title: Practical utility of amyloid and FDG-PET in an academic dementia center.
abstract: OBJECTIVE
  To evaluate the effect of amyloid imaging on clinical decision making.
  
  
  METHODS
  We conducted a retrospective analysis of 140 cognitively impaired patients (mean age 65.0 years, 46% primary β-amyloid (Aβ) diagnosis, mean Mini-Mental State Examination 22.3) who underwent amyloid (Pittsburgh compound B [PiB]) PET as part of observational research studies and were evaluated clinically before and after the scan. One hundred thirty-four concurrently underwent fluorodeoxyglucose (FDG)-PET. We assessed for changes between the pre- and post-PET clinical diagnosis (from Aβ to non-Aβ diagnosis or vice versa) and Alzheimer disease treatment plan. The association between PiB/FDG results and changes in management was evaluated using χ(2) and multivariate logistic regression. Postmortem diagnosis was available for 24 patients (17%).
  
  
  RESULTS
  Concordance between scan results and baseline diagnosis was high (PiB 84%, FDG 82%). The primary diagnosis changed after PET in 13/140 patients (9%) overall but in 5/13 (38%) patients considered pre-PET diagnostic dilemmas. When examined independently, discordant PiB and discordant FDG were both associated with diagnostic change (unadjusted p < 0.0001). However, when examined together in a multivariate logistic regression, only discordant PiB remained significant (adjusted p = 0.00013). Changes in treatment were associated with discordant PiB in patients with non-Aβ diagnoses (adjusted p = 0.028), while FDG had no effect on therapy. Both PiB (96%) and FDG (91%) showed high agreement with autopsy diagnosis.
  
  
  CONCLUSIONS
  PET had a moderate effect on clinical outcomes. Discordant PiB had a greater effect than discordant FDG, and influence on diagnosis was greater than on treatment. Prospective studies are needed to better characterize the clinical role of amyloid PET.
authors.affiliation: From the Memory and Aging Center and Department of Neurology (P.S.-J., P.M.G., J.H., B.G., M.H., L.T.G., M.G.-T., W.W.S., A.L.B., H.J.R., J.H.K., B.L.M.,W.J.J., G.D.R.) and Department of Pathology and Laboratory Medicine (E.J.H.), University of California, San Francisco; University Hospital "Marqués de Valdecilla," IFIMAV and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (P.S.-J.), Santander, Spain; Helen Wills Neuroscience Institute (P.M.G., W.J.J., G.D.R.), University of California, Berkeley; Lawrence Berkeley National Laboratory (P.M.G., J.P.O., M.J., W.J.J., G.D.R.), Berkeley, CA; Center for Neurodegenerative Research (J.Q.T.), University of Pennsylvania, Philadelphia; and Department of Pathology and Laboratory Medicine (H.V.V.), University of California, Los Angeles.
authors.forename: Pascual
authors.initials: P
authors.lastname: Sánchez-Juan
authors.forename: Pia M
authors.initials: PM
authors.lastname: Ghosh
authors.forename: Jayne
authors.initials: J
authors.lastname: Hagen
authors.forename: Benno
authors.initials: B
authors.lastname: Gesierich
authors.forename: Maya
authors.initials: M
authors.lastname: Henry
authors.forename: Lea T
authors.initials: LT
authors.lastname: Grinberg
authors.forename: James P
authors.initials: JP
authors.lastname: O'Neil
authors.forename: Mustafa
authors.initials: M
authors.lastname: Janabi
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Huang
authors.forename: John Q
authors.initials: JQ
authors.lastname: Trojanowski
authors.forename: Harry V
authors.initials: HV
authors.lastname: Vinters
authors.forename: Marilu
authors.initials: M
authors.lastname: Gorno-Tempini
authors.forename: William W
authors.initials: WW
authors.lastname: Seeley
authors.forename: Adam L
authors.initials: AL
authors.lastname: Boxer
authors.forename: Howard J
authors.initials: HJ
authors.lastname: Rosen
authors.forename: Joel H
authors.initials: JH
authors.lastname: Kramer
authors.forename: Bruce L
authors.initials: BL
authors.lastname: Miller
authors.forename: William J
authors.initials: WJ
authors.lastname: Jagust
authors.forename: Gil D
authors.initials: GD
authors.lastname: Rabinovici
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis / Q000378:metabolism / Q000473:pathology; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000814:Aniline Compounds; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D003072:Cognition Disorders / Q000175:diagnosis* / Q000378:metabolism / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D012720:Severity of Illness Index; D013844:Thiazoles
chemical_list: C475519:2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole; D016229:Amyloid beta-Peptides; D000814:Aniline Compounds; D019275:Radiopharmaceuticals; D013844:Thiazoles; D019788:Fluorodeoxyglucose F18