18FDG uptake associated with CT density on PET/CT in lungs with and without chronic interstitial lung diseases

Objective The dependent-density of computed tomography (CT) images of positron emission tomography (PET)/CT is sometimes difficult to distinguish from chronic interstitial lung disease (ILD) when it accompanies increased 18F-fluorodeoxy-d-glucose (18FDG) uptake. Though the possible utility of 18FDG-PET for the diagnosis of active ILD has been reported, the clinical relevance of mild lung 18FDG uptake in ILD cases without signs and symptoms suggesting acute progression has not been described. This study aimed to test relationships between 18FDG uptake and lung density on CT using PET/CT in patients with normal lung as well as clinically stable chronic ILD.