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Endometriosis on MRI Case 3

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So this case I put in here

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because it's a nice example of deep infiltrating endometriosis.

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So again, I start with the T2 non fat sat images.

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I scroll through on the sagittal.

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I don't see much going on in the anterior compartment.

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In the middle compartment,

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there are a couple of things going on in the myometrium that we can talk about.

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The uterus is anteverted and not terribly flexed one way or another.

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And then in the posterior compartment, there's something going on right here

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in the sigmoid colon that we're going to need to account for later.

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Looking at the axials to take a peek at the adnexa.

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We have one adnexa over here, another over here.

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Nothing super crazy there.

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Then I'll pull my T2 fat sat.

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Oh, sorry. My T1...

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My T1 pres alongside.

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I'm going to look at those together and make sure that I'm not seeing any

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T1 brightness in the ovary that would suggest an endometrioma.

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I'm not seeing any superficial endometriotic implants.

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This protocol happened to have been done without fat saturation.

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And then here with fat saturation.

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So there are a couple of little punctate

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areas of T1 hyperintensity that we see better with the fat saturation.

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That's why our protocol calls for that

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fat saturation on the T1s.

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And then on the sagittal,

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that area of concern involving the sigmoid colon

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we can see is T1 dark as well as T2 dark.

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All right, so now let's kind of talk about what each of these things are.

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And before we do, can we get the next question, please?

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So which portion of the bowel is most commonly involved with endometriosis?

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The terminal ileum, cecum, sigmoid colon, or rectum?

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All right, so people have answered the sigmoid colon.

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The answer is actually the rectum.

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So the rectosigmoid colon, together, account for like 90% of cases

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of bowel involvement.

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But the rectum out edges the sigmoid colon a little bit.

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This case, there is involvement

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of the upper portion of the rectum and then into the sigmoid.

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So I fooled you with this case.

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I'm sorry.

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Bowel involvement in general seen in about 37% of cases of endometriosis.

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So, here we have tethering of the uterus to the rectosigmoid colon here.

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We have obliteration of the rectocervical space

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and the lower part of the rectouterine space

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by this deep infiltrating endometriotic implant.

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There are two morphologies of deep infiltrating endometriosis, which,

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by definition, invades the peritoneal surface by greater than 5mm.

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So there's the chronic stromal fibrotic

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morphology and an active glandular morphology.

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This is a beautiful example of the chronic stromal fibrotic morphology.

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So that morphology is T2 dark and T1 dark.

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It can be nodular or stellate in appearance.

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It causes scarring and obliteration of spaces, meaning that,

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you know, the normal...

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the normal fat plane between the structures and the peritoneal cavity

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is obliterated by scarring that crosses it.

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This is the type of endometriosis that MRI is really great at detecting

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and that the surgeons really want us to tell them about before they go

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into the operating room, because when there is scarring

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and obliteration of spaces, they can't get to those areas

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laparoscopically, and it very significantly impacts

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the surgery that they need to do to help debulk the patient.

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This particular case is a nice example of what's called the mushroom cap sign.

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So that is a descriptor that we use to

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describe bowel involvement with endometriosis.

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You can almost imagine that this is

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a mushroom cap here if we had a little mushroom stalk coming down the bottom.

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And what that is, is it's basically deep endometrio...

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Deep infiltrating endometriosis that invades the muscularis propria

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and results in muscular hypertrophy of the wall of the bowel.

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And that's what is responsible for that mushroom cap appearance.

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When we are describing bowel involvement with endometriosis, it's really important

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that we describe the location of the bowel that's involved.

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Here we can see that area of involvement

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in the axial plane and appreciate just how long it is and how much bowel is involved.

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So we need to describe the location,

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the relationship to the peritoneal reflection.

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This one crosses the peritoneal reflection,

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the distance from the anal verge and the length and number of segments involved.

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And then finally, whether it is greater than 50%

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circumferential involvement or less than.

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And this would be an example of less than.

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And the reason the circumference involvement is important is because it,

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it dictates what type of surgery needs to be done to resect this lesion.

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So if it's less than 50% circumferential involvement,

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the surgeons can just remove that part as it discoid resection.

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If, however, it's greater than 50% of the circumference of the bowel,

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or if there is narrowing, they have to do a segmental resection

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and anastomose the two disconnected segments back together.

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So if there's a lot of bowel involvement,

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the gynecologist may opt to have colorectal surgery involved.

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So it's important to describe all of these features when you see them in the report.

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This patient also, if we focus on the uterus,

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the junctional zone of the uterus here,

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so the T2 kind of gray portion

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of the myometrium that's just below the endometrium is thickened.

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If I were to measure it for you here, it's 13, almost 14 mm.

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So there's junctional zone thickening, which is consistent with adenomyosis,

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which is basically the presence of endometrial tissue in the myometrium

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and is also commonly seen in conjunction with endometriosis outside the uterus,

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since it essentially is endometriosis of the uterus itself.

Report

Faculty

Kristine S Burk, MD

Instructor in Radiology, Harvard Medical School

Brigham and Women's Hospital

Tags

Uterus

MRI

Gynecologic (Gyn)

Gynecologic (GYN)

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