¹⁸F-FDG gallbladder uptake: observation from a total-body PET/CT scanner

Area of Science:

• Nuclear Medicine
• Radiology
• Oncology

Background:

• Total-body PET/CT scanners offer enhanced efficiency and resolution over conventional systems.
• These advanced scanners enable delayed imaging and improved image quality.
• Gallbladder (GB) 18F-FDG uptake is typically not visualized in routine PET/CT but is increasingly noted with total-body systems.

Purpose of the Study:

• To determine the visualization rates and characteristics of gallbladder 18F-FDG uptake.
• To assess GB uptake in both healthy and oncological subjects using total-body PET/CT.
• To identify potential correlations between GB uptake and patient characteristics.

Main Methods:

• Retrospective review of 73 participants (48 healthy, 25 lymphoma) undergoing 18F-FDG total-body PET/CT.
• Imaging performed at multiple timepoints up to 3 hours post-injection.
• Gallbladder 18F-FDG activity graded against liver uptake, with wall and/or lumen patterns noted.

Main Results:

• 100% of subjects showed GB uptake at 120 and 180 minutes post-injection.
• Gallbladder wall uptake observed in 60% of patients, primarily early; luminal activity in 97%, primarily late.
• No significant correlation found between GB uptake patterns and patient characteristics (age, sex, BMI, glucose).

Conclusions:

• Consistent gallbladder 18F-FDG uptake is a normal physiological finding on total-body PET/CT.
• This finding is observed in both healthy individuals and those with new oncological diagnoses.
• Diagnostic imaging professionals should be aware of this normal physiological visualization.