Carotid Flashcards
Where does the common carotid artery (CCA) move from?
Clavicle
The CCA moves up the neck from the clavicle.
At what level does the CCA bifurcate?
About the level of the thyroid cartilage
This is the point where it divides into the internal and external carotid arteries.
Which artery moves towards the ear?
External carotid artery (ECA)
Which artery moves behind the ear?
Internal carotid artery (ICA)
In a transverse view, which artery is usually larger?
Internal carotid artery (ICA)
In a sagittal view, how does the ECA typically appear at the origin?
Narrow
The ECA almost always appears to narrow right at the origin.
What orientation is medial to the right?
On the right side
What orientation is medial to the left?
On the left side
What casts a lot of acoustic shadows in the carotid region?
Trachea
What wraps around the trachea?
Thyroid gland
Where should you begin scanning the carotid system in transverse view?
Low in the CCA, bumping the clavicle
What should be kept centered in the transverse view?
The vessel
What is the highest priority when scanning the carotid arteries?
Clear walls
What should you do if the ends of the artery are closed off?
Rotate the beam to line up with the artery
What should the angle of the beam be for optimal imaging?
Perpendicular to the vessel (90 degrees)
Which scanning approach provides the farthest distal view of the ICA?
Posterior approach
What is the typical angle for velocity measurements?
60 degrees
What does walking the sample volume demonstrate?
Focal acceleration, distal turbulence, stenosis
What is atherosclerosis?
The most common arterial disease characterized by plaque formation
What is an embolus?
A piece of plaque or thrombus that travels and causes infarction
What is a common cause of cardioembolic infarction?
Originates from the heart
What is a dissection in the context of carotid arteries?
A tear in the intimal lining of an artery
What is fibromuscular dysplasia (FMD)?
Non-atherosclerotic arterial disease resembling a ‘string of beads’
How common are carotid aneurysms?
Very rare
What is the effect of vasculitis on blood vessels?
Inflammation resulting in damage to the vessel wall
What is a carotid bruit?
An abnormal sound generated by turbulent blood flow
What are the symptoms of hemiparesis and hemiplegia?
Hemiparesis is partial weakness; hemiplegia is complete paralysis on one side
What does TIA stand for?
Transient Ischemic Attack
Where is the most common location of diseases affecting the carotid arteries?
First 1-2cm of the internal carotid
What type of flow is seen in the ECA?
High resistance
What indicates high grade stenosis or occlusion in the CCA?
Low or zero end diastolic volume (EDV)
What is the ICA/CCA ratio used to assess?
Severity of stenosis
What is characterized by a PSV greater than 125 cm/s?
Abnormal ICA
What might a reversed blood flow pattern in the vertebrals indicate?
Abnormal vertebral artery condition
What is the origin of the aortic arch?
Originates from the left ventricle of the heart
Where does the aortic arch lie?
In the superior mediastinum
What are the three main arteries that arise from the aortic arch?
- Innominate artery (brachiocephalic)
- Left common carotid artery (CCA)
- Left subclavian artery
From where does the left common carotid artery arise?
From the aortic arch
From where does the right common carotid artery arise?
From the right subclavian artery
What is the typical measurement range of the common carotid artery?
Between 6 and 8 mm
Which common carotid artery is usually longer?
Left common carotid artery
Where are the bilateral common carotid arteries located in relation to the jugular vein?
Medial to the jugular vein
What does the common carotid artery terminate into?
The bulb into the internal carotid artery (ICA) and external carotid artery (ECA)
What is typically the smaller of the common carotid artery branches?
External carotid artery (ECA)
What does the external carotid artery primarily feed?
The majority of the face and neck
What is the typical measurement range of the external carotid artery?
3 to 4 mm
Which branch is most commonly visualized from the external carotid artery?
Superior thyroid artery
What is the main function of the internal carotid artery?
Main conduit of the brain
What is the typical measurement range of the internal carotid artery?
Between 5 and 6 mm
What are the vertebral arteries a large branch of?
Subclavian arteries
What percentage of vertebral arteries are asymmetric in size?
75%
What is the typical length of the vertebral artery without branches?
Approximately 4 to 5 mm
What type of flow do the ICA and ECA provide to the head?
Oxygen and nutrient-rich arterial blood
What is a TIA commonly referred to as?
Mini stroke
What is the duration of a TIA?
Less than 24 hours
What are common nonmodifiable risk factors for stroke?
- Age
- Sex
- Race
- Family history of cerebrovascular events
What are common modifiable risk factors for stroke?
- Hypertension
- Atrial fibrillation
- Other cardiac diseases
- Diabetes
- Elevated cholesterol
- Smoking
- Sedentary lifestyle
- Poor diet
What does the acronym F.A.S.T. relate to?
Stroke warning signs
What is a common characteristic of tortuous arteries?
Can result in typically higher PSV within tortuous portions of the artery
What is atherosclerosis?
The buildup of fats, cholesterol, and other substances in and on the artery walls
What is arteriosclerosis?
Occurs when blood vessels become thick and stiff, restricting blood flow
What are the characteristics to document about plaque?
- Location
- Extent
- Surface characteristics
- Echogenicity
What is the echogenicity of homogeneous plaque?
Uniform in echogenicity and texture throughout
What does heterogeneous plaque indicate?
Degenerative changes in the plaque or hemorrhage
What is the appearance of calcified plaque?
Dense and brightly echogenic (hyperechoic) with a posterior shadow
What does soft plaque appear as?
Dark (anechoic)
What is an aneurysm associated with?
A higher risk of thromboembolic events
What are the findings associated with carotid dissection?
- Different blood flow patterns in the two lumen
- Vessel lumen narrowing without visualized plaque
Where is the carotid body tumor typically located?
Within the adventitial layer on the posterior aspect of the carotid bifurcation
What is the normal spectral waveform measurement for no stenosis?
< 125 cm/sec – no plaque
What characterizes a near occluded carotid artery?
Increased stenosis – high low or undetectable, visible plaque
What common interpretation errors can occur in duplex exams?
- Increased velocity without stenosis
- Normal velocity with stenosis
- Absence of blood flow velocity with arterial patency
- Blood flow velocity recorded in presence of arterial occlusion
What is the initial position for examining the carotid system?
Begin the exam in the Transverse plane
Where should the probe be positioned at the start of the carotid scanning?
Against the clavicle bone at the Proximal CCA
What is the orientation of the probe while sliding it distally?
Stay perpendicular (90 degrees) to the vessel
What approach should be used to avoid the mandible in the distal CCA, ICA, and ECA?
A more lateral approach using the sternocleidomastoid muscle as a window
What anatomical structure is distal to the CCA?
The bulb
What is observed after the bulb during carotid scanning?
The bifurcation which is the beginning of the proximal ICA & ECA
Name the two scanning planes used in carotid scanning.
Transverse and Sagittal
What are the components examined in the Sagittal plane of the carotid system?
Sagittal Carotid Bulb, Sagittal ICA, Sagittal ECA
List the vessels measured for velocities during carotid scanning.
- Prox & dist CCA
- Prox & dist ICA
- ECA
- Vertebral
- Subclavian
What is the concept of ‘Walking’ the Sample Volume in carotid scanning?
Identifying Vessels and Placing & Sizing Sample Volume
How does the size of the sample volume affect the area being sampled?
Smaller gate samples a smaller area; larger gate samples a larger area
What should the sample volume be open to in relation to the diameter of the vessel?
1/3 of the diameter of the vessel
What technique is used to identify the vertebral arteries during scanning?
Sweep posteriorly until you see shadows
What happens to the small transverse arteries during the scanning process?
They appear as the sample volume is placed
