Quantitative accuracy remains after shortening of dynamic [18F]flortaucipir PET protocol: Neuroimaging / Optimal neuroimaging measures for tracking disease progression. (7th December 2020)

• Record Type: Journal Article
• Authors: Tuncel, Hayel; Visser, Denise; Yaqub, Maqsood; Timmers, Tessa; Wolters, Emma E.; Ossenkoppele, Rik; Van Berckel, Bart N.M.; Boellaard, Ronald; Golla, Sandeep S.V.
• Is Part Of: Alzheimer's & dementia. Volume 16(2020)Supplement 4
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-12-07
• Subjects: Alzheimer's disease -- Periodicals; Alzheimer Disease -- Periodicals; Dementia -- Periodicals; Démence; Maladie d'Alzheimer; Périodique électronique (Descripteur de forme); Ressource Internet (Descripteur de forme); 616.83
• DOI: 10.1002/alz.045710
• Languages: English
• ISSNs: 1552-5260

Abstract

Abstract: Background: Tau pathology can be assessed by [ 18 F]flortaucipir positron emission tomography (PET). Dynamic PET protocols allow for accurate quantification of [ 18 F]flortaucipir specific binding. However, dynamic acquisitions can be challenging or burdensome to patients given the long required scan duration of 130 min, especially in persons with cognitive impairment due to Alzheimer's disease (AD). Therefore, the current study assessed the effect of shorter scan protocols for [ 18 F]flortaucipir PET on its quantitative accuracy. Method: For this study, two study samples were used: 10 Alzheimer disease (AD) patients and 10 healthy controls (HC) with arterial blood sampling, and 8 AD patients and 6 HCs with a test‐retest scan protocol but without arterial sampling. All subjects underwent a 130‐minute dynamic [ 18 F]flortaucipir PET scan with a 20 min break after 60 minutes. First, the second part of the scan was shortened to 80‐120, 80‐110 and 80‐100 minutes p.i.. Second, the first part of the scan was shortened to 0‐50, 0‐40, and 0‐30 min p.i.. To fill the gap of missing time frames in the reference region (i.e. grey matter cerebellum) time activity curves, four different interpolation methods were tested: 2T4k_VB model using population‐based input‐function (2T4k_POP‐IP), cubic, linear and exponential interpolations. Regional BPND values estimated using SRTM and/or RPM and different scan protocols were compared to the respective values estimated using the original scan acquisition. In addition, test‐retest repeatability (TRT) of the RPM BPND values estimated using the optimal shortest scan duration was assessed. Result: RPM BPND values obtained using a shortened second part of the PET scan had negligible effect on the accuracy of parameter estimates (Table 1). The RPM BPND values using 0‐30/80‐100 min with 2T4k_POP‐IP interpolation had the best correlation with original DVR‐1, SRTM and RPM BPND (r 2 =0.95, slope=0.91; r 2 =0.97, slope=0.88; r 2 =0.99, slope=0.96). The TRT remained similar using the shortest scan duration (Figure 1). Conclusion: The current study demonstrated that accurate [ 18 F]flortaucipir quantification can be obtained using a scan protocol of 0‐30/80‐100 min p.i.. With this reduction in total scan duration the scan will be less burdensome while remaining quantitatively accurate.