Accuracy and limitations of intravenous digital subtraction angiography

Intravenous DSA of the carotid system may be used effectively as a relatively low risk, less invasive form of angiography to manage certain clinical problems, when specific limitations of this examination are kept in mind. DSA of the carotid system compares favorably with conventional selective arteriography for demonstrating anatomic stenosis and medium-to-large ulcers of the carotid artery bifurcation. Small ulcers are easily missed. Although some prominent intracranial lesions may be visualized, significant intracranial atheromatous lesions may be missed. Major venous structures of the head and neck are displayed very well. Clinical utility of DSA rests largely on the criteria used to diagnose and treat specific conditions. As a screening examination, DSA can detect many lesions at high cost and low risk, although errors in diagnosis and treatment will occur. For surgical consideration of carotid artery disease, many intracranial lesions and some carotid artery bifurcation disease probably will be missed. Some consider that DSA is the examination of choice for evaluating intracranial venous sinus disease. It can also be used to evaluate postoperative patency and to exclude gross vascular pathologic changes involving the cervical vessels. DSA can be used in asymptomatic patients who have positive indirect test findings (bruits, ocular lethysmography), in symptomatic patients without commitment to conventional angiography or surgery, in patients after operation, and in patients with intracranial venous sinus disease. The use of the examination must ultimately be based on the assessment of the individual patients's situation