Abstract
Over the last two decades, transcranial doppler sonography (TCD) has been used for measuring cerebral blood flow velocity and also for diagnosing and evaluating cerebral ischemia in patients with vasospasms after subarachnoid hemorrhage and in many individuals with ischemic cerebrovascular disease. TCD has also been reported as a useful tool for preventing cerebral ischemia during reconstructive surgery of the cervical artery such as a carotid endarterectomy, or an aortic arch reconstruction under cardiopulmonary bypass. Although clinical examiners require specific knowledge and skills to perform TCD, intraoperative TCD is recognized as a beneficial method for predicting cerebral ischemia that has a relatively high degree of sensitivity and specificity. Because TCD monitoring is non-invasive and has real-time characteristics, continuous assessment can be performed in the majority of patients in whom the occurrence of cerebral ischemia is anticipated. This article describes the principle of TCD and the usefulness of the procedure in various clinical settings, and reviews the factors that need to be considered when monitoring blood flow and interpreting the results.
