From February 2009 through March 2010, the study enrolled 152 individuals approaching the end of life to obtain 35 postmortem evaluations (brain autopsies) from those who received PET imaging 12 months or less prior to death. Individuals were recruited from in-patient and community hospice programs, long-term care facilities, and outpatient community health care facilities. The main inclusion criteria included a physician’s assessment that the individual was likely to die within 6 months of study enrollment, absence of any known destructive lesion in the brain (eg, stroke or tumor), and the individual’s willingness to have florbetapir-PET imaging followed by a brain autopsy at the time of death. Each participant received a brief physical, neurological, and cognitive evaluation that included assessments of memory, language, and constructional praxis. In the 35 individuals who were autopsied, the major comorbidities were hypertension (66%), cancer (49%), cardiac disease (46%), chronic lung disease (37%), and diabetes (29%). The primary study clinical diagnosis and cause of death (as noted by the study physician) are listed in TABLE 1.
The postmortem evaluations for the first 6 participants were evaluated separately as part of a preplanned interim analysis. The final 29 postmortem evaluations comprised the primary analysis data set.
A second group of 74 young cognitively normal, healthy individuals (aged 18–50 years) were recruited from the community and were evaluated using the same clinical assessment and PET imaging protocol as those in the autopsy cohort to determine (among individuals who presumably had no β-amyloid) the proportion that were categorized correctly by a florbetapir-PET scan as amyloid negative.
For all participants in this study, written informed consent was provided by the individual or by his/her designated decision maker and the study was approved by institutional review boards.