Patient underwent outpt bilateral carotid arteriograms. Catheter was inserted into right common femoral artery, advanced to aortic arch, inserted into left carotid artery, and contrast material was injected. Catheter was withdrawn from left carotid artery, advanced to brachiocephalic artery, inserted into right carotid artery, and contrast material was injected. Bilateral carotid arteriograms were performed. What is reported?