¹¹C-Pittsburgh compound B-positron emission tomography (PiB-PET) is a core biomarker for the in vivo detection of Alzheimer’s disease (AD) pathology, data on its correlation to cerebrospinal fluid Aβ42 (CSF) in real-world clinical performance in Latin America is limited.

We aim to describe the concordance between amyloid biomarkers, PET and CSF in a Latin American Memory Center

Methods • We performed a retrospective analysis of all ¹¹C-Pittsburgh compound B-positron emission tomography (PET) scans acquired between 2013 and 2023 at a tertiary memory center in Buenos Aires, Argentina. • Concordance with cerebrospinal fluid Aβ42 (CSF) was assessed. • Analyses focused on patients with complete clinical characterization. • We analyzed results across pre-test diagnostic categories.

A total of 1451 PiB-PET studies were performed. Paired biomarker analysis was available for 77 internal patients. • Overall concordance of 75.3% (58/77). • The association between PET status and CSF classification was statistically significant (χ² = 17.9; p = 3.37 × 10⁻⁵).

 

Conclusion: 

CSF Aβ42 and PiB-PET showed high concordance, with discordant cases mainly occurring in early or diagnostically uncertain presentations. These findings support the complementary use of both biomarkers and provide a baseline for the introduction of anti-amyloid therapies and bloodbased biomarkers in Latin America.