Ultrasound of Cervical Lymph Nodes - SD

Introduction

Good afternoon.

My name is Brooke Jeffrey.
I'm professor of radiology
and chief of Abdominal Imaging at Stanford University.
And this afternoon I'm going to talk
to you about ultrasound evaluation of cervical lymph nodes,
emphasizing criteria for normal and abnormal,
and try to provide you with some tips on how
to perform ultrasound guided FNA of these nodes.

Focus of the Lecture

This afternoon my lecture is going
to focus on the ultrasound evaluation
of cervical lymph nodes.
And what I'd like to do along the way is
to review the indications
and ultrasound technique for evaluating these nodes
to emphasize certain anatomic landmarks for distribution
of nodes and really to focus on the criteria that we'll use
for distinguishing normal from abnormal and discuss role
and technique of ultrasound guided FNA
of these cervical lymph nodes.

Role in Head and Neck Oncology

For the most part, the main evaluation
of cervical lymphadenopathy relates
to head and neck oncology.
And I think it's fair to say
that sonography has a relatively limited role in staging
most head and neck cancers
and current state-of-the-art ct, MR
and PET are used primarily, for many head
and neck carcinomas, many
of which are squamous cell carcinomas.
The exception to this is in the patient with thyroid cancer
and here sonography is equal or superior to ct
and MR in defining many
of the characteristics of nodal disease.
And of course once an abnormal lymph node is found with CT
or MR or pet, it's much easier as we'll see to be able
to biopsy that lymph node with sonographic guidance.

There has been some data to suggest
that in comparing ultrasound with ct,
that they're essentially of equal accuracy
with papillary carcinoma,
but ultrasound has the distinct advantage of low cost, lack
of radiation, lack of contrast agents,
and it has become the technique of choice,
particularly in the patient
with papillary cancer in which we suspect there is
involvement of cervical lymph nodes.

It should also be pointed out
that there's certain anatomic regions such
as the thoracic inlet that are somewhat tricky to evaluate
with ct and this is a patient who had, CT of head
and neck read as a negative for lymphadenopathy.
It's only in retrospect that we can see
soft tissue fullness in the thoracic inlet.
Now the cervical lymphadenopathy is much easier to see,
with ultrasound.
And of course if we can identify things with sonography,
we can then go on to biopsy.
And this is an example of a recurrence of non hunch lymphoma
that was much better, detected with ultrasound rather than ct.
The point to be made is
that there's certain anatomic areas like the thoracic in
inlet where ultrasound excels.

Ultrasound Technique

Now, in terms of technique, we want
to use the highest frequency transducer
that will give us adequate penetration in the neck.
And we, we say that for several reasons.
Number one is to improve the spatial res resolution,
but number two is
to improve the colored doppler sensitivity.
And we'll be seeing
that most clinically relevant lymphadenopathy is going
to be along the jugular vein,
what's called the lateral chain.
And once we identify a potentially abnormal node
with gray scale, we're going to go on to use colored ER
to further characterize that lymph node.

Key Anatomic Spaces

So let's look at the key anatomic spaces in the neck
that we're going to be looking at.
And here you can see the submental and submandibular spaces.
And then along the jugular chain we have the upper, middle
and lower cervical chain,
and then along the posterior triangle.

Now these spaces, correlate to anatomic levels
and you'll hear head neck surgeons refer
to a level two lymph node.
Well that's right around the submandibular gland
in the mid portion of the neck.
That's level three, the lower portion four
and posterior triangle five, et cetera.
And you'll also hear of the term the central compartment.
And these relate to nodes in the bed of the thyroid
that are removed at the time of total thyroidectomy.
So that's an important anatomic area as well.
And we'll talk about recurrence in the central compartment
for thyroid cancer.

Now, in beginning our anatomic search for lymph nodes,
we find it very easy to do a survey along the jugular vein
to detect lymphadenopathy.
And we can see here that levels two, three
and four really are the most prevalent sites
that we want to investigate.
There rarely are some metastasis in the submental area,
rarely in the posterior triangle, but levels two, three
and four really are the key anatomic areas.

Characterization of Cervical Lymph Nodes

In terms of characterization of cervical lymph nodes,
we wanna look at four parameters their size,
they're morphology, genicity,
and of course the color doppler characteristics.

Normal Lymph Nodes

Now, in terms of normal lymph nodes, again, it's important
to recognize how the literature has
designated by convention.
The measurement of nodes is in these short axis.
This is very critical
because the long axis really is not a relevant measurement.
In general, most normal neck nodes are elongated or oval,
and they're not round.
They tend to be hypo coic and they may
or may not have an echogenic hilum, which may relate
to fat in the, the central portion of the lymph node,
or it may be related to acoustic reflectivity
of the central lymphatics.

Now with colored doppler, normal neck nodes rarely have much
color, but when they do, it always is in a pattern
of central arborization
and that'll be very important
as we distinguish abnormal neck nodes.
Morphology, neck
and genicity always trumps eyes
determining if the node is abnormal.
It's a very important, observation.

Here are examples of classically normal neck nodes.
This one has a clearly defined echogenic hilum.
It's elongated, it has minimal flow coming in,
in a central pattern.
Again, I wanna make the point that only the short axis
of the node is a relevant measurement.
And you do not wanna be calling your clinician
with this very elongated node and call this a two
and a half centimeter lymph node.
It's really only a four millimeter node
because the short axis is the only relevant measurement.
And here are some other examples of normal,
elongated neck nodes.

And by by way of contrast, here's an abnormal rounded node
that had metastatic thyroid cancer immediately adjacent
to a normal elongated node.
So morphology is often a key first finding
for abnormal nodes.

Now, is it the case
that all elongated neck nodes are normal?
No, because if we see abnormal echogenicity
and abnormal color findings, that will trump,
the elongated morphology.
Here's an example of papillary carcinoma involving the N
nodes, which has microcalcifications and cystic change.
So we can see on the left
and then on the right in the color image instead
of a central pattern of arborization.
Now we have a peripheral flow pattern.
So, elongated lymph nodes may occasionally show other
findings that clearly indicate involvement with disease.
Here's another elongated lymph node
where there are clearly evident microcalcifications.

Now, microcalcifications are not strictly speaking
specific for papillary cancer,
although in the post thyroidectomy patient,
we rarely encounter anything else.
But depending upon your patient populations,
cervical tuberculosis
with granuloma formation may cause microcalcifications
again, but that's a very rare phenomena indeed.

Now, reactive lymph nodes tend to be slightly enlarged,
but there's for the most part elongated
and they have slightly increased flow.
But again, it has a normal central arborization pattern.
The echogenicity is usually always no normal,
and these were lymph nodes that were biopsied
and proven to be reactive Lymph nodes in a patient
who had pharyngitis,
and again, see the elongated slightly,
plump if you will, morphology again on color flow.
There's a central art pattern of arborization
and some reactive lymph nodes, can be quite large
and we can be clearly confident that they're reactive again,
by the elongated configuration, the preservation
of the echogenic fatty hilum
and the central flow abnormal neck nodes tend to be rounded
and they tend to have, borders that are often irregular.
That's not specific for tumors.
Sometimes other infectious diseases such
as TB adenitis may cause the borders to be irregular.
Frequently there's loss of the echogenic hilum
and often there are morphologic changes that we can see
with gray scale that tell us that node is abnormal.
We've seen some examples already
with internal cystic change calcification
or increased echogenicity.

The color doppler flow, shows a wide spectrum
of abnormalities,
but basically it's some deviation from the pattern
of normal central ar arborization.

Abnormal Lymph Nodes

So let's look at some, abnormal nodes
and some examples of rounded morphology
with lobulated irregular shapes.
And here's example of a patient
with metastatic breast cancer.
These are rounded nodes
and instead of having the central flow, peripheral flow,
here is a patient that has metastatic papillary cancer.
Notice how irregularly marginated the node is with subtle,
but a demonstrable, cystic change within the node and,
and markedly increased flow pattern, not
that we would associate it with a normal flow pattern.
These nodes compared
to the adjacent strap muscles show increased echogenicity
and they have a rounded morphology,
and these two are involved with papillary carcinoma.

Here's another patient with rounded morphologic nodes,
and this was,
supraclavicular lymphadenopathy related to lung cancer.
Other rounded nodes, we can see here
with abnormal flow patterns
and very rounded morphology related to lymphoma.
And again, another case with rounded morphology,
abnormal flow related to breast cancer.

When we see marked nodularity
or loation of the contour of the node, we have to consider
that there's extra capsular invasion,
and that's particularly common with a lymph node such
as squamous cell carcinoma.
Here's, such an example
and we can see in the correlative MRI the node is
invading right into the muscle.
The reason why that's important as the surgeon goes
to extract the node, forewarned
that this is locally invasive, the head
and neck surgeon will also take a surrounding cuff of muscle
to get negative margins.
So we can, when there's marked nodularity, often suggest
that there is extra capsular invasion.

Here's another example of abnormal morphology
with irregular contours.
And this too had extracapsular invasion notice the multiple
areas of microcalcifications.
So one teaching point to make about papillary carcinoma is
that echogenicity is often the key finding,
whether it's cystic areas or microcalcifications
or increased echogenicity.
So that trumps just about every other finding.

Now the reason the sonography has emerged as the technique
of choice to evaluate patients
with papillary carcinoma is the ability
with high resolution transducers.
Now to see these subtle microcalcifications subtle areas
of cystic change and cont irregularity.
And in addition to the features we've already mentioned,
such as loss of the normal echogenic hilum
and increased, nodal echogenicity, these are very
specific features and when we look at the data on this,
it's quite impressive.

Here's an example of,
198 nodes in 112 patients published in JUM
by Rosario et all.
And look at these specificities if there's internal cystic
change, a hundred percent specificity calcification, again,
a hundred percent specificity.
So really, a very specific technique for evaluation
of cervical lymphadenopathy.

Ultrasound-Guided Biopsy Techniques

Now, one of the reasons that ultrasound is
so helpful in terms of guiding biopsy is we can define the
areas that are gonna be most fruitful to direct our needle.
And here we can see the cystic change in the upper pole
of this lymph node telling us it's a metastatic,
node involved with papillary.
But of course, we wouldn't wanna biopsy that area.
We would want to direct our needle
to the solid vascularized portion.
Similarly, in this patient
with extensive int nodal cystic change, you do not want
to be aspirating simply the fluid components.
You want to direct your needle towards the central area
that has multiple calcifications.
Similarly, in this patient, the mid
and lower pole has cystic change.
The upper pole is more solid,
and here we can see examples
of increased echogenicity cystic change in a very,
abnormal, lymph node.
Another example where there is more focal cystic change,
again, we would want to direct our needle away from that.

Now, occasionally in patients that have sive lymphadenitis,
you'll have abscess formation.
And this was such a patient who had a chronic
infected lymph node and we aspirated this incentive
for culture and sensitivity.
So cystic change in lymph node, may be related
to infection in the appropriate clinical setting.
Generally in the patients who are post thyroidectomy
for papillary cancer, that's not a clinical concern.

Here's a really nice example of increased echogenicity,
marked a markedly abnormal node.
We can see they're focal microcalcifications.
And here's a more, confluent area of calcification.
So sometimes these calcifications sort of aggregate
and may cause acoustic shadowing.
So any calcification at all is always circumspect
and always very suspicious for metastatic papular cancer.
Whether it shadows
or not, some of the nodes are dramatically hypervascular.
And here is a patient,
actually the thyroid gland was completely normal in this
individual and a thyroidectomy had only a two millimeter
carcinoma yet presented with a neck node.
See how strikingly echogenic it is
and how strikingly vascular this is.
We'll make the point when we talk about biopsying highly
vascular lymph nodes that we have
to use a capillary technique rather than a suction technique
or it'll just get blood.

So in papillary carcinoma, the echogenicity
of metastatic nodes is often different
than the primary cancer.
Most primary cancers of the thyroid tend to be hypoechoic.
And here's an example of a lesion that's taller than wide.
It has, discrete margins has increased flow.
Typical thyroid cancer.
Here's another patient taller than wide hypo coic
thyroid cancer, but the lymph node is markedly
different than the primary tumor.
Notice that the lymph node is now echogenic
and despite the fact that no microcalcifications were seen
in the primary tumor, it's just loaded
with microcalcifications.
So don't require
that the neck nodes look the same as the primary.

Here's a patient with a primary cancer in the thyroid
and just immediately adjacent to it,
the cystic nodal mats has a extensive cystic change.
So again, there's often quite a discrepancy
in the echogenic appearance of nodes versus primary cancer.
There's a solid, Palo carcinoma that has calcification
and yet extensive cystic change within the nodal mets.

Now, we've made the point
that the normal doppler flow pattern,
is a central pattern
that's often very minimal in normal patients.
And here you can see increased echogenicity.
Notice how rounded the nodes
are compared to the strap muscles.
These nodes have increased echogenicity
and have really a striking degree of peripheral flow.
So here's an example where the color doppler
and the, morphology
and echogenicity all point to abnormal lymph adenopathy.
And these are nodes that are just stacked up each other,
in level three along the jugular vein.
And here we can see,
these hypervascular lymph nodes on a contrast enhanced
coronal and sagittal ct,
and you can see how vascular they are.

Notice again on the colored Doppler
examination of these two patients.
Some of these nodes have real spotty areas
of increased vascularity.
You will not see increased flow in cystic,
areas within the node.
And so again, we want to direct our needle
to the solid vascularized portion of the lymph node.

Here's just another patient with chaotic flow pattern.
It's often quite hard
to give morphologic descriptors of the flow patterns.
It's just that they look very different than the,
very subtle central pattern.
So any deviation from
that central pattern should be considered abnormal.

So when biopsying,
these nodes direct the needle away from cystic areas
and towards areas of visible blood vessels.
However, if there's a lot
of vascularity within the lymph node, we want
to first use an aspiration technique.
This is an example of a patient
who has very large lymph node, in the right neck.
Microcalcifications, this was biopsied an
outside institution several times with,
no,
adequate cytology.
And here we can see the reason for that is that the area
of the node that shows dramatic increased flow is,
quite vascular and we would only get blood.
So we directed our needle away from that node.
In this case, we could use a suction technique
because we're going into solid tissue,
but it wasn't ritually vascularized.
It's sort of a window of decreased vascularity.
And here you can see on the cytologic specimen the sort
of papillary front like nature of papillary carcinoma.

Now, when we're referred patients with head
and neck cancers, particularly when it's squamous cell
carcinoma, often these nodes have a striking degree
of central necrosis.
And here head
and neck gadolinium, MRI notice that on the right one
of them is homogeneously enhancing,
but the more anterior node, has extensive cystic change.
So with squamous cell carcinoma
because of the cystic appearance,
and here's just another example on,
now a T two weighted sequence, with fat suppression,
how cystic, these nodes can be
because of the extensive, central necrosis.

So when presented with, a patient, either
with squamous cell
or with papillary carcinoma,
that has extensive internal cystic change.
The key here in terms of making the diagnosis is
to direct the needle to the solid peripheral tissue.
And so you want to go towards the periphery
and not centrally.
And here's another example, comparing the ultrasound to,
the contrast enhanced mr.
And it's often very good to be looking,
at the mr at the time of biopsy to sort of,
map out in your mind exactly
where you're going to put the needle.
And here's another example of extensive cystic necrosis,
but you can see there's a little portion of solid tissue,
more medially and that's where you need to biopsy.
And in general, you'll get much more
cellularity in biopsying the peripheral
portion of a lymph node.
And here's such an example, previously biopsied at an
outside institution, negative results.
And you can see although the the node looks, uniform,
there was central necrosis and we can't always see it
because we don't have contrast agents as we do it head
and neck CT and mr.
And here's the example of of sewing how the, needle is on the periphery.

Now if you're presented with, a node
that's got extensive cystic change
and one that's very vascular,
and to biopsy these lymph nodes, you need
to take a different approach.
We can be successful biopsying cystic nodes if we direct the
needle in the so solid portion
and we would use the suction technique
because this tends, depending on the vascularity,
if this wasn't particularly vascular,
the point being is we would not want
to direct our needle in the cystic portion of the node.
Similarly, these hypervascular, these are small nodes,
but they were positive they can be biopsied successfully.
And the point being is we want to,
use a capillary technique, not a suction technique.
We'll just get blood if we use a lot of suction.
So it is possible to do FNA of less vascular nodes
and we have to know when to do suction versus capillary.
And it really depends on the, degree of vascularity.

Post-Thyroidectomy Evaluation

Let's talk a little bit about the post thyroidectomy patient
and using ultrasound to look
for recurrence either in nodal sites or in the thyroid bed.
And if we're talking about the thyroid bed, we want
to pay strict attention to any hypo coic tissue,
particularly if it's vascular.
And biopsy should be considered for lesions
that are five millimeters or greater.
And in general, they tend to, be hypo coic,
occasionally see microcalcifications,
and a lot of them we found have increased flow.

So here's a typical patient
that has recurrent papular carcinoma within the thyroid bed.
And here you can see we're directing our needle into,
this recurrent mass.
And this is proven to be papillary
carcinoma in the thyroid bed.
And again,
we can see another hypo coy nodule in the echogenic
fibro fatty tissue.
If we can see it, we can direct our, needle into it.
And here's an example, of actually going
to the operating room and performing an intraoperative
ultrasound to, to biopsy, this lymph node
and to guide the surgeon intraoperatively
the color can be very helpful, in looking for a variety
of thyroid bed recurrences.

And here's an example of very subtle increased thickening
of the soft tissues around the the trachea.
We can see subtle widening of the trachea here.
And with increased flow, we can see
that there is a more clearly evident
hypoxic soft tissue mass that is really richly vascularized.
And this is a extensive, recurrence
that's invading the trachea.
And the hallmark is hypo coic tissue.
That's richly vascularized.