Cerebrovascular Flashcards
1
Q
What are some examples of cerebroscular risk factors?
A
- Hypertension
- Diabetes
- Smoking
- Obesity/ diet
- Dyslipidemia
- Hypercholesterolemia
- Sex
- Age
- Patent foramen ovale
- Physical inactivity
- Genetic predisposition/ family history
- Homocystinaemia
- Cardiac disease
- Previous TIA or stroke
2
Q
Why do we do a carotid auscultation for Bruitis?
A
It indicates abnormal flow if present
3
Q
When doing a carotid auscultation for bruitis, turbulent blood flow does what?
A
Vibrate the vessel wall and creates a bruit
4
Q
A bruit may not be detected in the case of what?
A
A severe stenosis due to significant diminished flow.
5
Q
What is a thrill?
A
A palpable bruit
6
Q
What are bilateral blood pressures?
A
Difference of >20 mmHg between sides which indicates a possible subclavian steal
7
Q
What are signs and symptoms of anterior circulation steals?
A
- Behavioural abnormalities
- Hemiparesis/ hemiplegia
- Parenthesis
- Homologous hemianopia
- Amourosis fugax
8
Q
What is anterior circulation?
A
Internal carotid artery - ICA
9
Q
What is Hemiparesis/ hemiplegia?
A
Weakened or complete loss of function to one limb or side of the body
10
Q
What is paresthesia?
A
Tingling, numb or burning sensation
11
Q
What is homologous hemianopia?
A
Blindness or visual defect in half of the field of vision
12
Q
What is amourosis fugax?
A
Partial or complete loss of vision
13
Q
What is signs and symptoms of posterior circulation? (Vertebrobasilar artery)
A
- Ataxia
- Bilateral visual blurring
- Diplopia
- Drop attacks
- Dysphasia
- Motor/ sensory disturbances
- Vertigo
14
Q
What is ataxia?
A
Lack of muscle coordination, can affect walking
1. Walking
2. Swelling
3. Eye movement
4. Speech
15
Q
What is diplopia?
A
Double vision
16
Q
What is drop attacks?
A
Sudden fall while walking or standing that is recovered from quickly
17
Q
What is dysphasia?
A
Difficulty swallowing
18
Q
What are motor/ sensory disturbances?
A
Unilateral, bilateral, or alternating
19
Q
What are signs and symptoms of subclavian steals?
A
- Supraclavicular bruit
- Arm weakness
- Decreased arm pulses
- Arm pressures that are discrepancy by more than 20 mmHg
- usually the patient is asymptomatic with this condition therefore no treatment is undertaken
20
Q
What is signs and symptoms of non localizing steals?
A
- Dizziness
- Syncope
- Dysarthria
- Headache
- Confusion
21
Q
What is syncope?
A
Transient loss of consciousness
22
Q
What is dysarthria?
A
Abnormal speech or difficulty with speech
23
Q
What is arteriosclerosis?
A
Hardening of the arteries
24
Q
What is arteriosclerosis directly related to? What does it result in?
A
Related to age resulting in degenerative change of the arteries that include loss of elasticity and thickening of the Intima over time
25
What is atherosclerosis?
Both hard and soft plaque within the arteries beyond the intimacy thickening of arteriosclerosis
26
What is the most common arterial disease?
Arteriosclerosis
27
Atherosclerotic plaque builds in what? And limits what?
Plaque builds in the arterial wall and limits or stops the blood flow by either narrowing the lumen (stenosis) or blocking the artery (occlusion)
28
What is a hemodynamically significant lesion?
A stenosis or an occlusion resulting in decreased blood pressure or flow distal to the obstruction, usually >50% diameter reduction
29
The vessel diameter typically needs to be reduced by at least how much to see a significant increase in PSV?
50%
30
What does the development of atherosclerosis start with?
Injury’s to the endothelial lining of the vessel wall
31
During the development of atherosclerosis injury could be due to what? (Stage 1)
A wide range of causes including certain risk factors, vasculitis or any hemodynamic stress
32
During the development of Atherosclerosis, injury exposes areas of the intimacy layer allowing what to happen? Stage 2
Lipids from the blood to enter, this is the inflammatory response, leading to the fatty streak
33
What happens during stage 3 of the development of atherosclerosis?
Platelets are deposited at the site and the muscle cells respond by becoming consumed with fat
34
During stage three of atherosclerosis development, the bodies attempt to repair injury results in what?
The formation of scar tissue (fibrosis), leaving a tough fibrous cap overlying the soft fatty portion of the plaque
35
What happens during stage four of the development of atherosclerosis?
1. Fibrous cap can be disturbed by hemorrhage calcification and thinning lead to further disruption of the endothelial layer, resulting in **ulcerative plaque**. This type of plaque is **unstable** and can be release emboli or thrombus into the bloodstream
36
During stage four of the development of atherosclerosis there is hemorrhaging from what?
The vasa vasorum into the plaque causing ischemia learning to the breakdown of the fibrous cap and endothelium
37
What does this image demostrate?
Stage 1 of the development of atherosclerosis
38
What does this image demonstrate?
Stage two of the development of atherosclerosis
39
What does this image demonstrate?
Stage 3 of the development of atherosclerosis
*thickening- plaque formation*
40
What does this image demonstrate?
Stage 4 of atherosclerosis
*late changes*
41
What does the echogenicity of plaque morphology determined by?
Determined by the compositions of
1. Lipids
2. Collagen
3. Hemorrhage
4. Calcification within the plaque
42
What does anechoic mean for plaque?
No echogenicity, contains lipids and/ or intraplaque hemorrhage
43
What does hypoechoic mean for plaque?
Low echogenicity, fibrofatty plaque
44
What does hyperechoic mean for plaque?
Moderate echogenicity (fibrous plaque), shadowing may or may not be present
45
What does calcific mean for plaque?
Highly reflective plaque with shadowing
46
What does this image demonstrate?
Mixed echogenicity with hypoechoic regions
47
What does this image demonstrate?
Dominantly echolucent with small areas of echogenicity
48
What does this image demonstrate?
Dominant echogenic with small areas of echogenicity
49
What does this image demonstrate?
Calcified plaque
50
What does this image demonstrate?
Intraplaque hemorrhage
51
What does intraplaque hemorrhage present like?
Hypoechoic regions with thin fibrous cap, “Eggshell” pattern
52
What does this image demonstrate?
Ulceration
53
In terms of plaque formation and morphology, what is composition determined by?
The levels of lipid, collagen, hemorrhage and calcification
54
What does fibrofatty plaque contain and what does it look like sonographically?
Contains lipid material, low echogenicity, acoustics are similar to blood with a uniform echo distribution
55
What does fibrous plaque look like? What forms this?
Moderate to strong echogenicity, lipid or thrombus may create hypoechoic regions
56
What is complex plaque?
Multiple levels of echogenicity, acoustic calcific shadowing may or may not be present
57
In terms of plaque formation and morphology textures can be what?
Homogenous or heterogenous
58
In terms of plaque formation and morphology, what is surface?
Either smooth or irregular
59
What is a partial obstruction?
1. Intima bulges as the plaque grows gradually narrowing the lumen,
2. Leads to ischemia in the area being supplied
60
What is a complete obstruction?
Occlusion will cause infarction and necrosis of the area being supplied
61
What is a thrombosis?
Blood clot formed over the plaque which further decreases the lumen and contributes to ischemia or infarction
62
What is emboli?
1. Thrombus that has broken off and become embolus
2. Travels to areas downstream that are too narrow for it to pass causing ischemia and infarction
63
What is an aneurysm?
When plaque weaken the vessel wall and can cause a bulge to develop
64
Where is it rare to have aneurysms?
Cervical carotid arteries
65
What are vessel calcifications?
1. Calcium salts from the blood may be deposited
2. Results in hardening of the vessel walls making them brittle and prone to rupture
66
What is a asymptomatic neurologic defect?
When no cerebral and retinal symptoms of vascular disease
67
What is the most common indication for asymptomatic patients?
Auscultations of a bruit
68
What is a transient ischemic attack (TIA)?
Brief episode of neurological symptoms in which cell death does not occur
69
How long does transient ischemic attacks last?
1-30 minutes
70
In terms of transient ischemic attacks, neurologic deficit lasting less than 24 hours and consistent with ischemia is considered what TIA. T/F?
True
71
What is considered resolving/ Reversing/ ischemic neurological deficit (RIND)?
1. Neurological event with symptoms lasting longer than 24 hours to within 3 weeks
2. No permanent neurological damage
72
What is a cerebrovascular accident?
Results from a loss of blood supply that has left some permanent brain damage and subsequent loss of motor, sensory or cerebral function
73
What might SVA/ Stroke be further classified as?
1. Acute- sudden onset
2. Usable in evolution, symptoms come and go
3. Completed, no progression or resolution, stable
74
What does vertebrobasilar insufficiency (VBI) cause?
Causes bilateral symptoms of
1. visual blurring
2. vertigo
3. Ataxia
4. Drop attacks
75
What are Norma carotid velocities
Non-hemodynamically significant stenosis <50% diameter
76
In terms of normal carotid velocities what are the doppler waveforms and flow velocities?
1. Low resistance in the CCA, ICA and vertebral artery
2. High resistance in the ECA
3. PSV should be similar throughout the CCA
4. Younger people will have higher velocities
77
In terms of Anterior circulation, EDV is above the baseline except when?
1. CCA or ECA may have a short period of revered flow at end systole
2. Flow reversal can be seen in the bulb
3. If aortic regurgitation is present a longer period of reversed flow will be observed in the CCAs bilaterally
78
What is a stenosis or stenotic zone?
Narrowed portion of a vessel usually caused by plaque deposits but can be due to extrinsic compressions
79
What is a critical stenosis?
Reduces both flow and pressure. This is equivalent to a 50% diameter reduction/ 75% area reduction
80
Tandem stenoses have a what comparative effect on a single lesion?
These have a greater hemodynamic effect than a single lesion due to energy losses that occur at the entrances and exits of the stenotic segments
81
Most carotid stenosis occur in the first 1-2 cm (origin) of the what?
ICA
82
What are some factors affecting stenosis velocity?
1. Length and diameter of the narrowed segment
2. Endothelia surface roughness
3. Edge irregularity of narrowing
4. Flow rate
5. Physiologic
6. Collateral circulation presence
7. Normal Vessel anatomy
83
In terms of carotid stenosis, Colour doppler can help determine what? What does spectral doppler do?
The location and extend of a stenosis, but spectral analysis is used for accurately assess the stenotic zone?
84
Colour doppler is limited by what?
Vessel tortuous its and Shadowing from calcific plaque
85
Positive ultrasound results may be correlated with what in terms of carotid stenosis?
Angiographic studies, especially if surgery is indicated. MRA is also a direct test
86
In terms of assess/performing a carotid stenosis exam what must we do?
1. Compare both sides of the CCA for inflow/ outflow
2. Categorize and image ICA disease by referring to (ICA/CCA ratios)
3. Look at ECA for stenosis
4. Assess vertebras for flow direction and possible obstruction
5. Assess SCA for obstruction
6. Other pathology
87
When looking for a carotid stenosis specifically **peak** systolic velocity, what must we look for?
1. Search lumen for **highest** velocity
2. Significant stenosis has a high pitched hissing sound
3. **>50-60% diameter reduction** - Volume flow decreases rapidly
4. >**70 diameter reduction** - velocities start do decrease rapidly
5. **>80% reduction reduces** PSV to below normal levels
88
What is the most important factor when looking for carotid stenosis?
Peak systolic velocity
89
When looking for end diastolic velocity for carotid stenosis, what should we look for?
1. <50% diameter reduction the EDV remains within the normal range
2. >50% reduction causes an increase in diastolic velocity
3. >70% reduction sees a rapid rise in diastolic velocity
4. **valuable for detecting high- grade stenosis**
90
What is the systolic velocity ratio?
PSV in ICA/ PSV in CCA
91
What factors affect systolic velocity ratio?
Physiologic factors such as hypertension
92
What would make the systolic velocity ratio invalid?
When the CCA or Bulb has a stenosis.
93
What happens when the systolic velocity ratio is invalid/ abnormal?
When the ratio is abnormal and all other parameters are normal such as velocities and no plaque it should be disregarded
94
What is trickle flow or pre- occlusive stenosis?
When the stenosis is so severe that the blood trickles through the residual lumen
95
In terms of trickle flow or pre-occlusive stenosis, When an occlusion is being considered one Must set system controls for low flow how?
1. Low wall filter
2. Low PRF
3. Increased colour gain
4. Increased sample size
5. Power doppler may be very helpful in this situation
96
What does this image demonstrate?
Carotid stenosis
97
When is total occlusion present?
Total occlusion is present when **no flow is detected by colour or spectral doppler with appropriate setting**
98
When determining the extent of total occlusion what are some things we can look for/ see?
1. Lumen filled with plaque, may be obscured by calcific plaque
2. Colour flow or doppler signal should **NOT** be detracted with system controls set for low flow
3. Arterial vessel pulsations are absent
4. **Isoechoic** or **slightly echogenic** to surrounding tissue therefore making it difficult to visualize the vessel walls
99
In terms of occlusion specifically a long standing occlusion, what would the vessel size be?
Small vessel size
100
Nearly occluded vessels may have what kind of sign?
String sign
101
ICA to CCA occlusion has what ratio of predominance?
10-1
102
In terms of total occlusion, what is **internalization of ECA**?
When the ECA may have increased flow with a higher diastolic velocity than normal
103
In terms of total occlusion, the contralateral CCA may have what type of velocity?
A compensatory increased velocity
104
In terms of total occlusion, the ipsilateral CCA will have what kind of sound and show what?
1. Thump sound
2. Show a decreased PSV and an absent or reversed diastolic component
105
Bilateral diminished CCA velocities may indicate what?
Poor cardiac output
106
Unilateral diminished CCA velocity suggests what?
Ipsilateral Proximal disease
107
Spectral broadening increases with what?
An increase in severity of the stenosis
108
To confirm occlusions what must we do?
1. Low flow settings, increased colour gains
2. Increase sample volume size but **avoid** ECA branches and veins
3. Interrogate distal to the bulb in transverse and sagittal with PW and colour doppler
109
Should we measure the velocity in transverse to confirm occlusions?
NO! The angle is not accurate
110
When confirming occlusions, with ICA occlusions diastolic flow may appear how?
Absent
111
When confirming occlusions, in 2D the ICA may appear how?
With plaque and motion and may be observed with each pulse
112
When confirming occlusions intracranial ICA occlusion will demonstrate what?
No end diastolic flow in the more distal portal of the ICA
113
What can we see with a pre-stenotic region (proximal) in terms of pulsatility?
1. Increased pulsatility with severe stenosis
2. Staccato waveforms
114
What do staccato waveforms look like?
1. Sharp, narrow systolic peak
2. Low systolic velocity
3. Little diastolic flow
4. Reversal in early diastole
5. “Thump” sound heard
115
What does this demonstrate?
Staccato waveform
116
Where is the post stenotic region (distal)?
Immediately beyond stenotic zone
117
For post stenotic regions, what does the flow appear like?
1. Flow stream spreads out resulting in turbulence
2. Maximum disturbance is within 1cm
3. Turbulence diminishes by 2cm
4. Laminar flow usually resumes around 3 cm distal
118
What may be the only clue to a severe stenosis if the stenosis is obscured by calcific plaque?
Post stenotic region
119
Distal Damped waveforms will be seen with what?
A severe stenosis
120
What are some examples of things we will see with a. Distal dampened waveform?
1. PSV is lower than normal
2. Systolic peak is rounded
3. Diastolic flow is increased
121
What is post stenotic regions also called?
1. Pulses tarsus
2. Pulsus parvus
3. Tarsus parvus
122
Label the waveforms from left to right
1. Pre- stenotic area
2. Maximum stenosis
3. Post stenotic region (turbulence)
123
What does this image demonstrate?
The yellow arrow indicates the region of maximum stenosis
*Note that the sample volume is incorrectly placed distal to the plaque*
124
What does the velocity value look for in the CCA?
Normal
125
Low to zero EDV may indicate what in the CCA?
1. Distal CCA
2. Carotid bifurcation
3. Proximal ICA high grade stenosis or occlusion
126
In the CCA hemodynamically significant stenosis (>50%) will produce what?
1. A focal velocity increase (at least double that of a proximal segment)
2. Post stenotic turbulence
127
If a >30 cm/sec difference exists between the right and left CCA velocities at multiple levels what should be considered?
1. Proximal obstruction
2. Vessel tortuously
3. Tight distal CCA stenosis
4. Compensatory flow due to a contralateral occlusion
128
In the CCA what does a proximal obstruction look like?
Proximal CCA has a slow upstroke and lower velocity waveform
129
What does the vessel tortuosity velocity look like proximal in the CCA?
Higher proximal CCA velocities
130
What does tight distal CCA stenosis look like?
Proximal CCA waveforms with a quick upstroke but low velocities
131
What is compensatory flow in regards to the CCA?
CCA velocities that are much higher compared to the opposite side
132
What do these images demonstrate?
1. Occluded RT ICA
2. Contralateral ICA - overestimated
133
What happens in the ICA as higher velocities are reached?
Spectral broadening with PSV > 125 cm/s
134
What is the EDV of the ICA?
>40 cm/s
135
What do we use to calculate the ICA/ CCA ratio?
The highest PSV and EDV from the pre- bulb CCA and the first 3 cm of the ICA
136
Once we have the ICA/ CCA ratio what must we do?
1. Check the ICA/ CCA ratio and image measurement if they agree with the extent of disease suspected
2. Describe plaque location and characteristics
137
In the ICA Flow disturbances seen early post carotid endarterectomy (CEA) may do what?
Disappear on follow- up exams due to the natural remodelling of the vessel
138
What does the ECA branches appear in terms of resistance?
High resistances branches
139
What does a PSV >150-220 cm/s with plaque and post- stenotic turbulence indicate?
>50% stenosis
140
How does hemodynamically significant ECA stenosis (>50%) present?
Focal velocity increase with post stenotic turbulence and possible colour bruit
141
If we observed a severe ICA stenosis/ occlusion with low resistance flow pattern what might this be a result of?
1. The ECA acting as a collateral to supply the low resistance vessels of the brain.
2. It is especially important to look for branches in the situation to identify the ECA with certainty
142
When the CCA is occluded, what happens to the ECA?
ECA flow direction will often reverse in order to perfuse the brain by means of supplying blood to the ICA
143
The ECA can also be identified by performing what?
Temporal tap.
144
What does a spectral trace do when a temporal tap is done?
The spectral trace should “oscillate” when you tap the superficial temporal artery (STA)
145
Does occlusion change flow in collaterals?
Yes, it changes flow that are near or distal to the stenosis
146
What does change in the collaterals look like?
1. Increased velocity
2. Increased volume flow
3. Flow reversal
4. Decreased pulsatility
147
Where do we see examples of collateral flow changes?
1. Increased diastolic flow in ipsilateral ECA
2. Flow reversal in ipsilateral ECA
3. Increased contralateral ICA, CCA velocities
148
What are the three basic routes for collateral circulation?
1. Large inter-arterial connections through the circle of Willis
2. Intracranial- extra cranial anastomoses or pre- Willisian anastomoses
3. Leptomeningeal
149
What does large inter-arterial connection through the circle of Willis provides?
Provides pathways between the two carotids or between basilar and right or left carotid
150
What does the intracranial-extracranial anastomoses or pre-willisian anastomoses connect?
1. ECA to ICA (ophthalmic)
2. ECA (occipital) to Vertebral (Atlantic)
3. Cervical branches of subclavian to vertebral (lower and upper branches)/ occipital of ECA
4. ECA branches across midline to peri-orbital branches
151
What does the leptomeningeal connection do?
Connect terminal cortical branches of main cerebral arteries across vascular boarder zones. Not major but they can interfere with diagnosis if they become sufficiently developed
152
What is included in the collateral circulation- extracranial category?
1. Vertebral occluded
2. Large aortic branches occluded
153
What does the vertebral occluded category of the extracranial- collateral circulation category do?
1. Enlargement of opposite vertebral
2. Flow shunted to thyrocervical and costocervical branches
154
What is included in the large aortic occluded branches of collateral circulation - extracranial category?
Intercostals and internal mammary arteries to subclavian
155
When an occlusion or very high grade stenosis exists on one side, what does the opposite carotid artery do? What does this result in?
1. The opposite carotid artery my be supplying both sides of the brain
2. This results in increased flow within the CCA, ECA, and ICA of the compensating side
156
There is a possibility that other collateral systems may do what?
Contribute and compensatory flow may not occur
157
When compensatory flow occurs contralateral to an occlusion, what happens to the velocity?
The higher velocities may place a stenosis in a higher category
158
What characteristics identify when a stenosis appears higher due to compensatory flow and should be addressed in the interpretation?
1. ICA/ CCA ratio is a lower category than the velocity criteria.
2. Image measurement is in a lower category than the velocity criteria
3. PSV is generally higher throughout the CCA and is higher than the contralateral side
4. Interpretation should indicate which velocities are suspected to be falsely elevated and explained that compensatory flow is the likely factor
159
What are indications of posterior circulation?
1. Suspected vertebral- basilar insufficiency
2. Dissection
3. Subclavian steal
160
What is the primary cause of vertebral basilar insufficiency?
Atherosclerosis
161
Where are common sites of atherosclerosis?
1. Origin of vertebral artery at subclavian artery to its entrance into foramina at C6
2. Intracranial just beyond C1 arch (large curve)
3. Transverse foramina plaque development
4. Intracranial segments of VA and BA
162
What are some causes of posterior circulation ischemia?
1. Atheroscelerosis
2. Emboli
3. Cardiac dysthymia
4. Impingement from osteophytes
5. Artery to artery steal syndromes (subclavian)
163
What are some diagnostic test for posterior circulation?
1. Duplex ultrasound
2. Angiography
3. Magnetic resonance angiography (MRA)
164
What is the gold standard diagnostic test for posterior circulation?
Angiography
165
What is the vertebral artery assessed for?
1. Normalcy
2. Occlusion
3. Flow direction
166
Flow direction in the vertebral artery should be what?
Antegrade and low resistance
167
Vertebral artery stenosis most commonly occurs where?
In the proximal portion which is often not directly imaged.
168
A hemodynamically significant VA stenosis (>50%) is defined as what?
A focal velocity increase with post- stenotic turbulence and a possible colour bruit
169
Flow velocities can vary from side to side as one vertebral artery IS what?
Often dominant. (Usually the left)
170
What is subclavian steal syndrome? How should we confirm?
Reversed flow in the VA and should be confirmed by documenting an abnormal subclavian waveform or a decreased brachial pressure of >20 mmHg on the same side
171
Loss of the end diastolic component of the vertebral artery may indicate what?
Distal occlusion
172
Vertebral occlusion is indicated by what?
No flow detected despite low flow settings along with a well- visualized artery below the vein
173
Early systolic deceleration (bunny ears) indicate what/
Subacute subclavian steal syndrome (pre-steal)
174
What does the subclavian artery waveform look like normally?
Triphasic
175
Velocities of the subclavian artery are higher then what?
Carotid arteries but there is no precise number
176
When look at the subclavian arteries do we need to compare waveforms and bronchial pressure for both sides?
Yes
177
Hemodynamically significant stenosis (>50%) in the subclavian artery is defined by what?
A focal velocity increase with post stenotic turbulence and a possible colour bruit
178
Biphasic and monophasic waveforms may be observed in the subclavian artery when what presents?
A significant stenosis or occlusion is present
179
What are some biphasic subclavian arterial signals?
1. Strong forward flow in systole (sharp upstroke) with a loss of flow in early diastole (no flow below the baseline)
2. Decrease of the late diastolic component
180
What are some monophonic subclavian artery signals?
1. Blunted upstroke, decreased pulsatility and no revered flow in late systole
2. Diastolic flow may or may not be seen
181
What do we use the subclavian arteries to determine?
1. Plaque action and characteristics
2. PSV and flow characteristics
3. **Velocity ratio V2/V1** PSV (VR); where V2 represents the maximum PSV of a stenosis and V1 is the PSV of the proximal normal segment
4. Any change in spectral waveform analysis
182
What is a normal hemodynamically significant subclavian?
<50% lesion
183
How do we determine a normal hemodynamically significant lesion?
1. Greyscale
2. Doppler waveforms and flow velocities
184
What does the grey scale look like for normal hemodynamically subclavians?
1. No echoes are seen within the artery lumen
2. Colour doppler fills the entire lumen, wall to wall
185
What does Doppler waveforms and flow velocities look like for hemodynamically normal subclavian arteries?
1. Normally triphasic
2. Biphasic waveforms may be seen normally
186
What does this image demonstrate?
A normal doppler waveform for a normal hemodynamic subclavian lesion
187
Criteria for upper extremity arterial stenosis varies across institutions as it has not been what?
Widely addressed in literature, some labs use the same criteria for upper and lower extremities
188
What does grey scale look like for abnormal subclavian lesions?
1. Echoes are seen and the decreased lumen can be measured
2. Colour doppler does not fill the entire lumen
3. **Post stenotic turbulence** can cause a colour mosaic
189
What does this represent?
A Monophasic (abnormal) subclavian artery distal to stenosis delayed rise time (from beginning to peak systole)
190
What does this image demonstrate?
A monophasic (Abnormal) subclavian artery distal to stenosis delayed rise time (from beginning to peak systole)
191
What does this image demonstrate?
A monophasic (Abnormal) subclavian artery distal to stenosis delayed rise time (from beginning to peak systole)
192
What is a stenosis in the context of a subclavian artery?
Hemodynamically significant lesion >50%
193
What determines a stenosis for a subclavian artery?
1. Focal velocity increase
2. Spectral waveform changes
3. Post stenotic turbulence
4. Colour aliasing
5. Potential colour bruit
194
What kind of focal velocity increases would warrant a focal velocity increase?
> double that of the proximal segment
195
What spectral waveform changes would we look for in terms of a stenosis in the context of a subclavian artery?
Triphasic to biphasic or monophasic
196
In terms of a subclavian artery, what are indirect signs when a proximal velocity is difficult to obtain (no ratio)?
1. Increased velocities with lumen reduction and post stenotic turbulence
2. Spectral waveform changes from one segment to the next
3. Compare the waveform at the same site in the contra lateral artery
197
In terms of occlusion in the subclavian artery, DIstal occlusion is often indicated by what kind of waveform?
Staccato
198
In terms of a subclavian artery occlusion, what kind of colour and spectral doppler flow do we detect?
None
199
In terms of a subclavian artery occlusion, the extent of the occlusion can often be determined if what?
A large collateral is seen at the proximal and distal ends. These often enter and exit at a 90 degree angle to the vessel
200
In terms of subclavian artery occlusion, when the proximal artery is occluded, blood flow may do what?
Reverse in the collateral vessels
201
In a subclavian steal, patients present with what type of arterial arm pressure?
Arterial arm pressure differing by >20 mmHg
202
When determining a subclavian steal, what kind of waveform will we obtain, and what do we need to note?
We need to obtain an ipsilateral vertebral waveform on the arm with the lower BP and note the direction of flow.
203
In terms of a subclavian steal, what type of flow combined with what indicates a subclavian steal?
Reversed flow in the vertebral artery combined with a significant difference (>20mmHg) in arm pressures
204
What are some sonographic findings for subclavian artery abnormal?
1. Hemodynamically significant stenosis (>50%)
2. Changes in the spectral waveform
3. Post stenotic turbulence
4. Colour bruit
205
In terms of a subclavian artery, Additional interrogation may be performed to do what?
1. Identify any diameter reduction by greyscale or colour in the subclavian Artery (always combine with PSV documentation)
2. Compare bilateral axillary waveforms (PW)
206
What are some medical treatment for carotid artery disease?
1. Modify risk factors
2. Anti-thrombotics
3. Tissue plasminogen activator (TPA)
4. Anticoagulants
5. Surgery
6. Endovascular treatment
207
How does a patient modify risk factors to treat carotid artery disease?
1. Stop smoking
2. Lower cholesterol
3. Lose weight
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What are some surgical treatments for Carotid artery disease?
1. Carotid endarterectomy
2. ICA resection and re-anastomosis (for kinking)
3. Carotid thrombectomy
4. Bypass (subclavian- carotid or carotid- carotid)
5. Vertebral artery transposition to CCA
6. Direct focal repairs
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What are some examples of endovascular treatments for carotid artery disease?
1. Carotid angioplasty
2. Carotid stent
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What do we do to survey after carotid intervention?
Duplex after endarterectomy
211
When do we do a duplex after carotid endartectomy?
First exam is done within 30 days
212
For the duplex after carotid endarterectomy, exams performed within the first few days may display what?
Shadowing from air entrapment associated with a synthetic patch or graft and multiple views/ windows may be required
213
What are some complications for medical interventions of carotid artery disease?
1. Re-stenosis/ occlusion
2. Residual plaque
3. Tissue flaps
4. Vessel narrowing
5. Neointimal hyperplasia
6. Hematoma
7. Endovascular leak
8. Pseudoaneurysm
214
How would someone re-stenosis/ Occlusion?
1. Neointimal hyperplasia
2. Primary atherosclerosis
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In terms of neo-Intima hyperplasia, it can result in what?
Focal or diffuse narrowing at endartectomy site and is associated with increased flow velocity and post stenotic flow disturbance within the first 2-3 years
216
In terms of re-stenosis/ occlusion, Primary atherosclerosis is usually the case when?
Later stenosis, usually over 3 years
217
In terms of a normal dupex findings, how will the Intimal- media stripe seem?
Normal intimal- media stripe is not seen
218
In terms of a normal duplex finding, the arteriotomy sutures appear how?
As bright reflectors in the anterior wall
219
In normal duplex findings as wall remodelling progresses, what happens?
Wall thickening develops but the clinical importance is minimal unless it’s associated with a lumen reduction and increased PSV
220
What kind of flow is observed in normal duplex findings?
Laminar or only slightly disturbed blood flow
221
When do we do duplex evaluation for carotid stents?
First exam is done within 30 days of procedure
222
What are some complications of carotid stents?
1.Poor initial stent deployment
2. Re-stenosis by hyperplasia
3. Progressive stenosis distal to stent due to atherosclerosis disease
4. Stent positional shift
5. Stent kinking
223
What does poor initial stent deployment look like for complications?
Is there a gap between the stent and the artery wall?
224
What does re-stenosis by hyperplasia look like for carotid stents?
Neointimal hyperplasia can result in focal or diffuse narrowing and is associated with increased flow velocity and post stenotic flow disturbance within the first 2- 3 years
225
Where do we perform a standard duplex ultrasound for carotid stents?
1. Proximal native artery
2. Proximal stent attachment
3. Proximal, mid and distal stent
4. Distal attachment site
5. Native artery distal to stent (1cm)
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What are normal duplex findings for carotid stents?
1. Smooth velocity increase into the stent
2. Slight lumen narrowing may persist at the ends of the stent
3. Laminar or only slightly disturbed flow
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Label the arrows
1. ICA stent
2. Plaque
228
What does this image demonstrate?
ICA stent
229
What is the arrow pointing to?
Stent
230
What is the process for carotid artery dissection?
1. Tear in the **intimal lining** of an artery with or without involving the outer medial wall
2. Blood enters the media of the vessel through the tear and creates a tear and creates a **false lumen**
3. Simultaneously, blood is also flowing through the original **true lumen**
231
How does carotid artery dissection occurs due to what?
Trauma (violent or non violent), an **iatrogenic complication** (conditions that weaken the wall) or spontaneous
232
In terms of carotid dissection, ICA dissection typically starts where in the ICA?
In the first 2-4 cm
233
In terms of CCA dissection: it may be an extension of what?
Aortic dissection or from blunt trauma
234
In terms of carotid dissection, the false lumen can progressively dilate into what?
Pseudoaneurysm
235
What are some risk factors for carotid dissections?
1. Hypertension
2. Fibromuscular dysplasia
3. Marian’s syndrome
4. Euler-Danlos syndrome
5. Cystic medial necrosis
236
What are some less severe factors of carotid dissections?
1. Strenuous exercise
2. Rapid neck motion
3. Compression by spine
4. Mandible
5. Seat belt injury
237
What re some ultrasound findings for carotid dissections?
1. Intimal flutter with cardiac cycle
2. Duplicated lumen
3. Narrowed true lumen with thromboses false lumen
4. Distributed flow distal to dissection
238
How do we normally treat carotid dissection?
Anticoagulation therapy
239
What are some ways to image carotid dissections?
1. Ultrasound
2. MRA
3. Angiogram
240
What does this image demonstrate?
Carotid dissection
241
In terms of fibromuscular dysplasia (FMD) what is non- atherosclerotic artery disease?
Multiple focal stenosis, followed by widening, resembling a string of beads/ pearls on imaging studies
242
In terms of fibromuscular dysplasia, it affects what?
Medium and large sized vessels, especially the renal and ICA and can coexist in these locations
243
What is fibromuscular dysplasia?
1. Vessel wall abnormality of extra-cranial ICA (20% include vertebral)
2. Typically involves 2-6 cm segment of mid external cranial ICA
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Who is most affected by FMD? And where?
Women >90% and usually the mid section of the ICA
245
In terms of FMD what area typically has no evidence of disease?
Carotid bulb area
246
When does FMD usually becomes apparent?
40s or 50s
247
What are some things we see on ultrasound for FMD?
1. Series of tandem stenosis and dilations
2. Accompanied by moderate significant increase in PSV
3. Extensive turbulence
248
What is the technique for scanning FMD?
Scan as far distal in the ICA on middle aged females, especially with bruits and no atherosclerotic disease in the bulb
249
Incidental finds or TIA is what in terms of FMD?
Incidental findings
250
What are some complications of FMD?
Narrowing lumen causing
1. Flow reduction
2. Emboli
3. Dissection
4. Rupture
251
What are some ways to image FMD?
1. Ultrasound
2. Angiogram
3. MRA
252
What are some ways to treat FMD?
Symptomatic patients may be dilation of artery
253
What is this an image of?
Carotid dissection
254
What is this an image of?
FMD
255
What does this image demonstrate?
FMD
256
What is a carotid body tumour?
Small cluster of chemoreceptor cells at the split of the carotid bifurcation
257
Carotid body tumour is what type of tumour?
1. Paraganglioma
2. Rare and usually benign
258
What supplies blood to the Carotid body tumour normally?
ECA supplies blood
259
As the carotid body tumour grows what happens?
Blood flow may be also supplied by the ICA vertebral artery or thyrocervical trunk
260
What does the Carotid body tumour look like on ultrasound?
1. Ovoid structure 5x3x2 mm
2. Characteristic widening or bulging of the bifurcation
261
What are some symptoms of carotid body tumours?
1. Palpable mass
2. Headache
3. Neck pain
4. Hoarseness
262
What are some complications of carotid body tumours?
Compression of laryngeal nerve or invasion of vessels
263
How do we image carotid body tumours?
Ultrasound to assess and follow small tumours, angiography pre-surgery
264
What is the treatment for carotid body tumours?
1. Surgical resection
2. Embolization with angiography
265
Label the image
1. Sag CBT
2. Trans CBT
266
What does this image represent?
CBT high flow
267
In terms of extracranial aneurysm, how common are they?
Very rare
268
What are Pseudoaneurysms?
Decreased/ weakened wall, increased risk post endarterectomy
269
What are causes for pseudoaneurysms?
1. Infection
2. Tension at the anastomosis
3. Thin walled arteries
4. Suture deterioration
5. Improper suture technique
270
What are causes of aneurysms?
1. Atherosclerosis (most common)
2. Dissection
3. Trauma
4. Previous surgery
271
Where are aneurysms most common?
1. CCA
2. But are seen also in the ICA and ECA
272
Aneurysms are usually what? And located where?
Usually fusiform and located at CCA bifurcation or proximal ICA
273
What are extracranial aneurysm clinical features?
1. Pulsatilla mass
2. Pain
3. Dysphasia
4. Hoarseness
5. Neurological symptoms due to embolition or thrombus from the aneurism wall
274
What are treatments for extracranial aneurysms?
surgical resection and more recently endovascular therapy in select cases (stents, coils and balloons)
275
How do image extracranial aneurysms?
1. MRA
2. CT
3. Angiogram
276
What is arthritis/ vasculitis?
Inflammation of arterial walls resulting in blood vessel damage
277
What are some causes of arteritis/ vasculities?
Not well known by genetics, infectious, and toxic factors are suspected
278
How do we treat arteritis/ vasculitis?
Steroid drugs
279
What are some arteritis/ vasculitis disorders?
1. Takayasu’s arteritis
2. Temporal arteritis
3. Poly arteritis
4. Buerger’s disease
280
What is takayasu’s arteritis?
1. Pulseless disease
2. Concentric inflammation of aorta and its branches
281
What is temporal arteritis?
1. Giant cell arteritis
2. Inflammation of medium sized vessels of the head, neck, eyes and optic nerve and affect the extracranial branches of the carotid
282
What is polyarteritis?
1. Periateritis nodosa
2. Multiple sites of inflammation in small and medium sized arteries of the body
283
What is beurger’s disease?
1. Thromboangitis obilterans
2. Occurs in distal arteries of young male smokers
284
Radiation therapy causes what to the vessel wall?
Injury to the vasa vasorum ad necrosis to the vessel wall
285
In terms of radiation injury, what cells are affected?
Endothelial cells that line the walls of the arteries in the irradiated field are susceptible
286
In terms of radiation injury, what can form on the Intima once the wall is damaged?
Lipid containing plaques CAN form
287
What are tests to aid in the diagnosis of carotid pathology?
1. Physical exam and history
2. Doppler ultrasound
3. Computed tomography (CT)
4. Cerebral arteriography
5. MRA/ MRI
