Supraclavicular Brown Adipose Tissue 18F-FDG Uptake and Cardiovascular Disease

Abstract

Rationale: Pre-clinical data suggests a negative correlation between brown adipose tissue (BAT) and the degree of coronary atherosclerosis. We sought to evaluate the relationship between ¹⁸F-FDG uptake in supraclavicular BAT in relation to: 1) arterial inflammation and 2) subsequent cardiovascular disease (CVD) events in humans. Methods: Individuals who underwent ¹⁸F-FDG PET/CT for clinical indications, but who did not have either cancer or known atherosclerotic disease at time of imaging were included. While blinded to clinical data, ¹⁸F-FDG uptake was measured within BAT (in supraclavicular region) as well as in subcutaneous adipose tissues (SAT). Tissue density was evaluated using CT (Hounsfield units). Arterial inflammation was assessed by measuring of arterial FDG uptake and calculating target to background ratio (TBR). Cardiovascular disease (CVD) events were independently adjudicated by blinded cardiologists. Thereafter, the relationship between BAT activity and CVD events was evaluated. Results: A total of 443 patients (age, 43% male, body mass index (BMI) 26 (23-31)) were included and 34 experienced a cardiovascular event during a median follow-up of 4 years. BAT activity negatively correlated with arterial inflammation (r=-0.178, pP = 0.048) even after correcting for age (P = 0.037). Conclusion: Our results suggest that increased supraclavicular BAT activity is inversely associated with arterial inflammation, independently of age and BMI. Additionally, increased BAT may be associated with fewer cardiovascular events.