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. 2021 Feb 25;3(1):e200279. doi: 10.1148/ryct.2021200279

Figure 4a:

Honeycomb cysts and paraseptal emphysema. (a) Zoomed view of axial CT demonstrates classic honeycomb cyst formation with stacking subpleural cysts and associated adjacent fibrosis in a patient with idiopathic pulmonary fibrosis. (b) Zoomed view of axial CT in a different patient demonstrates paraseptal emphysema, characterized by a single layer of subpleural cysts, without any evidence of associated fibrosis in a patient with a history of marijuana cigarette smoking. The cysts of paraseptal emphysema are typically more than 1.0 cm in diameter, larger than honeycomb cysts, and have thinner walls.

Honeycomb cysts and paraseptal emphysema. (a) Zoomed view of axial CT demonstrates classic honeycomb cyst formation with stacking subpleural cysts and associated adjacent fibrosis in a patient with idiopathic pulmonary fibrosis. (b) Zoomed view of axial CT in a different patient demonstrates paraseptal emphysema, characterized by a single layer of subpleural cysts, without any evidence of associated fibrosis in a patient with a history of marijuana cigarette smoking. The cysts of paraseptal emphysema are typically more than 1.0 cm in diameter, larger than honeycomb cysts, and have thinner walls.