Scan-Time Corrections for 80-100-min Standardizetd Uptake Volume Ratios to Measure the 18 F-AV-1451 Tracer for Tau Imaging

• Published in: IEEE transactions on medical imaging Vol. 38; no. 3; pp. 697 - 709
• Main Authors: He, Mark, Baker, Suzanne L, Shah, Vyoma D, Lockhart, Samuel N, Jagust, William J
• Format: Journal Article
• Language: English
• Published: United States 01.03.2019
• Subjects: Aged; Aged, 80 and over; Alzheimer Disease - diagnostic imaging; Biomarkers - analysis; Carbolines - administration & dosage; Case-Control Studies; Cognitive Dysfunction - diagnostic imaging; Computer Simulation; Contrast Media; Humans; Image Processing, Computer-Assisted - methods; Magnetic Resonance Imaging - methods; Male; Monte Carlo Method; Radionuclide Imaging - methods; Reproducibility of Results; tau Proteins - analysis
• ISSN: 0278-0062; 1558-254X
• DOI: 10.1109/TMI.2018.2870441

The F-AV-1451 PET tracer binds to tau, an Alzheimer's disease biomarker. The standardized uptake value ratio (SUVR) 80-100 min window is widely used to quantify tau binding, although F-AV-1451 continues increasing relative to a reference region in regions with tau deposition. Left uncorrected, acquisition time inaccuracies can lead to errors from -4% to 6% in 20-min SUVR measurements in subjects with Alzheimer's disease. In 40 subjects with scans from 75-115 min following F-AV-1451 injection, we created 20-min reconstructions (4×5 min) of start-times ranging from 75-85 min, as proxies of offset scans and calculated the mean in regions of interest (ROIs). We developed a segmented least squares (SLS) method to obtain error-minimizing weighting coefficients for F-AV-1451 ROIs that best predict SUVR 80-100 from weighted means of SUVRs from offset start-times. We compared residual errors of our SLS method to those in: 1) uncorrected offset 20-min-SUVRs; 2) the mean of five-min frames within the 80-100 window; and 3) a least-squares interpolation method. We evaluated errors induced by start-time offset on SUVRs for each method. TheSLS, which corrected using least-squares coefficients of 5-min components, consistently reduced errors across all offset starttimes. Effect size analysis for simulated clinical longitudinal F-AV-1451 drug trials showed that uncorrected 20-min offset SUVRs would require up to 20% more participants to detect treatment effects compared with using SLS. Correction of SUVR scan-time errors by SLS minimizes errors compared with other correction methods and may be extended to other scanners and tracers.