Studies of the extracranial and intracranial cerebral circulation have been performed by arch arteriography and selective angiography in 2,384 patients with an incidence of major neurological complications of 0.5% and one death. The need for visualization of the arch, as well as the extracranial and intracranial arteries in most patients, is illustrated by cases of unsuspected tumors, proximal and distal stenoses, well-developed collateral circulation, and by detailed visualization of plaques on coned-down views. The elimination of "pseudo-occlusions" resulting from other techniques has been another advantage.