Date post: | 11-Apr-2016 |
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PNEUMOMEDIASTINUM• Def: free air/gas within the mediastinum• Gas origin:– Intrathoracic
• Trachea, bronchi• Esophagus• Lungs• Pleural space
– Extrathoracic• Head & neck injury• Retroperitoneum
• Can lead to pneumothorax, pnemopericardium, pneumoperitoneum
RADIOLOGICAL FEATURES• Subcutaneous emphysema• Hyperlucent lines enhancing mediastinal viscera
& outline lateral heart borders• Continuous diaphragm sign• Ring-around-pulmonary-artery sign• Thymic/spinnaker sail sign• Naclerio’s V sign• Tubular artery sign• pneumopericardium• Extrapleural sign
Subcutaneous emphysema• Lucencies overlying the shoulder
and upper chest (blue circle)• Red arrow: supraclavicular
emphysema• White arrow: air in mediastinum
Enhancement of heart borders
Enhancement on mediastinal structures
Air outlining ascending aorta
Continuous diaphragm sign
Ring around pulmonary artery sign
• Lucent ring around pulmonary artery
Thymic/Spinnaker sail sign
thymus separated from mediastinal structures
Naclerio’s V sign
Air outlining the descending aorta intersects with air outlining the left hemidiaphragm
Tubular artery sign
Air outlining left subclavian artery & left carotid artery
Pneumopericardium
Air between sternum & heart
Extrapleural sign
Air outlining the left hemidiaphragm
CT Scan
Air in supra-aortic, sub-aortic & para-cardiac mediastinum
Air within mediastinum (white arrows)Subcutaneous emphysema (black arrows)
PULMONARY CONTUSION
• Def: injury to the lung parenchyma without laceration (blunt trauma)
• often occur in small children in the absence of fractures due to the high compliance of the chest wall.
• a/w bruising, ribs #, flail chest• Pathology:– Hemorrhage into the lung parenchyma produces
airspace disease
Plain radiograph• Features seen within 6 hours after trauma• Not sensitive, low clinical value– Faint patchy consolidative regions following history of
blunt trauma.• Usually shows rapid improvement with time, signs
of contusion have often resolved within 48 hours• If consolidation > 72 hours, consider:– Aspiration– ARDS– Pneumonia
Blue: alveolar opacitiesRed: associated ribs #
CT Scan
Red: evidence of pulmonary contusionBlue: rib #
• Most sensitive
• Typically seen as focal, non segmental (typically crescentic) areas of parenchymal opacification