cerebrovascular: TCD

What are the capabilities and limitations of Transcranial Doppler?

• Intracranial stenosis and occlusions

• Assess for collateral circulation

• Evidence of vasospasm due to hemorrhage

• All of the above

In posterior-to-anterior collateralization, velocities in the ipsilateral PCA compared to the MCA are described as _______. PSV of the PCA is _______ greater than the MCA, with _______ flow direction changes.

• elevated; 125%; no

• elevated; 145%; no

• elevated; 120%; no

• elevated; 130%; no

Which statement best describes normal PCA flow compared to ICA branches and the change seen during compensatory posterior-to-anterior flow?

• Normal PCA flow has higher velocity than ICA branches; compensatory flow decreases PCA velocity

• Normal PCA flow has lower velocity than ICA branches; compensatory flow shows changes of the supplying vessel

• Normal PCA flow equals ICA branch velocity; compensatory flow reverses direction

• Normal PCA flow is absent; compensatory flow restores minimal velocity

Carotid duplex findings in posterior-to-anterior collateralization suggest which of the following?

• Normal ICA with reduced vertebral flow

• Evidence of ICA disease; vertebrals act as feeding vessels with higher PSV and low resistance

• ECA stenosis with high resistance vertebral flow

• Basilar occlusion with absent ICA signals

Match each finding to its clinical implication during cerebrovascular assessment.

• Absent signal or absent EDV

• Suggests occlusion (distal occlusion if absent EDV)

• High velocity flow in MCA >120 cm/s

• Indicates vasospasm as a complication of hemorrhage

• Changes in flow velocity/patterns during

• Indicates micro embolic event; may require surgeon to modify technique

During intraoperative monitoring, continuous Doppler on which artery and through which window is emphasized for detecting micro embolic events?

• ACA at suboccipital window

• MCA at transtemporal window

• PCA at transorbital window

• Vertebral artery at submandibular window

According to posterior-to-anterior collateral flow, blood travels from the basilar artery to the PCA and then to the MCA/ACA via which vessel?

• Anterior communicating artery

• Posterior communicating artery

• External carotid artery

• Ophthalmic artery

Which combination best matches the scenario described: distal ICA occlusion affects resistance patterns in which segments?

• Low resistance extracranial ICA and high resistance ECA on the same side

• High resistance extracranial ICA with low resistance same-side ECA

• Low resistance in both extracranial ICA and ECA

• High resistance in both extracranial ICA and ECA

According to the TCD vessel criteria, which vessel is insonated through the transtemporal window with a depth greater than 60 mm, an anterior/superior angle, and has retrograde (away) flow direction?

• ACA

• MCA

• PCA

• Basilar

Fill in the blank with the exact term from the content: In TCD, the term _______ means the flow is AWAY from the transducer or a negative Doppler shift.

• Retrograde

• Antegrade

• Orthograde

• Transgrade