Transcranial Doppler (TCD) is a noninvasive ultrasonic technique that measures local blood flow velocity and direction of the proximal portions of large intracranial vessels. TCD is operator dependent and requires training and experience to perform and interpret results. To perform an effective examination, it is important to understand proper patient and probe positioning, anatomical landmarks and appropriate scale settings, including spectral analysis, gray and color flow information. Further, it begins in understanding of cerebrovascular anatomy including the major cerebral vessels, circle of Willis and other potential collateral pathways, and the most common vascular anomalies. Journal of Neurosonology 2(1):5-9, 2010

Key Words: Transcranial Doppler, Cerebrovascular anatomy