Podcast
Questions and Answers
What characteristic of normal vertebral artery flow is NOT observed?
What characteristic of normal vertebral artery flow is NOT observed?
What does a focal velocity increase in peak systolic velocity (PSV) greater than 150 cm/s generally indicate?
What does a focal velocity increase in peak systolic velocity (PSV) greater than 150 cm/s generally indicate?
Which of the following findings is associated with proximal vertebral artery stenosis?
Which of the following findings is associated with proximal vertebral artery stenosis?
Power Doppler imaging is particularly useful for detecting what type of flow?
Power Doppler imaging is particularly useful for detecting what type of flow?
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What waveform pattern would indicate distal stenosis or occlusion in the vertebral artery?
What waveform pattern would indicate distal stenosis or occlusion in the vertebral artery?
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What is the primary criterion for classifying the severity of stenosis?
What is the primary criterion for classifying the severity of stenosis?
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What angle is considered optimal for Doppler measurements to ensure accurate flow velocity readings?
What angle is considered optimal for Doppler measurements to ensure accurate flow velocity readings?
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Which condition is NOT a special consideration for aortic stenosis assessment?
Which condition is NOT a special consideration for aortic stenosis assessment?
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Which Doppler flow pattern might indicate increased velocities contralaterally to severe stenosis?
Which Doppler flow pattern might indicate increased velocities contralaterally to severe stenosis?
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Which of the following is true regarding the classification criteria for disease?
Which of the following is true regarding the classification criteria for disease?
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What is required to ensure proper alignment during Doppler measurements?
What is required to ensure proper alignment during Doppler measurements?
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In Doppler flow assessments, which method enhances accurate flow measurement?
In Doppler flow assessments, which method enhances accurate flow measurement?
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What is a significant indicator of subclavian steal syndrome?
What is a significant indicator of subclavian steal syndrome?
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What effect do cardiac assist devices have on Doppler flow signals?
What effect do cardiac assist devices have on Doppler flow signals?
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Which flow condition is not associated with the progression of vertebral artery flow changes due to obstruction?
Which flow condition is not associated with the progression of vertebral artery flow changes due to obstruction?
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What is the purpose of the reactive hyperemia test in evaluating subclavian steal?
What is the purpose of the reactive hyperemia test in evaluating subclavian steal?
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Which description corresponds to complete reversal of vertebral artery flow?
Which description corresponds to complete reversal of vertebral artery flow?
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What physiological change occurs due to hemodynamically significant stenosis in the proximal subclavian artery?
What physiological change occurs due to hemodynamically significant stenosis in the proximal subclavian artery?
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What findings indicate severe stenosis or occlusion of the internal carotid artery (ICA)?
What findings indicate severe stenosis or occlusion of the internal carotid artery (ICA)?
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In the context of external carotid artery (ECA) stenosis, which of the following is true?
In the context of external carotid artery (ECA) stenosis, which of the following is true?
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What is a potential consequence of significant internal carotid artery (ICA) stenosis?
What is a potential consequence of significant internal carotid artery (ICA) stenosis?
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What characteristic of aortic valve stenosis can be observed in Doppler waveforms?
What characteristic of aortic valve stenosis can be observed in Doppler waveforms?
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When there is occlusion of the distal common carotid artery (CCA), what is a likely consequence?
When there is occlusion of the distal common carotid artery (CCA), what is a likely consequence?
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What is the recommended position for a patient during a carotid artery duplex evaluation?
What is the recommended position for a patient during a carotid artery duplex evaluation?
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Which of the following best describes the impact of brachiocephalic stenosis?
Which of the following best describes the impact of brachiocephalic stenosis?
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What Doppler findings are typically associated with significant stenosis in both ICA and ECA?
What Doppler findings are typically associated with significant stenosis in both ICA and ECA?
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Which transducer is typically used for carotid artery duplex evaluations?
Which transducer is typically used for carotid artery duplex evaluations?
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Which among the following statements is false regarding ECA stenosis?
Which among the following statements is false regarding ECA stenosis?
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Which components are generally included in a carotid artery duplex evaluation?
Which components are generally included in a carotid artery duplex evaluation?
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In which imaging modes should vessels be evaluated during carotid artery duplex evaluation?
In which imaging modes should vessels be evaluated during carotid artery duplex evaluation?
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What should be documented when identifying intraluminal echoes during the evaluation?
What should be documented when identifying intraluminal echoes during the evaluation?
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What is the purpose of using color Doppler during a carotid artery duplex evaluation?
What is the purpose of using color Doppler during a carotid artery duplex evaluation?
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How does the external carotid artery (ECA) differ in structure and behavior from the internal carotid artery (ICA)?
How does the external carotid artery (ECA) differ in structure and behavior from the internal carotid artery (ICA)?
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What does pulsed wave spectral Doppler measure during the assessment?
What does pulsed wave spectral Doppler measure during the assessment?
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Study Notes
Carotid Artery Duplex Evaluation
- Patient's chin is elevated, head turned 45 degrees away from the side being examined.
Equipment
- 7-4 MHz linear array typically used for image quality and visualization.
- Alternative transducers include:
- 8–5 MHz curvilinear
- 4–1 MHz sector
- 5–2 MHz curvilinear
Scanning Technique
- Includes evaluation of:
- Common carotid arteries (CCAs)
- Internal carotid arteries (ICAs)
- External carotid arteries (ECAs)
- Vertebral arteries
- Subclavian arteries
- Vessels evaluated in both transverse and longitudinal planes with B-mode imaging, color, and spectral Doppler.
Scanning Technique Tips
- Sweep through carotid system in transverse and longitudinal planes with B-mode imaging.
- Begin above clavicle and sweep up to angle of jaw.
- Document any identified intraluminal echoes (plaque or other intimal defects).
- Document any other areas of interest.
Color Doppler
- Used to identify:
- Areas of aliasing or mosaic flow patterns
- Speckling that could indicate color bruit
Pulsed Wave Spectral Doppler
- Used to:
- Measure flow velocities
- Document waveform contours
ICA vs. ECA Differentiation
- ECA has multiple branches within the neck and its spectral waveform will oscillate with “temporal tap.”
- ICA is typically larger and lies posterior to ECA.
Proximal ICA Occlusion
- No obtainable Doppler flow.
ECA Stenosis
- Lesions tend to involve origin and proximal segments.
- Associated with:
- Focal velocity increase
- Poststenotic turbulence
- Dampened distal waveform
- Watch for diffuse increase in velocity as a result of collateralization.
CCA Stenosis
- Can occur in the proximal, mid, or distal segments.
- Significant stenosis associated with:
- Focal velocity increases
- Poststenotic turbulence
- Dampened distal waveforms in both the ICA and ECA
- “Choke lesion” may result in retrograde ECA to supply ICA.
Aortic Valve or Root Stenosis
- Will generate symmetrically abnormal Doppler waveform contour in the bilateral carotid systems.
- Dampened waveforms throughout both carotid artery systems.
- May also cause bilateral low brachial systolic pressures.
- Brachiocephalic stenosis will only affect the right carotid system.
Special Considerations
- Low cardiac output and poor ejection fraction
- Aortic valvular disease
- Hypertrophic obstructive cardiomyopathy
- Cardiac arrhythmias
- Cardiac assist devices (ventricular assist device [VAD], intra-aortic balloon pump [IABP])
Doppler Flow Velocity
- Primary criterion for classification of stenosis severity.
- Depends on correct Doppler angle (60 degrees or less, parallel to vessel walls).
- Pulsed wave Doppler sample volume should be “swept” through all vessels.
Collateralization
- Posterior-to-anterior
- Side-to-side
- Extracranial-to-intracranial
- May result in increased velocities contralaterally to severe stenosis or occlusion
Criteria for Classification of Disease
- Classification has validated for the ICA ONLY.
- Criteria cannot be applied to CCA or ECA.
- Criteria were developed by comparing duplex results with “gold standard” imaging modalities or surgical findings.
Color and Power Doppler Findings
- Color Doppler displays flow based on frequency shift.
- Power Doppler displays flow based on blood flow amplitude, independent of the direction of blood flow.
Vertebral Artery Stenosis
- Proximal vertebral artery flow has the same pattern as ICA.
- Low resistance
- Antegrade flow throughout cardiac cycle
- Brisk systolic acceleration, sharp peak, and relatively high diastolic flow.
- Proximal vertebral artery stenosis will produce:
- Abnormal dampened waveforms distally with delayed acceleration and rounded peaks.
- Possible poststenotic turbulence.
- No specific criteria should be suspected if focal velocity increase in PSV is >150 cm/s.
- Generally occurs at origin from subclavian artery.
- Resistive or blunted waveforms indicate distal stenosis or occlusion.
Subclavian Steal
- Hemodynamically significant stenosis in the proximal subclavian artery causing changes to vertebral artery flow.
- Results in brachial blood pressure decrease on affected side (more than 15 to 20 mm Hg lower than contralateral arm).
- Causes decreased pressure at the origin of ipsilateral vertebral artery that can lead to reversed flow.
- Vertebral artery flow changes as obstruction progresses:
- Normal antegrade flow
- Antegrade flow with deep notch midcardiac cycle
- Alternating or bidirectional (to-and-fro) flow
- Complete reversal (fully retrograde) flow
Reactive Hyperemia
- Provocative test used to augment a subclavian steam from “latent” to “complete.”
- Procedure:
- Blood pressure cuff inflated to suprasystolic blood pressure on affected side.
- Left inflated for 3 to 5 minutes while vertebral artery is monitored.
- Cuff is rapidly deflated while ipsilateral vertebral artery is observed.
- Positive when vertebral artery completely reverses.
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Description
This quiz covers the essential techniques and equipment used in a carotid artery duplex evaluation. It includes details about patient positioning, scanning techniques, and the use of color Doppler imaging to assess neck vessels. Test your understanding of the procedures and equipment involved in this important diagnostic method.
