Sonography of Mammary Implants - SD

Introduction

I am Tom Stavros.
I'm from the Suter Pacific Women's Health Center
in Santa Rosa, California.
And today I'm gonna talk to you about ultrasound
of breast implants.

Sonography of Mammary Implants

Today we're gonna talk about sonography
of mammary implants in the United States.
MR has been the procedure of choice for evaluating implants.
It's efficacious, it's relatively operator
independent, it's well reimbursed.
And even today, if the sole question is,
is a silicone implant ruptured, we have a tendency
to go to MR first.

But with ultrasound, we can get just as good an evaluation
of the implants, but it's a much more operator dependent,
it's a very long exam because you have
to examine the entirety of both implants.
And in general, we don't use ultrasound
as our first test when the question is ruptured implant,
also ultrasound is relatively poorly reimbursed.

Having said that, it's still very important that anybody
who does breast ultrasound understand the range
of normal appearances of implants and implant abnormalities,
because the majority of women with implants that we see,
who are in the cohort who gets breast cancer,
are perfectly happy with their implants.
They have no implant related complaints,
and they're presenting to us for evaluation
of either a mammographic abnormality
or palpable lump, which are the same indications
that women without implants present to us for.

So in the process of evaluating either the mammographic
abnormality or the palpable lump, we have an opportunity
to look at the implant.
And the truth of the matter is,
since ultrasound is the procedure of choice for evaluating
mammographic or palpable abnormalities, the sonographer
who does breast ultrasound will actually see far more
implants than he will ever see on MR.
We'll probably see 10 times more implants on ultrasound than
we see on MR because the question again is not,
is there something wrong with the implant,
but what is the cause of the palpable lump
or the mammographic abnormality?
And the evaluation of the implants is incidental.
But for this reason, the breast imager must be familiar
with the range of normal and abnormal implant findings.

Principles for Evaluating Implants

Now, the principles to keep in mind are that the variety
of implants is so great that it's impossible
to detect implant abnormalities without totally
understanding the full range of normal,
the clinical problems,
and implant abnormalities may be related to each other
or may be totally unrelated.
So the palpable lump may be caused by a cyst or cancer,
but there may be an incidental implant abnormality.
On the other hand, the palpable lump may be related
to an implant valve or a radial fold.
So we have to keep in mind
that the implant abnormality may be related
or unrelated to the cause for presentation.
Most women with implants present with lumps
or mammographic abnormalities, not implant problems.
So I've said that,
and I'll say that over and over again.

Implant Problems and Complications

Now, implant problems
and complications include implant rupture,
and we divide those into extracapsular
or intracapsular, capsular contracture,
which is generally a clinical diagnosis.
But we can also make with ultrasound, herniation
of the implant through a tear in the capsule of the implant.
And we'll discuss what the difference between the shell
and a capsule is as we go along.
And abnormal peri-implant effusion,
they can be too large or tense.
They can be infected or hemorrhagic.
Capsular calcification is really a minimal or minor complication,
but can certainly adversely affect our ability to interpret.
And for retropectoral implants, we can get tears
of the overlying pectoralis muscle.

Variety of Implants

This collage is representative
of the great variety of implants.
We have different types
of implants in terms of contents.
We have different types of implants in terms
of shell characteristics.
And we have different implantation sites.
So the three main variables are the type of lumen contents.
And there's three main types.
You can actually subdivide it into even more types.
But in general, we have single lumen silicone gel contents.
We have single lumen saline contents,
and we have double lumen usually with the silicone on the inside and the saline on the outside.
Although expanders may have the opposite appearance,
the shell surface characteristics also vary.
And we can have smooth or nontextured implants.
We can have lightly textured implants,
and we can have heavily textured implants with
or without polyurethane.
And then finally, the sites
of implantation can be subglandular
or prepectoral in those terms can be used interchangeably
or retropectoral.

Now here we have four implants.
All of them have textured shells.
The one in the right upper corner is heavily textured,
and the other three are lightly textured.
But notice that the two on the left have valves.
This indicates that they're
single lumen saline implants,
and that valve is where the saline is put in to the implant.
After it's placed, the implant is put in collapsed,
and then it's expanded after it's placed.
The two on the right have no valves,
and they contain silicone gel contents.

Distinguishing Saline from Silicone Gel Implants

Now we can tell with ultrasound
whether an implant contains saline
or silicone gel by an artifact created
by difference in the speed of sound through silicone gel.
The speed of sound through saline is
1,540 meters per second.
The speed of sound through silicone gel is only about two
thirds of that, about 970 meters per second.
Since the ultrasound machine is calibrated to assume speeds of 1,540 meters per second,
that assumption makes the machine falsely make the posterior
wall of the implant look deeper than it really is.

So if we take a transducer
and we place it at the edge of the implant so
that we're showing half of the implant or
showing half of the field filled with implant
and the other half of the field filled with tissues,
we can see the difference on the left is a saline implant.
And because the machine is correctly assuming a speed
of 1,540 meters per second, it registers the posterior wall
of the implant correctly,
and it shows it to be flush with the posterior wall
of the enema basin in which this implant is being scanned.
And there's no step off at the edge of the wall.
On the other hand, the single lumen silicone gel implant
scanned within an enema basin phantom falsely projects the wall too deeply
because it's assuming the speed
of sound is 1,540 meters per second,
when in fact it's only two thirds that fast.
So you can see that there's a sharp
or an abrupt artifactual step off in the wall
behind the implant when it's a single lumen
silicone gel implant.

These are simply silicone gel on the right
and saline on the left in vivo instead of in vitro,
as the previous example was.
So we can see the chest wall
behind the single lumen saline implant on the left,
and notice that it's a continuous line.
There's no step off.
But behind the single lumen silicone gel implant,
the pecs muscle shows an abrupt step off.
So this is how we tell single lumen saline
from single lumen silicone gel implants.

Now, obviously in a double lumen implant,
you have both saline
and silicone with the saline in the outer compartment,
silicone in the inner compartment.
So we can see that the chest wall
behind the outer saline compartment shows no step off when
we get to the edge of the saline component
marked by the SA here.
But when we reach the silicone component of the implant,
we have a sharp step off in the wall.
Again, that's an artifactual step off.
Notice that because the shell
between the inner silicone gel containing compartment
and the outer saline compartment
is parallel to the beam.
We're not showing it well here,
but we can still tell where the edge is by the step off.

Now, one of the issues with this artifactual step off
is that its size will depend on the thickness
of the silicone gel through which
the ultrasound beam is passing.
So if we compress the implant too much,
then the beam is traversing through less silicone,
and the step off will be relatively small
and difficult to perceive.
If we scan less firmly
or with less compression, the AP dimension of the
silicone gel expands.
And that means that the beam is going
through a greater distance of silicone gel,
and we'll get a bigger, more obvious step off.
So the moral of the story is
if the implant is somewhat compressible,
don't compress it too much
'cause you may obscure the step off.

Also, the angle of incidence
with the chest wall has bearing on
how obvious the step off is, especially in people with capsular contracture.
The implant may be quite firm
and it may be somewhat difficult
to compress the implant enough to get a 90 degree angle
of incidence with the chest wall.
So we can see here that this is a single lumen silicone gel implant.
But because the chest wall is being projected obliquely
because the implant is so firm,
the step off is relatively difficult to perceive.
If in that same patient I heel
and toe the probe so that I can press the implant more
and create more nearly a 90 degree angle between the beam
and the chest wall, the step off is much more obvious.

So these are some technical tips
that could help you distinguish single lumen saline from single lumen silicone
gel with more accuracy.

Capsular Contracture

Now, one of the complications
of implants is capsular contracture.
And the theory is that capsular contracture occurs
because the capsule, which is a foreign body reaction
to the implant, it's actually the capsule is part
of the patient, becomes abnormally thick.
And the theory on textured implants was
that in nontextured implants,
all the collagen fibers in the capsule line up parallel
to each other, and then they can thicken and contract,
and make the implant under too much pressure
because of too thick and tight a capsule.
The theory with the textured shells is
that if you create this outward texture,
these little fuzzy little fibers
that protrude out at 90 degrees to the surface
of the implant, you'll disrupt the parallelism
of the collagen fibers in the capsule,
and you'll make the capsule weaker and less thick.

So on the left, we have a nontextured or smooth implant.
On the right, we have a lightly textured implant notice
that both have valves.
So these are both single lumen saline implants.

Implant Valves

Now the implant valve is well visible on ultrasound.
There are several types.
This is a diaphragm fill valve.
The actual valve is in the center
shown by the white arrowhead.
The anchors of the strap
that covers the valve are shown by the white arrows.
And the actual elastomer strap is
shown by the hollow arrows.
It covers the valve,
but it can be pulled to the side by the surgeon,
and then he can insert a needle.
He can insert a needle through the valve
and inject saline through that.

This is what it looks like in vivo.
This is a single lumen saline implant
scanned in a water path.
The valve is this hypoechoic rectangle in the center shown
by the white arrowhead.
The strap is the little white line superficial to it,
and the anchors of the two ovoid hypoechoic structures.

This what it looks like in vivo.
This is actually in a patient.
So again, the valve is the rectangular hypoechoic area
shown by the white arrowhead.
The strap that covered the valve is shown
by the white arrows, the hollow arrows,
and the valve anchors are shown by the small white arrows.

Now, on the left is a typical rectangular diaphragm valve,
but there's also a discoid diaphragm valve,
which I'm showing on the right.
It has a bit of a different appearance.
And so we're showing you here what the discoid diaphragm valve looks like.
Again, the valve is the rectangular
hypoechoic area in the center.
But instead of having a strap, there's an ovoid depression.
The actual point of injection is right here.
And notice that we don't have the anchors
that we have on the other thing.

Now, notice that the valve is either flush
with the outer layer of the shell or depressed,
but it shouldn't protrude
beyond the outer layer of the shell.

There is a third type of a valve, a leaflet fill valve,
which can simulate either a radial fold
or intracapsular rupture if you're not aware of what it is.
On the left, we have a short axis of it.
On the right, we have a long axis of it.
And in short axis, again, you can see that this is a leaflet
that extends into the implant.

Now, fill valves can present
as palpable abnormalities.
Notice on the left
that the rectangular valve is essentially flush
with the outer layer of the shell as shown
by the dotted yellow line.
This is the normal situation In some patients,
especially those who have capsular contracture
and increased pressure within the implant,
the valve can evert and become palpable.
So you can see here that about two thirds
of this valve has everted beyond the outer layer
of the shell, which is shown by the dotted white line.
This patient actually presented with a palpable lump,
and in this case, the palpable lump and the
implant abnormalities are related
because the palpable lump is the everted fill valve.

Normally, these valves are placed directly
behind the nipple and are not palpable.
But early on, they may rotate a little
and they might not be directly behind the nipple.
So if one is behind the nipple
and the other isn't, the valve may be palpable.
So that's another reason for palpability of implant valves.

Radial Folds and Wrinkles

Now, this isn't been defined in the literature,
but I distinguish a radial fold from a wrinkle.
A radial fold is when the shell invaginates
away from the capsule.
Remember, the shell is part of the implant.
It's made of a more cross-linked silicone elastomer, then the gel that fills the implant.
And the capsule is the part of the patient.
It's the foreign body reaction to the implant.
Radial folds are normal,
but they can cause clinical abnormalities,
and you will see later that they can become the site
of origin for intracapsular rupture.
A wrinkle is where the shell
and the capsule stay together and either invaginate
or evaginate together, but do not separate from each other.

The presence of radial folds is normal,
but they may cause palpable abnormalities in some
patients, and they're dynamic.
They come and go as the patient changes position.
And because they're dynamic at the apex of the fold,
a stress fracture can develop.
And through that stress fracture can be the site of origin
for intracapsular rupture.
It can be difficult in some patients
to distinguish a normal radial fold from early intracapsular rupture if the extravasated gel remains anechoic.

Now here's an example of two radial folds.
On the left is an anterior radial fold. This was palpable.
And on the right is a posterior radial fold.
These are virtually never palpable
because you can't dig your fingers deep enough into the
implant in order to feel them.
So only anterior radial folds can cause
palpable abnormalities.

Now, here's a patient in which the radial fold
was the cause of a palpable abnormality.
This patient had a palpable abnormality only in the upright
position, but she was scanned only in the supine position,
which I'm showing on the left.
And we always simultaneously scan
and palpate abnormalities while we're scanning them.
And we couldn't feel a palpable abnormality,
which is not unusual.
But you can see that the radial fold is rather small,
rather shallow, and rather rounded.

While the patient let us know in no uncertain
terms, that of course we couldn't find her palpable
abnormality because it was only present in the upright
position, and that we needed to scan her in the
upright position, which we did.
And you can see that in the upright position,
the radial fold has a dramatically different appearance.
It's now very sharp, very deep,
and it was palpable as sort of a crinkly sensation
as you ran your finger over this radial fold.
In the upright position, you could feel a little crinkle.

So the moral of the story is
radial folds may only be palpable in a certain position.
You need to listen to the patient
and you need to scan the patient in the position in which
the radial fold is palpable.

The other important thing from this is you can see quite
clearly why a stress fracture might develop at the apex of the radial fold.
You know that you can bend a nail or a metal rod over
and over and over, and if you bend it enough,
it will eventually fracture.
Where you can see here that at the point
of this radial fold, this radial fold will probably form several times a day
or several hundred times a day
as the patient's position changes.
And eventually a stress fracture may form there.
And this may be the beginning site
for intracapsular rupture.

Smooth vs Textured Shells

Now, we can also tell whether an implant is smooth
or textured by evaluating its appearance.
Now the shell shows up as a trilaminar structure.
The outer surface of the shell is a white line.
The inner surface of the shell is a white line,
and the thickness of the shell is denoted by an anechoic space between the two white lines.
So it's a trilaminar structure with two white lines
and a black center, and it looks
like a reversed Oreo cookie.
As a male, we're always focused on our stomach.
So I like to think of things in terms of food,
but this is the normal appearance of a nontextured shell.

Now, here we can see a closeup magnified view
of a lightly textured and heavily textured shell.
The texture is only on the outer surface.
The inner surface of the shell remains smooth.
So we would expect that it's only the outer white line
that's gonna be affected by texture.

So here again, I have nontextured
and lightly textured implants scanned in a
water path phantom.
These are in vitro scans.
You can see that in the nontextured shell.
The inner and the outer white lines are both sharp, thin,
and well-defined.
You can see that on the textured shell,
the inner line is still quite thin
and sharply defined, just it is in the nontextured shell,
but the outer surface of the shell is thicker
and less well-defined.
And in general, textured shells overall are thicker than
nontextured shells, but it's primarily in the outer
surface where this difference exists.

Now, in order to tell whether shell is textured
or nontextured, and to see that trilaminar appearance,
you can't scan with a great depth of field.
You have to use a shallow enough depth of field
and magnify the shell enough to see the lines.
This is the same nontextured implant on the left
and textured implant on the right scan
with the depth of field too great.
The shell is so minified
that we can't pick out the trilaminar structure.
So when you're evaluating shell
and the capsule shell complex, you do need to magnify enough
that you can separate the lines.

Now, a heavily textured shell has a variable appearance.
Many times the texture is so thick
that we just get an ill-defined incoherent
fuzzy single echo where we're not exactly 90 degrees to the shell.
And where we are exactly 90 degrees,
we may see a laminated
or multilaminar type of appearance.

Capsule Appearance

Now the capsule is part of the patient.
And so to create an in vitro model for the capsule,
I used a thin piece of prosciutto ham.
So we can see that the capsule also is trilaminar.
The leading edge of the capsule is a white line.
The trailing edge of the capsule is a white line,
and the thickness is generally isoechoic.
Although in capsular contracture with a lot of fibrosis,
it may be hyperechoic.

Now remember that we don't just have a capsule, just a shell.
We have a capsular shell complex.
So if we put the capsule directly on the shell,
what happens is that the posterior wall of the capsule
and the anterior wall of the shell merge
and we wind up with a trilaminar structure.
The leading white line is the outer surface
of the capsule, the middle white line represents the combination of the inner surface of the capsule
and outer surface of the shell.
And the trailing white line represents
the inner surface of the shell.
In general, the shell is gonna be anechoic.
The thickness of the shell will be shown by an anechoic space
between the middle and back line.
And the thickness of the capsule will be represented by the gray
or isoechoic tissue
between the leading echo and the middle echo.
In some patients with very thin capsules,
you may not be able to see an isoechoic space between the two.

On the left is an in vitro model
of the capsular shell complex.
Again, this is a piece of prosciutto ham on a
lightly textured implant in a water bath.
And we can see three white lines outer surface
of the capsule, combined inner surface of the capsule.
Outer surface of the shell is the middle line,
and the posterior line is the inner surface of the shell.

In vivo. In an actual patient, we see the same thing.
So the yellow arrowhead represents the combined capsular shell interface.
The yellow arrow in front is the outer surface
of the capsule, and the yellow arrow on back
is the inner surface of the shell.

You can see that capsules
and shells can vary greatly in thickness.
On the left is an older nontextured implant,
and you can see that its shell is quite thin
because a lot of these older implants are rupturing at 12 or 15
or 20 years after they've been placed.
The tendency is for newer implants to have thicker shells.
So you can see this is a newer implant on the right
with a thicker shell notice also that the capsule can vary greatly in size and thickness.
So on the left, you see that we also have a thin capsule
around this nontextured implant.
But on the right, we have quite a thick capsule.
In general, a millimeter and a half is considered upper
limits of normal for capsular thickness.
But I generally don't measure them. I just eyeball them.

Now, if we look at the entire capsular shell complex,
we can tell a nontextured from a textured implant
by the thickness of the middle echo.
'cause remember, it's the middle echo
that represents the junction of the posterior part
of the capsule with the anterior part of the implant.
Remember, it's the outer surface of the implant shell where the thickness varies.
So when we have a nontextured implant,
the middle line will be thin and sharp.
Where we have a textured implant,
the middle line will be thick and fuzzier.

So on the left in vivo, in an actual patient, you can see
that we have a thin, well-defined middle line
and a nontextured implant.
And on the right, shown by the aqua arrowhead,
we have a thicker less well-defined middle echo,
representing a textured shell.

And this is an in vivo example
of a heavily textured shell notice
that we see the inner surface of the shell,
but the outer surface and the capsule merge.
So we only get two echoes, a thin inner echo,
and a thick outer echo.
So in very heavily textured implants, we may not be able
to pick out a trilaminar structure.
Here's another case of a heavily textured shell.
And in this case, we have a multilaminar outer layer,
corresponding to the combined capsule shell complex.

Capsular Calcification

Now, calcification of the capsule is a variation of normal.
It's thought to be related to gel bleed.
Remember that the silicone gel within the implant
is a mixture of different chemicals
with different lengths of cross links and different lengths of the molecules.
The shorter, less cross linked elements are more oily
and can actually pass
through the shell into the surrounding tissues,
and they can stimulate calcification.
This is considered normal.

Here's a small capsular calcification.
I might mention that in the report,
but I certainly wouldn't make a big deal of it.
On the right is a little bit larger calcification.
The problem with calcification is when it gets really heavy,
it can make a sonographic evaluation
of the shell impossible,
and it can also simulate a thin layer
of extravasated silicone.
So there are some cases with real heavy capsular calcification in which we have to recommend MR.
We just can't get enough sound into
the implant to evaluate it.

Peri-Implant Effusion

Now, many implants have a peri-implant effusion,
and that's simply fluid that develops
between the capsule and the shell.
And this is actually a desirable thing,
and it's more commonly seen with textured shells.
It actually allows the implant to move slightly back
and forth within the capsule
and allows it to escape pinching or crushing trauma,
and perhaps prevents or at least minimizes the risk of rupture.
But it can create some problems for us
because it can sometimes become infected.
And additionally, it can in some cases make it difficult
to determine whether we're dealing with a double lumen
implant or simply a peri-implant effusion.
And I'll talk about some of the tricks
at making that distinction.

On the left. In vivo, we're showing a peri-implant effusion
in a single lumen silicone gel implant.
We know it's single lumen silicone gel
because of the step off in the chest wall.
But notice here's the outer surface of the shell,
and here's the capsule coming away from the implant.
And there's fluid in the capsule.
Notice that I can't see the shell well,
because it's nearly parallel to the beam,
and we see things best when
they're perpendicular to the beam.
But if I heel and toe the probe
and create a different angle of incidence,
then I can bring out the shell,
but I no longer see the step off very well.
So we may have to use a combination
of different angles in evaluating the type of implant
and assessing the peri-implant effusion.

Now, on the left is a double lumen implant,
and on the right is a single lumen silicone gel
implant with a normal peri-implant effusion.
Two ways to distinguish double lumen from a peri-implant effusion are number one,
having only a single layer representing the capsule,
A single layer of thin echogenic capsule,
rather than a multilaminar structure,
as would be the outer shell of a double lumen implant.
And number two is the acute
angle at the end of the effusion.
This doesn't work all the time
because some effusions are quite tense and can be rounded.
But in general, the outer compartment
of a double lumen implant is always gonna be rounded
unless it's ruptured.
Notice that again, we have a step off at the edge
of the single lumen silicone component on the double
lumen implant, and at the outer edge of the single lumen silicone gel on the right.

Site of Implantation

Now a another variation is the site of implantation.
So we can have a subglandular implant,
which is also prepectoral.
Those terms can be used interchangeably
or retropectoral as we're showing on the right.

So what I'm showing on the left here is a single lumen
saline implant that's subglandular or prepectoral.
Notice that there's no step off in the implant posterior wall at the edge of the implant.
On the right, we have a subglandular
or prepectoral single lumen silicone gel implant.
We know that because here's the pectoralis muscle,
and suddenly behind the implant it looks
about a centimeter deeper.
So we have that artifactual step off at the edge,
but these are both subglandular
or prepectoral implants, one saline
and the other silicone gel.

Now here's retropectoral implant.
This is a on the left, a single lumen saline implant, we know that
because there's no step off at the edge of the wall,
but we can clearly see the pectoralis muscle coming across
anterior to the implant.
And on the right we have a double lumen implant.
The outer component is saline, so there's no step off.
The inner component is silicone gel.
So there's a step off, but we can see the pectoralis muscle
passing in front of the implant.

Now notice that in this longitudinal view
of the pectoralis muscle in front of an implant,
it doesn't necessarily come all the way to the inferior aspect of the implant.
So if you wanna determine whether an implant is sub
glandular or retropectoral, it's necessary for you
to scan in the upper outer quadrant
where the pectoralis muscle is thickest P represents the pectoralis muscle.
Notice that as we go from cranio to caudad,
it's getting progressively thinner and thinner.
And at the point where you see the white
arrowhead, it stops.
So in the bottom half of the implant,
there is no pectoralis muscle.
So that means if you scan this patient in position A,
you won't be able to tell whether it's sub
glandular or retropectoral.
You have to scan in a sort of a radial plane in the upper outer quadrant in order
to know whether the implant is gonna be subglandular or retropectoral.

So here's a case where I'm scanning in the upper outer
quadrant, which I previously showed you to be plane B,
and you can clearly see
that the pectoralis muscle is
passing in front of the implant.
But in that same patient,
if I simply move into the lower outer quadrant, I'm already
below the pectoralis muscle
and it looks like it's a subglandular implant
'cause there's no pectoralis muscle there.
But that's incorrect.
I'm simply scanning too far inferiorly to know for sure
whether it's subglandular or retropectoral.

Capsular Contracture Evaluation

Now, in capsular contracture, the capsule becomes too thick.
What that causes is abnormal rounding of the implant.
Normally implant should be lenticular in form and shape,
and ought to be soft enough
that the chest wall indents the posterior wall.
And also we get increased redundancy of the shell
because a circular
or spherical shape has less surface area than
the lenticular form shape.
So as the capsule rounds up,
the radial folds become more and more pronounced.

Now, in order to assess whether there's capsular
contracture, you may actually have to use a very great depth of field
and sometimes even a curved linear array
as we're doing in this case.
Notice that on the left side, shown on the right side
of the image, the chest wall indents the posterior surface
of the implant as it should in a normal situation.
But in the contracture right side,
the posterior wall is convex posteriorly.
The implant is so firm
that the chest wall can no longer indent it.
So that's sign number one of capsular contracture.
Do we absolutely have to diagnose that with ultrasound?
No, that's generally a clinical diagnosis.
But in the process
of evaluating implants, you should know this.

Also, notice that associated
with this is an abnormal thickening of the shell.
Remember that the capsule,
the capsule should be less than a millimeter thick.

Here are two cases of capsular contracture.
On the left, I'm showing one
that has an abnormally thickened isoechoic capsule.
But on the right, I have one
that shows an abnormally thick hyperechoic capsule.
So when the fibrosis is real old
and it's a longstanding capsular contracture,
we may actually have a hyperechoic thickened capsule.

It's easiest to evaluate the thickness of the capsule
where it separates away from the shell.
And the two places where
that can happen is in the peri-implant effusion,
and at the base of radial folds.

So what I'm showing in this slide is a normal thin capsule
outlining the peri-implant effusion on the left
and an abnormal thickened isoechoic capsule in the peri-implant effusion on the right side
here, I'm showing a normal thin capsule at
the base of a radial fold.
In the left image on the right image,
I'm showing an abnormal thick isoechoic capsule at the base
of a radial fold on the right side of the image.

One of the things to note is
that capsular thickening is not necessarily uniform.
Notice that in this contracture implant,
there are far more radial folds than we would normally see
in a single field of view.
Here I have three separate radial folds.
But notice that the echogenicity and the thickness
of the capsule varies in different parts.
And notice that on the right most radial fold,
the capsule is quite thin.

Capsular Herniation

This brings us to our next complication,
which is capsular herniation.
It usually occurs in people
who have pre-existing capsular contracture,
and it's gonna occur through the place
where the capsule is the least thick or the thinnest.
So this particular area
with the thinnest capsule is gonna be at the greatest risk
for developing herniation of the implant.

What happens in herniation is that
the capsule actually tears,
and then the implant shell
herniates out through the capsule.

So what are the findings of herniation?
Well, we'll have an absent outer line
because the capsule is no longer present.
So instead of having three white lines,
we'll have only two white lines.
Generally, the shell will be thinner at that point
because as it herniates out, it becomes thinner as well.
And generally it will be closer to the skin, then the shell
in the mirror image location on the contralateral side.

So here we're looking at a herniated implant
in my right image at three o'clock in the left breast.
And notice that instead of having three lines,
there's only two white lines.
Why? Because the outer line
representing the capsule is gone.
The capsule is torn,
and the implant shell has herniated
through the rent in the capsule.
Notice that the shell is more superficial than in the mirror image location on the other side.

So on the left image, I'm showing you the mirror image location,
the right breast at nine o'clock, notice
that we still have our trilaminar capsule
or shell complex.
The capsule is still present.
Notice that it's deeper because it hasn't herniated through.
And notice that the shell is a little thicker here than
it is where it's herniated.
The herniation is associated with thinning of the shell.

Ruptured Implants

Now, when it comes to ruptured implants,
which is the next complication I want to talk about,
we don't need to do ultrasound to show
a ruptured saline implant.
The patient knows it's ruptured,
it's instantaneous in most cases.
Only in a few cases have I seen a slowly collapsing saline implant due in an abnormally leaky valve.
But in most cases, it's a sudden rupture.
And the patient says, my implant's ruptured.

This shows an intact implant on the left,
on the left image,
and then a completely collapsed single lumen saline implant
on the right, right on a mammogram.
This is what that ruptured implant looks like.
On ultrasound, we have the stepladder
or linguini sign,
but we don't have the abnormally echogenic gel.
We don't have any fluid left within the implant.
The rupture is always complete
as we're showing in this case.
On the contralateral side,
we have an intact single lumen saline implant.

Saline Implant Rupture Classification

Now, rupture
of single lumen saline implants can be classified
as extracapsular or intracapsular.
Extracapsular rupture is when the extravasated saline not
only has gotten out of the shell,
but it's passed through the capsule into the
tissue surrounding the capsule.

Silicone Implant Rupture: Extracapsular

There are two main places
that we can see extravasated silicone.
Most often we see it at the edge of the implant.
And so it's always important to evaluate the entire implant,
including the edges, because where the radius
of curvature is less
or where the curvature is sharper, the implant tends
to be thinner and subject to stress fractures.
But we can also see silicone granulomas occurring anterior the implant.
And these are almost always arising in the bases of radial folds.

The classical silicone granuloma has a snowstorm appearance.
It's hyperechoic.
It's well defined anteriorly,
and it has an incoherent dirty posterior shadow.

Here I'm showing a classical silicone granuloma anterior
to the implant On the left, I'm doing split screen mirror image scanning of the right side, and there's none in that location.

Now here's a case where scanning the entire anterior part
of the implant showed no abnormality,
but by scanning the outer edge of the implant,
we see a classical silicone granuloma in the upper outer
quadrant on the right, whereas there's nothing like
that in the mirror image location.
On the contralateral side, this is actually far more common
than seeing silicone granulomas anterior to the implant.
So it's very important not only to scan the anterior aspect
of the implant, but scan the entire
periphery of the implant.

Here's another case where the silicone granuloma classical snowstorm appearance
is only at the edge of the implant,
scanning the anterior aspect of the implant shows nothing.
And notice the mirror image location on the contralateral side
looks radically different.

It's important to realize that not all silicone
granulomas are classical.
Not only can you have the classical snowstorm appearance
that I'm showing with the asterisks here,
but you can have a complex cystic appearance.
And there's also a solid isoechoic nodular appearance,
and there's also a shadowing appearance.
So silicone granulomas can evolve
through different appearances at different points in time.
We think that the complex cystic appearance occurs from
larger, more acute extravasations,
and that the classical snowstorm appearance represents more
chronic or smaller extravasations that have undergone a lot of foreign body reaction
that breaks the silicone into smaller droplets.

In this particular case, we actually did core biopsy
of the two separate components and showed this difference.
So the asterisk represents the
classical snowstorm appearance.
The C represents the complex cystic appearance.
The biopsy of the classical snowstorm showed smaller drops
of silicone, giant cells
and foreign body reaction, a lot of fibrosis.
But I think it's the interfaces
between the smaller silicone droplets and the fibrosis
and foreign body reaction
that creates the snowstorm appearance.
And the complex cystic appearance had larger
silicone droplets with less foreign body reaction.
So this is either a larger bleed,
or in this case probably a more acute extravasation that hasn't
yet undergone foreign body reaction yet.

Now this is the third appearance of silicone granulomas.
And this points out two things that there is a phase
after complex cystic, but
before classical snowstorm
that can look like an isoechoic nodule.
The second point is that you can have silicone
granulomas that are intracapsular.
We can see that this isoechoic nodule occurs
between the capsule and the shell.
But six months later,
or one year later, this isoechoic solid nodule has evolved into a classic snowstorm appearance.
So complex cystic is the most acute, isoechoic solid is the next phase,
and classical snowstorm is the final phase.

Now in patients who had free silicone injections,
we can actually see a fibrotic
or scar phase that not only can have complex cystic
and snowstorm appearances,
but can have kind of a shadowing ill-defined appearance
that can be very difficult to tell from a diffusely
invasive cancer, such as invasive lobular carcinoma.

Now, instead of balling up into a classical silicone
granuloma nodular type of appearance,
extravasated silicone can form a thin layer over a shell
that even at surgery can be detectable only
by the tackiness or stickiness of the capsule to palpation, this is an example of very thin layer
of extravasated silicone over the
outer surface of the shell.
And notice how similar this looks
to the appearance we had in the dense capsular calcification.

So you may have to look at a combination of a
mammogram in the outset to determine whether you're dealing
with heavy capsular calcification,
or a thin layer of extravasated gel silicone can migrate away from the implant.
So we can see classical silicone granulomas
with extracapsular rupture that occur in the axilla
onto the abdominal wall or even onto the back.
This one actually was over the latissimus posterior to the axilla.

Extravasated silicone is often taken up into the lymphatic
system, and we may find it within axillary lymph nodes.
And once that happens,
we'll get the same snowstorm appearance that we get
with silicone granulomas.
And if a lymph node is completely filled
with silicone gel, it may be difficult
to tell whether it's a lymph node or a silicone granuloma.

In general, the silicone accumulates first within the
medullary sinusoids.
So the hilum of the lymph node becomes
snowstorm in appearance first,
and then later the cortex can be involved.
Notice in this case, we have two separate lymph nodes.
The one shown by the white arrows is more completely
replaced, and the one shown
by the white arrowhead is smaller
and was only partially replaced the cortex.
The hypoechoic cortex still persists.

Notice that in this case, we have a classical snowstorm appearance.
And now instead of a hypoechoic cortex,
the cortex has been replaced with hyperechoic gel.
As the gel has filled more
and more of the sinusoids, the whole lymph node has
become hyperechoic.

Silicone Implant Rupture: Intracapsular

Now, intracapsular rupture is something that
MR has an advantage over ultrasound in identifying.
Ultrasound really quite good at extracapsular rupture,
but less sensitive than MR for intracapsular rupture.
But I think part of the reason for that is
that people have looked for complete collapse
of the implant.
If we actually realize the normal range of implants,
we can actually do quite a bit better
than we have with intracapsular rupture.
Probably still not as good as MR,
but the classical findings are the stepladder linguini sign,
the same thing I showed you for a collapsed saline implant
and abnormally echogenic extravasated gel.

So the intracapsular extravasated gel becomes hyperechoic,
just like silicone granuloma.
Obviously mammography can't detect that
because the silicone is extravasated in this case from the
shell, but it's still contained within the capsule.
So this looks like an intact implant mammographically.
But ultrasound is showing you the stepladder sign of a sign
of a very high degree of collapse
of the implant within the capsule.

Notice that if I do split screen mirror image scanning,
I'm seeing two findings indicating intracapsular rupture with complete collapse.
Number one, the gel is abnormally hyperechoic on the side
with collapse as compared to the anechoic side.
The right side is ruptured, the left side is not.
And number two, I'm only seeing a single echogenic line
because the only thing there is the capsule,
the double echo from the shell is gone.
It's fallen into the implant,
whereas I'm actually seeing the shell
on the unruptured side.
So it's two findings.

Notice in this case, I'm doing split screen imaging
of the lateral aspects.
The left breast is normal.
The right breast shows intracapsular rupture.
Each of these rungs on the stepladder represents a fold
of partially collapsed implant.
The asterisk show the anechoic gel
that's still within the implant.
And the plus signs show the abnormally hyperechoic gel
that's extravasated outside the implant,
but still held inside the capsule.

Now, I mentioned that intracapsular rupture can start at
the apex of a fold.
And so we see various degrees of collapse.
What I've just showed you are the classical findings
with complete rupture.
But if we wanted to detect partial rupture, what we have
to look for is an abnormal two dimensional separation
between the outer capsular echo
and the inner two shell echoes
or abnormal echogenicity in the fluid
within the radial fold.

Now, here I'm showing partial collapse,
so I'm not showing a classical stepladder sign,
but what I'm seeing is an abnormal separation
between the capsule and the shell.
And I'm seeing abnormal echogenicity of the gel in the space
between the capsule and the shell.
Notice the gel
that's still within the implant remains anechoic.

Notice that I'm also able to see posterior extravasation.
It's been said that we can't see
that with ultrasound, but we can.

Now here's an intracapsular rupture that's partial,
and this is obviously filling a radial fold.
And I think we can presume in this case
that this probably is the site
of origin if a stress fracture probably developed right at
the apex of that radial fold.
But what we're seeing anteriorly is an abnormal separation
between the capsular echo and the two shell echoes
and abnormally echogenic extravasated silicone within that space.
But notice that we're also seeing posterior separation
of the capsule and the shell, as well as abnormally echogenic silicone between the capsule
and the shell posteriorly.

Now here I'm showing a single plane separation
of the capsule in the shell with anechoic fluid.
Is this always abnormal? And the answer is no.
You've got to image this in two orthogonal planes to know
for sure whether it's just a parallel to the long axis
of radial fold, which is a variation of normal
or partial rupture.

So here's a diagram showing
what intracapsular rupture looks like in two
separate planes, the aqua
and the yellow planes at 90 degrees to each other.
What we have is separation between the capsule
and shell over a long distance
and two orthogonal planes to each other in a radial fold.
In the aqua plane, which is parallel to the long axis,
the fold, we may see separation over a long distance
between the capsule and the shell.
But if we scan orthogonal
or in a short axis of the radial fold,
we can see the usual U
or V-shaped appearance of a normal radial fold.

So it has to be two orthogonal planes to each other
with separation over a wide distance in order
to distinguish partial collapse
with intracapsular rupture from a normal radial fold.

So here I'm showing two orthogonal planes to each other.
The separation between the capsule
and shell occurs over a long space.
So we know that this is intracapsular rupture
with partial collapse here.

My two orthogonal views show a long separation on the left
side, but just the normal radial fold on the right side.
So we have to assume this is normal.
We have to err on the side of caution,
and it's assume it's normal.

Now, since the apex
of radial fold can be site intracapsular rupture,
we have to not just analyze the distance over which the separation between the capsule and the shell occurs,
but the echogenicity of the fluid within the radial fold.
Remember, radial folds are dynamic.
They form and reform,
and the apex of the fold is subject to stress fracture.
But also remember that we can have normal peri-implant
effusion in the radial fold.
So there can always be some anechoic fluid in there.

So on the left, I'm showing a short
axis view of a radial fold.
With anechoic fluid, we have to assume that's normal.
Could it be extravasated gel?
Sure, it may just not have been there long enough for us to,
for it to become hyperechoic.

In the middle illustration, I'm showing slightly echogenic fluid, but not classical ring down.
Could this be extravasated gel?
Sure, the odds are slightly more likely than an image A,
but it could simply be proteinaceous
or old blood debris within the capsule,
especially if there was some bleeding after the implant was placed on the right.
I'm showing classical ring down within a radial fold,
and we know for sure that that's gonna be the earliest form
of intracapsular rupture.

So here's a normal radial fold with anechoic fluid.
We have to assume that this is just normal peri-implant effusion.

Here's a radial fold that has echogenic fluid,
but there's no ring down.
This could be early intracapsular rupture,
but I think since, unless the patient has some signs of lupus or something like that, I think we should err
on the side of caution and assume this is just echogenic
peri-implant effusion, either from old bleeding
or proteinaceous debris.

On the other hand, here's a radial fold
that has classical ring down.
We know that this is intracapsular rupture,
so it's the appearance
of the fluid within the fold that helps us.
We're gonna get some false negatives on the previous two
examples, but this one we're gonna nail.

Now, one of the problems with determining whether the fluid
within a radial fold is echogenic, is
that there's a big acoustic mismatch
between the implant shell and the surrounding tissues,
and that creates big reverberation echoes
and harmonics can be very helpful in sorting this out.

In this case, the reverberation echoes are
so severe that I can't tell whether the fluid
between the capsule and the shell is abnormally thicker.
That here I'm putting it on harmonics on the left
and using fundamental image on the right.
And you can see that the reverberation
echoes are much less severe.
And I can see that yes,
there's still abnormal separation of the capsule in shell.
And yes, the fluid is slightly hyperechoic compared
to the deeper normal fluids.

So harmonics is allowing me to assess the echogenicity
of the fluid between the capsule and the shell better.

Now, it's important not to mistake reverberation echoes for abnormal separation
of the capsule and shell,
and the left is a reverberation echo.
But notice that it's roughly a parallel
to the true shell.
And notice that we still have a trilaminar line right here,
an outer fibrous capsule, middle capsule shell interface and inner surface.
The shell here is a true separation.
Notice that they're not parallel
and notice that I only have a single
echogenic line anteriorly.

So you can distinguish reverberations from abnormal
capsular separation.

Now, it's been said that
extracapsular rupture can occur
without intracapsular rupture.
That's not true. Every case
of extracapsular rupture has intracapsular rupture.
But it may be difficult to actually demonstrate the
intracapsular rupture sonographically.
And that's why it's important to be able
to identify these intracapsular ruptures
with only partial degree of collapse.

Summary

Now, the final thing I wanna say is that
evaluating implants is very interesting
and many times it can give us very useful information.
But we have to remember that most of the patients
who present in our department are presenting
with either palpable lumps or mammographic abnormalities,
and evaluation of the implants is incidental.
Don't get so distracted by the implants that you forget to evaluate the patient for the reason why she presented.

People with implants don't have an increased
or decreased risk of breast cancer.
They have the same risk as everybody else,
but we have to remember to evaluate the problem
for which they presented first
and not be distracted by the implants.
And also, the presence
of implants shouldn't prevent us from doing any sort
of interventional procedure,
including cyst drainages, needle localizations, or biopsies.

So in summary, even though MRI is considered the
procedure of choice for isolated implant evaluation,
most patients with implants present for lumps
that require ultrasound or mammographic abnormalities
that require ultrasound.
And the breast imager who's doing breast ultrasound must be
familiar with the appearance of implants to know whether
or not the palpable or mammographic abnormalities related
or unrelated to the implants,
and also to show incidental implant abnormalities.
Thank you.