Non-Atherosclerotic Pathology of the Carotid Arteries - HD

Introduction

Hello, my name is Leslie Scout.

I am chief of ultrasound at Yale New Haven Hospital,

and I'm a professor

of diagnostic radiology at Yale University School

of Medicine, where I also serve as medical director

of the non-invasive vascular laboratory.

And today I'm going

to be discussing non atherosclerotic pathology

in the carotid arteries.

Today we're going to be talking about non atherosclerotic

pathology of the carotid arteries.

Objectives

And the objectives of this talk are

to discuss the diagnostic ultrasound features

of non atherosclerotic vascular pathology in the carotid

arteries, particularly focusing on carotid artery

dissection, arterial venous fistula, pseudo aneurysm,

and different types of vasculitis.

Carotid Artery Dissection

So we'll start first with carotid artery dissection.

Now whatever the etiology, the way this occurs is

that blood enters into the wall

of the carotid artery separating the different layers,

and this starts with a tear of the intima,

and then the intima plus

or minus the medial layer are lifted off the adventitial

outer layer of the vessel wall.

And the thickness of this flap depends upon whether

or not the media is lifted off in addition

to the intimal layer

and whether a mural hematoma develops versus whether

or not free-flowing blood persists in the false lumen is

dependent upon whether or not there is a reentry point.

In addition to the proximal entry point,

there are a variety of things

that can cause dissections in the carotid arteries.

These include, trauma, which could be just exercise,

rapid neck motion or seatbelt injury.

And in fact, the trauma may be quite minor

and may not in some cases even be noticed by the individual.

Another common way

that carotid artery dissections occur are due

to extension from dissections in the aortic arch,

but many are spontaneous occurring likely due

to weakness within the vessel wall.

Thus predisposing risk factors include anything

that will weaken the vessel wall.

And some of the most common predisposing risk factors

include Marfan syndrome, aler Danlos syndrome,

fibromuscular dysplasia, cystic medial necrosis

and hypertension.

Approximately 70% of spontaneous dissections occur in young

to middle aged patients.

In this situation, they occur equally in males

as well as females.

And the clinical presentation is a little bit different than

those who have traumatic dys dissections

or dissections from the aortic arch.

And these patients may present with headache, neck

or facial pain, hemispheric symptoms, cranial nerve palsy

and Horner syndrome.

Carotid dissections are actually a relatively common cause

of stroke in young patients,

and this is something you should consider in the young

patient who presents with stroke.

Other causes of stroke in young patients include cardiac

disease, tumor, and, vasculitis.

Carotid dissections differ a little bit also in terms

of whether or not they occur in the common carotid artery

versus the internal carotid artery.

Common Carotid Artery Dissections

And dissections

that occur in the common carotid artery are typically the

result of extension from a dissection within

the aortic arch.

These typically occur in older patients

and are very easily seen on ultrasound.

They're often relatively asymptomatic

and typically stabilized such that,

treatment may not be required.

It's estimated that strokes occur in only about three to 7%

of patients who have dissections that are limited

to the common carotid artery.

Internal Carotid Artery Dissections

On the other hand, carotid dissections

that occur predominantly in the internal carotid artery

are typically due to trauma or spontaneous dissection.

And these tend to occur in younger patients

and they most often start at the skull base

and dissect down towards the bifurcation.

In other words, dissect approximately.

However, in

some cases they do originate at the carotid bifurcation.

These are harder to see on ultrasound and unfortunately

or more likely to result in stroke.

And because they're more difficult to see on ultrasound,

these are actually better evaluated on MRCT

or cut film angiography.

The appearance on ultrasound does depend upon whether

or not there is a false lumen or a mural hematoma,

and if a false lumen is present very often you will see very

bizarre flow patterns,

particularly on spectral doppler interrogation.

A patent false lumen,

is more common in a common carotid artery dissection,

but the appearance really does,

or the waveform really does depend upon the size

and the length of the false lumen.

Often you might see retrograde flow in the false lumen

and sometimes the false lumen is large enough

that it compresses the true lumen resulting in decreased

flow within the true lumen.

A mural hematoma,

is more common in dissections involving the

internal carotid artery.

It often,

spirals

around the true lumen causing compression

and may result in a stenosis leading

to an increase in peak systolic velocity.

Since these stenosis are often long segment, often that

increase in peak systolic velocity

is somewhat lower than you might expect given the degree

of stenosis.

The ultrasound appearance of course, is going

to depend a lot upon whether

or not there is a mural hematoma and whether

or not the,

false lumen is patent.

So when you consider dissections in the common carotid

artery, which are those

that are most easily evaluated on ultrasound,

the first thing that you're going to look

for on the gray scale imaging is the presence

of the inal flap.

This flap is typically quite echogenic on ultrasound.

The thickness, as I've mentioned previously,

is variable depending upon whether just the intimate layer

is lifted off or the intimate layer plus the media is lifted

off the advent tissue

and the luminal flap may be mobile, so it may

pulsate or move during,

the cardiac cycle.

If instead of a patent false lumen,

one has a neural hematoma,

the most common gray scale ultrasound appearance is

of long segment,

wall thickening causing a smooth stenosis

of the common carotid artery.

This often spirals around the true lumen

and this homogeneous thickening,

of the carotid wall typically involves both the anterior

and posterior walls.

When two lumen are present, the doppler wave forms are

typically quite different.

In each lumen, you might see an increase

or a decrease in peak systolic velocity flow might be

bi-directional or reversed,

and it is very, very common

to see very bizarre flow patterns within the false lumen.

So here is an example on a transverse

and longitudinal image of the left common carotid artery.

You can clearly see this very thin

echogenic intraluminal flap.

When color doppler is used, you can see

that there is flow both within the true and the false lumen,

and you can see in fact the flow is reversed

or blue within the false lumen.

On Doppler interrogation, you can see

that the waveforms in these two lumen is quite different.

The waveform in the true lumen, which is antegrade

as you see here, is somewhat abnormal in

that you see decreased diastolic flow

and a little bit of a delay in systolic upstroke,

but certainly looks much more normal than the waveform

pattern in the false lumen, which is very irregular

and actually bidirectional

as you see on the spectral doppler waveform.

Here is another example where on the gray scale on the sagal

as well as the transverse view, you can see this echogenic

intimal flap and noted that this is quite lifted off

and is actually folded upon itself.

And you can sometimes see very bizarre patterns of the

intimal flap as in this particular case.

In this case, you can see

that the intimal flap on the sagal gray scale image is

somewhat irregular in configuration,

but very, very thick walled.

And notice that within the residual lumen you have a very

bizarre waveform pattern that is very spiky

with absent diastolic flow.

Here is another example where on the

frozen single frame film here,

that intimal flap actually looks quite thick

actually on real time it was thin.

And the reason that it is thick is that it was so mobile

and we couldn't,

capture a single image where it looked,

thin as it did on real time imaging.

Notice that their,

true

and false lumen are both patent

with flow going in opposite directions.

In this particular case, the color scale has been,

reversed and you can see

that the more normal appearing waveform is in the deeper

or more posterior lumen,

which is color coded blue in this image.

And the false lumen is color coded red

with a very bizarre bidirectional waveform pattern.

The pattern really depends upon the length of patency

as well as the relative size of the true and false lumen.

But as you can see in these

two, this case here,

you can really see very bizarre waveform patterns.

And although the waveform pattern is most commonly bizarre

within the false lumen in this particular example,

you can see the waveform is abnormal in both the true

as well as the false lumen.

When dissections,

occur secondary

to extension from dissection of the aortic arch,

it's important that you look as approximately as possible.

This is a patient who had Marfan syndrome who presented

with a known dissection in the aortic arch,

and we were asked to evaluate whether

or not the dissection extended

into the common carotid arteries.

And when we initially did the examination,

we didn't see any evidence

of dissection within the common carotid arteries.

However, when we went

and looked with the hockey stick transducer

and really looked as inferior,

as we could notice way down low in the left common carotid

artery, you can actually see this

dissection.

And here you can see it not quite to

as good advantage on the,

sagittal image as well,

but initially it was not seen

because we didn't look,

proximally enough.

And in this particular case,

the right common carotid artery was completely normal

and the dissection had only extended into the left common

carotid artery, but had not extended into the origin

of the right common carotid artery.

This is an example of a patient

who has a thrombosis false lumen

or aural hematoma noticed that when the thrombus is acute,

often it is very anti coic

and you can see clearly here

that it is compressing the true lumen, causing a little bit

of,

aliasing.

Where the vessel,

lumen is most

narrowed.

Here is an older case demonstrating

very smooth homogeneous thickening of the wall

of the common carotid artery.

Notice that both the anterior

and the posterior walls are involved.

And very often when you have a intramural hematoma,

it will cause this very,

smooth long segment stenosis.

And you will note that the hematoma spirals around the lumen

of the carotid artery, again involving both the anterior

as well as the posterior wall.

Ultrasound Appearance of Internal Carotid Artery Dissections

Now, the ultrasound appearance

of dissections in the internal carotid artery are

typically very, very different from

what I've just described in the common carotid artery.

And in fact, sometimes the ultrasound findings are

completely normal because the dissection begins at the skull

base up above your field

of view when you do your carotid ultrasound

lower down in the neck.

And if it doesn't particularly compress the lumen,

the proximal waveform and proximal gray scale

and color imaging may be completely normal.

So if there is strong clinical suspicion

of a dissection in the internal carotid artery

and your ultrasound exam is normal,

you should consider referring that patient to either MRCT

or angiography to look further,

despite the presence

of a normal carotid ultrasound.

If the lumen is significantly compressed

by the dissection in the internal carotid artery,

you may see a high

resistance waveform in the internal carotid artery.

And so if you see such a waveform in a young patient

who has no evidence of stenosis

or plaque at the carotid bulb, you ought

to be thinking about a distal dissection.

You ought to think about this diagnosis

and a patient who presents with an acute occlusion

of the ICA who is very young,

and sometimes you'll see a smooth tapering stenosis

of the internal carotid artery in a young patient.

And similar to the ultrasound appearance

of the mural hematoma

that I just described you in the common carotid artery,

this,

stenosis will be hogene,

the wall will be homogeneous in echo texture,

relatively hypo coic,

and you will not see underlying evidence of atherosclerosis

or calcified plaque.

Typically, this narrows the residual lumen

and you will see increased peak systolic velocity

at the site of this smooth tapering stenosis.

So this is an example of a young 24-year-old female patient

who presented with a headache.

And when you look in the right common carotid artery here

and the right internal carotid artery,

down

below you will see that the waveforms look totally normal.

Upstroke is sharp

and there is a normal amount

of diastolic flow both in the common

and in the internal carotid artery.

However, when you look on the left side,

you will see both in the common carotid artery as well

as the internal carotid artery

that there is no diastolic flow.

And in fact, there is a little bit of reversal

of early diastolic flow.

This is a very high resistance waveform suggesting

that there is a proximal obstruction.

In addition, there is marked asymmetry in

peak systolic velocity.

The peak systolic velocity in the right internal carotid

artery is 107 centimeters per second,

but is only 21 centimeters per second in the proximal left

internal carotid artery.

When you look on the gray scale, you'll notice

that there is no evidence of thrombus

or plaque in that proximal internal carotid artery.

It looks wide open, no underlying atherosclerosis,

but again, the spectral Doppler waveform is very abnormal

with decreased peak systolic velocity,

no end diastolic flow,

and actually frank reversal of flow in early diastole.

And the this constellation

of findings should make you consider the possibility of a

obstructing lesion up higher outside of the field

of view of your ultrasound.

And in a young patient,

the primary thing you should be considering is a carotid

dissection at the skull base.

This patient went on to,

have a CTA

and noticed that the right internal carotid artery,

although tortuous appears completely normal,

but on the left, although the internal carotid artery is

completely normal at the bulb

and bifurcation, as you follow it up towards the skull base,

you can see that it becomes extremely

attenuated and narrowed.

And when you look at the

contrast images,

you can see again that on the right the common carotid

and internal carotid artery are normal all

the way through the skull base.

But on the left you can see that there is a smooth tapering

of the distal internal carotid artery

as it enters the skull base consistent with a dissection

of the distal internal CID artery dissection.

Here is another example

where you can see on the sagittal color image

of the proximal right internal carotid artery

that it looks completely normal.

There's complete fill in of the lumen.

There's no abnormality of the vessel wall at all,

but when you get your spectral doppler waveform,

it is extremely abnormal, very, very high resistance

with significant reversal of diastolic flow

and early diastole, no end diastolic flow.

And once again, the peak systolic velocity is extremely low,

1718 centimeters per second.

This has been described as a thump wave form

or a knocking wave form,

and again, is indicative of a distal,

obstructing

phenomenon or distal obstructing etiology.

And in a young patient, the thing that is most likely

is a distal carotid artery dissection.

This patient,

went on to have a,

CTA several days after the ultrasound.

And here you can see this smooth tapering stenosis at,

just beyond the level of the carotid bifurcation.

This obviously had extended from the

stenosis

that you see up higher in the intervening two days.

Note that there is no evidence

of underlying atherosclerosis.

Occasionally you can actually see blood in the wall

on a CT or an mr

corresponding

to hypo coic thickening,

on the ultrasound.

So again, correlation

with the history is extremely important

and this etiology should be considered in a young patient

or a present patient presenting with neurological

symptoms following trauma.

Here is a,

different kind of appearance

of A ICA dissection.

Here you can see that while the distal ICA luminous patent

notice that there is smooth,

tapering of this vessel.

The wall is thickened, it's very homogeneous.

It is very, very hypo coic.

And again, in a young patient where you don't see evidence

of underlying atherosclerosis,

but you see this very smooth

homogeneous hypo coic wall thickening, you ought

to be thinking about a dissection as well

as a mural hematoma when the

pulse oler waveform was obtained in this particular patient.

Again, this confirms what you saw on the color image,

namely the lumin is narrowed velocity is increased

to 225 centimeters per second.

There's some spectral broadening,

actually increased diastolic flow.

This is the type of waveform that you see at a stenosis,

but what's atypical here is that there's no evidence

of atherosclerosis

and the wall is diffusely thickened in hypo coic.

This patient went on to have an Mr.

Notice that you can see increased signal intensity within

the wall of the vessel confirming the presence of blood.

And this is an intramural hematoma due to a dissection

of the internal carotid artery.

I want to point out, as you can see from the cases

that I've just presented, that the most typical appearance

of a dissection involving the internal carotid artery is

either that of a high resistance waveform,

without evidence of stenosis due to the distal obstruction

or a intramural hematoma

with hypo coic homogeneous thickening

of the wall causing a tapering of the vessel lumen.

But it is very, very uncommon

to see a dissection flap itself in the

internal carotid artery.

This is probably because the vessel is so small

and it tends to occur distally.

So unlike in the common carotid artery,

when you most often see a dissection flap, visualization

of the dissection flap is quite rare, rare in a patient

with a dissection of al in the internal carotid artery.

Arteriovenous Fistulas

Well, moving on to,

artery venous fistulas,

this is a connection most commonly seen

between the common carotid artery

and the internal jugular vein.

This is almost always due to trauma.

It could be blunt trauma or penetrating trauma,

and unfortunately the trauma is iatrogenic.

So we often see this in

our institution following an attempt to place a,

central catheter in the internal jugular vein.

And sometimes we see this in post,

surgical

patients.

However, occasionally it can occur in patients,

who have an underlying cervical malignancy

or have been treated with high dose radiation therapy in the

neck and either the,

fibrosis from the radiation therapy

or erosion from the malignancy may cause erosion into these

two contiguous vessels resulting in a fistulas

connection,

between them.

Extremely rarely a connection

between the common carotid artery

and internal jugular vein can be,

congenital,

but this is actually most usually referred to

as an arter venous malformation rather than an

arterial venous fistula.

These patients clinically present with a neck hematoma,

a bruery, sometimes a palpable thrill

if there is a very large shunt

of blood from the common carotid artery

to the internal jugular vein.

This sometimes can cause overload of the right heart

and patients may present in congestive heart failure

and sometimes one will see on physical exam distension

of the internal jugular vein

and can note that it is extremely pulsatile.

In today's practice, treatment is usually,

placement

of a carotid stent

and occasionally now surgery is still,

required

On ultrasound, you're going to see color sene within

the connection between these two vessels,

and sometimes the increased velocity

of flow will actually cause

a perivascular soft tissue vibration,

which one ultrasound will appear as a color brewing.

You'll see increased systolic

and diastolic velocity in the feeding artery.

Though sometimes we don't always note this in the common

carotid artery because peak systolic velocity

and diastolic velocity are quite elevated,

baseline.

But you should see pulsatile flow in the draining vein

that has higher than expected velocity.

Note that the artery up

above the fistulas connection should have a normal waveform.

And similarly, the waveform in the internal jugular vein

above the fistulas connection

most commonly has a normal waveform,

although occasionally you might see retrograde flow.

Another interesting phenomenon is

that if an arterial venous fistula is small,

it may collapse when a patient is supine.

And so in order to visualize it, you may have

to have the patient in an upright or sitting position.

So if there's strong clinical concern

for an arter venous fistula, a patient has a palpable brill,

for example,

thrill for example.

And if the,

patient presents with,

pain following,

an attempted line placement,

you don't see anything when you're doing

the patient's supine.

It probably is worth it to have the patient sit up

and take a quick look,

as well.

This is an example of a patient

who had had a carotid endarterectomy

and presented with a brewery in the neck as well

as a palpable thrill.

And notice on the color doppler ultrasound, you can see

what we describe a soft tissue brewery, this color mosaic

or speckled pattern in the soft tissues

between the common carotid artery as well

as the internal jugular vein.

This is due to the fact that increased velocity

of blood flow through

that small fistulas connection causes vibration

of the surrounding soft tissues.

And on color doppler, this,

results in this color mosaic.

The problem with this, of course, is

that it obscures visualization of the underlying structures.

So what should you do in order

to improve your visual visualization?

You can increase your scale

or your PRF, you can increase your wall filter

because typically this perivascular soft tissue vibration is

a very low frequency.

And the other thing that you can try to do is

to image in diastole.

So in this particular case,

we increased our PRF and our wall filter.

We eliminated that soft brewing,

and then you can see both with a color

and on the gray scale quite clearly, this connection

between the internal jugular vein as well

as the common carotid artery.

And on the spectral doppler tracing within the fistulas

connection itself, you can see a very

low resistance waveform pattern characterized

by an increase in both peak systolic as well

as end diastolic velocity.

And in the draining vein, namely the internal jugular vein,

you can see very high velocity flow nearly,

440 centimeters per second.

And it is also very pulsatile as you see here.

Notice though that there is still some respiratory variation

increase in peak systolic velocity in diastolic flow in the

common carotid artery,

is seen most commonly in patients

with arterial venous fistulas,

but occasionally can be seen in patients who have distal

cerebral arterial venous malformations.

And very rarely you can see this in a patient

who presents very early in the course

of an acute

stroke.

However, in this particular case,

you typically see only an increase in diastolic flow.

You don't typically see a significant increase in peak

systolic velocity, and this occurs really only very early,

following an acute stroke,

and it's usually in the setting

of a very extensive,

stroke.

Pseudoaneurysms

Well, the next thing I want to discuss is,

pseudo aneurysms arising from the carotid arteries.

And the most common,

pathophysiology here is that there

a hole develops in the arterial wall allowing extravasation

of blood, which becomes encased by compacted,

surrounding soft tissues.

However, in the setting of a carotid dissection,

the adventitia plus

or minus the media may be all that remains

of the arterial wall, and this wall therefore is weakened

and sometimes can bulge.

And this,

also is described as a pseudo aneurysm.

A true aneurysm is surrounded

by a full thickness vessel wall comprised in the intima,

the media as well as the adventitia.

So it's important to remember that

occasionally a pseudo aneurysm may be encased

by the adventitia and sometimes it,

however, is encased by

just compacted surrounding soft tissues.

A variety of things can cause pseudo aneurysms.

The most common is trauma, either,

typically penetrating trauma, though it can be iatrogenic.

Occasionally you can see this following infection

or malignancy, which causes erosion of the vessel wall,

but anything that weakens the arterial wall can cause

that second type of pseudo aneurysm, which is bulging

of this very,

thickened a wall,

particularly if the intima is lifted off.

So consider this diagnosis in patients

who have received radiation therapy to the neck

who have a known carotid dissection,

fibromuscular dysplasia, other types of vasculitis,

a aler Danlos syndrome and Marfan syndrome as well.

And the risk of course of a patient

with a pseudo aneurysm in the car,

carotid artery is a rupture.

And so these patients are typically treated with placement

of a carotid stent or surgery.

On ultrasound, you're going

to see on gray scale a cystic mass adjacent to the

vessel, which will fill in,

with color flow on color interrogation

unless it is completely thrombo.

When you see color flow within the patent pseudo aneurysm,

the flow swirls

around causing atypical ying yang appearance.

And if you interrogate the neck,

and if that neck is thin, you'll see the classic two

and fro flow within the,

neck of the pseudo aneurysm.

And this is described as flow, which is two

or towards the pseudo aneurysm in systole and away

or fro from the pseudo aneurysm in diastole.

But whether or not you see that two

and fro flow really depends upon the size of the neck.

And you will only see this if the neck is small.

If the neck is very wide, as in this particular case,

you will not see that to and fro flow.

This particular,

individual presented three years following carotid

endarterectomy telling the referring physician

that she had a palpable,

hard mass in her neck

that had been,

increasing in size over the past year.

And here you can see this outpouching from the

common carotid artery.

Notice that approximately half

of the pseudo aneurysm is thrombosis.

You can see the intraluminal echoes here.

And on the color Doppler image, you can see the swirling,

pattern of blood flow,

namely the ying and the yang pattern.

And this is the spectral doppler appearance of the ying

and the yang pattern as it just swirls around

and changes direction,

throughout the cardiac cycle.

In this particular patient, as I mentioned,

because that neck is so wide, you would not see the two

and fro pattern within the neck.

This patient,

went on to have a stent placed

and had an angiogram, as you can see here,

and very faintly,

an outline of the fill in of the,

pseudo

aneurysm.

This is a,

28-year-old IV drug abuser who presented

with neck pain, and you can see on the initial scans

evidence of a hematoma within the neck.

It's very echogenic.

This,

thrombus was,

subacute with a more hypo coic,

peripheral component, just reflecting the fact

that hematoma will have,

different levels

of echogenicity depending upon the time course

since the bleeding occurred.

When we look carefully at the common carotid artery,

you can see actually the,

track

of blood flow from the common carotid artery

to the more medial proximal part of this,

largely thrombo pseudo aneurysm.

You can see some color aliasing within the neck,

and again, that ying yang pattern

of swirling flow within the residual patent.

Component of the pseudo aneurysm

here is a spectral doppler waveform

obtained within the neck, demonstrating that classic two

and fro pattern with flow heading towards the pseudo

aneurysm in systole

and away from the pseudo aneurysm in diastole.

This is another example of a pseudo aneurysm obtained,

or that,

occurred following a drug addict's attempt

to inject in the common carotid artery.

Here you can see on the power doppler image the pseudo

aneurysm arising from the distal common carotid artery just

below the bifurcation.

And here on the angiogram,

you can see the pseudo aneurysm exactly

as we saw it on the power Doppler image.

This is a,

patient who presented

with a neck mass in the intensive care unit following an

attempt at placing a central line.

This is the common carotid artery near the bulb.

This is the pseudo aneurysm adjacent to it,

and here you can see this very thin neck

between the common carotid artery

and the paint and pseudo aneurysm.

This is the,

angiogram,

confirming the ultrasound,

findings and notice that in,

this neck again,

you had the classic two and for away form pattern,

but as I have said, you will only see

that pattern if the neck is thin.

If it's wide, you're going to have a very,

bizarre flow pattern.

This is a patient who had a mycotic pseudo aneurysm

demonstrating that you see just a bizarre way form pattern

in the neck because again, that neck is very wide

and typically you see a wider neck in a patient who has a,

mycotic pseudo aneurysm.

When the pseudo aneurysm occurs

because of penetrating trauma, it's typically

a narrower more pinhole neck that has the two

and fro wave form pattern.

This is a patient who presented actually five years

following carotid endarterectomy.

She actually had a TIA and

therefore had a CAT scan, which suggested a vascular

abnormality actually,

up fairly high

above the bifurcation,

when she had her ultrasound

to further evaluate what they'd seen on the CT notice,

you can see evidence of the,

crowded endarterectomy.

The bulb is,

distended, and here you can see the patch,

but the distal com internal carotid artery actually looked,

pretty normal, but up higher well

above the operative site.

You can see this focal outpouching,

which represented the pseudo aneurysm

that they'd seen on the CT scan,

and this probably was due to clamp injury.

Here on the color Doppler, you can see

that swirling blood flow pattern described as a ying

and the yang appearance, again, this is a wide neck,

so it would not have a two and fro pattern within the neck.

This patient went on to have an,

angiogram

because they were going to try

and exclude this by placing a stent across this.

And again, you can see the very wide base of this,

pseudo aneurysm, again, well above the operative side,

probably related to a clamp injury.

And it's kind of an interesting case

because as they attempted to place the stent,

across the pseudo aneurysm,

it actually got coiled within the pseudo aneurysm.

They weren't ever able to retrieve this,

and this had to be convert, converted to an open,

operative procedure,

to retrieve the stent

and to,

fix the pseudo aneurysm.

True Aneurysms

True aneurysms are actually very uncommon in the carotid

arteries and occur more commonly in the common carotid

artery than in the internal carotid artery.

Causes can include atherosclerosis

and underlying connected tissue disorders,

and these are differentiated from the pseudo aneurysm,

of course, because the lumen is encased by a

complete,

arterial wall that includes the intimate media

as well as the advent tissue.

But I've only seen a few examples of these cases,

and these would not show that swirling ying yang appearance

as you see in a pseudo aneurysm.

Vasculitis

Well, I'm going to talk briefly about several connect,

types of vasculitis.

And the most common type of vasculitis

that one sees in the United States is

fibromuscular dysplasia.

Fibromuscular Dysplasia

This is an arterial disease of unknown etiology.

It's been postulated

that deficiency in alpha one antitrypsin,

might,

be a cause of this,

but other etiologies

that have been postulated include ischemia,

hormonal changes, and even mechanical stress.

The incidence has been estimated in the general population

as being only between about 0.6 and 1.1%.

It's most common in,

women of middle aged

or younger women between age 25 and 50,

and it is,

three times more common in women than in men.

This typically involves medium

to large arteries causing the so-called string

of beads appearance on an angiogram or an ultrasound,

and it is the renal artery that is most commonly involved.

However, the internal carotid artery is the second most

common artery to be involved.

And if a patient has this beaded appearance

of the internal carotid artery, it's estimated

that about a third of these patients will also have

involvement of the renal arteries.

There's about a 10 to 20% incidence

of spontaneous carotid artery dissections, probably

because,

the vessel wall is weakened

and about 30% of patients

with fiber muscular dysplasia will have

intracranial aneurysms.

So it behooves the referring physician to,

order a study

to look at the intercranial arteries as well.

Patients with fiber muscular dysplasia involving the

internal crowded artery may present with TIA hemorrhage

or stroke, but very often they're asymptomatic.

And on ultrasound, just like on an angiogram, you're going

to see a beaded,

or scalloped appearance of the internal carotid artery.

Power doppler has the best edge resolution

or of,

the,

different types

of color doppler imaging.

And so we often use power doppler in order

to best bring out this beaded appearance.

The,

finding will be bilateral in up to 65% of cases.

Very often it involves a relatively long segment

of the internal carotid artery

and it will narrow the

lumen.

Here's another example where you see this beaded

or scalloped appearance involving quite a long segment

of the right internal carotid artery.

If the lumen is substantially narrowed,

you may see an increase in peak systolic velocity.

However, sometimes as in this case,

the peak systolic velocity may not be quite as high

as you expect because this is a long segment stenosis,

what you really have is a series of tandem lesions.

And in that case, particularly when you look

distally,

you may not see an increase in peak systolic velocity,

though sometimes you do see a tardis pars waveform,

as you did see in this particular individual.

Takayasu Arteritis

Tatsu, arteritis

or a arctic arch syndrome is a fairly rare type

of arteritis in the United States.

This is sometimes also referred to as pulseless disease

because patients,

most often present

with absent pulses in the upper extremities.

This is an inflammatory disease of unknown etiology.

One sees granulomatous,

inflammation

that predominantly affects the wall of the aorta as well

as the major branches at the origins.

This inflammation will result in thickening of the,

walls of these branch vessels at the origin,

resulting in arterial stenosis, sometimes progressing

to thrombosis, and occasionally patients may present

with aneurysms as well.

This most commonly occurs in young women between the ages

of 15 and 30.

In fact, it's estimated to occur eight

to nine times more commonly in females than in men.

And although this is very uncommon in North America, it's a,

has a very high incidence in,

Asia.

In fact, it's in India, it's the most common cause

of renal vascular hypertension.

These patients are treated with steroids.

Although this is not always terribly effective.

On ultrasound, you are going to see wall thickening

of the proximal common carotid arteries resulting in

narrowing of the lumen.

You will see increased peak systolic velocity at the

site of the stenosis, and this is often

but not always bilateral, though, even when it's bilateral,

it can be asymmetric.

And so here you see an example

where you see diffuse wall thickening

of both common carotid arteries.

Note that it is more prominent proximally

and improves as you go distally.

Here is a different patient though,

where you can see actually that the wall thickening extended

all the way to the carotid bone.

On spectral doppler interrogation,

you can see a relatively normal waveform pattern,

but the varsity is increased

because the vessel wall is narrowed.

Radiation Arteritis

This is a patient with a different problem.

You can see that there is diffuse thickening

of the left common carotid artery,

but notice that it begins in the midcom carotid artery.

The proximal common carotid artery is normal, extends up

to the bulb and the

right common carotid artery looked relatively normal.

Here you can see another patient with the same,

pathophysiology, where you can see diffuse,

relatively homogeneous wall thickening

that involved predominantly the midcom carotid artery.

And while this looks very similar to a patient

with taki issue's arteritis, the difference is

that the origins of the common carotid artery look normal,

and this predominantly affected the midcom carotid artery.

And this is a patient who has wall thickening due

to underlying radiation arteritis.

This is a well-known delayed effect

of high dose cervical radiation therapy.

We see this most commonly in patients who've been treated

for Hodgkin's disease

or squamous cell cancers of the head and neck.

And the underlying pathology is indeed an accelerated

atherosclerosis characterized by significant inflammation

as well as fibrosis.

In addition to the problems

that I've just described in the vessel wall itself

surrounding scar tissue

and soft tissue fibrosis can also contribute to,

compression of the common carotid artery causing stenosis,

and even occlusion.

It's estimated that there is an occurrence rate of as high

as 30 to 40% following high dose cervical radiation therapy.

It does take about five to 10 years

to develop radiation arteritis

after the cervical radiation therapy.

The stroke rate is estimated to be as high as 7%

in these patients, and often

therefore, treatment is recommended.

And the, in today's practice,

the optimal treatment therapy is considered to be,

stent placement in the common carotid artery,

which brings up a very interesting question.

Given the fact that this,

has a very high incidence

and that these patients,

about 7%

of them will develop stroke

and that there is good therapy for it,

should we screen patients

who have had high dose radiation therapy,

in order to,

prophylactically treat these patients

before complications,

develop

the ultrasound appearance mimics the appearance,

as I've mentioned, of takayasu arteritis, except

that this diffuse wall thickening

of the common carotid artery typically involves the middle,

part of the common carotid artery.

It may be very severe,

but is,

typically very, the stenosis is very smooth

and long segment.

Occasionally it can ulcerate

and it can be severe enough that a occlusion occurs,

and very rarely,

it can lead to the development

of pseudo aneurysms

and even rupture of the carotid arteries.

Here's another example where you can see that

although there is some underlying atherosclerosis,

you can see this echogenic plaque out at the wall

of the common carotid artery.

Notice the vast majority of this stenosis,

which is very long segment and smooth walled,

or

with a very smooth,

luminal interface, is due

to this very long segment homogeneous hypo coa, thickening

of the wall of the midcom carotid artery.

Here's another example where you can see that,

the wall is a little bit more irregular,

but again,

very homogeneous

and,

hypo coan

Moyamoya Disease

Moya Moya disease

is a uncommon type of vasculitis.

This is believed to be inherited, tends to be progressive,

and this typically involves the internal carotid artery

as well as the middle and anterior cerebral arteries.

Ultimately, this vasculitis will cause significant

constriction of these vessels and occlusion.

It tends to be bilaterally

and once occlusion occurs, it is the basal artery

that will ultimately supply most

of the blood flow to the head.

This is a very severe,

disease, often symptomatic

with patients presenting

with stroke, hemorrhage or seizures.

And there is no known,

medical therapy.

This tends to occur in children

and young adults in the third to fourth decade.

It is also more common in women,

and there's an increased incidence in individuals

with down syndrome, neurofibromatosis

and sickle cell disease.

On angiography, you will see occlusion of the internal,

carotid arteries in the,

skull as well as occlusion

of the middle and anterior cerebral arteries,

and the so-called puff of smoke appearance.

Due to compensatory dilatation

of the striate vessels on ultrasound, you won't see

that puff of smoke appearance,

and obviously you don't typically interrogate the

intracranial internal carotid artery or the middle

or anterior cerebral arteries.

But because of this occlusion of these distal vessels,

you will see a high resistance waveform in the more proximal

ICA as well as common carotid arteries.

Temporal Arteritis

The last type of arteritis I want

to talk about is temporal arteritis,

which is sometimes referred to as giant cell arteritis.

This is a chronic systemic inflammatory arteritis

and tends to occur in older women over the age of 50.

These women typically present with headache,

visual abnormalities, systemic myalgias or arthralgias,

and sometimes the temporal artery may be painful.

On physical examination,

it typically involves a superficial temporal artery,

which is a branch of the external carotid artery,

but it can involve any medium to large artery.

You'll see thickening of the vessel wall sometimes

with obliteration of the lumen,

and if it involves the internal carotid artery,

this can result in stroke,

though this is relatively uncommon, diagnosis is made

with biopsy of the temporal artery,

and these patients are relatively effectively treated

with steroid

therapy.

This is an example of a patient

where you can see a high resistance waveform in the common

carotid internal carotid artery, as well

as the external carotid artery.

Note that there's no diastolic flow in the

common carotid artery.

There's very reduced diastolic flow in the internal carotid

artery, and there's actually reversal

of flow in the external credit artery.

So again, a high resistance waveform pattern in

all the vessels on the neck.

This was a very extreme case,

but notice that the abnormality is more,

exaggerated in the external credit artery

because that's the vessel that is typically involved first.

Conclusion

So in conclusion, don't forget to look

for non atherosclerosis related pathology in the carotid

arteries during your Doppler ultrasound examination.

Ultrasound is an excellent way

to diagnose common carotid artery dissections,

artery venous fistulas, and pseudo aneurysms.

It is certainly not as accurate for detecting a pathology,

such as what I've just described in the internal carotid

artery or in the vertebral artery, particularly

vertebral artery dissections.

And so you may need an angiogram for complete evaluation

or STEM placement in patients who you think have disease,

particularly dissections involving the internal carotid

artery or the vertebral arteries.

I think ultrasound has a limited role in the evaluation

of vasculitis,

but consider the diagnosis of vasculitis dissection

or radiation arteritis in patients who present

with long segment smooth wall thickening,

particularly in the common carotid artery.

And I do think that we should consider screening patients

who've,

had high dose cervical radiation therapy

starting about five to 10 years following completion

of their cervical radiation therapy.

Thank you very much.