Amyloid PET in Dementia Syndromes: A Chinese Multicenter Study

Area of Science:

• Neurology
• Nuclear Medicine
• Genetics

Background:

• Distinguishing Alzheimer's disease (AD) from other dementia syndromes is crucial for accurate diagnosis and treatment.
• Positron Emission Tomography (PET) imaging of cerebral β-amyloid deposits and glucose metabolism are established diagnostic tools.
• Understanding the prevalence of amyloid deposits across various cognitive impairment (CI) diagnoses is essential for clinical practice.

Purpose of the Study:

• To estimate the prevalence of β-amyloid deposits using PET imaging in a diverse memory clinic population with cognitive impairment (CI).
• To assess the utility of amyloid PET in differentiating between AD and other dementia syndromes.
• To investigate the association between amyloid positivity, dementia type, and Apolipoprotein E (ApoE) genotype.

Main Methods:

• A multicenter study involving 1,193 consecutive patients with CI who underwent 11C-PIB PET or 18F-AV45 PET imaging.
• Patients were diagnosed with AD, frontotemporal dementia (FTD), dementia with Lewy bodies, mild cognitive impairment (MCI), vascular dementia, corticobasal syndrome, or unclassifiable dementia.
• Apolipoprotein E (ApoE) genotype analysis was performed on CI patients and controls.

Main Results:

• Overall, 72.1% of CI patients were amyloid-positive.
• Amyloid positivity was high in AD (86.8%) and MCI (9.7%), but low in FTD (5.6%).
• ApoEε4 allele frequency was significantly higher in amyloid-positive CI patients (30.5%) compared to amyloid-negative CI patients (14%) and controls (7.3%).

Conclusions:

• Amyloid PET imaging shows significant potential as a tool for differential diagnosis in dementia, particularly for distinguishing AD from FTD.
• Amyloid PET results, when combined with ApoEε4 genetic risk assessment, can aid in identifying amyloid deposits.
• The study highlights the varying prevalence of β-amyloid deposits across different dementia syndromes.