Normal patterns of 18F-FDG appendiceal uptake in children

Area of Science:

• Nuclear Medicine
• Pediatric Imaging
• Radiology

Background:

• Understanding normal fluorodeoxyglucose (FDG) biodistribution is essential for interpreting PET/CT scans, especially in pediatric patients.
• Normal FDG uptake patterns can differ between adults and children, with limited data on pediatric appendiceal activity.
• Children's higher levels of active lymphoid tissue, including in the appendix, suggest potentially increased FDG uptake.

Purpose of the Study:

• To establish the normal range of FDG uptake in the pediatric appendix.
• To evaluate appendiceal FDG activity in children using PET/CT scans performed for other clinical reasons.

Main Methods:

• Retrospective review of 128 pediatric FDG PET/CT scans.
• Exclusion of scans with non-visualized or pathologically abnormal appendices on CT.
• Calculation of appendiceal maximum standardized uptake value (SUVmax) and appendix-to-liver SUVmax ratios.

Main Results:

• Appendiceal SUVmax ranged from 0.5 to 9.4 (mean 2.2) in pediatric patients.
• Appendix-to-liver SUVmax ratios ranged from 0.3 to 3.1 (mean 1.1).
• No scans were excluded due to appendiceal pathology or inability to obtain measurements.

Conclusions:

• Appendiceal FDG uptake in children is generally comparable to background liver activity.
• Minor variations in pediatric appendiceal FDG uptake are common and typically not indicative of disease.
• These findings aid in the accurate interpretation of pediatric FDG PET/CT scans.