153 - Transcranial Doppler Sonography and Stroke

Abstract

This chapter describes transcranial Doppler sonography (TCD) and stroke. TCD is a noninvasive bedside method used for the evaluation of intracranial cerebral hemodynamics and may provide rapid and reliable data regarding the cause of stroke. TCD is also used to assess the degree of arterial vasospasm, evaluate patients with suspected brain death, and assist in the diagnosis of arteriovenous malformation (AVM). Transcranial Doppler is commonly used to detect abnormalities in cerebral hemodynamics among patients with cerebrovascular diseases, although its clinical usefulness has not been universally accepted. The use of TCD is becoming routine in detecting intracranial arterial lesions. The sensitivity and specificity of TCD for stenosis of a particular vessel varies in different studies. Platelet thrombi, air emboli, or atheromatous materials can be recognized by the examiner with the characteristic sound that they produce during the TCD study. The preoperative detection of high-intensity transient signals with TCD may help identify subgroups of patients with symptomatic as well as asymptomatic high grade carotid artery stenosis, as well as the hemodynamic changes during carotid endarterectomy or cardiac bypass surgery. It is suggested that the use of contrast agents and the new generation TCD machines with B-mode capabilities may enhance the utility of the technique.