Meta-analysis of 18F-FDG PET/CT in diagnosis and prognostic evaluation of thoracic sarcoidosis

18F-Fluorodeoxyglucose (FDG) PET/CT is emerging as a tool in the diagnosis and evaluation of thoracic sarcoidosis, however, there is limited consensus regarding its diagnostic performance and prognostic value. A meta-analysis was conducted with publication databases searched up to and including September 2023. 1,355 studies were screened, with 17 (n=708 patients) suitable based on their assessment of diagnostic performance or prognostic value of FDG-PET/CT. Forest plots of pooled sensitivity and specificity were generated to assess diagnostic performance and pooled change in SUVmax. These were correlated with changes in pulmonary function tests (PFTs) and quality-of-life. FDG-PET/CT for the diagnosis of thoracic sarcoidosis (6 studies, n=400) had a pooled sensitivity of. 971 (95%CI 0.909 – 1.000, p=<.001), with a specificity (1 study, n=169) of. 873 (95%CI. 845 –. 920). 11 studies were suitable for prognostic analysis (n=308) with a pooled reduction in pulmonary SUVmax of 4.538 (95%CI 5.653 – 3.453, p=<.001) following treatment. PFTs showed improvement following treatment with an increase in percentage of predicted forced vital capacity (FVC) and diffusion capacity of the lung for carbon monoxide (DLCO) of 7.346% (95%CI 2.257 – 12.436, p=.005) and 3.464% (95%CI -0.205 – 7.132, p=.064), respectively. Reduction in SUVmax strongly correlated with improvement in FVC (r =.644, p<.001) and DLCO (r =.582, p<.001). QOL indicators improved in 75% of the studies assessed (4 studies, n=116). FDG-PET/CT has a high diagnostic performance in thoracic sarcoidosis. Relative change in FDG-PET/CT SUVmax correlated with improvements in PFTs and QOL indicators and may be useful in guiding treatment response.