Prognostic Implications of Volume-based Quantitative 18F-FDG PET/CT Biomarkers in Pulmonary Sarcoidosis

BACKGROUND: Sarcoidosis is a multisystemic granulomatous disease with highly variable manifestations and outcomes, making clinical management challenging. This study evaluated the prognostic value of biomarkers derived from 18F-FDG PET/CT imaging. PATIENTS AND METHODS: From an institutional registry, 75 sarcoidosis patients with a 18F-FDG PET/CT scan performed at the time of initial diagnosis were selected. A composite progression endpoint was defined, comprising either a decrease in FVC>5%, in DLCO>10%, a worsening of radiologic findings, increasing clinical symptoms, or death. Disease progression was assessed by onset at 1 year, 2 years, and overall. The MV of thoracic and extrathoracic lesions attributed to sarcoidosis was calculated, using a SUV threshold of 2.5. SUVmax was also determined for these regions. RESULTS: Of 75 patients, 45 patients met the progression criteria while 30 patients remained in remission. Baseline MVthoracic (P = 0.002) and MVwhole-body (P < 0.001) were higher in patients subsequently showing progression, while no significant differences were observed in whole-body or organ-specific SUVmax. The optimum threshold of MVthoracic for prognosis of overall disease progression was determined at 150 cm3, yielding an OR of 1.9 in the univariate analysis (MVthoracic >150 vs <150 cm3; 95% CI: 1.00-3.49; P = 0.049). For MVwhole-body, the optimal cutoff value was also determined at 150 cm3, with an OR of 2.06 (MVwhole body >150vs <150 cm3; 95% CI: 1.08-3.95; P = 0.029). Neither total nor organ-specific SUVmax had significant associations with progression outcomes. CONCLUSIONS: Volume-based biomarkers derived from 18F-FDG PET/CT were associated with disease progression in pulmonary sarcoidosis, whereas SUVmax showed no prognostic implications.