title: Cerebellar Amyloid-β Plaques: How Frequent Are They, and Do They Influence 18F-Florbetaben SUV Ratios?
abstract: SUV ratios (SUVRs) are used for relative quantification of18F-florbetaben scans. The cerebellar cortex can be used as a reference region for quantification. However, cerebellar amyloid-β (Aβ) plaques may be present in Alzheimer disease (AD). The aim of this study was to assess the influence of Aβ pathology, including neuritic plaques, diffuse plaques, and vascular deposits, in18F-florbetaben SUVR when cerebellum is used as the reference.
  
  
  METHODS
  Using immunohistochemistry to demonstrate Aβ plaques and vascular deposits, and using the Bielschowsky method to demonstrate neuritic plaques, we performed a neuropathologic assessment of the frontal, occipital, anterior cingulate, and posterior cingulate cerebral cortices and the cerebellar cortex of 87 end-of-life patients (64 with AD, 14 with other types of dementia, and 9 nondemented aged volunteers; mean age ± SD, 80.4 ± 10.2 y) who had undergone18F-florbetaben PET before death. The lesions were rated as absent (none or sparse) or present (moderate or frequent). Mean cortical SUVRs were compared among cases with different cerebellar Aβ loads.
  
  
  RESULTS
  None of the 83 evaluable cerebellar samples showed frequent diffuse Aβ or neuritic plaques; 8 samples showed frequent vascular Aβ deposits. Diffuse Aβ plaques were rated as absent in 78 samples (94%) and present in 5 samples (6%). Vascular Aβ was rated as absent in 62 samples (74.7%) and present in 21 samples (25.3%). No significant differences in cerebellar SUVs were found among cases with different amounts or types of Aβ deposits in the cerebral cortex. Both diffuse and neuritic plaques were found in the cerebral cortex of 26-44 cases. No significant SUVR differences were found between these brains with different cerebellar Aβ loads.
  
  
  CONCLUSIONS
  The effect of cerebellar plaques on cortical18F-florbetaben SUVRs appears to be negligible even in advanced stages of AD with a higher cerebellar Aβ load.
authors.affiliation: Piramal Imaging GmbH, Berlin, Germany.
authors.forename: Ana M
authors.initials: AM
authors.lastname: Catafau
authors.affiliation: Piramal Imaging GmbH, Berlin, Germany santi.bullich@piramal.com.
authors.forename: Santiago
authors.initials: S
authors.lastname: Bullich
authors.affiliation: Molecular Neuroimaging, New Haven, Connecticut.
authors.forename: John P
authors.initials: JP
authors.lastname: Seibyl
authors.affiliation: University of Leipzig, Leipzig, Germany.
authors.forename: Henryk
authors.initials: H
authors.lastname: Barthel
authors.affiliation: Indiana University School of Medicine, Indianapolis, Indiana.
authors.forename: Bernardino
authors.initials: B
authors.lastname: Ghetti
authors.affiliation: VA-Puget Sound Health Care System and University of Washington, Seattle, Washington.
authors.forename: James
authors.initials: J
authors.lastname: Leverenz
authors.affiliation: University of Edinburgh, Edinburgh, United Kingdom.
authors.forename: James W
authors.initials: JW
authors.lastname: Ironside
authors.affiliation: Georg-August University Göttingen, Göttingen, Germany; and.
authors.forename: Walter J
authors.initials: WJ
authors.lastname: Schulz-Schaeffer
authors.affiliation: Bayer Pharma AG, Berlin, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Hoffmann
authors.affiliation: University of Leipzig, Leipzig, Germany.
authors.forename: Osama
authors.initials: O
authors.lastname: Sabri
mesh_terms: D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000000981:diagnostic imaging / Q000378:metabolism*; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D002531:Cerebellum / Q000000981:diagnostic imaging / Q000378:metabolism*; D005260:Female; D005462:Fluorine Radioisotopes / Q000493:pharmacokinetics; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods; D008297:Male; D057054:Molecular Imaging / Q000379:methods; D009928:Organ Specificity; D058225:Plaque, Amyloid / Q000000981:diagnostic imaging / Q000378:metabolism*; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013747:Tetrabenazine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D014018:Tissue Distribution
chemical_list: D016229:Amyloid beta-Peptides; D005462:Fluorine Radioisotopes; D019275:Radiopharmaceuticals; C549477:florbenazine F 18; D013747:Tetrabenazine
keywords: Alzheimer disease; florbetaben; positron emission tomography