Table 3.
Detailed information on the diagnostic impact of the second PET scan in the two diagnostic pathways (AMY-TAU and TAU-AMY)
| Diagnostic pathway |
N of patients |
T0 diagnosis |
First PET scan |
T1 diagnosis |
Second PET scan |
T2 diagnosis |
Observations |
|---|---|---|---|---|---|---|---|
| AMY-TAU | 8 | AD | AMY+ | AD | TAU– | Non-AD |
• Discordant PET results • Same diagnosis at T0 and T1 |
| 1 | Non-AD | AMY+ | AD | TAU– | Non-AD |
• Discordant PET results • T1 diagnosis changed after first PET scan |
|
| 1 | AD | AMY– | Non-AD | TAU+ | AD |
• Discordant PET results • T1 diagnosis changed after first PET scan |
|
| 1 | Non-AD | AMY– | Non-AD | TAU+ | AD |
• Discordant PET results • Same diagnosis at T0 and T1 |
|
| 1* | AD | AMY– | Non-AD | TAU– | AD |
• Concordant PET results • T1 diagnosis changed after first PET scan |
|
| TAU-AMY | 1 | AD | TAU– | AD | AMY– | Non-AD |
• Concordant PET results • Same diagnosis at T0 and T1 |
| 4 | Non-AD | TAU– | Non-AD | AMY+ | AD |
• Discordant PET results • Same diagnosis at T0 and T1 |
|
| 2 | AD | TAU– | Non-AD | AMY+ | AD |
• Discordant PET results • T1 diagnosis changed after first PET scan |
|
| 1 | Non-AD | TAU+ | Non-AD | AMY+ | AD |
• Concordant PET results • Same diagnosis at T0 and T1 |
AMY+/−: amyloid positive/negative, TAU+/−: tau positive/negative
This table includes only patients who changed diagnosis after amyloid-PET (n = 8) or tau-PET (n = 12) presented as the second exam
*The only case in which the diagnosis changed after a consistent PET result was a patient with a T1 diagnosis of MCI not due to AD based on a negative amyloid-PET whose diagnosis changed to AD at T2 after a negative tau-PET scan (Braak stage = I–III)