Transcranial Doppler: examination techniques and interpretation

Abstract

Transcranial Doppler (TCD) was introduced in 1982 to assess intracranial arteries noninvasively, since when it has been widely used to assess and monitor cerebrovascular hemodynamics. The clinical applications of TCD are broadening to include other fields that require monitoring of the cerebral blood flow. TCD has fewer temporal and spatial restrictions than other methods , can be performed on less-compliant patients, and causes no harm to the body. However, its reliance on high levels of examiner skill and experience, as well as a lack of standardized scanning protocols are obstacles that still need to be overcome. In this report we review TCD examination techniques and interpret their findings for several conditions. Visual evoked potentials (VEPs) are frequently used to assess the anterior and posterior visual pathways. In particular, the use of VEPs have been increasing in various fields such as evaluation of the optic nerves in patients with multiple sclerosis. The performance of VEP test can be affected by various factors such as stimulus type and subject condition, and its interpretation is also difficult. However, there have been no guidelines for performing and interpreting VEPs in Korea. Therefore, we aimed to provide comprehensive information regarding basic requirement and interpretation for VEPs.