RVT Cerebrovascular Anatomy and Disease 3

Question 1

When using the NASCET criteria to measure ICA stenosis, the denominator (reference vessel) is the:

Accepted Answer

Distal ICA beyond the stenosis and bulb

Answer

NASCET measures stenosis as (1 - stenotic lumen / distal normal ICA lumen) × 100%, using the distal ICA as the reference.

Question 2

A 'string sign' seen on duplex ultrasound of the ICA most likely represents:

Accepted Answer

Near-total occlusion with a thin residual lumen

Answer

The string sign describes a thin trickle of flow through a near-totally occluded ICA, distinguishing it from complete occlusion.

Question 3

Which Doppler waveform characteristic differentiates the external carotid artery from the internal carotid artery?

Accepted Answer

ECA has high-resistance pulsatile flow with little or no diastolic flow; ICA has continuous low-resistance flow

Answer

The ECA supplies high-resistance muscle and skin beds, producing a pulsatile waveform with minimal diastole, while the ICA supplies the low-resistance brain with continuous diastolic flow.

Question 4

A patient presents with transient monocular blindness (amaurosis fugax). Which artery is the most likely source of the embolic event?

Accepted Answer

Internal carotid artery ipsilateral to the affected eye

Answer

Amaurosis fugax is caused by emboli from the ipsilateral ICA traveling into the ophthalmic artery and its branch, the central retinal artery.

Question 5

The vertebral arteries typically originate from which vessels?

Accepted Answer

Subclavian arteries

Answer

The vertebral arteries arise from the subclavian arteries bilaterally and ascend through the transverse foramina of C6 to C1.

(RVT) Registered Vascular Technologist Practice Test

(RVT) Registered Vascular Technologist Practice Test

RVT Cerebrovascular Anatomy and Disease 3