Complex lesions are often assessed by MRI or CT.[citation needed] Several types of right-sided aortic arch exist, the most common ones being right-sided aortic arch with aberrant left subclavian artery and the mirror-image type.

The variant with aberrant left subclavian artery is associated with congenital heart disease in only a small minority of affected people.

The mirror-image type of right aortic arch is very strongly associated with congenital heart disease, in most cases tetralogy of Fallot.

There is evidence to show that symptoms of a vascular ring do not correlate with the appearance of the trachea in these patients so further assessment may be required.

[6] This could be in the form of a specialist CT scan which is timed with inspiration and expiration or a free breathing bronchoscopy.