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CAROTID DUPLEX ULTRASOUND
• Jenelle (General Ultrasound Department)• Anatomy• Normal Carotid Ultrasound
• Todd (Vascular Ultrasound Department-Coordinator)• Abnormal Carotid Ultrasound
• Live Scanning• Demonstration by Todd• Practice time – grab a partner!
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CAROTID DUPLEX ULTRASOUNDJenelle Beadle
March, 2015
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OBJECTIVES
• Anatomy• Classic• Variants
• Carotid Duplex Ultrasound• Indications• Position/Technique• Required Images• Normal spectral analysis
• Tips/Pitfalls
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Cerebrovascular System• supplies the head
Carotid Duplex Ultrasound• exams the extracranial
portion of the cerebrovascular system
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Extracranial Cerebrovascular System• Innominate/brachiocephalic• Subclavian• Vertebral• Common Carotid (CCA)• Internal Carotid (ICA)• External Carotid (ECA)
http://www.slideshare.net/shaffar75/doppler-ultrasound-of-carotid-arteries
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Innominate/brachiocephalic(Rt sided only)• Originate: Aortic Arch (1st)• Terminate: Rt CCA / Rt
Subclavian
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Subclavian Arteries• Originate:
• Rt – Innominate• Lt – Aortic Arch (3rd)
• Branches: Vertebral• Terminate: Axillary
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Vertebral Arteries• Originate: Subclavian
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Vertebral Arteries• Originate: Subclavian• Pass through transverse
foramena• C6• Atlas (C1)
• Terminate: join to form basilar (intracranial)
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Common Carotid Arteries (CCA)• Originate:
• Rt – Innominate• Lt – Aortic Arch (2nd)
• Terminate: ICA/ECA
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External Carotid Arteries (ECA)• Originate: CCA
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External Carotid Arteries (ECA)• Branches: numerous
• 1st: Superior Thyroid• Terminate: Superficial Temporal / Maxillary
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Internal Carotid Arteries (ICA)• Originate: CCA
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• NO extracranial branches
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Internal Carotid Arteries (ICA)
• Originate: CCA• Branches:
• Intracranial only
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Internal Carotid Arteries (ICA)
• Originate: CCA• Branches:
• Intracranial only
• Terminate: • Circle of Willis
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Innominate/Brachiocephalic
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Innominate/Brachiocephalic
Rt Subclavian
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Innominate/Brachiocephalic
Rt Subclavian
Rt Vertebral
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Innominate/Brachiocephalic
Rt Subclavian
Rt Vertebral
Rt CCA
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Innominate/Brachiocephalic
Rt Subclavian
Rt Vertebral
Rt CCA
Rt ICA
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Innominate/Brachiocephalic
Rt Subclavian
Rt Vertebral
Rt CCA
Rt ICA
Lt Vertebral
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Innominate/Brachiocephalic
Rt Subclavian
Rt Vertebral
Rt CCA
Rt ICA
Lt Vertebral
Lt ICA
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Innominate/Brachiocephalic
Rt Subclavian
Rt Vertebral
Rt CCA
Rt ICA
Lt Vertebral
Lt ICA
Lt ECA
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Innominate/Brachiocephalic
Rt Subclavian
Rt Vertebral
Rt CCA
Rt ICA
Lt Vertebral
Lt ICA
Lt ECA
Lt CCA
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Innominate/Brachiocephalic
Rt Subclavian
Rt Vertebral
Rt CCA
Rt ICA
Lt Vertebral
Lt ICA
Lt ECA
Lt CCA
Lt Subclavian
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Innominate/Brachiocephalic
Rt Subclavian
Rt Vertebral
Rt CCA
Rt ICA
Lt Vertebral
Lt ICA
Lt ECA
Lt CCA
Lt Subclavian
Aortic Arch
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ANATOMICAL VARIANTS
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Numerous anatomical variants involving the aortic arch branches
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VARIANTS• Bovine Arch (10%)• Left vertebral arises
from aortic arch (3%)• Aberrant right
subclavian artery (2%)
CLASSIC (85%)• 3 Branches:
Innominate, Lt CCA, Lt Subclavian
*All other aortic arch variants combined (<1%)
Classic 85% Bovine 10%
Aberrant Rt SCl 2%
Lt Vert 3%
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BOVINE ARCH (10%)
Bovine Arch: common origin for Innominate and Left CCA
Normal: 3 separate aortic arch branches
• Most common aortic arch branching variant
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BOVINE ARCH (10%)
Bovine Arch: common origin for Innominate and Left CCA
• Most common aortic arch branching variant
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Normal: 3 separate aortic arch branches
Bovine Arch: Left CCA originates from Innominate
BOVINE ARCH• Type 2
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“BOVINE” ARCH
Misnomer:• Erroneous reference to
cow’s anatomy• Actual cow anatomy
consists of a single trunk branch off the aortic arch
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LEFT VERTEBRAL – 3RD BRANCH(3%)• Left vertebral: 3rd branch
• Left subclavian: 4th branch
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ABERRANT RIGHT SUBCLAVIAN (2%)• Right subclavian: 4th branch
• Right CCA: 1st branch• No innominate
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ICA TORTUOSITY VARIANTS• Course variations are common
http://www.slideshare.net/shaffar75/doppler-ultrasound-of-carotid-arteries
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ICA TORTUOSITY VARIANTS• Course variations are common
http://www.slideshare.net/shaffar75/doppler-ultrasound-of-carotid-arteries
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ICA/ECA ORIGIN VARIANTS• Variations in origin of the
ECA & ICA are uncommon
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• C6 (93%) – most common• C5 (5%) – 2nd most
common
VERTEBRAL ARTERY COURSE VARIANTS
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CAROTID DUPLEX ULTRASOUND
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INDICATIONS
• Cerebrovascular Accident (CVA)• Transient Ischemic Attacks (TIA)• Cervical Bruit• Pulsatile Mass• Less Specific Symptoms• Dizziness• Headaches
• Pre-operative• Post-operative• Monitor known carotid arterial disease
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POSITION/TECHNIQUE
Patient Position
• Supine
• Head angled to the side
• Rolled towel under neck
• Position adjusted to optimize sonographic window
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POSITION/TECHNIQUE
Patient Position
• Supine
• Head angled to the side
• Rolled towel under neck
• Position adjusted to optimize sonographic window
Technique
• Highest frequency, penetrating transducer
• Keep angle at 60 degrees• Diagnostic Criteria• Reproducibility
• 3-5 cycles/waveform
• Waveform 2/3 of image• Lower baseline• Decrease scale
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EXAM PROTOCOL• Protocol will be available on Sharepoint
• Written and Image formats• Protocol still needs to be approved to be made
official
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EXAM PROTOCOL• Protocol will be available on Sharepoint
• Written and Image formats• Protocol still needs to be approved to be made
official• Scan Assistant protocol has been set up in
accordance with written protocol• Protocol will also be set up on Siemens
machine at SH
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EXAM PROTOCOL• Protocol will be available on Sharepoint
• Written and Image formats• Protocol still needs to be approved to be made
official• Scan Assistant protocol has been set up in
accordance with written protocol• Protocol will also be set up on Siemens
machine at SH• Examine all accessible portions of the CCA/ICA
• Basic assessment of the ECA/Vert/Subcl
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EXAM PROTOCOL• Protocol will be available on Sharepoint
• Written and Image formats• Protocol still needs to be approved to be made
official• Scan Assistant protocol has been set up in
accordance with written protocol• Protocol will also be set up on Siemens
machine at SH• Examine all accessible portions of the CCA/ICA
• Basic assessment of the ECA/Vert/Subcl• Protocol is designed to be the minimal required
images• Additional images will often be necessary when
the exam is normal• Additional images will always be necessary
when pathology is encountered
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CCA Proximal• Trans
*Image at the most proximal, straight segment
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CCA Proximal• Long
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CCA Proximal• Color Doppler
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CCA Proximal• Spectral Doppler
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CCA Distal• Trans
*2-3cm below the bifurcation
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CCA Distal• Color Doppler
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CCA Distal• Spectral Doppler
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CCA Spectral Analysis:• EDV should be above zero• EDV should be similar to the contralateral CCA, taken at
approximately the same level
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Bifurcation• Trans (bulb)
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Bifurcation• Trans (just
above bulb)
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ECA Prox• Long
*Look for branches
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ECA Prox• Color Doppler
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ECA Prox• Spectral Doppler
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ECA Spectral Analysis• Higher resistance than the ICA • PSV normally greater ICA• Sharp upstroke• Prominent dicrotic notch (may reverse)• EDV approach/reach zero
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*Include bulb
ICA Prox• Long
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ICA Prox• Color Doppler
*Obtained just below the bulb where vessel is no longer dilated
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ICA Prox• Spectral Doppler
*Waveform may reflect flow disturbances of the bulb extending into the prox ICA
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ICA Mid• Color Doppler
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ICA Mid• Spectral Doppler
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ICA Dist• Color Doppler
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ICA Dist• Spectral
Doppler
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ICA Spectral Analysis• Low resistance• Continuous forward flow• EDV well above zero
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Vertebral• Color Doppler
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Vertebral• Spectral
Doppler
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Vertebral Spectral Analysis• Low resistance• Slightly more resistive than the ICA
• Antegrade, bidirectional, retrograde
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Subclavian• Color Doppler
*Sampled close to the origin
Origin
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Subclavian• Spectral Doppler
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Subclavian Spectral Analysis• High resistance• Reversal late systole/early diastole
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ONLINE FORM
PSV EDV
PSV
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Long ECA/ICA• Two for the
price of one
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Long ECA/ICA• Two for the
price of one
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Temporal Tap• Tap on superficial temporal artery • ant/sup to ear
• Indicates ECA• Not reliable http://www.slideshare.net/shaffar75/doppler-ultrasound-of-carotid-arteries
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http://www.slideshare.net/shaffar75/doppler-ultrasound-of-carotid-arteries
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Bulb• “ICA Prox”• Widened portion of the proximal ICA• Disturbed flow• Unidirectional along the flow divider of the birfurcation• Zero/reversed flow at outer wall
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Vertebral Origin• Most common
location for stenoses
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Innominate• Not required
unless pathology is suspected
CCA
Subclav
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Innominate• Not required
unless pathology is suspected
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• Distal ICA• can be difficult to
demonstrate
• Prox/Mid ICA Doppler settings are not adequate to optimize the distal ICA• adjustments must be
made
IMAGE QUALITY
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Lowered Color Frequency
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Increase Color Gain
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Decreased Steer Box Angle