title: Performance characteristics of amyloid PET with florbetapir F 18 in patients with alzheimer's disease and cognitively normal subjects.
abstract: The objectives of this study were to examine the effective dose range and the test-retest reliability of florbetapir F 18 using, first, visual assessment by independent raters masked to clinical information and, second, semiautomated quantitative measures of cortical target area to cerebellum standardized uptake value ratios (SUVr) as primary outcome measures. Visual ratings of PET image quality and tracer retention or β-amyloid (Aβ) binding expressed as SUVrs were compared after intravenous administration of either 111 MBq (3 mCi) or 370 MBq (10 mCi) of florbetapir F 18 in patients with Alzheimer's disease (AD) (n = 9) and younger healthy controls (YHCs) (n = 11). In a separate set of subjects (AD, n = 10; YHCs, n = 10), test-retest reliability was evaluated by comparing intrasubject visual read ratings and SUVrs for 2 PET images acquired within 4 wk of each other.
  
  
  RESULTS
  There were no meaningful differences between the 111-MBq (3-mCi) and 370-MBq (10-mCi) dose in the visual rating or SUVr. The difference in the visual quality across 111 and 370 MBq showed a trend toward lower image quality, but no statistical significance was achieved (t test; t(1) = -1.617, P = 0.12) in this relatively small sample of subjects. At both dose levels, visual ratings of amyloid burden identified 100% of AD subjects as Aβ-positive and 100% of YHCs as Aβ-negative. Mean intrasubject test-retest variability for cortical average SUVrs with the cerebellum as a reference over the 50- to 70-min period was 2.4% ± 1.41% for AD subjects and 1.5% ± 0.84% for controls. The overall SUVr test-retest correlation coefficient was 0.99. The overall κ-statistic for test-retest agreement for Aβ classification of the masked reads was 0.89 (95% confidence interval, 0.69-1.0).
  
  
  CONCLUSIONS
  Florbetapir F 18 appears to have a wide effective dose range and a high test-retest reliability for both quantitative (SUVr) values and visual assessment of the ligand. These imaging performance properties provide important technical information on the use of florbetapir F 18 and PET to detect cerebral amyloid aggregates.
authors.affiliation: Avid Radiopharmaceuticals, Inc., Philadelphia, PA 19104, USA. joshi@avidrp.com
authors.forename: Abhinay D
authors.initials: AD
authors.lastname: Joshi
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Pontecorvo
authors.forename: Chrisopher M
authors.initials: CM
authors.lastname: Clark
authors.forename: Alan P
authors.initials: AP
authors.lastname: Carpenter
authors.forename: Danna L
authors.initials: DL
authors.lastname: Jennings
authors.forename: Carl H
authors.initials: CH
authors.lastname: Sadowsky
authors.forename: Lee P
authors.initials: LP
authors.lastname: Adler
authors.forename: Karel D
authors.initials: KD
authors.lastname: Kovnat
authors.forename: John P
authors.initials: JP
authors.lastname: Seibyl
authors.forename: Anupa
authors.initials: A
authors.lastname: Arora
authors.forename: Krishnendu
authors.initials: K
authors.lastname: Saha
authors.forename: Jason D
authors.initials: JD
authors.lastname: Burns
authors.forename: Mark J
authors.initials: MJ
authors.lastname: Lowrey
authors.forename: Mark A
authors.initials: MA
authors.lastname: Mintun
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Skovronsky
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000000981:diagnostic imaging*; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000814:Aniline Compounds / Q000008:administration & dosage; D005026:Ethylene Glycols / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D049268:Positron-Emission Tomography / Q000379:methods*; D011874:Radiometry; D019275:Radiopharmaceuticals / Q000008:administration & dosage; D012016:Reference Values; D015203:Reproducibility of Results
chemical_list: D016229:Amyloid beta-Peptides; D000814:Aniline Compounds; D005026:Ethylene Glycols; D019275:Radiopharmaceuticals; C545186:florbetapir