Pulmonary Artery 18F-Fluorodeoxyglucose Uptake by PET/CMR as a Marker of Pulmonary Hypertension in Sarcoidosis

Objectives This study investigated whether pulmonary artery (PA) 18F-FDG uptake is associated with hypertension, and if it correlates to elevated pulmonary pressures. Background 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) combined with computed tomography or cardiac magnetic resonance (CMR) has been used to assess inflammation mostly in large arteries of the systemic circulation. Much less is known about inflammation of the vasculature of the pulmonary system and its relationship to pulmonary hypertension (PH). Methods In a single-center cohort of 175 patients with suspected cardiac sarcoidosis, who underwent hybrid thoracic PET/CMR, 18F-FDG uptake in the PA was quantified according to maximum standardized uptake value (SUVmax) and target-to-background ratio (TBR) and compared with available results from right heart catheterization (RHC) or transthoracic echocardiography (TTE). Results Thirty-three subjects demonstrated clear 18F-FDG uptake in the PA wall. In the subgroup of patients who underwent RHC (n = 10), the mean PA pressure was significantly higher in the group with PA 18F-FDG uptake compared with the group without uptake (34.4 ± 7.2 mm Hg vs 25.6 ± 9.3 mm Hg; P = 0.003), and 9 (90%) patients with PA 18F-FDG uptake had PH when a mean PA pressure cutoff of 25 mm Hg was used compared with 18 (45%) in the nonuptake group (P Conclusions We demonstrate that 18F-FDG uptake by PET/CMR in the PA is associated with PH and that its intensity correlates with PA pressure.