Second-order subtraction with simultaneous bilateral carotid, internal carotid injections.

Second-order subtraction technic in conjunction with simultaneous bilateral carotid angiography has definite advantages in comparing subtle changes in expansive processes. Displacement of minor blood vessels or variations in circulation time can be better appreciated. During the capillary phase, the brain can be seen with contrast loading. History Second-order subtraction was described in 1961 by Ziedses des Plantes (1) in his monograph. Little interest in this technic has been expressed in the American literature (2, 3). Simultaneous injections of both carotid arteries have not been widely advocated (4, 5). The fear of subintimal injections into both carotid arteries with resultant sudden, near total, reduction in blood supply to the cerebral cortex reduces the attractiveness of the procedure. Amundsen et al. (6), Saltzman (7, 9), and Gryspeerdt (8) have made extensive use of the cross compression test to get opacification of the opposite internal carotid artery system with no adverse reactions. Amundsen...