YNIMG Journal 2022 Journal Article
β-amyloid PET harmonisation across longitudinal studies: Application to AIBL, ADNI and OASIS3
- Pierrick Bourgeat
- Vincent Doré
- Samantha C. Burnham
- Tammie Benzinger
- Duygu Tosun
- Shenpeng Li
- Manu Goyal
- Pamela LaMontagne
INTRODUCTION: The Centiloid scale was developed to harmonise the quantification of β-amyloid (Aβ) PET images across tracers, scanners, and processing pipelines. However, several groups have reported differences across tracers and scanners even after centiloid conversion. In this study, we aim to evaluate the impact of different pre and post-processing harmonisation steps on the robustness of longitudinal Centiloid data across three large international cohort studies. METHODS: F-Florbetapir pairs and longitudinal consistency were evaluated. RESULTS: F-Florbetapir improved inter-tracer agreement, effect size, correlation with MMSE, and longitudinal consistency. The best results were however obtained when using the NMF method which outperformed all other quantification approaches in all metrics used. CONCLUSIONS: FWHM smoothing has limited impact on longitudinal consistency or outliers. A Composite reference region including subcortical WM should be used for computing both cross-sectional and longitudinal Florbetapir Centiloid. NMF improves Centiloid quantification on all metrics examined.