Table 1.

Classification of LDCT patterns in subjects with definite and equivocal ILA

Predominant LDCT pattern	LDCT features
Definite UIP pattern	Predominant lower lung zone subpleural reticular opacities and honeycombing With or without traction bronchiectasis/bronchiolectasis and signs of architectural distortion (eg, lung fissure displacement) Focal ground glass
Possible UIP pattern	Predominant lower lung zone subpleural reticular opacities With or without traction bronchiectasis/bronchiolectasis and signs of architectural distortion (eg, lung fissure displacement) Focal ground glass
RB	Predominant upper middle lung zone fluffy centrilobular nodules with or without GGO
Indeterminate	Any combination of features that do not fit UIP or RB patterns and do not consist of AEF (eg, bilateral GGO and predominant upper lung zone subpleural reticular opacities)

Abbreviations: LDCT, low-dose computed tomography; ILA, interstitial lung abnormality; UIP, usual interstitial pneumonia; RB, respiratory bronchiolitis; GGO, ground glass opacity; AEF, airspace enlargement and fibrosis.