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CASE STUDY
Chris van Zyl KHC
MR X
21 Year old male Stab wound L parasternally, 3 ICS (sucking wound) Surgical emphysema extending to neck Haemodynamically stable,
no signs of tamponade / vascular injury Mild resp distress, clinically no pneumothorax
CXR
Differential
Pneumomediastinum Pneumothorax Haemopericardium Pneumopericardium
Mr X
Proceded to insert ICD Consulted Radiology for heart US
No haemopericardium seen
Due to location of wound, proceded to CT chest
AXIAL CT CHEST
Sag + Axial neck
THE SIGNS
Pneumomediastinum
Introduction
Can be diagnostic challenge Demonstrate radiological findings that are difficult
to differentiate from other disease entities
Needs good understanding of normal anatomy, pathophysiology and radiological signs to meet the challenge
Anatomy
Tissues and organs separating two pleural sacs Between sternum and vertebral column Extending from thoracic inlet and diaphragm
Communicates with: Submandibular space Retropharyngeal space Vascular sheaths of the neck
Anatomy
Tissue plane extending anteriorly from mediastinum to retroperitoneal space via diaphraghmatic sternocostal attachment
Continuous along flanks and extends to pelvis
Communicates with peritonium via periaortic and peri-esophageal fascial planes
Air can dissect allong these planes
Potential Sources of Mediastinal Air
Extrathoracic Head and neck Intraperitoneum and retroperitoneum
Intrathoracic Trachea and major bronchi Esophagus Lung Pleural space
Radiographic Signs of Pneumomediastinum
Subcutaneous emphysema Thymic sail sign Pneumoprecordium Ring around the artery sign Tubular artery sign Double bronchial wall sign Continuous diaphragm sign Extrapleural sign Air in the pulmonary ligament
Pneumoprecardium
Thymic sail sign
Ring around the artery sign, Tubular artery sign
Double bronchial wall sign
Continuous diaphragm sign
Extrapleural sign
Challenges and Pitfalls
Differentiating pneumomediastinum from medial pneumothorax
Pneumopericardium Suspect when paricarial sac itself is visualized Line formed by pneumopericardium confined to
lenth of pericardial sac
Pneumopericardium
Chanllenges and Pitfalls
Subpulmonary pneumo + pneumoperitonium can be difficult to defferentiate from extrapleural air collections
Decubitis view helps
Challenges and Pitfalls
Normal anatomic structures can mimic air within mediastinum
Anterior junction line Imaged obliquely or lordotically
Superior aspect of major fissure Lordotic positioning
Major fissure
Anterior junction line
Challenges and Pitfalls
Mach band effect Optical illusion Region of lucency associated with convex
structures
Chanllenges and Pitfalls
Iatrogenic
entities
Conclusion
Pneumomediastinum can be a diagnostic challenge Correct assessment of radiological signs is vital in
diagnosis.
REFERENCES
Radiographics Jun – Aug 2000 Pneumomediastinum Revisited
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