Brown adipose tissue detected by FDG PET/CT is associated with less central abdominal visceral fat

1416 Objectives Studies indicate that central abdominal visceral fat (VF) is more closely associated with metabolic syndrome than subcutaneous fat (SF)(1, 2). Previously we reported that brown adipose tissue (BAT) was protective against developing features of the metabolic syndrome (3). In this study, we tested the hypothesis that patients with BAT have less VF compared to BMI matched control patients without BAT. Methods Retrospective analysis of PET/CT studies performed from 2011 to 2013 identified 37 adult (>21 yrs) oncology patients with FDG BAT uptake. The control cohort consisted of two adult patients without FDG BAT uptake, matched for BMI/gender/season, for each patient with BAT. BMI were obtained from the PET/CT records. BAT was determined by two board certified nuclear medicine physicians. VF and SF were assessed at L4/L5. Fat enclosed by the visceral cavity was considered VF, and fat outside the visceral cavity was considered SF. Fat density was determined by CT using Hounsfield unit interval (-190 to -30). CT imaging was interpreted blinded to clinical information. The ratio of VF/(SF+VF) was calculated. The two cohorts were compared by t test. Results The BAT cohort had significantly less VF (124.4±70.8 cm2) compared to controls (153.7±87.3 cm2)(P=0.04). There was no difference in SF for the BAT cohort (299.3±158.6 cm2) compared to controls (303.0±175.3 cm2)(P=0.91). The BAT cohort had a significantly lower ratio of VF/(SF+VF) compared to controls (0.30±0.10 vs. 0.35±0.11 respectively; P=0.01). Conclusions Patients with BAT had significantly less VF and a lower ratio of VF/(SF+VF) compared to BMI/gender/season matched control patients without BAT. There was no difference in SF between the two cohorts. The findings suggest that active BAT detected by FDG PET/CT may be protective against developing VF. Research Support None