| Aerated lung (normal findings) |
Predominant anterior bilateral A-lines (batwing sign), associated with lung sliding (seashore sign), and the curtain sign, at the costophrenic recess. |
| Interstitial syndrome |
Diffuse bilateral anterior B-lines (at least three or more B-lines in 2 or more thoracic regions) associated with lung sliding. |
| Pleural effusion |
Anechoic fluid or homogeneously echogenic fluid between the pleural leaflets, with or without floating debris, septations, or other structures within the effusion. |
| Pneumothorax |
Absent anterior lung sliding (barcode or stratosphere sign), absent anterior B-lines and present lung point. |
| Pneumonia |
Predominant anterior B-lines on one side or in one thoracic region, with predominant anterior A-lines on the other; or presence of alveolar (tissue-like) consolidation |
