Doppler Trans-Cranial Assessment, Protocols, and Interpretation

Transcranial Doppler (TCD) is a non-invasive ultrasound technique, not utilizing ionizing radiation. This technique takes advantage of acoustic windows present in the skull to interrogate the intracranial vascular structures. Various vascular measurements can be determined, including cerebral blood flow velocity, which can affect many different pathologies. Common indications for TCD include screening for vasospasm in patients with subarachnoid hemorrhage, screening for signs of angiopathy in pediatric sickle cell disease patients, and evaluation for a right-to-left shunt in the setting of stroke and suspected paradoxical embolism (patent foramen ovale and other pathologies). This article will focus on these common indications.