Extensive brown fat activation (18F-FDG PET-CT)

Case contributed by Dr Justin G Peacock


Surveillance scan for history of anaplastic large cell lymphoma.

Patient Data

Age: 16 years
Gender: Male

AC MIP: Extensive, intense uptake in the cervical, axillary, thoracic paraspinal, and retroperitoneal soft tissues.

Axial fused PET-CT and CT: In the supraclavicular region there is intense FDG uptake corresponding with regions of fat on CT.

Case Discussion

Key points:

  • notice the classic location for brown fat activation, including intensity and distribution
  • correlate FDG uptake with the CT findings, brown fat activation leads to uptake solely in areas of fat on CT.
  • use caution when interpreting PET-CT with brown fat activation, consider having the patient return with brown fat activation precautions

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