Alzheimer's Disease
Conditions
Brief summary
This study will evaluate whether the addition of quantitation as an adjunct to visual interpretations significantly improves the accuracy of Amyvid scan interpretation.
Interventions
No Florbetapir (18F) will be administered in this study.
Sponsors
Avid Radiopharmaceuticals
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
DIAGNOSTIC
Masking
SINGLE (Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Healthy volunteers
No
Inclusion criteria
* Readers have undergone Amyvid reader training * Readers have not more than minimal experience with quantitation of amyloid PET scans
Exclusion criteria
* Readers have previously been trained to quantitate amyloid PET scans
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Reader Accuracy After Application of Quantitation Software | 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. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Scan Interpretation Reliability After Application of Quantitation Software | 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. |
Countries
Netherlands
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Florbetapir PET Scans No subjects were enrolled in this study. Readers interpreted 96 Florbetapir scans from subjects enrolled in previous studies (A16\[NCT01447719\] and A17\[NCT01400425\]). Scans used in the study included 46 scans with autopsy (A16) and 50 randomly selected non-autopsy scans (A17). | 96 |
| Total | 96 |
Baseline characteristics
| Characteristic | Florbetapir PET Scans |
|---|---|
| Age, Continuous | 76.9 years STANDARD_DEVIATION 10.23 |
| Ethnicity (NIH/OMB) Hispanic or Latino | 4 Participants |
| Ethnicity (NIH/OMB) Not Hispanic or Latino | 92 Participants |
| Ethnicity (NIH/OMB) Unknown or Not Reported | 0 Participants |
| Race/Ethnicity, Customized Asian | 1 participants |
| Race/Ethnicity, Customized Black or African American | 5 participants |
| Race/Ethnicity, Customized Other | 1 participants |
| Race/Ethnicity, Customized White | 89 participants |
| Region of Enrollment United States | 96 participants |
| Sex: Female, Male Female | 48 Participants |
| Sex: Female, Male Male | 48 Participants |
Adverse events
| Event type | EG000 affected / at risk |
|---|---|
| deaths Total, all-cause mortality | — / — |
| other Total, other adverse events | 0 / 0 |
| serious Total, serious adverse events | 0 / 0 |
Outcome results
Primary
Change in Reader Accuracy After Application of Quantitation Software
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.
Time frame: Scan acquired 50-60 minutes post injection
| Arm | Measure | Value (NUMBER) |
|---|---|---|
| Physician Readers | Change in Reader Accuracy After Application of Quantitation Software | 0.0746 Net Reclassification Index |
p-value: 0.0001Asymptotic Z-test
Secondary
Change in Scan Interpretation Reliability After Application of Quantitation Software
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.
Time frame: Scan acquired 50-60 minutes post injection
| Arm | Measure | Group | Value (NUMBER) |
|---|---|---|---|
| Physician Readers | Change in Scan Interpretation Reliability After Application of Quantitation Software | Kappa Qualitative | 0.66 Fleiss Kappa |
| Physician Readers | Change in Scan Interpretation Reliability After Application of Quantitation Software | Kappa VisQ | 0.73 Fleiss Kappa |
| Physician Readers | Change in Scan Interpretation Reliability After Application of Quantitation Software | Change in Kappa | 0.06 Fleiss Kappa |
| Autopsy Cases | Change in Scan Interpretation Reliability After Application of Quantitation Software | Kappa Qualitative | 0.66 Fleiss Kappa |
| Autopsy Cases | Change in Scan Interpretation Reliability After Application of Quantitation Software | Kappa VisQ | 0.72 Fleiss Kappa |
| Autopsy Cases | Change in Scan Interpretation Reliability After Application of Quantitation Software | Change in Kappa | 0.06 Fleiss Kappa |
| Non-autopsy Cases | Change in Scan Interpretation Reliability After Application of Quantitation Software | Kappa VisQ | 0.73 Fleiss Kappa |
| Non-autopsy Cases | Change in Scan Interpretation Reliability After Application of Quantitation Software | Change in Kappa | 0.07 Fleiss Kappa |
| Non-autopsy Cases | Change in Scan Interpretation Reliability After Application of Quantitation Software | Kappa Qualitative | 0.66 Fleiss Kappa |
Comparison: Evaluate whether the VisQ interpretation significantly improves the reliability of Amyvid Scan interpretation.p-value: 0.006Monte Carlo test
Comparison: Evaluate whether the VisQ interpretation significantly improves the reliability of Amyvid Scan interpretation.p-value: 0.1229Monte Carlo test
Comparison: Evaluate whether the VisQ interpretation significantly improves the reliability of Amyvid Scan interpretation.p-value: 0.026Monte Carlo test