What is the main mediastinal outline finding?
There is prominence of the right border of the ascending aorta, implying likely dilatation.
What are some causes of dilatation of the ascending aorta?
Atherosclerosis and hypertension are probably the most common, typically seen in the elderly. Aortic stenosis (post stenotic dilatation), connective tissue diseases (Marfan syndrome, Ehlers-Danlos syndrome), aortitis (syphilis, Takayasu's disease, rheumatoid arthritis, ankylosing spondylitis), dissection, and many congenital cardiac / vascular conditions (e.g. coarctation of the aorta).
Chest x-ray shows prominent of the right mediastinal border occupied by the ascending aorta. The descending aorta is unfolded but of normal calibre. Heart size is normal. No lung or pleural abnormality.