The study is designed to test the relationship between measurements of brain amyloid using florbetapir F 18 PET imaging and true levels of amyloid by dissection of the brain at autopsy. Amyloid in the brain is a key feature of Alzheimer's Disease (AD).
There will be two primary analyses: * The first primary analysis will evaluate the correlation between the blinded readers' rating of amyloid plaque density on the PET scan and the cortical amyloid plaque density at autopsy. * The second primary analysis will evaluate the specificity of the blinded readers' rating of presence or absence of amyloid plaque density on the PET scan For the autopsy population, subjects will be enrolled from various end-of-life (e.g. hospice / hospital / nursing home) and late-life (longitudinal studies of aging) populations. Enrollment will include subjects with various levels of cognitive status, ranging from cognitively normal through dementia. It is expected that amyloid plaque density in this elderly population will range from very low (normal aging) through moderate (e.g. cognitively normal subjects with asymptomatic amyloid deposits or mild cognitive impairment (MCI) subjects with intermediate levels of amyloid deposits) to very high (subjects with AD). The study will also enroll younger healthy subjects presumably devoid of amyloid in the specificity cohort. Screening assessments may take place over several days and will include collection of demographic information, diagnostic interview, and safety assessments. At the time of screening, subjects or caregivers will be asked to provide consent for brain donation if they are not already enrolled in a brain donation program affiliated with this study, in addition to providing informed consent for the screening and imaging procedures in the study. Subjects who qualify for the study will have a catheter placed for intravenous (i.v.) administration of florbetapir F 18. Subjects will receive a single i.v. bolus of 370 MBq (10 mCi) of florbetapir F 18 followed by brain PET imaging for 10 minutes duration, beginning approximately 50 minutes post-injection. Vital signs and safety labs will be obtained prior to the administration of florbetapir F 18 and at the completion of the imaging session. Adverse events will be continuously monitored during the imaging session. Subjects who experience an adverse event will not be discharged until the event has been resolved or stabilized.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
DIAGNOSTIC
Masking
SINGLE
Enrollment
226
Single i.v. bolus injection of 370MBq (10 mCi) followed by saline flush, 50 minutes prior to imaging, 10 minute image duration
Research Site
Phoenix, Arizona, United States
Correlation of Florbetapir-PET Image and Amyloid Plaque Density
Spearman's rank order correlation of the median semi-quantitative visual read of the florbetapir-PET image and the amyloid plaque density assessed post-mortem by quantitative immunohistochemistry (IHC) averaged across 6 brain regions (precuneus, parietal cortex, frontal cortex, temporal cortex, posterior cingulate, anterior cingulate). Spearman's rank order correlation ranges from -1 to +1. A value of -1 indicates perfect negative correlation, and a value of +1 indicates a perfect positive correlation.
Time frame: at autopsy up to 12 months post-scan
Specificity Analysis
Specificity of florbetapir-PET scan in younger healthy controls presumed to be negative for amyloid. Specificity results are reported as the number of subjects who had a negative scan based on majority of 3 blinded readers.
Time frame: 50-60 min after injection
Regional Correlation Analysis
Spearman's rank order correlation of median visual read of the florbetapir-PET image vs. amyloid plaque density assessed post-mortem by quantitative IHC of six individual brain regions (precuneus, parietal cortex, frontal cortex, temporal cortex, posterior cingulate, anterior cingulate). Spearman's rank order correlation ranges from -1 to +1. A value of -1 indicates perfect negative correlation, and a value of +1 indicates a perfect positive correlation.
Time frame: at autopsy up to 12 months post-scan
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