The purpose of this study is re-read of brain amyloid positron emission tomography (PET) scans acquired in previous florbetapir F 18 clinical studies by readers trained using updated reading methodology. The scans in this study came from subjects who had an autopsy to reveal the subject's true amyloid status.
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
DIAGNOSTIC
Masking
SINGLE
Enrollment
35
IV injection, 370MBq (10mCi), single dose
Sensitivity of Florbetapir PET Scans to Detect Moderate to Frequent Amyloid Plaque
Nine readers blinded to all clinical information using the binary read methodology (amyloid positive/negative). Sensitivity will be calculated as the percent of true positives (as determined by the reference standard, moderate or frequent amyloid plaque at autopsy) that are correctly identified as amyloid positive by the PET scan read. Reported as the median sensitivity of the nine readers.
Time frame: 50-60 min after injection
Specificity of Florbetapir PET Scans to Detect Moderate to Frequent Amyloid Plaque
Nine readers blinded to all clinical information using the binary read methodology (amyloid positive/negative). Specificity will be calculated as the percent of true negatives (as determined by the reference standard, no or sparse amyloid plaque at autopsy) that are correctly identified as amyloid negative by the PET scan read. Reported as the median specificity of the nine readers.
Time frame: 50-60 min after injection
Inter-reader Agreement
Percentage of individual scan reads that agreed or disagreed with the majority read across nine readers
Time frame: 50-60 min after injection
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