Florbetapir (Amyvid) Amyloid Pet Imaging is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
| Property |
Value |
| Drug Name |
Florbetapir F 18 |
| Brand Name |
Amyvid |
| Drug Class |
PET Radiotracer |
| Target |
Amyloid-beta plaques |
| Route of Administration |
Intravenous |
| FDA Approval |
2012 |
| Company |
Eli Lilly |
Florbetapir F 18 (Amyvid) is a radioactive diagnostic agent used in positron emission tomography (PET) imaging to detect amyloid-beta (Aβ) plaques in the brain. It received FDA approval in 2012 for use in patients with cognitive impairment being evaluated for Alzheimer's disease (AD) or other causes of cognitive decline.
Florbetapir is a stilbene derivative that binds with high affinity to amyloid-beta plaques in the brain:
- High Affinity: Kd ~0.7 nM for aggregated Aβ plaques
- Selectivity: Shows minimal binding to other protein aggregates (tau, α-synuclein)
- Blood-Brain Barrier Penetration: Rapid brain uptake due to lipophilic structure
- Radionuclide: F-18 label (half-life 109.8 minutes) allows for optimal imaging timing
- Administration: IV injection of 370 MBq (10 mCi) ± 20%
- Uptake Period: 30-50 minutes post-injection
- Scan Duration: 10-20 minutes PET scan
- Analysis: Visual assessment and/or quantitative SUVr analysis
- Confirmatory Testing: Supports clinical diagnosis of AD in patients with cognitive impairment
- Differential Diagnosis: Helps distinguish AD from other dementias (vascular, frontotemporal, Lewy body)
- Rule-Out Test: Negative scan reduces likelihood of AD pathophysiology
- Patient Selection: Enrichment of clinical trials with amyloid-positive patients
- Biomarker Endpoint: Used as a biomarker endpoint in AD clinical trials
- Treatment Response: May track changes in amyloid burden over time
- Epidemiological Studies: Understanding amyloid prevalence in aging populations
- Biomarker Correlation: Correlating amyloid burden with other biomarkers (CSF, PET tau)
- Natural History Studies: Tracking amyloid accumulation over time
| Result |
Interpretation |
| Positive |
Amyloid plaques present; consistent with AD pathophysiology |
| Negative |
Amyloid plaques not detected; AD pathophysiology less likely |
- Centiloid Scale: Standardized measurement allowing cross-study comparison
- Threshold: Typically SUVr ≥1.4 (or ≥20 Centiloids) considered positive
- Regional Analysis: Composite of frontal, parietal, lateral temporal, cingulate regions
- Cerebellar Reference: Cerebellum cortex often used as reference region
¶ Sensitivity and Specificity
- Sensitivity: ~92-96% for detecting histologically confirmed Aβ plaques
- Specificity: ~78-90% for distinguishing AD from non-AD subjects
- Accuracy: High negative predictive value in excluding AD
- Strong correlation between antemortem Florbetapir uptake and postmortem Aβ plaque density
- Validated in numerous neuropathological confirmation studies
- Cerebral amyloid angiopathy (CAA) can give positive scans
- Some non-AD conditions may show incidental amyloid
- Very early AD (preclinical) may have negative scans
- Technical factors (scan quality, interpretation)
- Radiation exposure (~7 mSv effective dose)
- Cost and availability of PET facilities
- Not for use in patients under 55 years (low pre-test probability)
| Tracer |
Brand Name |
FDA Status |
Half-life |
| Florbetapir F 18 |
Amyvid |
Approved 2012 |
110 min |
| Florbetaben F 18 |
Neuraceq |
Approved 2014 |
110 min |
| Flutemetamol F 18 |
Vizamyl |
Approved 2013 |
110 min |
- Covered by Medicare (Part B) for patients with:
- Clinically uncertain dementia diagnosis
- Progressive cognitive decline of unknown cause
- Onset of dementia before age 65
- Prior authorization may be required
The study of Florbetapir (Amyvid) Amyloid Pet Imaging has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.
- {{cite journal | author=Clark CM et al. | title=Use of florbetapir-PET for imaging beta-amyloid pathology | journal=JAMA | year=2011 }}
- {{cite journal | author=Joshi AD et al. | title=Performance characteristics of amyloid PET imaging | journal=J Nucl Med | year=2015 }}
- {{cite journal | author=Schmidt ME et al. | title=Florbetapir F18: a review | journal=Ann Nucl Med | year=2018 }}