Digital subtraction angiography of the intracranial vascular system: comparative study in 55 patients.

Intracranial vessels were examined in 55 patients with both conventional selective catheterization and intravenous digital subtraction angiography using a prototype digital subtraction unit. In 65% of the patients, the digital subtraction angiogram was diagnostic, but the overall quality was inferior to conventional selective angiography. In 22%, the digital subtraction angiogram provided diagnostic information, but there was a significant chance of misinterpreting the results of the study. In 13% of cases, the subtraction angiogram was not diagnostic. As now developed, digital subtraction angiography can replace conventional cerebral angiography for preoperative evaluation of the juxtasellar carotid artery prior to transphenoidal surgery because the large intracerebral vessels are consistently well visualized with digital subtraction. The dural sinuses are better visualized with digital subtraction than with conventional angiography because with digital subtraction all the vessels of the brain are opacified, whereas with conventional angiography, there is a mixture of opacified and unopacified blood in the sinuses. Combined with computed tomography, digital subtraction angiography can replace conventional angiography for determining the preoperative extent and vascularity of tumors. It can be used for postoperative evaluation of aneurysms, arteriovenous malformations, extracranial to intracranial bypasses, and after the embolization of vascular lesions.