title: Does a positive Pittsburgh Compound B scan in a patient with dementia equal Alzheimer disease?
abstract: OBJECTIVE
  The clinical role of amyloid brain positron emission tomographic imaging in the diagnosis of Alzheimer disease is currently being formulated. The specificity of a positive amyloid scan is a matter of contention.
  
  
  METHODS
  An 83-year-old Canadian man presented with a 5-year history of predominantly short-term memory loss and functional impairment. Clinical evaluation revealed significant, gradually progressive short-term memory loss in the absence of any history of strokes or other neuropsychiatric symptoms. The patient met clinical criteria for probable Alzheimer disease but had a higher than expected burden of white matter disease on magnetic resonance imaging. A positron emission tomographic Pittsburgh Compound B scan was highly positive in typical Alzheimer disease distribution. The patient died of an intracerebral hemorrhage 6 months after the assessment. Autopsy revealed cerebral amyloid angiopathy in the complete absence of amyloid plaques or neurofibrillary tangles.
  
  
  CONCLUSIONS
  This patient demonstrates that a positive Pittsburgh Compound B scan in a patient with clinical dementia meeting criteria for probable Alzheimer disease is not proof of an Alzheimer disease pathophysiological process. A positive Pittsburgh Compound B scan in typical Alzheimer disease distribution in a patient with dementia can be secondary to cerebral amyloid angiopathy alone.
authors.affiliation: Department of Neurology, Massachusetts General Hospital and McLean Hospital, Harvard University, Boston, USA.
authors.forename: Simon
authors.initials: S
authors.lastname: Ducharme
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Guiot
authors.forename: James
authors.initials: J
authors.lastname: Nikelski
authors.forename: Howard
authors.initials: H
authors.lastname: Chertkow
mesh_terms: D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000378:metabolism; D016229:Amyloid beta-Peptides / Q000378:metabolism*; D000814:Aniline Compounds; D002543:Cerebral Hemorrhage / Q000473:pathology*; D003937:Diagnosis, Differential; D017809:Fatal Outcome; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis*; D009483:Neuropsychological Tests; D049268:Positron-Emission Tomography; D012680:Sensitivity and Specificity; D013844:Thiazoles
chemical_list: C475519:2-(4'-(methylamino)phenyl)-6-hydroxybenzothiazole; D016229:Amyloid beta-Peptides; D000814:Aniline Compounds; D013844:Thiazoles