Table 2.

Definition of Imaging Patterns in e-Cigarette or Vaping Product Use-Associated Lung Injury

CT Pattern	Parenchymal Opacity	Craniocaudal Distribution	Axial Distribution	Volume Loss	CNs	Septal Thickening	Effusions
Parenchymal OP
Upper	GGO ≥ consolidation	Upper lung predominant	Peripheral or diffuse	No	No	±	No or trace
Lower	GGO ≥ consolidation	Lower lung predominant	Peripheral or diffuse	No	No	±	No or trace
Diffuse GGO	GGO > consolidation	Diffuse	Peripheral or diffuse	No	No	±	No or trace
Diffuse consolidative	Consolidation ≥ GGO	Diffuse	Diffuse	No	No	±	No or trace
Patchy	GGO > consolidation	Patchy	Patchy	No	No	±	No or trace
Airway-centered OP	Absent or mild	Diffuse CNs	Diffuse CNs	No	Yes (dominant finding)	±	No or trace
Mixed OP	GGO ≥ consolidation	Diffuse	Peripheral or diffuse	No	Yes (parenchymal opacity ≥ nodules)	±	No or trace
Diffuse alveolar damage	Any mix of GGO and/or consolidation	Diffuse	Diffuse	Yes	No	±	No or trace
Acute eosinophilic-like pneumonia	Any mix of GGO and/or consolidation	Diffuse	Diffuse	No	±	Pronounced	Yes
Diffuse alveolar hemorrhage	Any mix of GGO and/or consolidation	Patchy and asymmetrical	Patchy or diffuse	No	Acinar ground-glass nodules	±	No or trace
Atypical	Imaging pattern that does not fit into any of the listed categories

Except for diffuse alveolar hemorrhage, which may be symmetrical or asymmetrical, all other patterns of e-cigarette or vaping product use-associated lung injury are symmetrical. For an example of acinar ground-glass nodules seen in diffuse alveolar hemorrhage, please refer to Figure 8. Airway-centered OP = diffuse craniocaudal and axial distributions related to distribution of CNs and associated parenchymal opacity is absent or mild; CN = centrilobular nodule; GGO = ground-glass opacity; OP = organizing pneumonia.