Biomarkers

Area of Science:

• Neuroscience
• Medical Imaging
• Biochemistry

Background:

• Alzheimer's disease (AD) is characterized by amyloid-beta (Aβ) plaques in the brain.
• Aβ is also present and degraded in peripheral organs like the liver.
• Current PET imaging for AD is limited to the brain, overlooking systemic Aβ distribution.

Purpose of the Study:

• To utilize total-body PET imaging to characterize liver Aβ signal over time.
• To investigate differences in liver Aβ deposition between individuals with and without AD.
• To establish optimal imaging windows for liver Aβ detection.

Main Methods:

• ¹⁸F-florbetaben dynamic PET imaging was performed on the total-body uEXPLORER PET system.
• Regions of interest were defined in eight liver segments and a composite liver region.
• Standardized Uptake Value Ratio (SUVR) time-activity curves were analyzed using linear mixed effects models.

Main Results:

• Individuals with AD (Aβ+) showed significantly increased liver SUVR compared to controls (Aβ-) at later time points (90-110 min).
• Discrimination between Aβ+ and Aβ- groups was most significant at later time points.
• Early and middle time points showed limited discrimination in liver SUVR.

Conclusions:

• The liver exhibits an amyloid signal that changes over time, similar to the brain.
• The 90-110 minute time window is optimal for evaluating liver amyloid burden using PET.
• These findings support the liver as a potential peripheral biomarker for AD and systemic molecular processes.