A Study to Evaluate the Improvement in Reader Accuracy When Using a Read Method That Incorporates Commercially Available Quantitative Analysis Software as an Adjunct to the Clinical Visual Interpretation of Amyvid Brain Scans

Change in Reader Accuracy After Application of Quantitation Software

时间窗: Scan acquired 50-60 minutes post injection

Evaluate whether the use of quantitation software improves florbetapir (18F) scan interpretation by using the net reclassification index (NRI). The NRI is a prospective measure that quantifies the correctness of upward and downward reclassification or movement of predicted probabilities as a result of adding a new marker. NRI Values \>0 indicate an improvement in scan interpretation accuracy and values \<0 indicate a decline in scan interpretation accuracy after application of quantitation software. NRI = \[P(up,event)-P(down,event)\]-\[P(up,nonevent)-P(down,nonevent)\] Where P(up,event) = # events up/# events P(down,event) = # events down/# events P(up,nonevent) = # nonevents up/# nonevents P(down,nonevent) = # nonevents down/# nonevents and events: true positive case nonevents: true negative case up: scan change from negative to positive down: scan change from positive to negative Only the 46 scans with autopsy from A16 are used for this outcome measure.