Aberrant origin of the right subclavian artery, arising after the left subclavian artery as the 4th aortic arch branch, with a retro-oesophageal course to the right side (arteria lusoria).
Irregular focus in the right apicoposterior segment is predominantly linear, most in keeping with scarring. Smaller foci of scarring and several tiny calcified granulomas in the lung apices, and further mild linear scarring in the left lower lobe.