What’s New in 3D Ultrasound of the Pelvis - SD

Introduction

Hi, I'm Beryl Raf.
I'm from Harvard Medical School and the Brigham
and Women's Hospital in Boston, Massachusetts.
And I'm gonna be talking today about 3D ultrasound in gynecology.
What is new in 3D ultrasound of the pelvis
and how do we use it to evaluate the gynecologic patient?

Basics of 3D Ultrasound

3D ultrasound is really a volume acquisition
and it's done to obtain an image
that actually can be displayed in three different planes,
all of which can be related by one point in space.
And then you can navigate through those planes
using the dot at right angles to each plane.
And the technology enables us
to see anatomic sections in an orientation different from
the actual acquisition section.
And this is an example
where you can see we acquired the
image transversely transvaginally.
You can ask, actually also acquire it longitudinally,
but what you can't acquire is the coronal view.
You can only reconstruct it and see it
after the volume has been taken and worked on.
So the 3D is volume imaging.
It's very different from a CA loop.
It is not operator dependent because you have the volume
and somebody else can then navigate through the volume
just as though they were actually scanning the patient.
So it is much less operator dependent
than any CA
or individual image
that a sonographer might be able to take.
And we can then reconstruct the view of the uterus
in the very same orientation as a netter diagram.
As you can see here on the right, the netter diagram
is showing the coronal view of the uterus,
both cornew and the cervix.
And we can duplicate that with a 3D ultrasound.
And that is actually one of the best ways
to image the uterus that we really haven't had access to
with regular 2D ultrasound.
So really the most important benefit of 3D
ultrasound in gynecology is the ability to
generate this coronal view of the uterus
and of the other portions of the pelvis,
and show that coronal view that short of an MRI,
we would not otherwise be able to demonstrate.
And here you can see that there's an IUD
within this uterus.

Applications in IUD Evaluation

Let's look at a couple of
at least more than a couple
of ways in which we can implement this view
to help our patients.
For example, here are two different patients
who had an IUD in the uterus, both abnormally located.
They came in because of bleeding and pain.
Here is the IUD shaft of the IUD here.
And the two arms are in the cervix here.
The shaft of the IUD is in place,
but one of the arms is really poking into the myometrium.
No wonder the patient has pain and bleeding.
So where's the IUD here?
It's a little low in the uterus on 2D,
but in fact, 3D shows
that both arms are embedded in the
lower uterine segment here.
And in fact, the lower uterine segment does not really,
is not really wide enough to be able
to deploy an IUD completely.
And so no wonder that when it's low,
it's going to be embedded.
Here's another one, again, quite low
and again, embedded in the myometrium.
The uterine cavity can't accommodate the IUD that low.
It's not wide enough. Here's another one.
Where's the IUD here?
Well, we can see that it's the shaft is in the center
of the uterus, a little low, and here are the arms.
But what we can't see is where the uterine cavity is.
So when we look at the 3D, we can see
that the uterine cavity is depicted a little brighter,
and the IUD is oblique within the uterine cavity.
The uterine cavity really wasn't big enough in this patient
to accommodate the IUD.
Now here we are with three orthogonal planes,
and what we have is an IUD that is actually upside down
and backwards in a sense
where it's headed actually down instead
of up very abnormal in appearance.

Study on IUD Positioning

So we actually did a study looking
at consecutive patients who had IUDs in place.
And turns out that 16.5%
of those patients had IUDs
that were embedded in the myometrium or cervix.
And all of the ones that were low in the uterus
were all embedded.
And it turns out that if you look at,
if you compare the IUDs that were embedded to those
that were not embedded, the patients came in 70% of the time
for either pain
or bleeding when the IUD was embedded compared to only 34%
of the time when the IUD was not embedded.
So most of the patients when the IUD was embedded had either
pain or bleeding, whereas less than half
or only a third of the patients
where the IUD was not embedded came in for those reasons.
And here are some more examples
of the IUDs embedded in part.
And this is only by a little bit,
and I don't know whether this would really be an explanation
for pain and bleeding.
Certainly those that I showed you
before are more severely embedded.
So in conclusion, the coronal view is necessary
to image the position of the IUD,
particularly the arms of the IUD.
An abnormal positioning
of the arms may result in abnormal bleeding or pain,
and you really can't see the arms
of the IUD very well without the coronal view.

Uterine Cavity Size and IUD Fit

So the question is, are IUDs too big
for the average uterus?
And we looked at the group
of patients that we're talking about, some of which had
embedded IUDs
and found that the width
of the uterine cavity was 32 millimeters across in patients
with the IUD in a normal location versus 25 millimeters
across for those with embedded IUDs.
And it turns out that the standard IUD is
32 millimeters in width.
So no wonder some
of the uterine cavities were not big enough.
And the IUD was embedded.
Now, here is the width of the
uterine cavity transverse in a patient with
a normally placed IUD versus one
where the cavity was narrow
and the IUD was not normally located.
Now the question is, is the uterus too small?
And does the IUD fit in this case?
It doesn't, it never really got deployed.
The transverse diameter of the shape of the IUD
when it is open in a t is 32 millimeters
and only four
or 13.8% of patients
with the embedded IUDs had a cavity greater than 32
millimeters versus 32.6% of patients
with a normally placed IUD.
So who decided that the IUD should measure 32
millimeters across the top?
Maybe there should be smaller size IUDs for smaller patients,
and perhaps it might help
to do a 3D ultrasound prior to the insertion of an IUD.

Challenging IUD Cases

So these are hard to find IUDs.
And here is an IUD, which is seemingly in the center
of the cavity, but if you look at it in 3D,
it actually looks like an anchor
because it is actually upside down.
Here's another one, lots of different arms here,
don't know which is which,
but here you can see that the endometrium is actually quite narrow, the cavity,
and we were not able to deploy the IUD fully.
And here is a retroverted uterus.
Again, where is the IUD, lots of different branches here.
We don't know what's what here it is.
And one arm is really quite a bit embedded into the myometrium.
Now, sometimes we can use the shadow of the IUD.
You can see that this IUD has a shadow.
Now that should not be mistaken for the IUD itself.
You can back into the IUD using the shadow.
Here's another one. There's a shadow of an IUD clearly misplaced,
and we can back into the IUD
itself using the shadow.
So sometimes the shadow is more obvious than the IUD itself,
and we can back into it quite nicely.
Now, the width of the uterine cavity in a large number
of patients that we looked at is 29 millimeters.
And in the lippers patients, it is 27 millimeters compared
to 32 millimeters in those with one or more pregnancies.
So clearly the more pregnancies you have,
the wider the uterine cavity.
And no wonder that those within the lipper uterus have a cavity
that is only 27 millimeters in size.

Uterine Cavity Shape and Abnormalities

Now let's look at the shape of the uterine cavity.
The prevalence
of mullerian duct abnormalities is really quite elevated in
those who have infertility between three
and 10% in patients who have infertility
and recurrent pregnancy loss.
So let's look at an example here.
Here is a patient
who has a septate uterus all the way down into the cervix.
And here are two patients, both with mullerian
duct abnormalities.
You can see that there is a island of endometrium
within the myometrium here.
And you can see that these in fact, are very different.
This is an arcuate uterus versus a deeply septate
uterus here.
And they look the same in 2D.
So the 3D was really absolutely necessary here to
evaluate the shape of the uterine cavity.
And here are two uterine cavities that are both septate.
This one has a deeply septate cavity,
whereas this one has a rather wide
and broad septum very different in appearance.
Now the bico uterus has an indentation at the top
of the uterus, whereas the
septate uterus has a flat top.
And you can see that the
uterine cavity looks the same in both of these.
And if you did a
hysterosalpingogram, they would look the same.
But they are very different entities
because one is actually a septum
and the other one is a bico uterus.
Here is a view of a uterus, such is a unior.
It, you can see how the transverse longitudinal view
of this uterus look essentially normal,
but clearly the coronal view
of the uterus has a one single horn.
When you have a unior uterus,
you can have sometimes a rudimentary horn,
which may not be connected as you see here.
And here are two different uterine.
One here showing a small rudimentary horn,
which is connected to the unicorn uterus.
Here is a second horn, which is actually not connected,
and that would be a site perhaps for an ectopic pregnancy
which would be damaging.
And here is another example
of a complex uterine shape abnormality with at the top here
you have an indentation of the serosa.
So this is bicornuate.
It's also a complete septate uterus with two cervices.
Here are the two cervices with a little bit
of fluid in each cervix, so very complex abnormality,
which we can really depict very, very nicely.

Post-Surgical Evaluation

Now here's a patient that had a rather broad
and shallow sub septum,
and there was a fibroid right in there,
and she underwent surgery.
And so we get to take a look
after surgery to see whether they were able to shave down
the entire septum.
And in this case, they were the top of the myometrium
here is a little bit ratty,
but it is actually fairly straight,
so they successfully removed the septum.

T-Shaped Uterus and Scarring

Now here is a T-shaped uterus.
You can see the T shape of the endometrial cavity.
And this was typical of DES daughters. Luckily.
Now, that's mostly a thing of the past in
that DES daughters are now largely post-menopausal
and no longer reproducing
because the T-shaped uterus is really not compatible with
having a normal pregnancy.
Most of the time they don't get pregnant.
And if they do, they miscarry very early on.
Here is a uterus that is severely scarred.
You can see on the 2D that there's an indentation here.
And on the 3D you can see the scarring in the cornu
you hear probably from multiple DNCs
and perhaps prior pregnancies.
Here is also another uterus where the calcification,
and in 2D you can't really tell where this calcification is.
But in 3D, when we can depict the uterine cavity,
you can see the calcifications are in the endometrial
region in the region of the cornu.

Fibroids and Imaging

Now the fibroids are best seen in the reconstructed views.
You can use the endometrium as a contrast.
Media, here is a fibroid.
It's located within the cavity in part,
but with 3D you can see exactly where it is,
how far into the cavity it protrudes,
and where exactly in the cavity it sits.
Here's another one. Is this fibroid submucosal or not?
Let's take a look at the 3D
and sure enough, here is the uterine cavity a little lighter in color,
and there's the fibroid.
The fibroid is about a third
of the way into the endometrium,
so it's sub partly submucosal.
And you can also see the space behind the fibroid in case
this fibroid gets resected using hysteroscopy,
you can tell that there is some myometrium
outside the fibroid.
Here's another rather large fibroid, is that intramural
or submucosal?
The coronal view will show you that it is clearly intramural
and not submucosal, that the triangular shape,
uterine cavity is intact.

Sonohysterography with 3D

If you do sonohysterography by all means do it
with 3D ultrasound
because you can put some fluid within uterine cavity.
And rather than having to take a whole bunch
of pictures one at a time, you can take a volume
and then reconstruct that volume later
and be able to view the polyps
or whatever else is inside the uterine cavity.
While you just re-scan the volume.
Once the patient is gone in this image,
you can see a rather large polyp in the cornu
and near the cornu you hear.
And you can see that the rest
of the myometrium is relatively smooth except
for one little area down here.
Now this is what you get on a normal sono hystero gram
when you acquired it transversely,
I have the dot right here, which is the intersection
between all three planes right here and right there.
And you can navigate through this entire volume live
after the patient is gone, right on your laptop
and view every single part of the endometrial cavity
as though you were actually scanning it de novo.
And here is what happens when you have a polyp
inside the cavity.
You can see the cyst on this little polyp,
which is inside the cavity.
And well surrounded by fluid.
You can also render the inside of the cavity
and demonstrate that polyp on the coronal view.
And here we're also actually seeing part of the catheter
that is inside the uterine cavity.
Here's another patient who had a thickened endometrium.
You can see that not only was it thickened in regular 2D
here, but it was also heterogeneous and abnormal.
Having put a little bit of fluid in, you can see
that there's multiple polyps here.
We're just measuring one polyp.
And normally you would have to take quite a few pictures
to get all these polyps measured up,
but if you take a volume, you can display all of the polyps
altogether or one at a time, whichever way you want
after the patient has gone and you can remeasure
and re-image those polyps nicely.

Adnexa and Hydrosalpinx

Now looking at the adnexa,
3D ultrasound is also very helpful in the adnexa in this
case, we had multiple cysts in the adnexa as this,
the hydros or these multiple cysts.
And sure enough, in the reconstructed view you can see
that this is a hydrosalpinx, the hydrosalpinx
is in a plane other than the planes
that we could image in,
but it certainly was a plane that we could reconstruct.
Many hydrosalpinges, however, are out of plane.
They're really not in any one given plane.
So what you can do is get your complete acquisition
and then use an inverse mode where everything
that is cystic within a volume becomes opaque like a cast
and everything that is solid melts away.
And then you have a cast
or anything that's cystic within that volume.
And in that case you can see a rather large hydrosalpinx
with a very large cystic area at one
end of the hydrosalpinx.
So this is not an ovarian cyst, this is a hydrosalpinx.
And here are two other patients.
This there, these are separate patients.
Here's one where we thought maybe there might be
a hydrosalpinx here.
Here's another one where we couldn't tell perhaps
that was part of a hydrosalpinx,
but we couldn't tell where the ovary was.
And in fact, both of those were hydrosalpinges.
As you can see on the inverse mode.

Bladder and Pelvic Floor Imaging

When you are scanning the pelvis, remember
that you also can take a look at the bladder.
And in this case, these are two different cases.
We have a lesion in the bladder right here
and right here, which is irregular.
And very sessile in appearance.
And these are bladder carcinomas.
And this is a patient who had perineal pain.
And as we put the probe on the perineum,
looking down at the vagina here,
and this is part of the uterus, this is the bladder.
You can see the lesion right here.
There's a cystic area surrounded
by a thick rind right here, right there.
And so we can take a 3D of that
and have a look at where we put the dot right here
and right there and right there.
And you can see that this is a lesion which is right next
to the urethra.
As we look at the floor of the pelvis,
this is the vagina here and this is the rectum.
And this is a urethral diverticulum next to the bladder.

Conclusion

So the ability to see the reconstructed planes as in the pelvis
is really key to developing these imaging techniques.
And I believe that 3D ultrasound has a lot more
to offer a GYN patient than an OB patient.
And I suspect that 3D will be used routinely in gynecologic
patients because we know that it is so much more useful
to see the uterus
and the adnexa in these reconstructed planes.
3D has been used in CT and MR for years,
and now we can bring ultrasound into the era of other forms
of cross-sectional imaging.
Thank you very much.