Venous Duplex Examinations: What Else Do We See? - HD

Introduction

Hi, I'm John Rito.
I'm from the North Shore LIJ health system
and the Hofstra North Shore LIJ School of Medicine.
My topic today is venous duplex examinations.
What else can you see?
And I'm going to talk about some of the non
venous pathologies that you can encounter
during your lower extremity venous examinations.
In this presentation, we are going
to discuss the numerous findings that can be encountered
during the venous examination.
These findings can indicate the cause of pain
or swelling that exists apart from venous disease.
And of course recognition is important
to institute appropriate treatment.
Some of the nonvascular pathologies that we will discuss
include edema, hematoma, lymph nodes,
and popliteal cyst.
These are the most common abnormalities
that we see during our studies.
Less common pathologies include abscess, joint effusion,
adenopathy and tumor.

Soft Tissue Edema

Let's start out by talking about the most
common abnormality.
Soft tissue edema.
This obviously is a common cause of limb swelling.
It's associated with elevated venous pressures.
Causes of increased hydrostatic pressure includes congestive
heart failure, fluid overload, as well
as deep vein thrombosis, venous compression
and venous obstruction.
On this gray scale image, you can see fluid interspersed
between the soft tissues of the lower extremity.
Besides seeing fluid in the tissues,
congestive heart failure is associated
with increased pulsatility in the venous waveforms.
As you can see from this image,
these waveforms are usually bidirectional.
And this finding is also seen with tricuspid regurgitation.
This occurs because there is increased transmission
of cardiac phase changes.
And if you look at the waveform, you can see
that it mimics arterial pulsations.
So you have to be certain where the sample volume is
before making your interpretation of the flow pattern.
Here's a look at a chest x-ray in a patient
with this flow pattern.
And of course seeing the increased pulsatility makes one
think about the possibility of CHF
or tricuspid regurgitation.
And you can see on the radiograph the patient is
in congestive heart failure.
Venous congestion is associated with bilateral leg swelling.
And a study that we did a few years ago showed
that DVT in bilateral leg swelling
with no risk factors is less than 5% of cases.
But it's important to recognize that in patients
with risk factors, this can increase in up
to 23% of patients.
So in the absence of risk factors,
bilateral leg swelling is usually not associated with DVT,
but with risk factors you have to consider the possibility
of underlying clot.
When we see patients with soft tissue edema,
we will see
that fluid collects in the subcutaneous tissues.
And in this image you can recognize a marbled
or reticulated appearance that we see the fluid
interspersed between the soft tissue.
Sometimes you'll actually recognize collections
of fluid in patients that have marked edema
with soft tissue swelling can come attenuation of sound.
So if you have marked attenuation, you may want
to consider switching from
that high frequency linear transducer
to a lower frequency probe.

Lymphedema

Lymphedema is also associated with leg swelling,
and this can also be unilateral
or bilateral lymphatic obstruction, which produces the fluid
that we see in the tissues as associated with malignancy
trauma and prior surgery.
And the appearance is very similar to what you'd see
with soft tissue edema.
One difference may be that you may have concomitant
lymph node enlargement.

Hematoma

Hematoma is another soft tissue abnormality
that we may encounter
during our lower extremity duplex examinations.
Hematoma may be a focal abnormality
or it may present as diffuse swelling. In patients
that have underlying pain, one thing is important
is to elicit a history of trauma prior vigorous exercise
surgery or anticoagulation.
These are important factors when considering the etiology
of masses in the soft tissues.
The mass may be cystic complex or solid in nature
and may have smooth or irregular borders.
One feature of hematoma is
that it will retract over time.
And so following up these abnormalities may be helpful
when the etiology is uncertain,
hematoma may spread within the fascial muscle planes
and may become hypoechoic or isoechoic to tissue.
One of the key features of hematoma is
that there will be no flow in the mass
or collection on doppler study.
We want to assess in large hematomas whether there is actual
compression of underlying vascular structures
because this is certainly going to produce
abnormalities related to venous obstruction, as well
as the potential for underlying DVT.
And when there is compression of the venous structures,
you may have low velocity flow,
which may be difficult to detect.
So whenever we see low velocity flow, particularly
with loss of phasicity and
waveforms that do not have any pulsatility,
we may want to consider proximal obstruction.

Muscle Injury

Muscle injury is another abnormality that can be associated
with lower extremity pain and swelling.
This may result from blunt or penetrating trauma.
It could also occur with a muscle pull
or tear with exercise. Is associated
with hematoma and inflammation.
And this particular example, you can notice
that there's a hypoechoic structure within the body
of the muscle in this case representing
bleeding within a muscle tear.
Initially, the hematoma and injury may be hyperechoic
and heterogeneous and over the course
of time may become more intermediate to low echogenicity.

Lymph Nodes

Lymph nodes are another common abnormality that we see
during our duplex studies.
Lymph nodes can occur in the groin, cervical regions,
and axillary regions.
During our studies,
we also see lymph nodes in the perivascular areas such as
around the aorta, inferior vena cava and iliac vessels.
It's important to recognize the normal lymph node.
We typically describe a normal lymph node
as having an ovoid shape with a hypoechoic peripheral mantle.
Here you could see on the longitudinal view
of the lymph node we have a hypoechoic periphery.
And then we'll see an echogenic hilum usually containing fat
and blood vessels.
The normal lymph node is usually less than one
centimeter in diameter.
So in the example in the top left hand side here,
you see the longitudinal view.
And then on the axial view,
you can appreciate the peripheral hypoechogenicity
and the central echogenicity related to the hilum.

Lymphadenopathy

Lymphadenopathy is identified as a large area
of enlarged lymph nodes or masses.
They may cause swelling due to venous
or lymphatic obstruction
and when inflamed can cause underlying limb
or extremity pain.
Here we have a very enlarged lymph node with
normal architecture where we can see peripheral
hypoechoic mantle
and central echogenic hilum where the vessels will pass.
Color doppler will typically reveal arterial flow in the hilum,
which we can identify right here.
We see the central feeding vessel
with branching from the center
of the lymph node to the periphery.
If we sample these vessels with pulse doppler,
we typically will see a low resistance arterial pattern.
Now this pattern doesn't necessarily distinguish
between inflamed or malignant lymph nodes.
It's not a discriminating feature.
In fact, distinguishing inflammatory from malignant lymph
nodes can be difficult, benign, or inflamed.
Lymph nodes typically maintain their normal ovoid shape.
In other words, the short axis diameter is less than half
of the length of the node.
And besides maintaining its normal shape,
typically we will see that the central hilum is intact
as we have in this example.
Malignant lymph nodes on the other hand, tend to be rounder.
They lose the echogenic central hilum
as we see from this example.
Notice here we just see a heterogeneous mass without the
normal architecture of the lymph node.
And with color doppler we can see irregular branching
and disordered vascularity.
And these features tend
to be helpful in distinguishing malignant nodes
from inflammatory nodes.

Popliteal Cyst

Another common finding is a popliteal cyst.
A popliteal cyst represents a focal fluid collection found
behind the knee, posterior and medial to the knee.
Joint fluid typically collects in the gastrocnemius,
semimembranosus bursa due to inflammation.
This can be related to arthritis such
as rheumatoid arthritis
or degenerative joint disease may be related to trauma,
infection, dialysis or hemophilia.
And although the typical popliteal cyst is a localized
collection of fluid, it can extend into the calf
muscles and may rupture.
This will produce underlying extremity pain, tenderness,
and clinically can mimic deep vein thrombosis.
Typically the popliteal cyst termed the baker cyst,
and this occurs when it's seen adjacent to the medial head
of the gastrocnemius in this location.
Popliteal cyst or baker cyst are synonymous terms
and as I mentioned it commonly found
during our venous duplex studies.
The classic popliteal cyst will appear as a simple cyst
with smooth margins, with well-defined walls,
no internal echoes and good posterior sound enhancement.
Here in this example of a popliteal cyst,
you can actually see the connection
with the underlying bursa.
Now a popliteal cyst can become complicated, usually
with rupture of the cyst.
And when the popliteal cyst becomes a complex cyst,
it may demonstrate irregular cyst margins,
echogenic internal debris.
You may see extension into the calf,
But there should be no internal vascularity.
And this is one way we can distinguish it from a some type
of mass or tumor.
The differential diagnosis for a complex
baker cyst would be hematoma, abscess, and edema.
As I said, we can exclude tumor by the absence
of vascularity.

Joint Effusion

Less commonly. We may identify a joint effusion
during our investigations for lower extremity DVT.
In this example here you can see there's a collection
of fluid in the joint space
separating the joint capsule from the underlying bone.
And the fluid here is anechoic.
Many times we'll see distention
of the joint capsule with fluid.
This can be due to an inflammatory, infectious
or traumatic event.
And of course, if we're concerned about infection,
we can use ultrasound to guide needle placement
to sample the fluid.
These effusions may appear simple or complex.

Abscess and Soft Tissue Infection

On our ultrasound studies,
many times we'll have patients who present with pain,
swelling, focal skin, thickening and erythema.
And in those patients we consider underlying infection.
Now they may be difficult to identify,
but there are certain things that we can look for to help
with the diagnosis.
As in this example, you can see that there are collections
of fluid interspersed in the soft tissues
and there'll be overlying soft tissue swelling,
erythema, local pain that help us to look
for a diagnosis of soft tissue infection or cellulitis.
Cellulitis representing a diffuse soft tissue, inflammation
of the skin and subcutaneous tissues.
And of course, anytime we have a focal area of pain
or swelling, we need to be careful
to exclude underlying DVT.
Now sometimes when we evaluate patients with infection,
we may actually identify an abscess
and we can make the diagnosis
by finding a well-defined collection in the soft tissues
as we have in this particular case.
The collection may be simple or complex in appearance
and may contain gas bubbles.
And we recognize the gas bubbles as very bright reflectors,
which may produce comet tail ring down artifacts
with posterior shadowing.
Commonly there'll be peripheral vascularity
around the wall of the abscess.
And also a typical finding would include increased echogenicity
of the fat surrounding the abscess.
And notice here how bright the surrounding subcutaneous fat
is around this focal fluid collection,
which was evidence of an abscess.

Tumors

One thing we must consider when we find soft tissue masses
during our venous studies is the possibility
of underlying tumor.
Less commonly they can cause leg swelling and tenderness
and may be benign or malignant.
Solid masses in the tissues need to be
distinguished from superficial or deep vein thrombosis.
And this can be difficult particularly in the calf
where the veins may be difficult to find.
And we may see small scattered hypoechoic lesions
that can represent tumors.
A particular example is neurofibromatosis
where you'll have multiple masses associated
with the vascular structures of the calf.
Benign tumors are not uncommon.
They may represent lipomas
and myofibromas desmoid tumors, as I mentioned,
neurofibromas and of course hemangiomas. Lipomas are the most common
benign soft tissue tumor that we will see.
They tend to be iso
or hyperechoic to the surrounding structures
and can demonstrate scant internal vascularity.
They may require CT or MR for definitive diagnosis.

Malignant Tumors

Malignant tumors may be related to primary
or metastatic disease.
The more common primary neoplasms
that we may see would include sarcoma
and lymphoma metastatic disease.
One should think about lymphoma, leukemia, or melanoma.
These typically solid but may be complex.
And if we turn on color doppler,
we can see internal vascularity.
And the classic flow pattern
for malignant masses would be a high velocity,
typically greater than 25 centimeters per second waveform
with a low resistance arterial pattern.
So be sure to sample the vessels
that you see in the soft tissue tumors when
you encounter them during your exam.

Non-Venous Vascular Pathology

One last example that I wanted to share
would be a non venous vascular pathology.
And in this particular case, this patient presented
with right leg pain.
And we notice here that we're looking at the femoral vein
and the superficial femoral artery at the mid thigh level.
And in this particular case, we notice
that the superficial femoral artery is patent to the level
of the mid thigh, and then there's abrupt cutoff of flow
and the arrow is pointing to a collateral vessel.
So in this particular case, right leg pain may be related
to arterial occlusive disease.
And since the artery and the vein always run together in
the during examination of the deep structures,
one should always be paying attention to the arteries
as well as the veins looking for evidence
of arterial stenosis or underlying arterial occlusion.
This patient went on to have a magnetic resonance angiogram
to better delineate the extent
of the arterial occlusive disease.
And you can see the nice correlation between the
duplex examination showing occlusion
of the superficial femoral artery at the mid thigh level
and the MR also demonstrating the arterial occlusion
and the collateral coming off at the same level.

Conclusion

So in conclusion, there are numerous nonvascular findings
that are common during the venous duplex examination.
The cause of the extremity pain and
or swelling can be identified by being careful
during these examinations
to pick up these nonvascular findings
and recognition of the finding is critical
for appropriate diagnosis.
And of course, integration of the clinical history
with the sonographic
and clinical findings is essential to accurate diagnosis.
Thank you.