title: Standardized Expression of 18F-NAV4694 and 11C-PiB β-Amyloid PET Results with the Centiloid Scale.
abstract: A common quantitative output value for PET measures of β-amyloid (Aβ) binding across tracers and methods would allow better comparison of data across sites and application of universal diagnostic and prognostic values. A method has recently been developed that generates a unit of measurement called the centiloid. We applied this method to 2-[2-(18)F-fluoro-6-(methylamino)-3-pyridinyl]-1-benzofuran-5-ol ((18)F-NAV4694) and (11)C-Pittsburgh compound B ((11)C-PiB) Aβ images to derive the scaling factor required to express tracer binding in centiloids.
  
  
  METHODS
  Fifty-five participants, including 10 young controls (33 ± 7 y old), underwent both (11)C-PiB and (18)F-NAV4694 imaging no more than 3 mo apart, with the images acquired 50-70 min after tracer injection. The images were spatially normalized and analyzed using the standard centiloid method and regions (cortex and whole-cerebellum reference) downloaded from the Global Alzheimer Association Interactive Network website.
  
  
  RESULTS
  SUV ratios (SUVRs) showed a strong correlation in tracer binding ((18)F-NAV4694 SUVR = 1.09 × (11)C-PiB SUVR - 0.08, R(2) = 0.99). The equation to convert (18)F-NAV4694 to centiloids [100 × ((18)F-NAV4694 SUVR - 1.028)/1.174] was similar to a published equation for (11)C-PiB [100 × ((11)C-PiB SUVR - 1.009)/1.067]. In the young controls, the variance ratio ((18)F-NAV4694 centiloid SD divided by (11)C-PiB centiloid SD) was 0.85.
  
  
  CONCLUSIONS
  The results for both (11)C-PiB and (18)F-NAV4694 can now be expressed in centiloids, an important step that should allow better clinical and research use of Aβ imaging. The standard centiloid method also showed that (18)F-NAV4694 has slightly higher Aβ binding and lower variance than (11)C-PiB, important properties for detecting early Aβ deposition and change over time.
authors.affiliation: Department of Molecular Imaging, Austin Health, Melbourne, Australia Department of Medicine, University of Melbourne, Melbourne, Australia Christopher.rowe@austin.org.au.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Rowe
authors.affiliation: Department of Molecular Imaging, Austin Health, Melbourne, Australia.
authors.forename: Gareth
authors.initials: G
authors.lastname: Jones
authors.affiliation: Department of Molecular Imaging, Austin Health, Melbourne, Australia CSIRO Health and Biosecurity, Brisbane, Australia; and.
authors.forename: Vincent
authors.initials: V
authors.lastname: Doré
authors.affiliation: Department of Molecular Imaging, Austin Health, Melbourne, Australia.
authors.forename: Svetlana
authors.initials: S
authors.lastname: Pejoska
authors.affiliation: Department of Molecular Imaging, Austin Health, Melbourne, Australia.
authors.forename: Laura
authors.initials: L
authors.lastname: Margison
authors.affiliation: Department of Molecular Imaging, Austin Health, Melbourne, Australia.
authors.forename: Rachel S
authors.initials: RS
authors.lastname: Mulligan
authors.affiliation: Department of Molecular Imaging, Austin Health, Melbourne, Australia.
authors.forename: J Gordon
authors.initials: JG
authors.lastname: Chan
authors.affiliation: Department of Molecular Imaging, Austin Health, Melbourne, Australia.
authors.forename: Kenneth
authors.initials: K
authors.lastname: Young
authors.affiliation: Department of Molecular Imaging, Austin Health, Melbourne, Australia Department of Medicine, University of Melbourne, Melbourne, Australia Florey Institute of Neuroscience and Mental Health, University of Melbourne, Melbourne, Australia.
authors.forename: Victor L
authors.initials: VL
authors.lastname: Villemagne
mesh_terms: D000328:Adult; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000814:Aniline Compounds; D001572:Benzofurans / Q000493:pharmacokinetics*; D052160:Benzothiazoles / Q000493:pharmacokinetics*; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism*; D005260:Female; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics; D006801:Humans; D006845:Hydrocarbons, Fluorinated / Q000493:pharmacokinetics*; D007090:Image Interpretation, Computer-Assisted / Q000592:standards*; D008297:Male; D057054:Molecular Imaging / Q000592:standards; D049268:Positron-Emission Tomography / Q000379:methods / Q000592:standards*; D017410:Practice Guidelines as Topic; D025941:Protein Interaction Mapping / Q000592:standards; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013844:Thiazoles; D014018:Tissue Distribution
chemical_list: C475519:2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole; C552498:AZD4694; D016229:Amyloid beta-Peptides; D000814:Aniline Compounds; D001572:Benzofurans; D052160:Benzothiazoles; D005462:Fluorine Radioisotopes; D006845:Hydrocarbons, Fluorinated; D019275:Radiopharmaceuticals; D013844:Thiazoles
keywords: Alzheimer’s disease; amyloid imaging; beta-amyloid; centiloid; standardization