Fig 1.

DSA images in a 53-year-old man who was examined for a subarachnoid hemorrhage.

A, Aortic arch, left anterior oblique view. On this early arterial-phase image, both carotid axes and both subclavian arteries are well opacified with the contrast agent. The LVA (L) and RVA (R) arise bilaterally from the aortic arch and are opacified, with some delay, when compared with the other supra-aortic trunks. Note that the origin of both VAs is located between the left common carotid and left subclavian arteries (arrows).

B, Aortic arch, left anterior oblique view. This later arterial-phase image shows complete opacification of the VAs and allows better appreciation of their proximal segments.

C, Right internal carotid artery, lateral view. This angiogram shows a small saccular aneurysm located at the A2-A3 junction of the right anterior cerebral artery (arrow). Note the presence of a large right posterior communicating artery and retrograde filling of the distal basilar artery, with opacification of the right superior cerebellar artery (arrowhead). A similar filling pattern was observed on the left side.