Quantitative 18F-FDG PET/CT to assess pulmonary inflammation in chronic obstructive pulmonary disease

Abstract

Ationale Chronic obstructive pulmonary disease (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 was measured by Patlak graphical analysis in four subject groups: 84 COPD, 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 4-months follow up. Results COPD, α1ATD patients and smokers had increased whole lung FDG uptake (nKi) compared to never-smokers (0.0037±0.001, 0.0040±0.001, 0.0040±0.001 versus 0.0028±0.001\u2005ml·cm−3/min−1 respectively, p Conclusions FDG PET/CT has potential as a non-invasive tool to enable whole lung and regional quantification of FDG to assess smoking and COPD-related pulmonary inflammation.