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Normal conus medullaris FDG uptake in children
Adina L Alazraki1, Stephen F Simoneaux, J Bradley Wyly
1Department of Radiology, Emory University and Children's Healthcare of Atlanta, Decatur, GA 30322, USA. adina.alazraki@choa.org
Insights
Low-level fluorodeoxyglucose F 18 (18F-FDG) uptake in the conus medullaris is common in children. This normal finding on PET/CT scans should not be mistaken for central nervous system (CNS) metastatic disease.
Area of Science:
- Pediatric Nuclear Medicine
- Neuroimaging
- Oncology
Background:
- 18F-FDG biodistribution is established in adults and children.
- Pediatric-specific findings require dedicated understanding for accurate interpretation.
Purpose of the Study:
- To quantify normal 18F-FDG uptake in the pediatric conus medullaris.
- Establish baseline values for conus medullaris uptake on FDG PET/CT in children.
Main Methods:
- Retrospective review of 100 pediatric 18F-FDG PET/CT scans.
- Objective evaluation of conus medullaris FDG uptake and SUV determination.
- Comparison of conus SUV to background, liver, and lung values.
Main Results:
- Seventy percent of scans (70/100) demonstrated 18F-FDG uptake in the conus medullaris.
- Conus medullaris SUV ranged from 1.33 to 4.2 (mean 2.14).
- Patient ages ranged from 5 months to 24 years.
Conclusions:
- Low-level 18F-FDG uptake in the conus medullaris is a normal finding in children.
- This uptake represents normal physiological distribution, not CNS metastatic disease.
- Understanding normal conus medullaris uptake is crucial for accurate PET/CT interpretation in pediatric oncology.
Background:
The biodistribution of 18F-FDG has been well described in both adults and children. Many findings are limited to children and warrant understanding prior to interpretation.
Objective:
To determine the normal level of conus medullaris uptake, not previously reported in the literature to date, in a series of consecutive FDG PET/CT scans performed in children.
Materials And Methods:
With IRB approval, we retrospectively reviewed 100 consecutive whole-body pediatric 18F-FDG PET/CT examinations obtained for various clinical indications. Scans that showed visible uptake of FDG at the conus were objectively evaluated, and standardized uptake value (SUV) was determined. Maximum SUV of the conus was compared to background, normal liver and lung, and ratios were recorded. Pathology in the conus was excluded.
Results:
The scans of 100 patients ages 5 months to 24 years (mean 11.7 years) were reviewed. Three patients were excluded. Seventy percent showed uptake at the conus medullaris. SUVs ranged from 1.33 to 4.2 (mean 2.14).
Conclusion:
Low-level 18F-FDG uptake is common in the conus medullaris, represents normal distribution in children and should not be interpreted as metastatic disease to the CNS.
