Chest ultrasound syndromes: typical sonographic findings and relevant differential diagnoses
| Chest ultrasound syndrome | Sonographic features | Differential diagnosis |
| Pleural | ||
| Pneumothorax | Absent lung sliding Absent B-lines Lung point (specific for pneumothorax) | Pneumothorax, emphysema, pleural adhesions |
| Pleural effusion | Echo-free space Quad sign (fluid-colour and sinusoid signs more specific for effusion) | Pleural effusion, pleural thickening, parenchymal fluid collection |
| Parenchymal | ||
| Consolidation | Tissue-like pattern (iso- or hypo-echoic) Echogenic air-bronchograms | Pneumonia, atelectasis, neoplasm, pulmonary infarct |
| Interstitial syndrome | B-lines | Diffuse: cardiogenic pulmonary oedema, non-cardiogenic pulmonary oedema, interstitial lung disease Focal: pneumonia, focal fibrosis, pulmonary contusion, pulmonary infarction, lymphangitis |
| Musculoskeletal | ||
| Chest wall applications | Interrupted parietal pleura and restricted pleural movement in the context of subpleural mass | Malignant chest wall invasion |
| Diaphragm applications | Impaired thickening Reduced excursion | Diaphragmatic paresis, extrinsic limitation of diaphragm |