2. Current noninvasive diagnosis of carotid artery stenosis: indications and limitations.

Noninvasive techniques are widely used to assess patients with cerebrovascular disease. The most common method is duplex ultrasonography, which has an accuracy of approximately 90% in the detection of carotid stenosis. There are many potential limitations to the technique of duplex ultrasonography, but in the hands of experienced technologists and physicians who recognize possible sources of error, it provides excellent clinical accuracy. Transcranial Doppler is complementary to duplex ultrasonography in the assessment of the intracranial circulation. Magnetic resonance angiography shows promise as a noninvasive method of assessing carotid stenosis, but its availability is limited, and this technique is still in the developmental stage.