title: Use of Standardized Uptake Value Ratios Decreases Interreader Variability of [18F] Florbetapir PET Brain Scan Interpretation.
abstract: OBJECTIVE
  Fluorine-18 florbetapir is a recently developed β-amyloid plaque positron-emission tomography imaging agent with high sensitivity, specificity, and accuracy in the detection of moderate-to-frequent cerebral cortical β-amyloid plaque. However, the FDA has expressed concerns about the consistency of interpretation of [(18)F] florbetapir PET brain scans. We hypothesized that incorporating automated cerebral-to-whole-cerebellar standardized uptake value ratios into [(18)F] florbetapir PET brain scan interpretation would reduce this interreader variability.
  
  
  METHODS
  This randomized, blinded-reader study used previously acquired [(18)F] florbetapir scans from 30 anonymized patients who were enrolled in the Alzheimer's Disease Neuroimaging Initiative 2. In 4 separate, blinded-reading sessions, 5 readers classified 30 cases as positive or negative for significant β-amyloid deposition either qualitatively alone or qualitatively with additional adjunct software that determined standardized uptake value ratios. A κ coefficient was used to calculate interreader agreement with and without the use of standardized uptake value ratios.
  
  
  RESULTS
  There was complete interreader agreement on 20/30 cases of [(18)F] florbetapir PET brain scans by using qualitative interpretation and on 27/30 scans interpreted with the adjunct use of standardized uptake value ratios. The κ coefficient for the studies read with standardized uptake value ratios (0.92) was significantly higher compared with the qualitatively read studies (0.69, P = .006).
  
  
  CONCLUSIONS
  Use of standardized uptake value ratios improves interreader agreement in the interpretation of [(18)F] florbetapir images.
authors.affiliation: From the Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: A P
authors.initials: AP
authors.lastname: Nayate
authors.affiliation: From the Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: J G
authors.initials: JG
authors.lastname: Dubroff
authors.affiliation: From the Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: J E
authors.initials: JE
authors.lastname: Schmitt
authors.affiliation: From the Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: I
authors.initials: I
authors.lastname: Nasrallah
authors.affiliation: From the Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: R
authors.initials: R
authors.lastname: Kishore
authors.affiliation: From the Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: D
authors.initials: D
authors.lastname: Mankoff
authors.affiliation: From the Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania. daniel.pryma@uphs.upenn.edu.
authors.forename: D A
authors.initials: DA
authors.lastname: Pryma
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging*; D000814:Aniline Compounds; D001921:Brain / Q000000981:diagnostic imaging*; D005026:Ethylene Glycols; D005260:Female; D006801:Humans; D008297:Male; D059906:Neuroimaging / Q000592:standards*; D015588:Observer Variation; D049268:Positron-Emission Tomography / Q000379:methods / Q000592:standards*
chemical_list: D000814:Aniline Compounds; D005026:Ethylene Glycols; C545186:florbetapir