PET Scans Vary in Detection of Amyloid Plaques

As the population in the United States continues to age, dementia and other neurodegenerative diseases have become an increasing concern. Diagnostic tools for Alzheimer’s disease are essential as an early, accurate diagnosis can impact treatment, allow for earlier interventions, and improve outcomes. A recent study compared PET scans’ ability to detect amyloid plaques across multiple races.

The study was a secondary analysis of data collected from Imaging Dementia-Evidence for Amyloid Scanning, a study focused on the association between β-amyloid PET and patient management. The data used information from 17,107 participants with dementia or mild cognitive impairment who were Medicare beneficiaries over the age of 65. The researchers found that PET scans detected amyloid plaques in 57.8% of White participants, while Asian participants had a positive detection rate of 45.4%.

Hispanic participants had a positive detection rate of 61.8%. Conversely, the rate for Black patients was 58.4%. These conclusions contradict known statistics that find that Black and Hispanic populations are statistically more likely to have dementia or Alzheimer’s disease.

“Racial and ethnic differences found in amyloid PET positivity among individuals with MCI and dementia in this study may indicate differences in underlying etiology of cognitive impairment and guide future treatment and prevention approaches,” concluded researchers in the publication.

This data implies that an exclusive reliance on PET scans to analyze dementia rates and progression may lead to racial discrepancies.

“There are implications of our findings in the context of the recently approved disease-modifying anti-amyloid monoclonal antibody aducanumab. This drug received FDA approval for treatment of MCI or mild dementia due to AD based on the lowering of amyloid PET signal as a surrogate biomarker. Lack of inclusivity of diverse populations in clinical trials for aducanumab (2 phase III studies included 10% Asian participants, 1% Black, and 3.4% Hispanic) along with our findings must be considered in the context of recommendations for novel therapies,” noted the investigators in the study.

Understanding the findings of this study and its implications provides clinicians with additional considerations when diagnosing and treating patients with dementia and Alzheimer’s disease. Further research must be conducted to determine why these differences occur.