Essentials of transcranial doppler ultrasound

Abstract

Transcranial Doppler (TCD) ultrasound imaging is a noninvasive, portable imaging technique that can be used to evaluate the intracerebral arteries. TCD ultrasound has become an important modality in the monitoring and evaluation of vasospasm of the intracerebral arteries in patients with subarachnoid hemorrhage due to aneurysmal rupture. Advances in transcranial ultrasound imaging utilizing gray-scale, color Doppler flow, and spectral Doppler allow for direct visualization and flow velocity measurements within the vessels in real time. This is a significant improvement over the older “blind” technique which utilized a range-gated Doppler probe that inferred the vessels being interrogated by a complex set of parameters including vessel depth, flow direction, and probe orientation. TCD has also been found to be useful in the evaluation of patients with sickle cell disease who may be at the risk of stroke and determination of brain death, internal carotid artery (ICA) occlusion and collateral pathways, stenosis, arteriovenous malformations, and intracardiac right-to-left shunts.