Figure 8b. (a) Type A1 IAA. VR image (posterior view) shows the left aortic arch with aortic interruption just distal to the left subclavian artery (arrows). (b) Type B3 IAA. VR image (left posterior oblique view) shows interruption between the left common carotid artery and the left subclavian artery (arrowheads). An isolated right subclavian artery is also seen (arrow).