Chest and Cardiothoracic Imaging
Chest and cardiothoracic imaging tests a structured search pattern, recognition of classic patterns, and safe triage of emergencies. Expect plain film interpretation, CT patterns of diffuse lung disease, and CT pulmonary angiography.
Rules to apply every time
- Check film quality first: rotation, inspiration and penetration. A rotated portable film can mimic mediastinal shift.
- Use the silhouette sign: loss of a border localizes disease to the adjacent structure.
- An air bronchogram indicates alveolar filling (consolidation), not pleural disease.
- Mediastinal compartments are prevascular, visceral and paravertebral; location narrows the differential.
Patterns and emergencies
- UIP: basal, peripheral honeycombing with traction bronchiectasis.
- NSIP: ground-glass opacity with subpleural sparing.
- Organizing pneumonia: peripheral or peribronchial consolidation.
- CT pulmonary angiography is first-line for PE; an RV/LV ratio above 1 suggests right heart strain.
Worked example
Right upper lobe collapse pulls the trachea to the right, elevates the right hilum and raises the minor fissure. If a central mass makes the fissure convex, this is the golden S sign. By contrast, right lower lobe collapse displaces the fissure downward without tracheal shift.
Traps
- Missing an apical pneumothorax on a supine film.
- Calling atelectasis pneumonia without clinical correlation.
- Overlooking a subtle rib fracture or lytic lesion on chest wall review.