Upper Extremity Venous Exam: Technique and Interpretation - SD

Introduction

Hi, I am Larry Needleman.
I'm the medical director of the Noninvasive Vascular Lab at
Thomas Jefferson University Hospital.
This lecture is about upper extremity venous ultrasound.

Etiology of Upper Extremity Thrombosis

The upper extremity venous examination is being increasingly
ordered for patients with indwelling catheters prior to the placement of indwelling catheters or patients with arms swelling.
This mirrors the etiology of upper extremity thrombosis
in prior years before catheterization was so common.
Physical strain such as lifting certain
exercises such as weight lifting were associated with
this disease.
These are all much rarer.
Now today, the overwhelming presence
of upper extremity thrombosis is associated
with catheters either in place
or preexisting catheters where there has been scarring
of the vein
and in many cases the presence of hypercoagulable states
as patients are living
with their cancers longer hypercoagulable states are present
and thrombosis in less usual spots than the lower extremity
such as now upper extremity are also present in up to 15%
of patients who have upper extremity thrombus.
There are a variety of other etiologies for this,
but they are far less common.

Anatomy of Upper Extremity Veins

The anatomy of the upper extremity veins
is quite different than the lower extremity in
that we have the bony thorax, which covers many of the veins
and the presence of numerous collateral vessels
and numerous other vessels which are present
besides the large veins that we evaluate.
And these veins can grow quite large as collateral vessels
and can mimic the
veins that we typically study in lower extremity.

Examination Techniques

Venous examination compression is the most useful part.
Duplex and perhaps color are secondary players
in the upper extremity
because we can't compress many of the veins and
because blood flow is faster, we can utilize all
of our modalities
and they're all very important for diagnosis.
Gray scale imaging, color doppler
and spectral evaluation are all used
to evaluate these veins.

In terms of technique, the patient should be lying supine
and a symmetrical posture
because symmetry is going to be quite important.
For evaluation, we prefer a small footprint transducer.
Oftentimes we use transducers which are appropriate
for neonatal head ultrasound because it offers a vector scan
and a small footprint from which we can see
inside the thorax.
As a general rule, a supraclavicular medial approach is used
for the central veins.
An infraclavicular approach is used
for the peripheral subclavian and axillary veins.
From our technique point of view,
we typically are setting the jugular vein adjacent
to the carotid angling down
or obliquely to evaluate the right
and left innominate veins, scanning then out peripherally
to evaluate the subclavian and axillary veins
and compressing the arm veins as needed.
In some patients who have clear cut arm abnormalities such
as patients who have arm swelling following an intravenous
catheter placed peripherally,
we might limit the study to the arm alone.
But the vast majority of patients who are evaluated for
this DVT, the central veins are evaluated
as long as well as the arm veins.

Anatomy of Central Veins

Simplified view of the anatomy
of the central veins is demonstrated.
Here we can see the jugular vein,
the subclavian vein,
and they join to form the innominate vein on the right.
The innominate vein has a coronal orientation here,
the left jugular and left subclavian
and the left innominate vein is longer
and has a more oblique orientation.
The two innominate veins together join
to form the superior vena cava.

Imaging Central Veins

Small footprint transducers are quite important.
The good news is the color doppler
and filling of the entire vessel is easier
than in lower extremity.
We can also use other tricks such as sniffing
where compression is impossible.
And again, bilateral studies are the usual
in these patients.
Here we are using a curved array transducer
and we can see that
because of all the fat
and material in the mediastinum,
the veins are somewhat more filled in
with echoes than perhaps we're used to.
But we can see that even with this with compression,
the vein goes away completely leaving just the artery.
And so this is a normal collapsible vein.
Here in the innominate vein, we can see the structures
of the vein and you can see that as we take a sniff,
the change in the intrathoracic pressure can cause the vein
to change size and actually disappear.
And if we can see the veins collapsing completely
with sniffing, then we can actually accept that
just the same as if we were compressing it
with probe pressure.

Venous Protocol

The venous protocol in the upper extremity uses imaging
color and spectral doppler,
and we use all three modalities for the subclavian,
jugular and innominate veins.
And if we see the superior vena
cava, we evaluate that as well.
We typically try to look in both long and short axis,
but in some veins that's not possible.
The innominate vein is typically a vein
that we can only image in one plane
and we scan from anterior to posterior
to see as much of it as we can.
Again, we recognize that
because of beam width artifacts in the presence
of the nearby pleura or lung
or mediastinal fat, that there may be echoes
inside of these structures.
Compression is appropriate and used whenever possible,
and that includes the peripheral subclavian vein,
the jugular vein, the axillary and the arm veins.
As a rule, we scan in the following order,
we start in the jugular vein, proceed to the innominate vein,
then the central subclavian out to the mid subclavian,
peripheral subclavian, axillary and arm veins.

Imaging Examples

Let's look at some images. This is the common carotid.
This is the jugular vein in short axis
here in long axis we can see the jugular vein changes
shape a little bit as we go from cephalic
to caudal, it gets a little bit bigger.
Again, asymmetry between the left
and right jugular veins in terms of size is not unexpected.

Waveform Analysis

Waveform shapes in the
upper extremity veins are quite typical.
We can see variation from phasic variation here you can see
the vein nearly stopping.
And then going back to a more phasic change,
we can also see that there is cardiac variation
in this waveform.
This waveform to the lower right
demonstrates much more profound cardiac variation
with some areas of reversal related to the A and C waves.
And again, you can see that that's present as well as a
slower change in peak velocity as related to here
and here indicating respiratory change.
So we have both respiratory phasic
and pulsatile cardiac variation.
So the central veins typically the central innominate
and sometimes the jugular veins demonstrate pulsatile
and phasic variation peripheral
to the mid subclavian.
We will see phasic variation and we may
or may not see pulsatile variation.
We do expect to see symmetry.
So if one arm demonstrates pulsatile variation,
we expect the other arm
to show the same degree of pulsatility.
We also expect to be able
to fill the entire vein with color.

Looking at some other waveforms here,
the coronal orientation showing us the innominate vein,
we can see the innominate vein here, the subclavian vein joining.
And this structure is typically
not the external jugular vein that we're used to seeing,
but another vein typically another anterior jugular vein.
The innominate coming away from us.
We see it filling completely in color
and our waveform shape showing again the difference in
variation in velocity from respiratory change as well
as the superimposed greater changes
indicating cardiac pulsation.
Cardiac pulsation can be much more prominent
and can cause aliasing
cause of the higher velocity as we see here.
And in the color we can also see the aliasing related
to the higher velocities
that are present in the upper extremity veins
and aliasing is much more common in the upper extremity
compared to the lower extremity.

As we proceed, we angle our transducer to bring in
to view the central subclavian vein here, joining
with the innominate vein
and the color filling in of that structure as well.
And again, our normal pulsatile
and phasic variation on our spectral doppler.
As we scan to the mid portion of the vein, we realize
that the angle of the vein may make it impossible
to see the innominate vein completely as it will travel
through 90 degrees.
And we need to therefore angle our transducer backward
and forward as demonstrated
by the two right hand slides here.
Here we can see the mid subclavian vein throughout its
whole course, but not being able to be evaluated throughout
with one image because some
of the vein is at 90 degrees our transducer.
And we can see that we can evaluate this as well
with our spectral doppler indicating our pulsatile phasic
variation peripherally as subclavian vein
can be seen quite well in both long
and short axis as identified by the color images above.
And we can see that the normal
spectral doppler tracings in the peripheral subclavian vein,
again showing relatively high velocity flow during part
of the cardiac cycle or part of the respiratory cycle,
rather here on the left example
and on the right example showing diminution of the
flow velocity also related to respiratory change.

Axillary veins may demonstrate some reversal
or may just be phasic looking more like a leg vein,
but in most cases you can identify a bit of flow reversal.
In the axillary vein, I remind you
that the peripheral subclavian
and axillary veins can also be compressed.
The left innominate vein can be seen in its in part
of its course and we never usually see the entire course
of the right or left innominate.
It's junction within the, with the superior vena cava is
usually not visible with our transducers.
But again, we can see this oblique course of the innominate
and the normal spectral variation that's present here.
In a very unusual example, we can actually see the right
and left innominate coming together
to form the superior vena cava adjacent to the aorta.
Again, this is a very pretty picture,
but one that is unusual to obtain.

Criteria for Abnormalities

So what criteria can we use for abnormalities?
If the pulsatile variation is lost,
even if respiratory variation is present
in the central veins, that is abnormal
obviously more profound blunting of the signal such
as a continuous signal, an absence signal
are also indicative of abnormalities.
One of the aspects of the upper extremity is the collateral
flow can happen and so the normal
obstructed signal may not be present,
but the vein may just show flow in the reverse direction.
Also, because of the higher velocity in the presence
of catheters that stenosis the veins,
we can sometimes see areas of narrowing associated
with high velocities of stenotic jet
indicating a stenotic vein.
And lastly of course, we always consider bilaterality
and asymmetry as a sign
that central obstruction may be present here in this
subclavian venous waveform.
We can appreciate the fact that there is little variation.
With respiratory change and no cardiac variation.
This indicates that there is obstruction of flow
on the right we can see an axillary waveform,
which is showing some phasic variation,
but when we compare the two sides, we immediately appreciate
that the waveform on the right is clearly
blunted compared to the left.
And this asymmetry again indicates obstruction
in a vein proximal to the axillary.
This could be at the subclavian or innominate level.
We can't know where the level of obstruction is
unless we identify it directly.

Identifying Thrombus and Flow Abnormalities

Echoes with inside the veins are extremely common.
We wanna look at the echoes inside the vein
and see if they're fixed in position,
which would indicate a fixed filling defects like a thrombus
or whether they're moving through the field, such
as happens in rouleaux where the slow moving flow moves
through in one direction
or that this simply represents noise
from beam width artifact.
And here as we can identify in our color,
the vein fills in completely indicating
that this is just normal noise.
In this particular patient,
as I alluded to before,
if there's obstruction, the flow can reverse.
Here we can see actually a patient
with acute deep venous thrombosis.
We can see the waveform.
The color of the vein is red, which is the same
as the carotid artery near it.
So blood is flowing towards the head
instead of towards the heart.
But a few months later, after this resolve,
the vein has some more normal shape
and the color is now flowing in the proper direction.
The jugular vein is the most common place
to see reverse flow,
although in more central obstructions you can even see it
in other veins such as the innominate or subclavians.

Let me first point out the central subclavian vein here,
which has this very high velocity waveform shape to it,
indicating a jet.
As we go peripheral to the subclavian vein,
the waveform is blunted.
We don't see the normal pulsatile phasic variation.
This indicates obstruction.
When we have an abnormal doppler, it indicates obstruction.
The etiology is not necessarily identified
and as we know from the lower extremity,
the obstruction may be acute, it may be chronic
or it may be extrinsic.
The site of the abnormality indicates
the level of obstruction.
So for instance, if all of your veins,
the innominate bilaterally, subclavians
and jugulars are all showing blunting, then the waveform
and obstructions are created from the level
of the superior vena cava.
If the innominate on one side is normal
and the innominate on the other is blunted,
the obstruction is at the level
of the innominate on the affected side.
If you see an abnormality in the doppler
but can't figure out why it is being caused,
the report should say that there is obstruction
and it should give a differential of the level
of disease and the possible etiologies that are present
and to recommend perhaps other imaging such as CT
or MRV or rarely or more
and more rarely.
Now, contrast venography.

Importance of Imaging for Thrombus

Not only is the doppler important, but imaging is important.
As I mentioned, the gray scale is important for imaging.
The thrombus itself, our ability to see the thrombus varies
by its echogenicity as we've seen noise may occur in the vein,
which can obscure or mimic clot.
And so color becomes very important to identify thrombus
as a filling defect in the color column
and in veins that are compressible, non compressibility
or sniffing may be helpful.

Here we have a catheter present within the vein
and we can see low level echoes lying in the lower
portion of this vein.
This is not reverberation
as the echoes are not in the upper part of the vein.
And you can see here on the short axis view that again,
the upper portion of the vein is anechoic.
And this represents pericatheter thrombus
Color is not always helpful in identifying
the filling defect if you're not careful
because as you see here,
the color is overriding the thrombus.
And so you have to be very careful with your color gain
to make sure that you're not overriding the low level echoes
that may be present within the thrombus.

The criteria for acute thrombus are that it expands the vein
that it's free floating, that it's smooth,
and when we can compress the vein, it can change shape
because it's still rather soft.
Here we can see a jugular vein thrombus,
which is markedly enlarged compared
to the corresponding carotid artery.
And this indicates marked distension from acute
deep venous thrombosis.
In this case, we can see the thrombus,
which is rather echogenic and heterogeneous,
but what's striking is as we follow the edge
of the vein wall, we can see
that it distends out in this region.
Again, the distension indicates acute
axillary vein thrombosis.
The echogenicity of a thrombus is not helpful
to determine whether it is acute or whether it is chronic.
Whenever we see catheters, we wanna look around the walls
of the catheters to see if there's
echogenic material within them.
And here you can see this echogenic heterogeneous material
associated with this triple lumen catheter indicating an
acute pericatheter venous thrombosis.
When we can compress in the mid region, we can see the lines
of the catheter, we can see that the catheter is sitting
inside the middle of the vein,
but there is many, many echoes within the vein.
And when we compress that, those echoes don't disappear
and that we can't make the catheter disappear,
the vein disappear completely even in
the presence of catheters.
The vein should be completely coapted around the catheter.
And the presence of residual vein
around the catheter indicates pericatheter acute
deep venous thrombosis.

Here, a slightly different image
where we can see a catheter again
and this fine material which is sticking out of the vein.
And this more linear material, which is kind
of almost looks like a Q-tip
hanging off the edge of the vein, is much more typical
of fibrin sheathing as opposed to pericatheter thrombus.

Pitfalls in Upper Extremity Venous Ultrasound

Let's look at some pitfalls.
Again, we have to be careful
that color may overwrite our image,
and this again reiterates to us that
that gray scale is important.
Similarly, if the thrombus is small, it may not cause
distortion of the spectral doppler.
So here we can see the spectral doppler is normal,
the color is really not helpful,
but when the color is turned off, we can see
that there is some asymmetrical echoes on the wall
of the vein here in the subclavian vein
near the innominate junction.
And as we change our orientation and scan back
and forth across that vein,
now we can see from a different plane the thrombus,
which is now projecting in a different plane, again, front
to back, and we can now diagnose acute deep venous
thrombosis, the same thrombus which we did find
could be seen with a linear array probe.
And so we can appreciate the fact that we can use a variety
of probes that are helpful to us.
In fact, here in the linear array probe, we can see that
that there is thrombus, which is present
inside the vein and extends down.
And then as we go further peripherally in the,
we can actually now see the catheter
and the echogenic pericatheter thrombus around it.
You'll note by the way, that the catheter
isn't seen on either the images on the above.
And that's because unless you hit
catheters at the proper angle,
because they're specular reflectors,
they may not be obvious.
And so we do not always follow the catheters,
even though we know they're present when they can't always
be seen throughout their entire course,
even when we know they're in the vein.

Another example of very echogenic looking veins
and it's very difficult to distinguish between noise
and thrombus,
but when we turn the color on, we can see
that the vein changes caliber from rather large
to rather small around a structure.
Again, this is in power doppler here in the lower left
here in the upper right,
we can also see the filling defect with color doppler.
And now as we angle
and rotate our transducer from a different orientation,
we can see the echogenic thrombus projecting from a different
wall in the innominate vein.
So the color, again, can overwrite the clot
but also can point to clot.

In other cases in distinction
between acute venous thrombosis.
Scarring is very frequently found in these patients
because the catheters are sitting inside for long periods
of time and the veins will scar as a result.
Scarred veins typically are normal or small.
The material of the scar is firm irregular.
The vein may retract and be pulled in.
We can also sometimes see circumferential narrowing
or web-like changes,
although circumferential narrowing in my experience is more
common than synechiae in the upper extremity compared
to lower extremity and of course stenosis.
And we need to recognize that arm swelling may be caused
by stenosis and not always by acute venous thrombosis.
Here we can identify the vein.
There's, it's filled with middle level echogenic material
and the lumen is reconstituted in irregular shaped smaller
in this region, larger in this region.
And this irregular lumen again indicates the recanalization
partial recanalization of the material
and the scarring in the vein.

So as we look at upper extremities, we realize
that there are many, many more difficulties
because of our inability to see the veins in all planes
and we can't compress all the veins that are present.
In addition, we have to be very careful about echoes
inside the veins, either being caused
by reverberation or noise.
We always need to remember that the doppler,
the spectral doppler may not be altered if the thrombus is
not large enough to obstruct the vein,
and that collaterals may mimic a normal vein.
Here we can see reverberation.
As we scan down the middle of the vein,
you can see the reverberation fills the lumen
and at the periphery
where we're not striking the veins at the same angle there,
the vein lumen is anechoic.
And then as we look with color,
we can now fill the vein in quite adequately.
And as we change the orientation of our image, in fact,
we can see that the echoes move to different portions
of the vein up and down.
And finally we confirm that it's normal
with both the presence of a normal spectral doppler
and the presence of a normal color doppler,
which fills the entire vein.

Example: Complex Case

So now a question. We have a short axis
view in the subclavian area.
We have an arterial signal and a venous signal,
and two echogenic structures.
What do you think's going on?
Is it breast cancer, is it venous obstruction?
Is it venous occlusion or is it a combination?
The first structure that we see are two
soft tissue structures which don't correspond to veins,
and those do represent metastatic breast deposits.
When we do the venogram, we see
that the subclavian vein is completely obstructed
as we go back to our image.
We appreciate the fact
that this small echogenic structure here
is the subclavian vein,
which is obstructed chronically and therefore small.
And this other structure here is not the subclavian vein,
but instead is a large collateral which
mimics the subclavian vein.
And as we scan in different planes, we realize
that it no longer follows the subclavian artery,
but goes off in an entirely different direction.
So remember, one view is not adequate enough to make sure
that we're looking at normal vessels,
and you really wanna show
that the entire vein is running in normal orientation.

Asymmetry in Waveforms

Here we can see a series of images
and there is some pulsatile variation.
There is some phasic variation.
We can see the phasic variation nicely in the subclavian.
We can see some of the pulsatile changes here.
Again, some of the pulsatile
and phasic variation in the peripheral subclavian.
The innominate vein showing some phasic variation.
Phasic variation not so much,
but it is seen a bit more in the subclavian.
And so this I think is a rather difficult study to interpret
and it certainly could be considered normal.
However, when we compare the right side, we just saw
with its corresponding left side,
we can immediately appreciate the asymmetry, the normal
extreme pulsatility that should be present.
And therefore it's no problem to diagnose the right side
as blunted indicating obstruction at the
right innominate level.

Conclusion

So I hope we reviewed successfully for you the techniques
and interpretation of upper extremity venous disease.