[Patterns and characteristics of brown adipose tissue uptake of 18F-FDG positron emission tomograph/computed...

To characterize the brown adipose tissue (BAT) uptake of 18F-FDG on positron emission tomography (PET)/computed tomography (CT) imaging.

We retrospectively analyzed the clinical data of 1 080 patients who received all whole-body PET/CT studies in Peking Union Medica College Hospital from July 2008 to February 2009.

Forty-one patients (3.8%) were identified to be with BAT uptake, especially during cold seasons. BAT uptake was mostly observed at the neck regions symmetrically (n = 39), and was also seen at paravertebral junctions (n = 30), perinephric regions (n = 21), and mediastinum (n = 10). Patients with BAT uptake had significantly lower male/female ratio (P = 0.0030), younger age (P = 0.0001), and less body mass index (BMI) (P = 0.0415). Three patients with high BAT uptake underwent repeat PET/CT scans 3-7 days later. By keeping warm and full relaxation, BAT uptake disappeared in 2 cases and dramatically decreased in the other case.

BAT uptake commonly occurs during cold seasons in Beijing, especially in young females with low BMI. It usually has specific patterns, and can be avoided or remarkably reduced by asking the patients keep warm and full relaxation a few days before the scanning.