Acute Neurologic Injury in the ICU: Role of Transcranial Doppler in Disorders of the Vertebrobasilar Circulation

Transcranial Doppler (TCD) ultrasound of the vertebrobasilar system offers a practical, non-invasive evaluation of the posterior circulation and may be helpful in the identification of cerebral vasospasm, intracranial vascular stenotic disease, and microembolus signal detection. Hemodynamics of the posterior circulation can be assessed using ultrasound in stroke and traumatic brain injury (TBI) and basilar artery flow characteristics are part of the complete TCD assessment for brain death. Cerebral autoregulation and vascular reactivity can offer insight into brain health in the posterior circulation, particularly in TBI. While anatomic limitations exist, size, patency, direction, and velocity of flow as well as microembolus detection are all feasible in the vertebrobasilar circulation using ultrasound.