How To: Lower Extremity Ultrasound - HD

Introduction

Hello, my name is Anne Marie Kapinsky.
I'm from Albany, New York,
and we are going to demonstrate the basics
of a lower extremity venous ultrasound examination for DVT.

Patient Positioning

We start with the patient's leg positioned
as you see it here, slightly bent at the knee
and externally rotated at the hip.
One thing to note, some folks with arthritic issues,
find this position slightly uncomfortable.
We'll put a small roll of towel
or pillow behind their knee.
It gives their knee a little bit of support,
so it takes pressure off of their hip here.

Scanning the Upper Leg: Groin Area

I usually begin with a transverse orientation
and we start at the top of the leg,
just about at the groin crease.
And what I try to do is just sort of get oriented first
to see what's what.
And at this level here,
what we're seeing is the common femoral vein
and common femoral artery.
There's the common femoral vein, common femoral artery.
We position this always of course,
so the patient's right is on the left
side of the screen here.
If I come down slowly, you can start to see some changing
taking place, both with the artery as well
as over here we see the terminus of the great saphenous vein
and we see the common femoral artery branch into the superficial
femoral and deep femoral or profunda femoral.
Basically we begin at this point,
and I'm going to sort of take us through
really evaluating this just on gray scale image.
That is the important part
of venous ultrasound is being able to look for thrombus
and make sure that there's nothing going on,
in that vein, anything subtle.
So at this point, basically I'll just do a slight
compression and it won't take much pressure
with your patient supine like this.
The pressure at the femoral vein at this point at the top
of the leg is probably between five
and 10 millimeters of mercury.
So it doesn't take much to compress in terms
of documentation.
We can use a split screen feature
where we have the non compressed image on the left
and then we'll switch to the right and then just compress
and freeze and then we can label that as a common femoral.
You can do add in more compressed
and non compressed, but most physicians realize the
proper documentation is non compressed over
here and compressed here.
So just come back to the full screen here
and we would probably document at this level here
where it's just common femoral and then come down
and also document right here
to show the terminus of the GSV.
And you can actually see his terminal valve right here.
But everything's nice and fully compressible.
We don't have any pathology
and we would again, either record this as a loop
or as a still image now.
And other than taking a look at those last couple
of centimeters of the GSV, we're pretty much done at
that point unless a patient's presenting with any kind
of symptoms suggestive of superficial thrombophlebitis.

Profunda Femoral and Superficial Femoral Veins

We'll return back to the deep system here,
the artery branches first, as I said.
And here's the vein and we can see that
the vein is starting to change.
It's moved its position a little bit.
We were basically almost even laterally with the artery.
And as I've moved down the leg, it's come deeper
and underneath it.
And now we can see that it's gone from just a circle
to an oval to now two.
And we're just gonna increase our depth here no other way.
There we go. Increase the depth a little bit
so we can visualize.
This is the profunda femoral artery or deep femoral artery
and profunda femoral vein or deep femoral vein.
And again, press and we get everybody to compress.
We know that there's no thrombus there now
because we've got the superficial femoral artery,
femoral vein and profunda femoral vein.
To get this vein down here
to compress fully may take a little bit more pressure
because we're kind of going through
the other couple of vessels.
So we'll wanna be able to vary our position a little bit.
And you can kind of see where I am on the thigh.
We're down a maybe five
or six centimeters from the groin
and we're seeing those vessels.
So we'll document the terminal area of the profunda femoral
and we'll also continue now just looking
at the femoral vein.
So here we have the superficial femoral artery
and the companion vein.
And this is probably a adequate point where we would
document again, if we wanted the right
and left side by side, showing good compression.
And that would be obviously labeled.
However you prefer.
You could say just prox femoral vein
or whatever kind of short nomenclature you'd like to use.
Of course, all the systems have preset labels
as well that you can use if you don't like to type.
So it's press and release, press
and release every couple of centimeters.
Now interestingly,
perhaps you've noticed here,
I'm just gonna come back up a little bit.
Here's the artery, there's the vein and down a little bit
and we see this other vessel over here.
And obviously with a little bit of a pressure, it's
collapsing away.
Oftentimes there are multiple femoral veins.
Some people say half the time,
a third of the time, it's fairly variable.
Just know that they can occur and to look for 'em.
And you wanna just get full pressure
and there's no magic place.
But somewhere when you're about halfway down the thigh
is again where you'd wanna document your mid femoral vein
again with a split and then go to the other screen
and compress and freeze and label it accordingly.
So further documentation, we did the common femoral,
we did the great saphenous, we did the termination
of the profunda, we did the upper thigh femoral,
mid thigh femoral.
And we'll continue on down
and we'll look at the distal thigh.
Now you can see the vessels are getting deep
and they're coming on down
and we'll be getting through going
through the adductor canal.
We can see muscle here and muscle here.
And our model today is a pretty easy
subject, so it's pretty easy to compress.
But another thing you can try is with your free hand is
to come up behind the leg
and you can actually press from behind
and do the same thing in terms of collapsing that vein.
So somewhere again, just as far down
as you can see, we'll document that one more time,
compressed and non compressed.
And remember, you're by yourself, you've got your
feature, you can scroll back to capture
where the compression is.

Doppler Examination

Okay, before we turn our attention to the lower part
of the leg, let's look at some doppler.
That would be the other thing that we'd wanna record.
You can record the whole thing and color as well.
I don't think transverse color is all that
helpful because it's difficult to get good filling.
So if I want to look at color,
I will use a sagittal view or longitudinal view.
But we'll come back up here at the groin
and we're gonna bring up this image again.
So I'm just gonna come up here
and get the common femoral vein in view
and drop our doppler in.
And we'll just turn that volume down a little bit
and we'll want to adjust baseline down just a little bit.
There we go.
I'm sorry.
Can we just move that baseline down? Oh, I see.
It's just a toggle down. There we go.
Sorry, I like to make sure that I can,
and I'll just drop that volume a second.
I like to make sure I can see a little bit on both sides
of the baseline, particularly obviously if we're gonna do
reflux study, we're not gonna do reflux study in the supine
position because the results are gonna be inaccurate.
So let's just bring the Doppler back up
and I'm just going to come
back to my live screen.
Some folks like to be able to have full simultaneous duplex
where we're seeing the live image and live spectral doppler.
And I think that that is helpful,
particularly if you're following down, to make sure
that you don't fall out of the vessel.
And what we're gonna have is we're just gonna, again,
with your free hand, take a little and do a little squeeze.
And we just augmented the signal here.
As you can see, when I squeezed,
I augmented the return back up the leg
and that was detected with that increase
in the doppler pattern.
We'll come back here alive
and I'm just gonna ask the patient
to take a big deep breath in.
Alright, and relax.
And we can see that we stop the flow.
In fact, we actually get a little bit of reversal of flow,
which is not uncommon in this position.
It does not mean that he has our patient has reflux.
It is just actually physiologic flow moving retrograde
because we don't have enough pressure to engage the valves.
So this is why we don't do reflux studies
to pine, but that's another story.
So we've augmented the flow with Valsalva
and distal compression
and we've documented our venous doppler pattern
and usually we get just the femoral.
We will always get a contralateral femoral vein
if we're only doing a unilateral study.
So we can compare the symmetry right to left.
The other thing that we'll do, many folks will
also grab a mid thigh portion again just to see
we need to do our doppler sagal
'cause we need a decent angle of intonation.
So here we are And I'm getting a little bit
of the artery in there just 'cause I was up a little high.
And you can adjust your controls here
to get a nice clean signal, nice normal phasic flow
with just quiet respiration is exactly what we wanna see.
There's really no need to document
and color if we've shown the image
and we've shown the doppler, but we can just go through
and show you just
to be complete since we do have wonderful color imaging.
See, good color filling on the vessel.
Although color is still considered complimentary.
We'll just
Steer this back.
Is that right? Oh, sorry.
There we go. Work with the natural angle
of the vessel so we can get good color filling.
And you can see a beautiful picture here.
I'm just gonna drop the overall color gain.
You'll wanna be adjusting your gain
and your scales a little bit if you've got
some artifact.
And what we see here,
Obviously the artery on top, the artery is aliasing,
the color signal is aliasing.
Because we have our PRF set very low,
our scale is set low so that we can get good venous filling.
And we have the common femoral vein splitting into the
femoral vein and the profunda femoral vein.
So that's a very nice documentation
of the color flow there.
And you can scan all the way down if you prefer,
looking at the color signal
and documenting the color signal.
But the interpretive component to this exam is going
to show, going to be the illustration
of the full compression of those walls together.
And we can see vessels coming and going.
We've got, again, the companion artery aliasing
because of the low scale or PRF
and we're following this all the way
down very nicely.
One thing to remember, most of the equipment nowadays
have multiple frequencies for color
doppler and image.
And if we were in a little bit of a jam
and we weren't getting good filling, we could change our,
our color frequency.
Although this is set pretty low already,
but we have multiple frequencies
that are available on all the most
of the systems nowadays.
So, and you can see we're pretty much down to,
where we were when we were doing the image.
So you can document the color if
that's part of your protocol.

Scanning the Lower Leg

Now we're gonna move down to the lower part of the leg.
So one thing when you're scanning, you don't want to scan
behind the center of your body.
You're gonna move yourself back
and move your equipment back.
Maybe
that'll be well good enough.
And from this view we can actually see pretty well,
if you needed to, you could turn the patient over.
But it works pretty well.
We're gonna come up where we left off
and I'm moving up onto his lower thigh.
Yeah, And we're visualizing here
the vein and the artery.
And I'm just gonna press a little bit,
make sure we still got a nice compressible vein.
Okay. And we're just gonna come down
and basically even with the knee joint here
and we would wanna record the
same left right compression, non compression
of the popliteal vein.
While I'm also here, I'm just,
because this is the last point that I routinely record a venous doppler.
I'm gonna go into a sagal mode
and obviously fix the doppler angle
and grab a doppler,
Do a little augmentation
and record that for our popliteal vein.
So at this point I'm done with the amount of doppler I need
to record and the rest is based on image.
So we come down here
and we start to see,
I'm just gonna zoom up for a second here.
We start to see a lot of vessels.
If I come back up to the popliteal, we see a lot
of branching coming off.
We've got the small saphenous way up at the top.
We've got a bunch of veins and arteries right here.
Those are the gastrocnemius.
They're staying within the muscle.
And there are paired lateral and medial gastrocnemius.
And other than taking a look here,
I don't really follow them much more.
And let me come back and let up on the leg a little bit
and then compress.
And I like to actually record a little loop
of this data versus a still image.
But you could do the same thing as we've done before.
You could do the right left, still compress
and freeze that and store that.
But with these small veins,
I think loops are pretty helpful.
So we'll just come down.
It's important to look at the calf and look at an area.
If the patient's presenting with a focal pain,
that's important.
'cause a lot of times it is one
of the smaller gastrocnemius veins that are involved with a partial thrombus.
So I'm gonna come back up to the popliteal,
which is in the center of you there.
And I'm just going to see how well I can follow it
without changing my view
In terms of my approach onto our patient's leg here.
And you can see it's a little deep, a little hard to follow,
but now we're getting into the point where
the calf is most muscular
and the vessels are starting to branch.
So you're going to try to follow from behind
and kind of swing up forward.
Okay? And now we're over where we see our tibial vessels.
And from this point on down,
then we can use a much more medial approach
and follow all the tibial vessels.
Remember, there are not under a lot of pressure,
so if we push too much, we will get them
to collapse away.
So let's just point out
what we're looking at here on the image.
I'm using a lot of gel here.
So we can reduce any artifact by any little bits of air
that might be trapped under the,
by the skin as a result of hair on the leg.
So we will get 'em nice and gooped up.
We see some vessels here that are kind of deep
and we see some vessels up here that are more,
a little more superficial.
Okay? The tibia is over here
and actually the fibula is right here.
These guys right here, vein, artery,
vein sitting right on top
of this bone from this medial approach.
Those are the fibular vessels
or what we now call more commonly the peroneal vessels or peroneal if you're from the UK.
But we've got the vein, artery vein
and we can get good compression
and we'll follow them up a little bit.
We lose them a little bit right up and through here
and that's when we're gonna vary our approach
and try to come around.
And this point in
through here on the leg is probably the point
where you're gonna have to press the hardest.
You might wanna warn your patient
or apologize in advance
because they're so deep, they're deep to the muscle there.
Okay? So we kind of follow them right on up.
Getting good compression,
actually pretty much compressing 'em away.
If you have very small veins that are difficult
to visualize, you can sit the patient up
and have them fill more.
Now I'm gonna look up here
and I'm gonna look at these vessels up here, pier
here we have a large vein, well large
by tibial level standards,
which is probably a so vein.
It looks like it's coming right on in.
Let's see if color will make things any more apparent.
Not too much. That's the hard thing.
I mean we can see the vessels colorized as I compress,
but it's not all that helpful.
I think the better thing is to rely on the ability to
compress those vessels and record that either as a loop.
So these are the posterior tibial vessels.
That's what we're following up here now.
And again, we're gonna do the same thing,
follow them back up to
where they connect into the peroneals.
And I've zoomed up our depth a little bit,
but you can see we're coming up and following up.
And then in a minute we're gonna be back up to
where we started at the popliteal level.
Now the posterior tibs are right here.
They're very easy, very nice.
We're gonna continue to follow them basically all the way
to the level of the ankle.
And I don't like to use a ton
of goo, although I will use a fair amount of gel.
The more gel you put on is that starts to evaporate.
The cooler your patient will get when they get cold,
they vasoconstrict, which also makes your job harder.
So keeping them warm, wrapping their foot in a blanket,
keeping the rest of them covered is very helpful.
So you can see I'm all the way down to the ankle
and I've got very nice visualization of
the posterior tibs and it's the only vessel up here
and I'm just working my way back up.
We see this guy at the top of the screen up here.
That's the great saphenous.
And that was actually a perforator coming down.
Again, topic of another lecture.
But we can see,
and we're kind of getting back up to
where we started in the mid-calf.

Anterior Tibial Vein

Now there's one vessel that we haven't looked at
and that's the anterior tibial vein.
Most folks don't image it. I'll just show you.
I'm gonna have you just roll your knee for me,
Mike A. Little bit this way.
The anterior tibial veins gonna course along here,
along the anterior lateral aspect.
They are really small.
It might be very hard to see,
In this view, but actually, and I didn't even plan this,
but this is them right here.
Here's the tibia.
This is the anterior compartment over here.
And here's our distal anterior tibial artery,
which will turn into the dorsalis pedis in a few more
centimeters distally.
But here are the companion veins right here.
And you see I've kind
of taken the image depth up a bit to see them.
But these are the only vessels that are gonna be over here.
And that's where you'll follow 'em from
the foot from here
and back up this way if there was an issue.
But most labs don't routinely include the anterior tib,
but that's where I would go to find them.
They're gonna continue on up
and then about somewhere in here, dive deep to come back up
and connect into the popliteal.

Conclusion

So we've gone through the B mode imaging
and we've gone through the required doppler imaging
and how we can use color if we want to help follow.
We've talked about requiring doppler at the popliteal
and femoral or common femoral levels,
but compression of the veins all the way from
the groin to the ankle.
And that is the basic exam for lower extremity DVT.
Thank you very much.