Tau PET imaging is a molecular imaging biomarker that enables in vivo visualization and quantification of tau protein pathology in the brain. Tau aggregation into neurofibrillary tangles (NFTs) represents one of the hallmark pathological features of Alzheimer's disease (AD) and several other neurodegenerative disorders collectively termed tauopathies[1][2].
Tau PET serves as a critical biomarker for:
Flortaucipir was the first FDA-approved tau PET tracer for imaging tau pathology in AD[3]. Key characteristics:
Second-generation tau PET tracer with improved characteristics[4]:
Tau PET signal follows the characteristic hierarchical spread:
| Braak Stage | Regions Affected | Clinical Correlation |
|---|---|---|
| I-II | Transentorhinal cortex | Preclinical AD |
| III-IV | Limbic (hippocampus, entorhinal) | MCI to mild AD |
| V-VI | Isocortical (frontal, parietal) | Moderate to severe AD |
| Metric | Value |
|---|---|
| Sensitivity for AD | 85-95% |
| Specificity vs other tauopathies | 90-95% |
| Detection window | Preclinical to moderate-severe |
Differential Diagnosis
Disease Staging
Prognostic Information
| Method | Description | Clinical Use |
|---|---|---|
| SUVR | Standardized uptake value ratio | Regional burden |
| Centiloid-T | Tau-specific centiloid scale | Cross-study comparison |
| Braak ROI | Region-specific staging | Disease staging |
| Feature | CSF p-tau | Tau PET |
|---|---|---|
| Specificity | High | Very high |
| Spatial information | Global only | Regional patterns |
| Disease staging | Limited | Excellent |
| Accessibility | Good | Limited (PET facility) |
| Cost | Lower | Higher |
Negative tau PET does not rule out AD in very early stages
Off-target binding can cause false positives
Regional analysis preferred over global
Longitudinal comparison more informative than single scan
Mintun MA, et al. FLORTauCIPIR (F 18 AV-1451) PET imaging in Alzheimer's Disease (2020). 2020. ↩︎
Scholl M, et al. PET Imaging of tau pathology in Alzheimer's Disease (2016). 2016. ↩︎
Fleisher AS, et al. Phase 3 trial of flortaucipir for detecting Alzheimer's Disease tau pathology (2020). 2020. ↩︎
Hostetler ED, et al. Preclinical Characterization of 18F-MK-6240, a PET Tracer for Imaging Neurofibrillary Tangle Tau (2016). 2016. ↩︎
Bullich S, et al. Tau PET imaging with 18F-PI-2620 in patients with Alzheimer's disease and healthy controls (2019). 2019. ↩︎
Sepulveda-Falla D, et al. Tau pathology propagation in AD: spreading of pathological tau in the brain (2022). 2022. ↩︎
Niccolini F, et al. Tau imaging in progressive supranuclear palsy (2015). 2015. ↩︎
Ali F, et al. Tau PET patterns in corticobasal syndrome (2020). 2020. ↩︎
Hansson O, et al. Tau PET imaging: present and future directions (2022). 2022. ↩︎