The Ultrasound Diagnosis of Deep Endometriosis: How I do it - HD

Introduction and Disclosure

I'll just say that I've given a version of this talk a lot, and it's usually two gynecologic surgeons, not to radiologists.

It's really kind of fun to talk to radiologists, not just radiologists, but ones that specialize in ultrasound.

I do have a new disclosure from the outline that you'll have with AbbVie Pharmaceuticals.

The lecture today is really about deep endometriosis. It's not about endometriosis in general.

Definition of Deep Endometriosis

Deep endometriosis is endometriosis that infiltrates more than five millimeters below the peritoneal surface.

We won't go over endometriosis. I know you know what they look like.

We were not gonna go over adenomyosis. Hopefully you're learning what that looks like.

During the scans we're looking for those things.

Why Use Ultrasound Instead of MRI

Why would we use ultrasound and not MRI?

One of the things is that if you're doing a transvaginal ultrasound, you have much higher spatial resolution, particularly when it involves the bowel wall. And we'll see that.

You have the opportunity to push on things and ask the patient where it's tender. And this is a dynamic exam, completely unlike MRI.

Historical Context and Sensitivity

I show this particular slide because this is the group of people that produce this work in 2007 and they're the ones that taught me how to do it.

They showed very high sensitivity and specificity for transvaginal ultrasound. Much better than MRI, and certainly much better than physical exam all the way back in 2007.

The location of deep endometriosis is almost exclusively in the pelvis. Most of the things that we can see in deep endometriosis can be seen transvaginally.

I'm going through these fairly quickly because I want to get to as many examples 'cause there's no sense in saying how I do it if you don't know what it is.

Components of the Examination

A group last year, including and others got together and they put together these four components of the examination.

Since people that were involved that taught me how to do this, this is the same way I do it.

These four components that you can read there are how we do it.

Most importantly, we want to look for obliteration of the cul-de-sac, and we're gonna look very specifically in certain locations in the anterior and posterior compartments.

I would add in the vaginal compartment for deep endometriosis lesions.

Of course, this being the United States, we have sonographers, not just radiologists. Internationally, these are typically done by radiologists and surgeons.

When we use our sonographers to do the basic imaging and we also use them to take kidney pictures of the kidneys, and then the radiologist goes in and does a fairly short survey of the rest of the exam, and we'll go through each of those things.

Bowel Preparation

We do use bowel preparation in our practice. We've been doing this for about five and a half years.

The most important part of that is the fleet enema.

If you wanna see just the rectum, that's fine, but if you wanna see anything higher in the rectosigmoid, it really is beneficial to try and clear out the gas and stool in order to see around.

Anatomical Compartments

Just briefly about these different compartments, so we're all on the same page, anterior fornix.

We need to place the transducer there. We're gonna look at the bladder, we're gonna look at the anterior uterine serosa.

We're gonna find the ureters and follow them. And then we're also gonna press on the cervix from the anterior fornix and look at a sliding sign. I'm gonna show you all of that.

Then in the posterior fornix back here, we're going to look at the retro cervical region up close. In particular, we're going to find the uterosacral ligament areas.

Then we're gonna do that primary imaging of the rectum and following it up to the sigmoid colon.

One other thing that we should consider is the rectovaginal septum and the vaginal canal itself.

Some patients you won't see anything until you put some gel into the vagina and distend.

At the very end, hopefully we'll get to a picture of that.

Evaluating the Adnexa

When we're evaluating the adnexa, and we're not just looking for endometriomas, but we're looking for adhesions around the ovaries.

We want to see are they stuck to the pelvic sidewall, are they stuck to the uterus? Are they stuck behind the uterus or stuck to each other like kissing ovaries?

Malposition and mobility are additional components.

Imaging the Anterior Compartment

This is just a simple image of a normal looking anterior serosa.

You can also push on here and in normals you can kind of push the bladder a little bit away from the uterus.

This is one of the landing points for deep endometriosis. And you can find little bars of tissue sometimes that are early signs of deep endometriosis in this location. And they are associated with heat adhesions.

This is a big mass. The reason I show this one is that notice this location, it's in the base of the bladder extending to the trigone.

Most lesions of deep endometriosis involving the bladder are gonna be in this base area, and they may extend to the trigone.

You also would want to try and figure out its location with respect to the ureter.

Many of you probably know how to find the ureter. If you haven't, maybe try to learn this.

You're gonna find it between the bladder and the anterior fornix, and then you'll follow in.

Once you identify it, you kind of push in and follow it around as far as you can.

If you kind of twist the probe counterclockwise when you're on the left or clockwise on the right, you can kind of elongate it.

Here's an example of hydronephrosis caused by a deep endometriosis implant.

The Sliding Sign

This is that important overview that I was talking about called the sliding sign.

Basically what we want to do is see tissue slide freely from the back of the uterus.

This is called the TAUs utes. That's where the uterosacral ligaments come and meet in the midline. And this is a important location for deep endometriosis.

This one shows an abnormal sliding sign. There's a implant back here, and you can see that the tissue just doesn't move.

Locating Lesions

A couple of things about how do you figure out where you're at, when you're in the vaginal introitus, that location's about two to three centimeters from the anal verge.

When you get into the posterior fornix, you're about seven to eight centimeters from the anal verge, and then you can kind of count up from there.

Bowel Wall Layers

You do need to know a little bit about bowel wall layers. I'm not gonna go through this in great detail, but let's look very quickly at just the anterior wall. And you can see these layers.

What it turns out to be quite important is this the muscularis propria. And not just that, the fact that there's muscularis propria, but there's a thin connective tissue layer that runs down the middle of it.

It turns out that obliteration of that layer is very important in identifying deep endometriosis involving the bowel wall.

Here's a example of those layers. Submucosa, most of the mucosa and submucosa is just the submucosa, which is echogenic.

Then you have hypoechoic layers of muscularis propria with a thin white line between them. And then of course, the serosa.

If we do identify a lesion, we need length and width. And in particular, we want to know what percent of the bowel wall circumference involved in the lesion.

If it's more than 40% involved, or if it's more than about three centimeters in length, that is very difficult to do a discoid resection. They will almost always have to do segmental bowel resection.

The Cul-de-Sac

Where's the cul-de-sac? If there's fluid in the cul-de-sac, you can tell where it ends, but if not, the posterior lip of the cervix roughly ends at the end of the cul-de-sac.

A lesion here is in the rectovaginal septum. This one involves the rectum and rectovaginal septum.

This lesion is on the uterosacral ligament.

Sometimes we just see big masses that involve the whole area of the retro cervix and rectum.

Now, when we push in, we're going to go past that lip of the cervix. And a lesion on the uterosacral ligament will be very close to the transducer. And as we press, it's gonna be right under the transducer.

Normal Uterosacral Ligaments

These are what the normal uterosacral ligaments look like, but we don't see them that often unless there's a lot of free fluid, and folks are working on and sort of visualizing these better.

There's right and left.

Depth of Invasion

A little bit about depth of invasion. Some lesions are completely separate from the bowel wall. Others will just involve the outer layer.

We often recognize those because there's some distortion.

Sometimes they just involve that outer muscularis, or rather, muscularis propria layer.

The ones that involve the entire area will obliterate that connective tissue band. And then we also wanna look for submucosal invasion.

Sometimes we just see speculated complex masses.

If it's not in the anterior rectal wall and the posterior rectal wall, it's probably not deep endometriosis.

Echo Texture Patterns

A little bit about echo texture pattern. Most of the ones that involve the rectal wall are gonna be quite hypoechoic. This is probably because of muscular hypertrophy that goes along with the disease.

We also tend to see ones involving the outer layers that are usually pretty hypoechoic, often with distortion.

The lesions that involve other areas have variable echogenicity. They may not be as hypoechoic.

We often see the bright dots like we see on the edges of endometriomas, but deep endometriosis is a solid fibrotic process.

These bright dots can be anywhere. They could be in the lesion, they can be in the rectal wall. Sometimes they look little like little dashes on rare occasion might think you see some ring down.

Examples of Deep Endometriosis Lesions

Let's look at a video of a sigmoid colon lesion. We're starting at the introitus.

This fine white line here is the rectovaginal septum. We're coming to that first curve of the rectum. All the bowel wall here is very thin.

As it curves back into the sigmoid colon, there's thickening.

Let's show that again, transverse, you can see it a little bit better. There's this sort of involving maybe 20% of the bowel wall here, and a segment, maybe a little more than three centimeters.

This might be able to be shaved off or discoid resection.

I wanna show you in the last three minutes as many examples as I can. Because again, it's one thing to know what it how to do it, but if you don't know what it looks like, it doesn't really help.

Now we sometimes see superficial endometriosis, particularly if there's free fluid. The specificity of this sort of lesion is very high, but the sensitivity is low as you can imagine.

Here's another small nodule of the uterosacral ligament. Again, high specificity be relatively low sensitivity.

Now this one is a very typical nodule of the uterosacral ligament. This one happens to be outlined by a little bit of free fluid. You can see it's over five millimeters in size.

Here's a little video clip of it. This is a big uterosacral ligament nodule. We're just showing that it's not attached to the bowel there.

This is a nodule on the rectovaginal septum. The posterior lip of the cervix is here, and this is south of that. So that's in the rectovaginal septum.

Here's that distortion. It's really only involving the superficial layers and extending off to the uterosacral ligament.

But again, you can see that distortion that's helpful in identifying these lesions.

This nodule is a low rectal nodule. It's not very big. As we come in, we get to that first curve. And then right here is this nodule with bright internal foci.

This is a very typical nodule that you might see. This is what Dr. Iff referred to as the comet signs.

These thin lentiform edges are commonly seen in rectal wall lesions.

Here's a video clip of that one.

Here's another one that's quite similar here. There's some free fluid you can imagine. The laparoscopies only sees the very superficial this edge of this. They don't know the depth of invasion.

Also look very carefully here, the smooth interface with the submucosa. So it's only involving the inner and outer layers of the muscularis propria.

A lot of times we see distortion. So we see this sort of plication of the bowel and it's tethered up to the retro cervical region.

Here's a video clip of a similar thing. This has been called the Ebola sign or the hourglass sign.

There's a portion that involves the retro cervical region, uterosacral ligaments. And then there's another portion here that involves the bowel wall.

Here's another fairly typical lesion. These can be a little bit tricky in terms of measurement. It's probably better to try and get curved measurements on these.

You can kind of underestimate the length of these because look how the bowel wall is placated up to the lesion.

Here's another example where you see the bowel wall involvement itself is very hypoechoic, whereas the part that's more fibrotic on the uterosacral ligament is a little bit more echogenic.

This one is just a video clip of that.

Here's a primarily fibrotic lesion. Here's the ovary. The ovary, and you see just superficial involvement of the sigmoid colon going past.

Here's a big retro cervical lesion. Here's kissing ovaries, big band of tissue between the ovaries, again with a bright foci.

This is my last one. This is patient was incredibly tender and this is gel cell angiography.

This is an isolated lesion of the rectovaginal septum involving the rectal wall.

Why is it isolated? Shouldn't be isolated there. But she had had surgery previously to remove rectal disease and she had this recurrence and she was in absolute agony because of this lesion.

I dare you to find that on an MRI. You will not see it.

Conclusion

I think we owe it as radiologists who specialize in ultrasound to consider this topic.

Thank you.