Abstract

Semi-quantitative PET measures like SUVr) have several advantages over quantitative measures, such as practical applicability and relative computational simplicity. However, SUVr may potentially be affected by changes in blood flow, whereas quantitative measures such as BP ND are not. For 18F-flortaucipir-PET the sensitivity of SUVr for changes in blood flow is currently unknown. Therefore we compared semi-quantitative (SUVr) and quantitative (BP ND) parameters of longitudinal 18F-flortaucipir PET scans, and assessed their vulnerability to changes in blood flow. Subjects with subjective cognitive decline (SCD; n=38) and Alzheimer's disease (AD) patients (n=24) underwent baseline (BL) and 2-year follow-up (FU) dynamic 18F-flortaucipir-PET scans. BP ND and R 1 were estimated using receptor parametric mapping (RPM) and SUVr (80-100min) was calculated. Regional SUVrs were compared to corresponding DVR (= BP ND+1) using paired T-tests. Additionally, simulations were performed to model effects of (large(r)) flow changes in different binding categories. Results in SCD and AD showed only minor differences between SUVr and BP ND changes over time. R 1 changes were small in all groups. Simulations illustrated a variable bias for SUVr depending on the amount of binding. Concluding, SUVr provided an accurate estimate of changes in specific binding for 18F-flortaucipir over a two-year follow-up during which changes in flow were small. Notwithstanding, simulations showed that large(r) flow changes may affect 18F-flortaucipir SUVr. Given that it is currently unknown to what order of magnitude pharmacotherapeutic interventions may induce changes in cerebral blood flow, caution may be warranted in situations where changes in flow are potentially large(r) like in clinical trials.

Original languageEnglish
Pages (from-to)281-286
Number of pages6
JournalJournal of nuclear medicine : official publication, Society of Nuclear Medicine
Volume64
Issue number2
DOIs
Publication statusPublished - 1 Feb 2023

Keywords

  • Alzheimer disease
  • Alzheimer's disease
  • dynamic (DVR/BP )
  • dynamic (DVR/BPND)
  • longitudinal 18F-flortaucipir PET
  • longitudinal F-flortaucipir-PET
  • quantification
  • static (SUVr)

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