Assessment of cardiomediastinal contours on chest x-ray (approach)
Described below is one approach to systematic assessment and associated pathology of the cardiomediastinal contours on chest x-ray.
Mediastinum
- size: widened mediastinum can be seen in aortic dissection, traumatic aortic injuries
- abnormal contour, e.g. lymphadenopathy, anterior mediastinal mass
- abnormal gas pattern, e.g. pneumomediastinum, hiatus hernia
Heart (cardiac silhouette)
- assess position (frontal view): normally one-third right of midline and two-thirds left of midline
- assess borders and both frontal and lateral for silhouette sign and abnormal appearance
- pericardial fat pad (frontal view): normally in the cardiophrenic angle(s)
- assess overall size
- normally the cardiothoracic ratio <0.50 on a PA chest x-ray obtained in full inspiration
- can be enlarged most commonly in cardiomegaly and pericardial effusion