Intra-arterial digital subtraction angiography of the head and neck.

Intra-arterial digital subtraction angiography (IA DSA) was compared with conventional film/screen angiography in 70 patients with suspected atherosclerotic disease or intracranial disease. It was found that, although the contrast detectability of IA DSA was superior to that of conventional angiography, its spatial resolution was not as great. In all 70 cases, however, the spatial resolution of IA DSA was satisfactory for diagnosis, and it is concluded that the increased spatial resolution of conventional angiography should be necessary only in rare circumstances. The main disadvantage of IA DSA is the smaller field size, and it has several advantages over conventional film/screen angiography: (a) it is safer, since less contrast material is needed to visualize large vessels; (b) costs are lower since the magnetic recording tape and hard copies result in a savings of between $45 and $140 per examination; and (c) there is less need for darkroom personnel and film storage.