PT - JOURNAL ARTICLE AU - Laurence Vass AU - Marie Fisk AU - Joseph Cheriyan AU - Divya Mohan AU - Julia Forman AU - Adelola Oseni AU - Anand Devaraj AU - Kaisa M. Mäki-Petäjä AU - Carmel M. McEniery AU - Jonathan Fuld AU - Nicholas S. Hopkinson AU - David A. Lomas AU - John R. Cockcroft AU - Ruth Tal-Singer AU - Michael I. Polkey AU - Ian B. Wilkinson TI - Quantitative <sup>18</sup>F-fluorodeoxyglucose positron emission tomography/computed tomography to assess pulmonary inflammation in COPD AID - 10.1183/23120541.00699-2020 DP - 2021 Jul 01 TA - ERJ Open Research PG - 00699-2020 VI - 7 IP - 3 4099 - http://openres.ersjournals.com/content/7/3/00699-2020.short 4100 - http://openres.ersjournals.com/content/7/3/00699-2020.full SO - erjor2021 Jul 01; 7 AB - Rationale COPD and smoking are characterised by pulmonary inflammation. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) imaging may improve knowledge of pulmonary inflammation in COPD patients and aid early development of novel therapies as an imaging biomarker.Objectives To evaluate pulmonary inflammation, assessed by FDG uptake, in whole and regional lung in “usual” (smoking-related) COPD patients, alpha-1 antitrypsin deficiency (α1ATD) COPD patients, smokers without COPD and never-smokers using FDG PET/CT. Secondly, to explore cross-sectional associations between FDG PET/CT and systemic inflammatory markers in COPD patients and repeatability of the technique in COPD patients.Methods Data from two imaging studies were evaluated. Pulmonary FDG uptake (normalised Ki; nKi) was measured by Patlak graphical analysis in four subject groups: 84 COPD patients, 11 α1ATD-COPD patients, 12 smokers and 10 never-smokers. Within the COPD group, associations between nKi and systemic markers of inflammation were assessed. Repeatability was evaluated in 32 COPD patients comparing nKi values at baseline and at 4-month follow-up.Results COPD patients, α1ATD-COPD patients and smokers had increased whole lung FDG uptake (nKi) compared with never-smokers (0.0037±0.001, 0.0040±0.001, 0.0040±0.001 versus 0.0028±0.001 mL·cm−3·min−1, respectively, p&lt;0.05 for all). Similar results were observed in upper and middle lung regions. In COPD participants, plasma fibrinogen was associated with whole lung nKi (β=0.30, p=0.02) in multivariate analysis adjusted for current smoking, forced expiratory volume in 1 s % predicted, systemic neutrophils and C-reactive protein levels. Mean percentage difference in nKi between the baseline and follow-up was 3.2%, and the within subject coefficient of variability was 7.7%.Conclusions FDG PET/CT has potential as a noninvasive tool to enable whole lung and regional quantification of FDG uptake to assess smoking- and COPD-related pulmonary inflammation.FDG PET/CT has potential utility to noninvasively evaluate pulmonary inflammation in COPD. Pulmonary FDG uptake is increased in COPD patients, positively associated with systemic inflammatory markers and shows low inter-occasion variability. https://bit.ly/3dELYAW