Jonas, Antoni, Gunnar, Nordberg, Agneta, Lubberink, Mark
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.01.2019; Elsevier
• Subjects: Aged; Alzheimer Disease - diagnostic imaging; Alzheimer Disease - metabolism; Alzheimer's disease; Aniline Compounds; Cluster Analysis; Humans; Image Processing, Computer-Assisted - methods; Image Processing, Computer-Assisted - standards; Neuroimaging - methods; Neuroimaging - standards; Parametric images; PET; Positron-Emission Tomography - methods; Positron-Emission Tomography - standards; Quinolines; Radiology; Regular; Supervised clustering; Tau imaging; tau Proteins - metabolism; Tau imaging; Supervised clustering; Alzheimer's disease; PET; Parametric images
• ISSN: 2213-1582; 2213-1582
• DOI: 10.1016/j.nicl.2019.101681

[18F]THK5317 is a PET tracer for in-vivo imaging of tau associated with Alzheimer's disease (AD). This work aimed to evaluate optimal timing for standardized uptake value ratio (SUVR) measures with [18F]THK5317 and automated generation of SUVR-1 and relative cerebral blood flow (R1) parametric images. Nine AD patients and nine controls underwent 90 min [18F]THK5317 scans. SUVR-1 was calculated at transient equilibrium (TE) and for seven different 20 min intervals and compared with distribution volume ratio (DVR; reference Logan). Cerebellar grey matter (MRI) was used as reference region. A supervised cluster analysis (SVCA) method was implemented to automatically generate a reference region, directly from the dynamic PET volume without the need of a structural MRI scan, for computation of SUVR-1 and R1 images for a scan duration matching the optimal timing. TE was reached first in putamen, frontal- and parietal cortex at 22 ± 4 min for AD patients and in putamen at 20 ± 0 min in controls. Over all regions and subjects, SUVR20–40-1 correlated best with DVR-1, R2 = 0.97. High correlation was found between values generated using MRI- and SVCA-based reference (R2 = 0.93 for SUVR20–40-1; R2 = 0.94 for R1). SUVR20–40 allows for accurate semi-quantitative assessment of tau pathology and SVCA may be used to obtain a reference region for calculation of both SUVR-1 and R1 with 40 min scan duration. •This study evaluates optimal timing for SUVR-1 estimation of tau binding with [18F]THK5317 PET.•A time interval of 20–40 min was optimal for SUVR-1 estimates of [18F]THK5317 PET.•Later scanning times induced spatially-varying biases in binding estimates.•A clustering method can be used to extract a reference time activity curve from dynamic [18F]THK5317 PET data.•The clustering extracted reference TAC was used as input for generation of parametric images of SUVR-1 and R1.