How To: Lower Extremity Arterial Duplex Exam - SD

Introduction and Patient Positioning

Hello, my name's Annemarie Kapinsky
and I'm gonna take you through doing a lower extremity
arterial duplex ultrasound exam.
As you can see from the patient, this is
how we would like to have folks position having their hip
slightly externally rotated and their knee slightly flexed.
From this orientation,
we can pretty much see from the common femoral artery appear
down through most of the superficial femoral.
Then we'll come behind more posterior approach here
to look at the popliteal and then continue on down the calf.
And we can pretty much see everything from this view.
We'll just have to turn the leg when we go
and evaluate the anterior T,
but we'll start up here at the groin and orient.

Common Femoral Artery Evaluation

I usually just start
with a transverse view, right.
Pretty much as high up as I can
and try to find the saphenofemoral junction,
which, let's see.
Let me just bring up a track ball
or the arrow, the cursor, right?
Yeah. Up here on the screen, you can see
we have this oriented, obviously, so the patient's right
is on your left and, and the patient's left is on our right.
We can see the common femoral vein in the center,
the common femoral artery right here
and the great saphenous vein coming up here.
And if I press down, I know I've got the veins where they,
are as I just described.
And that's really our starting point for most,
lower extremity evaluations.
I'm just going to go into, a sagittal
or longitudinal view of the artery.
And I'm adjusting the DGCs a little bit
because most of the time when we do vascular, we kinda like
to see the lumen nice and dark,
and we can throw in our color.
Okay? And we wanna make sure we're not in the vein.
I'm just slid over a little more medially
to show you the vein and the appearance of the vein.
Obviously the, the color flow is more continuous,
obviously phasic with the respiration,
the artery here is a lot more pulsatile.
I haven't adjusted the presets for color.
And it's totally showing us the multiphasic pattern we'd
expect to see in the common femoral artery.
I take color off just for a second
and we take a look at the gray scale image
and what we're seeing here.
And obviously this is a very nice, normal, subject.
We have no plaque, nice thin walls.
If I put the color back in again, we see good color filling.
You would adjust your color PRF and your gain.
'cause we don't want,
we don't want the gain up too high.
And I'm gonna just increase the gain for a second
to show you what we don't want.
We don't want this, we don't want it spilling
out into the gray scale.
You wanna drop it right back until it's pretty much filling
to the edge of the wall, but not spilling out.
If I put in the pulse doppler, we want
to be able to sample fairly, close to the center
of the blood vessel, because that's going
to have the highest velocities.
And we can see, again, a nice multiphasic pattern.
We're pretty well aligned here to 60 degrees.
I'm gonna freeze it for a second. And this system is set up.
It automatically seeks a peak and end diastolic velocities.
And in this case, our peak velocity is 73
and diastolic velocity is just under nine.
And that is, again, the common femoral artery.
Now, if we saw anything other than this
and did not see a multiphasic waveform,
we would extend further north up into the iliac vessels
and make sure that there was no disease up
in the iliac vessels.
But we can see here clearly on the screen,
this is a nice sharp upstroke, a narrow peak,
a rapid deceleration.
So this is a very good upstroke here in systole.
And it's telling us that that blood flow has not passed
through any kind of a stenosis in any way.
We see the reflected wave here telling us we're dealing
with a high resistance bed.
Again, textbook normal.
And this third component in end diastole.
This antegrade flow at the end of diastole is basically due
to, healthy compliant elasticity of the vessels,
further central to where we're imaging.

Bifurcation and Profunda Femoral Artery

So I'm gonna go back just to gray scale here,
and I'm gonna come down just a little bit
and I hardly move my hand at all.
I basically just angled it.
And now we see we're coming to a bifurcation.
And that bifurcation is, the bifurcation
into the superficial femoral artery
and the profunda femoral artery,
or is that sometimes is called the deep femoral artery now,
'cause they're kind of angling a little bit in,
in different orientations.
I'm gonna capture the profunda femoral artery first,
and we'll wanna get a doppler signal from there as well.
So we're gonna look right at the origin here.
And again, a multiphasic pattern. Nice sharp upstroke.
All right. And we see here our peak velocities
are around 63.
Again, usually in the peripheral artery,
we want the velocities less than one 50,
although in most folks
it's probably even less than a hundred.
That's a ballpark criteria that we can use.
But again, we're really looking at the,
the shape of this waveform.
And that's very characteristic of,
of a nice normal high resistance arterial bed.
This is probably the only area that we really need
to look at for the profunda femoral or deep femoral.
Basically just the origin just to look at plaque.
If there was disease perhaps in the SFA, the profundo femoral artery might be a choice
for a bypass inflow site.

Superficial Femoral Artery Scanning

Now we're gonna come back again
and we're in the SFA now here up at the top of the screen,
this is the SFA.
Alright, we're seeing a little bit of the vein underneath.
The profunda is down here
and it angles away, in a manner
that we really don't see much of it.
So I'm just gonna look at the SFA here just
for a little bit, just to point out a couple of things.
And I've, I'm trying to make it really flat
because obviously when we're at 90 degrees
to the ultrasound beam, we're gonna get the best image.
And here again, the the things we wanna look
for is this nice thin wall, this very smooth wall.
There's no bumps, crevices, no sign of any plaque, no sign
of any calcification.
We can even right here, kind
of appreciate the inter medial complex,
which is not something we really look at in the,
the lower extremity arteries,
but it is there and we can see it.
So we know we're dealing with a very healthy blood vessel.
And what we wanna do is really doppler
through the entire length of the vessel.
So whether that's in color, first to give sort
of an overall scan or if we do it in triplex with doppler.
But I'm gonna look first in color,
'cause color certainly is a good tool.
And you can see I'm just sort of,
rocking my hand just a little bit back
and forth to keep that lined up.
I wanna see the vessel all the way from one edge
of the screen to the other.
I know I'm, I'm completely dead center over that nice
and lined up with that vessel.
I'm not oblique if I kind of see this
and see this sort of like, kind of oval shape,
I'm oblique to that vessel.
And, and that's not really how I wanna follow it down.
I wanna follow it, where I can line it right up.
And obviously as you move, you're gonna have
to adjust yourself, adjust the position.
But this is the technique that you would use
to follow all the vessels, whether upper extremity,
lower extremity, and let me just move that, oh,
that's not what I wanted it to do.
There we go. I'm just gonna move the color
box a little bit deeper.
I don't like to make it too large.
'cause then it'll, decrease the frame rate a little bit
in some systems anyways, not in, as we get deeper,
it's certainly, it, it can, it has to travel further
and listen longer and so forth.
So it may drop the frame rates.
So now we're getting a little bit deep here, okay,
not very far down his leg.
So I'm just gonna stop for a second
and get a little more gel.
I don't like to put a, an absolute ton of gel on patients
just because, just
because that as that gel, starts to dry up
and the water evaporates from it, it cools them off,
the patients get cold, they vasoconstrict
and then you're kind of,
particularly if you're doing a venous exam,
you're gonna create more trouble for yourself.
Now you'll probably see, let me just change the orientation
of that color box for a second.
You'll see various
branches off of the SFA that are normally there.
Now I know I'm not getting good color filling here in the
SFA, but I just wanted to show you
that you can see small tributary, small branches coming in
and out of the SFA.
They're not important for the routine scan.
However, when you have a vessel that's diseased
or occluded, these can get very large
and you can see them, become pretty pronounced.
So we're gonna continue scanning down as far as we can.
We would change the steering back.
Sometimes there's enough of an angle on the vessel itself
that we don't really need to angle the color box
but just sort of keep it kind of straight.
And now I'm getting a little bit further,
a little bit deeper and the color is totally being my guide
here 'cause I'm, getting now deep.
If you look at where my hand is in relation
to the knee joint, I'm really just about at the adductor
canal at about this point that artery
and vein are gonna pass through the muscle
and come up behind the knee.
So we've really scanned the superficial femoral artery
for the extent that we'd want to and you'd want to come back
and record some velocities.
And we would come up and I'll just show you again either
with the color on
and we'll now we'll need to just,
see steer this a little.
So, And then we'll put our doppler again,
we wanna keep 60 degrees or less
and it's very easy in the leg
to just toe heel a little bit and,
and create a good angle.
And here we are again, velocity
of about 109, 108 textbook normal.
We would repeat this
getting a signal, say mid SFA
And then one further down.
And if you had any issues you could just take the color off,
have the machine work a little less hard
and concentrate mostly on gaining that doppler signal.
And you can see it cleared up just a little bit
because we're asking it to do less.
So if you come in
and out of modes, remember,
the machine has only so much capability.
So as you add it more and more in and make it do more
and more, it will sacrifice somewhere.
But that's an excellent waveform again,
high resistance phasic waveform.
And that's exactly what we would expect
to see the whole way down the leg.
So we started the common femoral up here.
We scanned through the superficial femoral to the point
where we really started to lose it
and it started to go through and come up behind the leg.

Popliteal Artery Evaluation

So now without having to make the patient change their leg,
we're gonna come back here
and find the popliteal vessels.
I'm just adjusting the focus a little bit
'cause the vessels are a little bit more
because superficial here, once we're behind the knee, now
what we see is the popliteal vein on top
of the popliteal artery.
And again, if I hold still obviously you can see
that the artery's beating
and if I compress the vein compresses away.
Again, depending upon your individual lab protocols,
you can follow the popliteal artery up
as much as you want.
I'm really now on the lower part
of his thigh, probably right about here.
So I'm really picking it up just about where I left off.
And again, it's nice and smooth walled
and I believe this guy coming off right here,
which is the first big branch,
is the anterior tib.
And I followed it a little bit
before we started the demonstration.
So I'm pretty sure that's the anterior tib.
But let's look at some color
and again, 'cause there's a nice angle to the vessels here,
I don't really have to work at
adjusting the color box too much.
And we see another branch down here
who knows one of the ular branches not too important
to us again, but this is the area we'd wanna scan.
And now here for our doppler will wanna
give us a little more angle.
60 degrees is perfect,
but less than 60 is okay
in here without having to fuss too much.
I've adjusted it now met 56 degrees
and again, multiphasic, high sharp up, stroke,
narrow peak and so forth.
That's a normal Doppler signal.
And we're down to about 68 centimeters
per second for velocity.
As we go out the arterial tree,
we expect the blood to slow down.
We want it to slow down.
So by the time you get to the capillaries,
you have good exchange.
So most folks record, oh most folks record just,
a representative signal from the pop seal coming down.
We'll come back
to the anterior tib in a little while once you see the
anterior tib branch off.
Now where we're at is really the tibial perineal trunk.
And that's a varying length.
And as we come down,
and I'm just gonna adjust my focus a little bit in depth
'cause we're getting just a little bit di deeper.
That vessel splits and it's splitting right here.
Let me put the color on, maybe that'll help
show a little bit better.
I'm just gonna move the machine a little closer to me here.
Okay, so we're up here in got the tibial perineal trunk
and if I come down real slow
now we have two vessels here just coming
and branching off two groups of vessels.
It's a little hard to appreciate.
There you go a little bit better.
Now you can see the two separate arteries here.
One is going to be the posterior tip
and one is gonna be the peroneal.
And the perineal artery is gonna stay deep
right on top of the fibula.
This is the edge of his fibula right here.
The perineal vessels used to be called the fibular vessels.
Fibular artery fibular vein because of their orientation.
This guy up here that's gonna sit up a little higher
and a little close to the edge
of the tibia is gonna be the posterior tibial.
So you can see we followed these right on down
and you can see if I move, you know,
we get some venous flow in there as well. Gotta switch
It. Pretty good.
I'm just upping the gain just a little bit
'cause I'm actually running low of gel.
But we can really appreciate here
where we're at and what we see.
We can see these two vessels.
So same thing,
you know down here they're getting a little smaller.
I'm gonna take color flow off for just a second
and Show
you the gray scale.
Now again, the, these guys are small
and they change their orientation a little bit,
do a little bit of twisted and turning.
So we wanna make sure we stay on the artery
and don't get fooled that we're slipping off into a vein.
But there's the artery that's a posterior tip.
And put the color back on.
And again, I'm looking up here at the top vessel
and what we wanna do is probably record,
and this is again gonna depend on your individual protocols,
but a representative signal in terms of the, peak systolic velocities.
And we see again this phasic flow pattern peaking out at
around 58 57.
So that's perfectly fine.
Now you can follow it in gray scale, but which is fine.
You do wanna assess it and make sure there's no plaque
or no calcification.
But you can see beautiful color filling.
And, and our subject today has wonderful anatomy.
We're getting both the posterior tibial
and the perineal in the same view.
This may not be possible in most patients
and an alternate way would be to come,
and I'm just gonna show you for a second
with the transducers to basically come
and really come around more posterior to kind
of catch the perineal in a heavier, deeper leg.
So you'll follow these vessels down again, recording,
velocity recording color, looking along.
Eventually the post the perineal vessel, the deeper one here
will start to branch into a couple little branches
and you won't see it anymore.
Basically it has some communicating branches
that will connect into portions of the distal anterior tip
and posterior tip.

Posterior Tibial Artery

So now I'm just gonna focus a little bit on
the posterior tip.
Now as I started earlier, I said, you know,
we don't want our color to look like this, so I'm gonna drop
my color gain back a whole bunch, Okay?
So we can get it out of the tissue.
'cause we don't want it in the tissue,
we want it in the blood vessel.
So again, it's nice laminar flow,
filling the vessel completely.
We're coming down and as you can see, I'm just about down
to our subject's, sock here.
And if we were doing this, depending on the,
I'm just gonna take this down just a little bit.
Depending on the reason why we were scanning a patient,
we would include really following the vessel all the way
down here to behind the ankle as well as when we come
around we'll follow the dorsal PDUs on top.
So we wanna get all the way down to these pedal vessels
because it's those pedal pedal vessels
that may be an outflow source for some patients.
So it'll just show you down here, you know, when you doppler
or do a regular doppler, you know where you're putting,
your transducer to listen for an ankle pressure.
It's the same kind of thing that we're gonna do here.
Now, I didn't change the frequency
of this transducer or anything.
If it's a very skinny patient,
these are very superficial vessels
and you might wanna change the frequency.
But we can see here on the ultrasound image
a very nice healthy posterior tibial artery.
We're way distal
and a little bit further, we won't be calling this the
posterior tib anymore.
It'll become part of one of the plantar arches.
And we'll take another Doppler way down here just
just to be complete.
I'm just adjusting my scale a little bit
so we can fit everything on the screen.
I'm gonna take the color off just for a second
And just clean up that signal so I don't have any noise.
And again, we still see a multiphasic pattern here.
Our peak velocity of 73 end diastolic velocity is zero.
And that's a normal pattern.
So we've shown how to follow all the way down.

Anterior Tibial Artery Evaluation

The only other vessel we haven't evaluated is the
anterior tibial artery.
So I'm gonna have you straighten your knee for me
and the anterior tib,
I'm gonna have you just roll it a little bit to the inside.
That's fine, is over here. Okay?
It's on the outside lateral compartment.
Now sometimes they're easy to find
and sometimes they're not as easy to find.
So let's just take a gander here.
I'm gonna increase my depth again a little bit
and sometimes it's a little bit challenging
to see what's what.
All right, so what I like to do,
and it's sort of cheating, but not really.
You can follow these vessels any way you want.
I'm gonna come down to the foot
'cause right across the top of the ankle here,
there's only one thing going on.
And that one thing is the dorsal PDUs artery.
The dorsal PDUs artery is the distal extension onto the
foot of the anterior tibial artery.
So here we have the dorsal fetus
and we can see
color, we can see it filling.
It's a little vessel, two
or three millimeters, you know, depends on the,
on the subject obviously,
but we should still see this kind
of high resistance pattern.
And we see that multiphasic pattern.
So what we wanna do here, you can do a couple things.
You can follow it in gray scale, you can follow it in color.
It's curving up around some of the ankle bones.
And here we see coming back up
and we could see even on color.
I think you can appreciate this vessel is a little bit
smaller than the posterior tib,
but we're gonna follow it back up.
Here we are coming along
And we saw where it took off, up off the popliteal
and now we're gonna follow it right along
the anterior compartment.
And it, if you can appreciate his tibia is about here.
Alright, the, the top edge of it.
So we're just a couple of centimeters over
and if I take color off for a second
and show you transverse where I am, okay,
I'm just a little bit off of the side of the edge
of the tibia here and we're kind of deep sort of sitting,
you know, in between the two bones.
But it's pretty easy
If You can't see it in the midcalf region, follow it
and evaluate it
by finding the dorsal BetUS and coming backwards.
And again, here's the color, nice and normal
and filling all the way up.
There's that doppler.
If we don't see that multiphase, multiphasic doppler,
then we have to think either we're dealing with somebody
who is in a hyperemic state
or perhaps they have an occlusion.
It all depends on what's going on in this
portion of the waveform.
If we basically only see one systolic component
just this bit right here and no reflected wave
and no antegrade component at the end we're probably dealing
with a patient who we are upstream from an occlusion.
It's, experiencing pretty significant resistance if we see this.
But then we see a lot of diastolic flow,
then now we know we're in a low resistance bed
and that could be the result of disease
or it could be a hyperemic state.
But this is what we wanna see pretty much in any artery
outside, arms, legs, so forth in a,
in a normal individual.
So from here we would follow
and continue to follow on up
how whatever mechanism is easiest for you
if you wanna do color.
'cause color certainly is kind of quick
and not too difficult.
We can follow it all the way back up and color.
And again, you know,
it's gonna take a little tweaking here and there.
As the vessel changes shape, we might need to change,
you know, our scale or color gain to keep it filling.
And we might need to change our approach a little bit
from a more, lateral approach instead of a more anterior approach.
And you'll see it's gonna come up.
What I'm gonna have you do actually is just can you roll
just a little bit that way?
Okay. I just wanna be able to show you the very upper edge
where the anterior tib dips away.
And it's just a little easier here.
So when we start over, we come back to where our, where,
where we were, where we knew, we had the vessel
and come back on it.
Of course we gotta get back on it.
I was trying to figure out the best way to kind
of approach it coming back up.
Just wanted to see how the,
You getting a little artifact here
and it goes, follow it better in the other orientation.
But
here we see it.
And again, we wanna make it line right up
so we know we're following the vessel
and we're kind of losing it a little bit up here.
I'm just gonna have you just relax your leg a little bit,
just relax like that, okay?
Because it's really usually can fall this pretty easily up.
So I'm not sure if it's,
just a little bit, actually we'll have you roll
back over on your back.
It was actually a little bit better to follow
that from that approach.
And I'm just gonna hold on here a little bit different.
Okay. So again, we started down here
'cause we can clearly see it on the ultrasound image
as it crosses the ankle.
All right, so we're gonna come up
where we found it last.
All right. And this is just like real, real world.
When you get lost, you come back to where you were
and then continue to follow it.
And again, I'm kind of over off to the, the side
of the tibia and here it's just a little bit easier view.
I think as I turned him, some
of the muscles got extended, some
of the tendons a little bit
and it just sort of pushed things a
little bit more out of you.
Now we should be able to come up and follow it.
We're still losing it a little bit here, so I'm gonna see
what I can follow it more and transverse.
Now he might have a little bit,
his anatomy might be such.
We're getting a little bit of artifact right here. Okay.
And we're losing it a little bit here,
but some folks, you know,
you can follow it up pretty far
and others you don't get to follow it quite so far.
The important part though, we saw the takeoff
of the anterior tib.
I'm just following it here, transversely
and we're coming up, it's getting a little deeper,
but again, we had a nice normal waveform
and we're getting a little bit, a little bit up here now.
Okay? And in a minute, not much further.
It's gonna take a, a nose dive and go away from us.
Let's put our color on here for a sec.
Okay. And I'm coming up. I'm coming up.
I'm still coming. Still coming.
And now we can see where's it going?
It's dipping away from us right here. Okay.
As you can see where my hand is, it's coming up,
it's gonna go behind the tibia
through an opening in the interosseous membrane
and hook back up to the popliteal.
So we've got a nice,
and there's the companion veins alongside as I move here
and there, but we should still see that nice
multiphasic pattern
And that's exactly what we're getting.
Okay. So basically we could follow it further than I
thought, but again,
about at this point it's gonna dip down and go away from us.

Conclusion and Recap

So to recap, we've taken you
through the lower extremity arterial duplex.
We started up here at the common femoral artery.
And as I said, if that's all nice
and normal, we're good here.
If it's not, then we'd wanna go further north
and look at the iliacs and even the aorta.
But that's not routinely done in some labs.
Some labs do the whole thing.
That's a matter of your preference.
Up at the top we looked at the common femme and the,
and the origin of the profunda femoral
or deep femoral artery.
We scan through the whole length
of the superficial femoral artery.
Then we kind of came from behind the knee like this
and we evaluated the popliteal, the takeoff
of the anterior tib, the tibial perineal trunk,
and then from a more posterior medial approach in
through here, we followed the posterior tibial
and perineal arteries down following the posterior tibial
artery behind the ankle.
And then just to wrap it up,
we found the dorsal pettus at the top of the foot
and followed it back as it became the anterior tib
and continued all the way up to about here
where it dove down away from us
to come back up into the popliteal.
We looked at color, we looked at the gray scale,
and we looked at doppler and we recorded everything.
And that is the lower extremity arterial duplex scan.