CCI Cerebrovascular Duplex Examinations 4 — Questions and Answers
Question 1: Which Doppler spectral finding is MOST consistent with external carotid artery identification during carotid duplex?
- Low-resistance waveform with high diastolic flow
- High-resistance waveform with little or absent diastolic flow (Correct answer)
- Retrograde diastolic flow
- Monophasic waveform with continuous forward flow
Correct answer: High-resistance waveform with little or absent diastolic flow
The ECA supplies high-resistance facial musculature, producing a high-resistance waveform with minimal diastolic forward flow.
Question 2: Which criterion best distinguishes a 50–69% ICA stenosis from a <50% stenosis using the SRU consensus guidelines?
- PSV ≥125 cm/s and ICA/CCA ratio ≥2.0 (Correct answer)
- PSV ≥300 cm/s and EDV ≥100 cm/s
- PSV <125 cm/s with no spectral broadening
- ICA/CCA ratio >4.0 and EDV >135 cm/s
Correct answer: PSV ≥125 cm/s and ICA/CCA ratio ≥2.0
SRU criteria classify 50–69% ICA stenosis as PSV 125–229 cm/s and ICA/CCA PSV ratio 2.0–4.0.
Question 3: When assessing for vertebral artery occlusion, which finding would support the diagnosis?
- Normal antegrade low-resistance flow at V2
- Absent color flow and Doppler signal despite optimal technique (Correct answer)
- Retrograde flow with augmentation during arm hyperemia
- High-resistance biphasic waveform with preserved systolic flow
Correct answer: Absent color flow and Doppler signal despite optimal technique
Absent flow signal with proper technique and confirmed vertebral artery visualization on B-mode is indicative of vertebral artery occlusion.
Question 4: In the evaluation of carotid artery dissection, which duplex finding is MOST commonly observed?
- Concentric calcified plaque at the bifurcation
- Eccentric hypoechoic thickening of the arterial wall with luminal narrowing (Correct answer)
- Absent spectral broadening with normal peak velocities
- Posterior acoustic shadowing from the vessel wall
Correct answer: Eccentric hypoechoic thickening of the arterial wall with luminal narrowing
Carotid dissection produces an intramural hematoma seen as eccentric hypoechoic wall thickening that narrows the true lumen.
Question 5: A post-carotid endarterectomy patient shows a focal PSV of 280 cm/s at the operative site 6 months later. What is the most appropriate interpretation?
- Normal post-surgical healing response
- Recurrent ICA stenosis ≥70% requiring urgent re-intervention
- Likely myointimal hyperplasia causing significant restenosis (Correct answer)
- Artifact from surgical clips causing velocity overestimation
Correct answer: Likely myointimal hyperplasia causing significant restenosis
PSV ≥260 cm/s at a CEA site within 2 years typically indicates myointimal hyperplasia–related restenosis, which is the most common early cause of recurrent disease.
Question 6: Which finding would indicate a hemodynamically significant proximal CCA stenosis or occlusion on duplex examination?
- Elevated PSV in the ipsilateral ICA
- Dampened, low-velocity, tardus-parvus waveform distal to the stenosis (Correct answer)
- Normal CCA waveform with spectral broadening at the bulb
- Increased ICA/CCA PSV ratio
Correct answer: Dampened, low-velocity, tardus-parvus waveform distal to the stenosis
Significant proximal CCA obstruction produces a tardus-parvus (slow-rising, rounded systolic peak with reduced amplitude) waveform distal to the lesion.
Question 7: Which of the following best describes the sonographic appearance of a carotid body tumor on duplex imaging?
- Hyperechoic mass anterior to the carotid bifurcation
- Hypervascular mass splaying the ICA and ECA at the bifurcation with high diastolic flow (Correct answer)
- Anechoic cystic structure compressing the CCA
- Calcified plaque at the bifurcation with posterior shadowing
Correct answer: Hypervascular mass splaying the ICA and ECA at the bifurcation with high diastolic flow
Carotid body tumors (paragangliomas) appear as hypervascular solid masses that splay the ICA and ECA apart, demonstrating high-flow Doppler signals.
CCI Cerebrovascular Duplex Examinations 4
Which Doppler spectral finding is MOST consistent with external carotid artery identification during carotid duplex?