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Adv. Vas. Son.

Test 4 Carotid Reveiw

QuestionAnswer
Cerebrovascular anatomy what carotid arteries do we need to know? CCA, ICA, ECA, and Vertebral arteries
Common Carotid Arteries (CCAs) Facts: Left arises directly from the Ao. Right originates from the Brachiocephalic Art. They Ascend the neck laterally. Bifurcate @ the upper border of the thyroid cartilage into ICAs & ECAs
Internal Carotid Arteries (ICAs) Facts: Originates from CCA, Posterior/Lateral to ECA-Tip towards back of head, NO extracranial branches, Give rise to ophthalmic artery in the skull, Carotid Siphon- Distal curve of ICA, Provides blood to Anterior Brain, Eyes, & Nose, LOW RESISTANCE WF
External Carotid Arteries (ECA) Facts: Originates from CCA, Anterior/Medial to ICA,-Tip toward face when scanning, Several extracranial branches, Supplies blood to face, HIGH RESISTANCE WF
How many branches does the ECA have? 8
What are the 8 ECA branches? Superior Thyroid, Ascending pharyngeal, Lingual, Facial, Occipital, Posterior auricular, Maxillary, Superficial temporal
What is the first branch of the ECA? Superior Thyroid
Vertebral Arteries (2) Facts: Originate from subclavian artery, Ascend neck through transverse processes of cervical vertebrae, Enter skull through the foramen magnum, Join intracranially to form singular Basilar artery, Provides blood to posterior brain
Branches of ICA & Vertebral arteries form the what? Circle of Willis (COW)
ICA terminates into 4 branches, What are they? Anterior Cerebral, Middle Cerebral, Posterior Communicating, Anterior Choroidal
Anterior Cerebral arteries are connected through what? Anterior Communicating Artery
Posterior Cerebral Arteries (branches of the Basilar Artery) are connected to the ______ _______ through the __________ ___________ __________? Connected to the Anterior Circulation through the Posterior Communicating Arteries
The Circle of Willis is an important what? Collateral pathway for circulation in the brain
Supraorbital, Frontal, & Nasal Artery are connections between what? ICA & ECA- Collateral pathways
Supraorbital connects what? Ophthalmic Artery (ICA) to Superficial Temporal Artery (ECA)
Frontal connects what? Ophthalmic Artery (ICA) to various ECA branches
Nasal connects what? Frontal to Facial Artery (ECA)
What are the goals of extracranial duplex? Identify PTs who are at risk for stroke, Facilitate treatment, Document disease progression (plaque), Detection of non-atherosclerotic conditions, Follow-up PTs post surgery
Carotid Artery Duplexaxam evaluation generally includes examination of bilateral what? CCAs, ICAs, ECAs, Vertebral As, And Subclavian As- Vessels should be evaluated in TRV & Long, w/ B-mode, Color, and Doppler
What are NORMAL B-mode characteristics? Smooth vessel walls, Intimal-Medial layer clearly visible & uniform (Thin, white line on innermost poart of vessel wall), Lumen is anechoic
The Intima-Medial thickness can be measured, what is considered NORMAL? IMT: ≤ 0.9mm=NORMAL, it is a predictor of cardiovascular disease, Measure far wall on vessel, Often done @ DCCA & PCCA,
What has diagnostic relevance secondary to Doppler velocities? Color
What are the advantages of Color? Rapid identification of flow disturbances, Rapid determination of location/direction of high vel jets, Determining occlusion vs. tight sten, Demonstration of post-stenotic turbulence, Following tortuous vessels, Visualization of ECA branches
Power Doppler displays what? Flow based on amplitude rather than frequency shift, No direction info, Relatively independant of angle
What is Power Doppler extremely helpful in detecting what? Extremely low flow velss (Trickle flow)
Spectral Doppler provides the most what? Reliable means for assessing vessel tenancy and classifying degree of stenosis
Pulsed wave Doppler should be what? "Swept" through all vessels
Doppler waveform contour is related to what? Cardiac output, Vessel Compliance, and Status of distal vascular bed
What should the Doppler angle be? 60 degrees or less, & Parallel to vessel walls
What are NORMAL waveform contours for CCA, ICA, & ECA? Brisk systolic acceleration, Sharp systolic peak, And Clear Spectral Waveform
ICA has the HIGHEST ______ _____ and LOWEST _________? HIGHEST DIASTOLIC velocities, LOWEST RESISTANCE
ECA has the LOWEST _______ ______ and HIGHEST _________? LOWEST DIASTOLIC velocities, HIGHEST RESISTANCE
CCA has? Intermediate diastolic vels, has characteristic of both ICA & ECA
You must evaluate the ENTIRE LENGTH of what? ICA, Continue through the carotid bulb, Sample Prox, Mid, & Distal segments of ICA, Measure PSV & EDV throughout, Distal segment may be difficult beyond angle of jaw, May need posterior scan window
ICA waveform is less __________ than ECA? Pulsatile than ECA, More continuous flow, LOW RES, Feeds Brain and Eyes
ECA waveform is more ________ than ICA? Pulsatile, Rapid upstroke & downstroke, HIGHER RES, Low diastolic flow component(not much dastole present on WF), May go to BL or have small reversal flow, Feeds Face and Scalp
ICA vs. ECA: ICA- typically larger (bc bulb), Lies posterior to ECA, No branches. ECA- Typically smaller, Multiple branches, WF will osillate w/ temporal tap, Tip TD towards PT's face (typically on side where thyroid was located)
To evaluate vertebral artery what do you do? Place TD @ anteromedial aspect of mid-neck on long axis, Identify CCA then slide or angle posteriorly to identify vertebral A between transverse processes of vertebrae
What does a Vertebral artery appear as on ultrasound? Anatomy has "H" appearance, shadow of vertebrae & anechoic of vessel = H, Take care to identify flow direction & waveform contour
How is NORMAL vertebral artery flow? Similar to ICA WF pattern- LOW RES, Antegrade flow throughout cardiac cycle, Brisk systolic acceleration, Sharp peak, & Relatively high diastolic flow component, Usually a lower vel (Lower scale)
What are the indications for exam? ASX neck bruit, HX of risk factors (DM, HTN, Smoking, & Hyperlipidemia), HX stroke & TIA, Screening prior to surgery, & Follow-up after carotid endarterectomy or stenting
What are the mechanisms of SXs? Reduction of flow due to high-grade sten (As can become thick, not elastic), Emboli from atherosclerotic plaques (Can cause thromboembolic event), Arterial Thrombosis (Blood clot adhering to plaque)
What is a TIA? Transient Ischemic Attack- Neurologic deficits which occur intermittently, lasting from several mins to a few hrs, SX resolve within 24 hrs
What is RIND? Reversible Ischemic Neurologic Deficit- Neurologic deficits that last between 24 & 72 hrs
What is a CVA? Cerebrovascular Accident or Completed Stroke- Fixed or permanent neurologic deficits
What are the symptoms of Carotid Artery lesions? Focal weakness (Paralysis) or Numbness/Tingling (Paresthesia)- Involving combo of face, arm, & leg on one side (Opposite to the affected cerebral hemisphere) Difficulty speaking (Dysphasia (impaired) or Aphasia (absent), Amaurosis fugax
What is Amaurosis Fugax? "Shade drawn over eye"- Partial blindness, Same side as responsible carotid lesion (ipsilateral)
What are symptoms related to Vertebrobasilar insufficiency? Less specific than carotid circulation SXs, Dizziness/Vertigo (difficulty maintaining equilibrium), Diplopia (Double vision), Ataxia (muscular incoordination)
What most commonly occurs at the CCA bifurcation? Plaque
What are the early stages of plaque? Plaque appears as thickened areas of the intimal-medial layers, "Fatty streak"-thin layer of lipid material, Fibrous cap may form between plaque & lumen
By ultrasound plaque is usually classified as? Smooth vs. Irregular ("ulcerated" term is usually discouraged) Homogenous vs. Heterogenous
Extensive characterization of plaque by B-mode imaging is what? Controversial
What are ABNORMAL WF contours? High-velocity jet in the stenois, Post-stenotic turbulence
What does the waveform look like DISTAL TO STENOSIS? Dampened, decreased flow velocity, Delayed acceleration, Rounded peak. "TARDUS PARVUS"
ABNORMAL DOPPLER WF contours PROXIMAL to STENOSIS: Varies w/ disease severity & amt of collateral vessels, May be relatively normal until sten ↑es, W/ V significant stenosis, PROX WF will display a more HIGH RES pattern, Decreased or Absent diastolic flow. "RESISTIVE SPECTRA"
What is String Sign? Blunted, somewhat resistive waveforms that precede complete occlusion
Where is the String Sign most commonly found? ICA
How to detect string sign? Image in both TRV & LONG, Use low scale & high gain Doppler settings, Use Power Doppler, Carefully evaluate distal for any flow
Distal ICA stenosis or occlusion is associated with what? Following findings in the ICA: ↓ed diastolic flow or resistive component, Overall "blunted" appearing waveform, Same abnormalities in the CCA, Important to compare bilaterallyCan occir ICA End Diastolic Vels
CCA stenosis facts: Can occur in the Prox, Mid or Distal segments, Significant sten is associated w/ Focal Vel ↑es, Poststenotic Turbulence, Dampened Distal WFs in both ICA & ECA. "Choke Lesion" may result in retrograde ECA to supply ICA
What will PROX vertebral artery stenosis produce? Abnormal dampened WFs distally w. delayed acceleration & rounded peaks, Possible post-sten turbulence, No specific criteria but should be suspected if focal vel ↑ in PSV is > 150 cm/s, Usually occurs @ origin from Sub A
Resistive or Blunted Wfs indicate what? Distal Stenosis of occlusion
What is a Subclavian Steal? Hemodynamically significant stenosis in the PROX subclavian artery causing changes to Vertebral Artery flow- Results in brachial BP ↓ on affected side (more than 15 to 20 mmHg lower than contralateral arm)
What does a subclavian steal cause? Decreased pressure @ the origin of ipsilateral vertebral artery that can lead to reversed flow
Vertebral Artery flow changes as what? Obstruction progresses: Norml antegrade flow, Antegrade flow w Deep notch mid-cardiac cycle, Alternating or bidirectional (To&Fro) flow, Complete reversal (fully retro) flow
Latent Steal facts: Flow that is beginning to show signs of reversal but not completely retrograde, WF characteristics can be: Hesitant (deep flow reversal notch) & Alternating or bidirectional
Complete Steal Facts: Complete retrograde flow of vessel involved, W/ severe subclavian artery stenosis, the vertebral A will reverse in order to provide blood flow to the arm
What is Reactive Hyperemia? Provocative test used to augment a subclavian steal from "Latent" to "Complete"
Reactive Hyperemia procedure: Blood pressure cuff is inflated to Suprasystolic BP on affected side, Left inflated for 3-5 mins while vertebral A is monitored, Cuff is rapidly deflated while ipsilateral vertebral A is observed. POSITIVE when Vertebral A COMPLETELY REVERSES
Cardiac effects on vascular flow aortic valve or root stenosis: Cardiac pathology, Will generate symmetrically abnormal Doppler WF contour in the bilat carotid systems (Dampened WFs throughout both carotid artery systems). May also cause bilat low brachial systolic pressures
Aortic Vavle regurgitation insufficiency: Double systolic peak (pulsus bisferiens) may also be seen in normal young PTs (wall compliance), Diminished diastolic flow or reversed diastolic flow seen on WFs
High Cardiac output facts: May cause systemic ↑ in PSV, Can be normal in athletic, young adults (R/O vessel wall irregularities) Can be related to non-cardiac disorders (anemia), May cause overestimation of stenosis degree
Low Cardiac output facts: Systemic ↓ in PSV w/ normal upstroke (typically, represents low EF secondary to cardiomyopathy), In severe cases: low vel, round peak may be seen, May underestimate degree of stenosis
Intra-Aortic Balloon Pump: Temp assistance w/ left ventricular contraction, Alters arterial patterns systemically, PSV may underestimate stenosis degree
Ventricular Assist Device: Aids PTs in heart failure (assists weakened ventricles by mechanically pumping blood out of heart)- Blood flow may be continuous or pulsatile depending on type of device
LVAD- Left ventricular assist device: Most common! Most are continuous flow- resulting in non-pulsatile arterial flow, W/out PSV & EDV- Vel clcs can't be done, Pulsatile flow pump may underestimate degree of stenosis
BiVAD- Biventriculat assist device: Required when both ventricles require assistance (morbid CHF) Altered flow pattern systemically depending on type used, If pulsatile PSV may underestimate stenosis degree
Criteria for classification of disease: Classification has been validated for the ICA only (criteria can't be applied to CCA or ECA), Criteria was developed by comparing duplex results / "Gold standard" imaging modalities or surgical findings
Is surgical intervention usually done with complete occlusion of ONE side in the carotid system? NO, not an embolic risk anymore if occlusion complete, There is another patent carotid & the vertebral system to supply the brain
NASCET criteria (North American Symptomatic Carotid Endarterectomy Trial) facts: > 70% stenosis is defined as (ultrasound) PSV >230 cm/s, ICA/CCA Ratio >4.0 (Highest PSV from stenotic ICA) (CCA PSV from normal mid-to-distl segment) Angiogram correlation came from residual lumen compared to distal ICA diameter
For CCA and ECA stenosis geberal criteria can be applied: Focal velocity↑, Post sten turbulence, Distal waveform changes *These changes correlate w/ a >50% stenosis in the vessels
< 50% stenotic lesion will be best characterized/Evaluated by what? Greyscale and Color Flow
> 50% stenotic lesion will be best characterized/Evaluated by what? Spectral Velocities
>99% stenotic lesion will be evaluated with what? Greyscale, Color flow and Power Doppler
Dissections/ Intimal flaps: Separation of layers of an artery due to intimal tear, Typically intima from Media (intimal flap can flutter in the arterial lumen) Results in creation of falase vesse lumen (can have a blind end or connect back due to true lumen through secondary tear
False lumen flow pattern variation include: Antegrade flow due to blood continuing through a 2ndary tear, Blood flow into & out of the false lumen in a to&fro pattern, No flow as thrombus may form that may create a stenosis or occlusion in the true lumen, Reversed flow direction
Dissections/Intimal Flaps: Usually originate from Ao & extend into CCA, May originate in distal ICA & extend Proximally, Dissection can be spontaneous or traumatic, Intimal flap may occur after carotid endarterrectomy (CEA)
Spontaneous Dissection often associated with: History of HTN
Trauma Dissection may be what: Subtle (I.E. Head rotation) or More obvious (Blunt trauma to head or neck)
Dissection/ Intimal Flaps Signs/Symptoms & Duplex findings: ASX usually, Head, Face, or neck pain (usually associated w/ICA dissection), Hemispheric stroke or TIA SXs, Dissection should be suspected in young PTs who present w/stroke SXs
Duplex findings associated with dissection include: Unusual color flow pattern in an artery that otherwise shows no atherosclerosis, Presence of thin white line in vessel lumen (May flutter w/ each pulse, Should be identified in both Long & TRV)
Blind-ended tear: True lumen may shoe LOW res Doppler signal (Depending on degree of lumen tightening) If false lumen becomes thrombosed, stenotic flow profiles may be noted in true lumen, False lumen will demonstrate HIGH resistance flow patterns unless thrombosed
What may also be noted in false lumen? Reversed flow
Dissection with secondary tear: Blood is allowed back into true lumen, True & false lumen may demonstrate antegrade flow, however, WF contours may be diff
Color imaged can be used to demonstrate: Location of dissection, Prox and distal ends of dissection, Open or thrombosed lumens, Tapering & length of stenosis
Fibromuscular Dysplasia (FMD): Abnormal grow of smooth musce cells & fibrous tissue in arterial walls, MAy involve intima, Media, &/or Adventitia (Media is MOST COMMON), Can cause narrowing of the arterial lumen in multiple sections
FMD Cont: Normal walls or flight aneurysm dilation may be noted in between stenotic sections, Causes a "String of beads" appearance of artery on arteriography
What will cause a String of Beads appearance? FMD
What should be suspected in a young PT? FMD, suspected when no evidence of atherosclerotic disease, Bilat disease is typical
FMD usually involves which segments? Mid to distal ICA segments
Doppler analysis on FMD is likely to show? Turbulent and High Vels past the PROX ICA segment
What is useful to identify distal ICA flow? Lower freq TDs and Power Doppler
Additional images for FMD should include: Distal ICA w/ color, Spectral Doppler of highest vels in the mid to distal segments of ICA. Document of poststen turbulence, Power Doppler images demonstrate "string of Beads" look, B-mode image of affected area to demonstrate diameter changes
Carotid Body Tumor: A stricture in the adventitia of the carotid bifurcation, Tumor is often easily seen on Duplex sonography, Usually benign, ASX, PT may notice small lump in anterior neck (May be slightly uncomfy), Rarely can cause Dysphagia, Headaches, or voice changes
Carotid Body Tumor on US: Presents as a well-defined mass located between ICA & ECA @ bifurcation (Causes Splaying of the 2 vessels), Highly vascular tumor, demonstrating a LOW RES WF on Spectral Doppler
Carotid Body Tumor on US cont: Color image should be taken demonstrating mass & vascularity, Color image to show proximity of tumor to ICA & ECA, Multiple B-mode images in multiple planes to document dimensions of mass
Carotid Aneurysm: Dilatation of the carotid artery, True aneurysm involves all 3 arterial walls, True ones are v rare, Most commony occur in the CCA, near bifurcation, Atherosclerosis appears to be the majority cause, May result in infection
Carotid aneurysm clinical presentation: Nontender, pulsatile mass in neck, ASX, TIA or Stroke SXS, Rupture is rare
Pseudoaneurysm: AKA Fake Aneurysm Perforation in arterial wall allowing blood to Perforation into arterial wall allowing blood to extravasate into surrounding tissue, Uncommon in carotid As, Usually the result of penetrating trauma or iatrogenic injury
Where may a pseudoaneurysm form: Endarterectomy site or @ anastomotic site of carotid bypass graft
Mass is connected to artery by what? "Neck", Blood flow in neck has to&fro appearance, Swirling flow may be noted within mass (Yin-yang)
Pseudoaneurysm facts: Palpable, pulsatile neck mass, Use spectral Doppler to document to&fro flow of neck & flow patterns Prox & Distal to defect
Pseudoaneurys, mass appearance on US: Partially or completely filled with thrombus, Low Vel, "Yin-Yang" flow pattern (Swirling pattern) Identify neck w/ to&fro
Arteritis: Inflammation of artery wall- Results in breakdown of parts of wall structure, May result in occlusion & distal ischemia
2 forms of Arteritis most often encountered w/ carotid system: Takayasu disease & Temporal Arteritis (Giant cell)
Takayasu: Typically affects younger peeps
Temporal (Giant Cell): Typically affects elderly peeps
Arteritis facts cont: No definitive US characteristics, Diagnosed through blood tests & clinical presentations
What are the clinical presentations for Arteritis: No known etiology, Autoimmune deficiencies are suspected, Women are affected more commonly than men (2:1)
Surgical procedure- CEA: Carotid Endarterectomy: Open operation, Arteriotomy is made through ICA, Atheromatous material is removed, Arteriotomy is closed (primary closure: Arterial wall only, Patch closure: patch is used to enlarge closure area
Common problems associated with CEA: Probs are more common @ distal ICA border, Narrowing as a result of closure, Plaque retained form incomplete excision, Neointimal hyperplasia a surgical site (restenosis)
Carotid Artery Stenosis: Catheter access for CAS is usually through the common femoral artery, Complications can occur not only in carotid system but in pathway of catheter & may include: Dissection, Thrombosis, & Perforations
Stenting procedure is similar to other locations: Predilation w/ angioplasty balloon, Self-expanding stent placement followed by balloon expansion
Stent must what? Cover full lesion length & extend beyond proximal & distal margins of lesion
What stenosis is most common? Stent border stenosis, Document highest vels in these areas
Stent Evals and Pitfalls: Color & Power Doppler can be used to eval for narrowing, B-mode image must be crefully examined for: Stent compression, Incomplete Deployment, & Other Deformations
Atherosclerotic Plaque is not removed in CAS because: May result in dense calcification & Shadowing, May compromise B-mode image & Doppler interrogation, Use multiple views to overcome, Distal signals are important to document (turbulence may indicate PROX sten)
CAS is still not what? Widely used- Complication rates (decreasing), Low insurance reimbursements
Restenosis rates after CAS may be _________ than after CEA? HIGHER- Hyperplasia may be an ongoing response to implanted foreign object
Follow up surveillance appears to be more significant for what? More significant for CAS than for CEA
Created by: EmilyGriffin