0:33

Okay.

0:34

Um, so I'm going to be talking to you

0:35

today about Müllerian duct anomalies.

0:37

And not to get into too much embryology, the

0:40

Müllerian ducts are paired embryologic structures

0:42

that undergo fusion and resorption in utero, and that

0:45

gives rise to the uterus, the fallopian tubes, the

0:48

cervix, and then the upper two thirds of the vagina.

0:51

So the lower third of the vagina, as well as the

0:53

ovaries, are not involved with the Müllerian ducts.

0:56

So when you have an interruption of this normal

0:58

development of the ducts, that's when you can

1:00

get these Müllerian duct anomalies, or MDAs.

1:03

And depending on the type, patients can have different

1:05

types of symptoms, such as primary amenorrhea, pelvic

1:09

pain, or fertility issues with recurrent miscarriage.

1:12

So these patients usually undergo

1:14

ultrasound first, and if that doesn't

1:16

answer the question, MRI is the way to go.

1:19

That's the most sensitive and specific, particularly

1:21

for those complex and indeterminate MDA cases.

1:25

So I'll be using the American Society for Reproductive

1:28

Medicine Classification to divide these MDAs up.

1:31

Uh, and I'll start with the abnormalities of septal

1:34

reabsorption, which is septate and arcuate, then I'll

1:37

go on to the abnormalities of ductal fusion, like

1:40

bicornuate and didelphys, and then finish with the

1:42

ductal development abnormalities, like unicornuate

1:45

and then uterine agenesis and hypoplasia.

1:49

So actually, let's start with a question.

1:51

Can we have question one?

1:53

So what is the best MRI series to evaluate

1:55

the anatomy of the female reproductive tract?

1:58

Excellent!

1:59

100% T2.

2:00

That is correct.

2:02

So let's start with reviewing the T2 anatomy here.

2:04

So here we have a sagittal T2-weighted

2:06

image, and you can see the uterus is here.

2:08

The endometrial stripe will be T2 bright, and then the

2:11

junctional zone will be T2 dark, and that's right here.

2:14

That's usually less than 8 millimeters in thickness.

2:17

And then the outer myometrium will

2:19

have this intermediate T2 signal.

2:21

And then as we move inferiorly, you can see

2:23

the junctional zone continues into this T2

2:26

dark stromal, uh, hypointense rim of cervix.

2:31

So you can see that's a little

2:31

darker than the junctional zone.

2:34

And then the collapsed vagina, even though

2:36

it's collapsed, we can see it quite well

2:38

on the sagittal T2-weighted image here.

2:40

And then that's just behind the urethra right here.

2:43

Uh, and here's the bladder.

2:45

Remember fluid will be bright on T2.

2:47

And then there's the rectum and then

2:50

if we look at the, uh, axial images,

2:56

You can see here's the anal canal, there's

2:58

the collapsed vagina, which usually has

3:00

a Honda shape on axial images, and then

3:02

there's the urethra, and you'll see that's

3:04

immediately posterior to the pubic symphysis.

3:06

So that's a great landmark for finding the

3:07

urethra, whether you're looking at it on

3:10

MRI or CT, like for urethral diverticulum.

3:12

And then here we have the levator ani

3:14

muscle continuing into the puborectalis.

3:17

And as we come up, the, uh, urethra continues

3:19

into the bladder, and then the vagina continues

3:23

into that cervix here, which is T2 dark.

3:25

And then there's the right kidney.

3:27

Now we don't normally see the

3:28

right kidney in the pelvis.

3:31

So that's why, uh, that brings me to another

3:33

important point, that when you're doing

3:35

a Müllerian duct anomaly protocol, you always

3:38

want to include a large field of view, uh,

3:40

T2-weighted image to take a look at the upper

3:43

abdomen and see what's going on in the kidneys.

3:45

And here you can see the left kidney is in its normal

3:48

place, but it seems to be congenitally malrotated.

3:50

The collecting systems are exiting towards

3:53

the left, and it's actually a duplex

3:54

system that fuses into a single ureter.

3:57

And then we don't see the right kidney where it

3:58

should be, but instead it's down here in the pelvis.

4:01

So actually that brings me to question

4:03

two, if you could please bring that up.

4:06

What percentage of MDA cases

4:07

have associated renal anomalies?

4:09

Is it 15%, 40%, 85%, or 100%?

4:16

Oh, great.

4:16

40%, yes.

4:18

It's kind of in the range of 30 to 50%,

4:20

but, uh, 40% is, is a nice average.

4:23

And, uh, it's a variety of malformations.

4:25

You can have, uh, horseshoe kidney, renal

4:28

dysplasia, ectopic kidney, as in this

4:30

case, or duplicated collecting systems.

4:33

And it's actually most common with

4:34

the subtypes of uterine agenesis, uh,

4:36

uterus unicornis and uterus didelphys.

4:41

All right, so then going back to the

4:43

axial here, let me bring up the sagittal.

4:48

So, another important point when we, when

4:50

you're protocoling a Müllerian duct anomaly

4:53

case is the, the typical transverse axial

4:57

view that we get for a routine pelvis is

5:00

actually a true axial relative to the patient.

5:02

But you can see as we move through the uterus,

5:04

that's not really a true axial of the uterus.

5:06

We're getting kind of an oblique view, which

5:08

might be fine in some cases, but we really

5:11

need to look at that outer fundal contour.

5:13

So that's why we will align the scout so

5:18

that we're perfectly parallel to the uterus.

5:20

So instead of a straight axial, we're getting an oblique

5:23

axial, which gives us a perfect coronal of the uterus.

5:26

And that lets us look at the outer fundal contour.

5:29

So here you can see the fundal

5:30

contour is flat to slightly convex.

5:33

So by seeing that there's no fundal cleft,

5:36

which would be an outer indentation here.

5:38

So you've eliminated biconuate or didelphys.

5:42

So then that tells you this is either

5:44

a partial septate or an arcuate.

5:46

We know it's not a full septate because this,

5:48

this septation doesn't extend inferiorly.

5:51

So how do you differentiate

5:53

arcuate and subseptate uteri?

5:55

So if you could please bring up question three.

5:58

So regarding arcuate versus subseptate

6:00

uteri, which of the following is false?

6:03

Both have a normal outer fundal

6:05

contour with no fundal cleft.

6:07

A subseptate greater than

6:11

1.5 centimeters, where the subseptate fundal

6:12

endometrial indentation forms an obtuse angle.

6:17

And again, that's not referring to the

6:18

outer fundal cleft, that's referring to this

6:21

bulge of, uh, myometrial fundal tissue and

6:24

the indentation it has on the endometrium.

6:28

Excellent.

6:29

The obtuse angle—that is incorrect.

6:33

So, uh, let's look at those two features.

6:35

So, a measurement you can do is to draw a line

6:39

from the top of the endometrial cavities here.

6:41

And then that line can measure the depth

6:44

of this myometrium to the endometrium.

6:46

And you can see here it's 1.2 centimeters.

6:48

So that's less than 1.5 centimeters.

6:48

So that would not be consistent

6:49

with a subseptate uterus.

6:51

Usually, that will be greater than 1.5 centimeters.

6:58

And then the other thing you can do is

7:00

look at this angle of the endometrium.

7:02

And so if we draw an angle there to that

7:07

point, you can see it's an obtuse angle.

7:10

It's 115 degrees in this case.

7:12

So that also is not consistent with a subseptate.

7:14

So this is an arcuate uterus.

7:15

So that bulge should be less than 1.5 centimeters,

7:17

and then it will have

7:19

a broad base, uh, or an obtuse angle.

7:22

So the arcuate uterus is a

7:25

very mild form of MDA, and usually these

7:27

patients will have a normal term gestation.

7:29

Rarely, though, they may, uh, pursue surgery

7:32

if there is repeated pregnancy loss.

7:38

All right, let's go on to the next case.

7:40

This is case two.

7:41

This was a 27-year-old female.

7:43

So, uh, just to show you the importance of

7:46

which plane you're evaluating these cases in.

7:48

If we look at this coronal T2, uh, you can see

7:51

that there are divergent endometrial horns,

7:54

but it's really hard to evaluate that fundus.

7:55

So it's hard to tell what's going on.

7:58

You know, otherwise, is this a, is this a septate?

8:01

Is this an arcuate?

8:02

It does kind of look like a disturbing face, but

8:05

that's not very helpful for diagnostic purposes.

8:08

If we look at the sagittal image, we're

8:09

not really getting much help there.

8:11

So again, we want to get a nice, uh, perfect

8:14

oblique axial to give us a coronal of the uterus.

8:18

So as we start inferiorly here again, you can see

8:20

the anal canal, the levator ani, puborectalis,

8:23

there's the collapsed vagina, and then the urethra.

8:26

And as we move superiorly, we

8:28

see that there's a single cervix.

8:31

And then we have these divergent

8:33

endometrial cavities superiorly.

8:35

And again, look at that outer fundal contour

8:37

first, and you can see it's flat to minimally

8:40

concave, but there's not a deep cleft.

8:42

So you, again, you've eliminated

8:44

didelphys and bicornuate.

8:46

So the question is again, is this

8:47

arcuate or is it a subseptate?

8:51

So again, let's measure the top of the endometrial

8:53

cavities here to that tip of the myometrial bulge.

8:57

And that's 1.6 centimeters.

8:58

So that's greater than 1.5 centimeters.

9:01

And then also you can tell just by looking at this,

9:03

that this is an acute angle, but let's just measure

9:06

it from that point there, you can see it's 73 degrees.

9:10

So we have an acute angle and

9:12

then a bulge greater than 1.5 centimeters.

9:14

So this is consistent with a subseptate uterus.

9:19

So, uh, can we please have question number four,

9:23

what's the most common Mullerian duct anomaly,

9:26

which corresponds to 55 percent of cases.

9:28

So bicornuate, didelphys, septate,

9:31

unicornuate, great, septate, that is

9:35

correct, as we have in this case, septate.

9:39

So look at that outer contour and

9:41

then look at the depth of the bulge.

9:44

Alright, so let's look at case 3.

9:47

So here again, if we start with the coronal, we can

9:49

see that there are divergent endometrial cavities,

9:52

but it's hard to look at the endometrial, the

9:55

endometrial, the, sorry, the outer fundal contour.

9:58

But we do see that there appears to be a single cervix.

10:01

So again, let's do that.

10:03

Um, oblique axial to give us a

10:05

perfect coronal view of the uterus.

10:06

You can see we're nicely lined up

10:08

directly parallel to the endometrium.

10:11

And again, you can see that the outer

10:13

fundal contour is convex in this case.

10:15

So it's not a bicornuate.

10:16

It's not a didelphys.

10:18

And then we have this sharp angle of the

10:20

myometrium extending inferiorly with this bulge.

10:24

And it's more than just a subseptate because it

10:26

extends more than one and a half centimeters deep.

10:28

And we see it's mostly muscular, but there is a

10:31

thin fibrous septum extending a bit inferiorly.

10:35

So this patient actually, uh, was referred to

10:38

us at an outside site had had an ultrasound and

10:41

an HSG that called the MDA a bicornuate uterus,

10:47

but in this case you can see it's actually a

10:48

septate and we do have a single cervix there.

10:51

So why is it important to

10:53

differentiate septate and bicornuate?

10:55

If you could please bring up question number five.

11:00

So compared to uteri have a higher risk of miscarriage,

11:05

cannot be repaired surgically, or are less common.

11:09

Excellent.

11:10

Yes.

11:10

Septate uteri are much more important to diagnose

11:12

because of the higher risk of miscarriage.

11:14

Often, patients with

11:15

bicornuate uteri come to term normally.

11:19

So, uh, another example too, is how MRI is much

11:23

more specific than HSG or even ultrasound, unless

11:27

it's a 3D ultrasound, but even then it can be

11:29

challenging depending on the uterine configuration.

11:34

Alright, let's go on to the next case.

11:36

This is case four.

11:38

So I'll tell you, this was a 24-year

11:39

old female and a clue is on physical

11:42

exam, two cervices were identified.

11:45

So let's look at that.

11:47

So if we start in fairly, there's the

11:49

vagina, the inner canal, and their urethra.

11:52

And as we come out of that, to the lower uterine

11:54

segment, you can see there are these two hypo

11:57

intense cervical rims of cervical stroma.

12:00

So there are indeed two cervices.

12:02

And then as we come up, even though this is an axial

12:05

series, it's kind of hard to see what's going on.

12:07

The two horns are divergent, but we don't

12:10

really get a good look at the uterine fundus.

12:13

And that's because if you look at the sagittal

12:15

here, the uterus is oriented vertically.

12:18

So even though we have an axial here, this isn't

12:21

really giving us a good look at the uterine fundus.

12:24

And this doesn't really help either.

12:25

You can see again, two horns, but then, and two

12:28

cervices, but then what's going on with the fundus?

12:31

So again, we want to get a true coronal to the uterus.

12:35

So if we orient the plane like so, you

12:38

can see we're nicely parallel to the

12:39

endometrial stripe here on the sagittal.

12:43

And then look at how well that gives

12:44

us a look at the uterine fundus.

12:47

So here you can see it's clearly

12:49

a convex arcuate uterine fundus.

12:51

So even though we have two cervices, you can eliminate

12:54

this being a didelphys or a bicornuate uterus.

13:01

And this is another septate.

13:02

So this is a septate uterus with a complete septum.

13:05

And, uh, two cervices.

13:08

And you could see here nicely that this,

13:10

the upper part of the septum is muscular,

13:12

meaning it's formed out of myometrium here.

13:14

It has that same T2 ISO intensity or intermediate

13:17

T2 signal, uh, that the arterial myometrium has.

13:21

But then as you move inferiorly, it's very dark,

13:23

uh, indicating that it's mostly fibrous tissue.

13:25

Here, there might be a little, uh, fibromuscular tissue

13:29

inferiorly, but it seems like it's primarily fibrous.

13:33

So if you could show question six, please.

13:36

So, true or false, it is not important to differentiate

13:40

muscular from fibrous tissue in a uterine septum.

13:44

Great.

13:45

Yeah, that's false.

13:46

Yeah, it's very important, actually, because

13:48

that can change the surgical management.

13:50

So, if it's a fibrous septum, that can actually

13:52

be treated with a less invasive hysteroscopic

13:56

septoplasty, where they can go in, through the

13:57

cervix, uh, hysteroscopically and just resect that.

14:00

But if it's muscular, that requires more

14:02

of a transabdominal surgical approach.

14:06

And again, since septate uteri are more

14:08

associated with miscarriage, these are

14:10

more likely to be treated surgically.

14:14

Alright, so let's move on to case five.

14:18

So this case was not actually done as a Müllerian duct

14:21

anomaly protocol, but we can still make the diagnosis.

14:25

So here, if we start inferiorly again,

14:28

You can see there's the

14:29

anal canal. This is an axial T2.

14:32

We have the collapsed vagina with a

14:33

cyst here, a Gartner cyst most likely.

14:37

And then we have the urethra here.

14:39

And as we move superiorly, you

14:41

can see there's a single cervix.

14:43

We have a T2 hypointense domal ring in

14:45

the central T2 hypointense mucosa.

14:49

And then as we come up, there

14:50

are very divergent uterine horns.

14:52

So now we're actually seeing a fundal cleft.

14:56

So let's, we don't have to measure this because it's

14:58

so deep, but just for measurement purposes, you can

15:02

see if we draw a line from the outer fundal contour

15:05

to where this deep cleft is, you can see here it's

15:08

2.1 centimeters.

15:10

So if you could please bring up question seven.

15:14

What is the uterine fundal cleft depth required

15:17

to make the diagnosis of a bicornuate uterus?

15:19

Is it just greater than five millimeters?

15:22

Is it less than a centimeter?

15:23

Or is it greater than a centimeter?

15:26

Excellent.

15:27

Yes, greater than a centimeter.

15:29

So here we have much greater than a centimeter.

15:31

It's 2.1 centimeters.

15:32

So this is a bicornuate unicollis

15:32

uterus, meaning it has a single cervix.

15:35

And, um, it can be a little difficult in this case

15:37

because the horns are so divergent, but because

15:39

we have a single cervix, it can't be a didelphys.

15:48

And, uh, there's actually a bonus finding here as well.

15:51

So if we look at the left horn, you can see that

15:53

there are these multiple T2 hyperintense foci here.

15:56

And on this coronal image,

16:00

This is a T2 fat-suppressed series.

16:01

You can see there's the right horn with the

16:03

normal junctional zone, but the left horn

16:06

has a thickened junctional zone superiorly.

16:09

So if we measure that, we're getting 1.5 centimeters.

16:12

So that's greater than 12 millimeters.

16:13

So that's consistent with focal adenomyosis.

16:16

Uh, there's another feature there too

16:18

that tells you this is adenomyosis.

16:23

Let me pull up, this is a T1 fat-suppressed image, and

16:28

you can see here that you have these multiple little T2

16:30

hyperintense foci within it that are also T1 bright.

16:34

Oops,

16:38

let me window that a little.

16:40

And that's, uh, that just adds

16:41

specificity to the diagnosis.

16:43

So if the junctional zone is bigger than 12

16:45

millimeters, that tells you there's adenomyosis.

16:47

If you also see these T2 hyperintense glands that may

16:50

be T1 bright due to hemorrhage, that tells you those

16:52

are the ectopic endometrial glands that have T1 bright.

16:55

migrated into the myometrium, and you

16:57

have some smooth muscle hyperplasia

16:58

around them, giving you that thickening.

17:00

So that just gives you a more specific diagnosis.

17:03

So this was a bicornuate uterus with

17:05

focal adenomyosis in the left horn.

17:10

All right, moving on to the next case.

17:13

So this is case six.

17:17

Um, so this is a 22-year-old female and this

17:21

also is not done as by a Müllerian duct anomaly

17:24

protocol, but we can still make the diagnosis here.

17:27

So this is a coronal T2 here that we're looking at.

17:30

And if we start.

17:31

Let me move back.

17:34

So if we start here at the cervix, again,

17:37

you can see that there are two cervices.

17:39

We see these two T2 dark stromal rings

17:42

surrounding the hyperintense mucosa.

17:44

And then as we move up, the horns diverge.

17:49

And then on this view, it's difficult

17:51

to tell what's going on with the fundus

17:53

because we're looking at a coronal T2.

17:56

So if we pull up, uh, an axial, even

17:59

though this isn't an oblique axial, we can

18:02

still get a sense of the fundal contour.

18:05

And it's certainly not convex or flat, right?

18:08

It's, we've got some concavity here.

18:12

And I'll also pull up

18:16

the T2 fat-suppressed, that could do another look at it.

18:19

You can see the fundal contour there.

18:21

And then we can measure that.

18:28

And you can see that fundal cleft is 1.5 centimeters.

18:31

So that's greater than a centimeter.

18:31

So that's consistent with

18:33

either a bicornuate or a didelphys.

18:35

So, well there's two cervices.

18:38

So, hmm, what could it be then?

18:42

Actually, could we have the next question please?

18:44

Question eight.

18:46

So which Müllerian duct anomaly can have two cervices?

18:47

Is it didelphys, bicornuate, bicalis,

18:51

septate, or all of the above?

18:57

Great, all of the above, yes.

18:59

So didelphys will always have two cervices,

19:03

bicornuate will sometimes have two,

19:05

and then septate will rarely have two.

19:10

Okay, good.

19:13

Um, so the other way you can tell—so is

19:16

this, we still haven't really answered,

19:17

is this didelphys or bicornuate or bicolis?

19:20

Well, you could look at the outer fundal

19:22

contour and then, deep to that, you want

19:24

to look for any bridging myometrium.

19:26

Let

19:28

me just go here.

19:30

So you see there is all this myometrial tissue

19:33

here bridging between the right and the left horn.

19:36

You can also see that on the T2-weighted images.

19:40

There's myometrium between the two.

19:42

So that tells you that this is a bicornuate

19:45

bicolis because the didelphys should

19:46

have no bridging myometrial tissue.

19:48

You'll have two cervices and then two

19:49

completely divergent uterine horns

19:51

with no communicating myometrium.

19:54

So here you can very nicely see that

19:57

and it tells you that there is indeed

19:59

myometrium bridging these two structures.

20:02

So bicornuate bicolis uterus.