Premium
Quantitative accuracy remains after shortening of dynamic [ 18 F]flortaucipir PET protocol
Author(s) -
Tuncel Hayel,
Visser Denise,
Yaqub Maqsood,
Timmers Tessa,
Wolters Emma E.,
Ossenkoppele Rik,
Van Berckel Bart N.M.,
Boellaard Ronald,
Golla Sandeep S.V.
Publication year - 2020
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1002/alz.045710
Subject(s) - nuclear medicine , repeatability , medicine , positron emission tomography , mathematics , statistics
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_V B model using population‐based input‐function (2T4k_POP‐IP), cubic, linear and exponential interpolations. Regional BP ND 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 BP ND values estimated using the optimal shortest scan duration was assessed. Result RPM BP ND values obtained using a shortened second part of the PET scan had negligible effect on the accuracy of parameter estimates (Table 1). The RPM BP ND values using 0‐30/80‐100 min with 2T4k_POP‐IP interpolation had the best correlation with original DVR‐1, SRTM and RPM BP ND (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.