Purpose or Case Report: Vaping is a recreational activity of inhaling heated liquid vapor from electronic cigarettes which has been increasingly used as an alternative to cigarettes. Common substances that may be used in the liquids include nicotine, tetrahydrocannabinol, cannabinoid oils and other additives. There is increasing concern about lung injury associated with vaping, especially in children. While a nascent body of literature is beginning to develop regarding this entity, further investigation from different geographic regions (with access to varying chemical profiles of vaping material) and in differing age populations is necessary to ascertain the imaging patterns of vaping associated lung injury. In this poster, we describe the imaging patterns of pediatric vaping associated lung injury we encountered in our institution. Although this is inherently a diagnosis of exclusion, we consider these imaging patterns strongly suggestive if there is a history of vaping and absence of other risk factors or preexisting disease. We observed the following imaging patterns of lung injury associated with vaping:

Chest radiograph findings:
1) Normal.
2) Coarse bilateral interstitial opacities.
3) Pseudo pulmonary edema pattern: bilateral central predominant air space opacities with peripheral sparing.
4) Mixed pattern: combination of air space opacities and reticular opacities.

Various patterns of computed tomography findings:
1) Bilateral central ground glass opacities (GGO).
2) Sub pleural sparing , in most of the cases.
3) Interlobular septal thickening in association with GGO - crazy paving pattern.
4) Lower lobe predominant thick subpleural parenchymal bands.
5) Scattered GGO without any lobar predominance - an atypical finding seen in one patient.
6) Mild bronchial wall thickening

Take home message:
- Bilateral central predominant ground glass opacities with lower lobe predominance and sub pleural sparing are the most consistent findings seen in most of the cases. The GGO show an anteroposterior (dependent) gradient of increasing attenuation.
- Posterior dependent parenchymal bands were observed subjacent to subpleural spared lung parenchyma in several cases, a finding which has not been described previously to our knowledge. These parenchymal bands, in association with above mentioned findings, are highly suggestive of vaping associated lung injury in the appropriate clinical setting.
- We have observed complete resolution of findings in at least two of the cases on short term followup.
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