0:01

So the next topic we need to cover in

0:03

evaluating Crohn's is how do we distinguish

0:04

inflammation from fibrotic processes?

0:07

Because oftentimes Crohn's is a mixture of both.

0:11

However, the gastroenterologists and surgeons

0:13

really want to know if one or the other is

0:15

predominant because the treatment is very different.

0:18

The treatment for inflammatory or inflammation

0:22

disease is vastly different from fibrotic disease.

0:26

Inflammation is treated very differently

0:28

from fibrosis, and inflammation you see is

0:31

treated with steroids and immunologics.

0:33

So the gastroenterologist is really in charge of that.

0:36

However, when it's a predominantly

0:37

fibrotic process, the steroids and

0:39

immunologics no longer are going to work.

0:41

And it's come beyond that and really it's a

0:44

diet, so restrictive diet, trying to eat things

0:47

that prevent bowel obstructions because of the

0:49

strictures that you get with fibrosis, or it's

0:51

surgery and that's when the surgeons need to get

0:53

involved, but they don't want to get involved if

0:56

it's primarily inflammatory component which can

0:58

still be treated with steroids and immunologics.

1:02

So the way we differentiate these is

1:04

looking at the features on imaging and

1:06

really, MRI is the best way to do this.

1:09

CT isn't going to get you very far compared to

1:11

MRI in terms of what you can tell about what's

1:14

actually going on in the acute versus chronic piece.

1:18

So for the inflammatory cases, they have early

1:21

enhancement, a high T2 signal because of the edema.

1:25

And then they also can have ulceration

1:27

of the mucosa and blurred margins.

1:29

And those things are all highly specific for inflammation.

1:33

That is highly specific for inflammation.

1:35

Fibrosis, on the other hand, has more of a

1:36

progressive enhancement, and this is where

1:38

those seven-minute images are really helpful

1:41

to see, is it more or less enhancing on seven

1:44

compared to the earlier enhancing sequences.

1:47

The signal component on the T2 will be

1:49

dependent on how much edema there is, so

1:52

because fibrosis and inflammation coexist, just

1:55

because it's edematous doesn't mean it's not

1:57

also fibrotic, so that's important to remember.

2:00

And then, lastly, the ulcerative and blurred

2:03

margins are predictors of inflammation

2:06

and don't necessarily say whether there's

2:08

also a fibrosis component on top of that.

2:11

So really in the end, what you end

2:12

up with is a two-by-two kind of table.

2:15

And so this is a nice paper that kind of

2:17

looked at this, and this specifically was

2:20

looking at the importance of those seven-minute

2:22

delayed images and what we can do with those.

2:24

And

2:26

if you use that in conjunction with

2:27

your T2 signal, you can really break

2:29

most cases into one of four categories.

2:32

So if it's low inflammation and there's no fibrosis,

2:38

what you get is a normal signal intensity T2,

2:42

and then you don't have more enhancement at seven minutes.

2:46

On the other side, if you get low inflammation and

2:49

marked fibrosis, you have that normal T2 signal.

2:52

But you do get the delayed enhancement because

2:54

the delayed enhancement indicates fibrosis.

2:56

When you have those with severe

2:59

inflammation, then you have edema on T2, and you

3:03

don't have more enhancement on the delayed phase.

3:06

And when you have marked fibrosis and severe

3:08

inflammation, so when both are present, you get the

3:10

delayed enhancement, and you get the appearance.

3:13

And so we're going to look at some cases showing how we

3:15

can use that in practice because it's really helpful.

3:18

And when I get questions from my gastroenterologist,

3:21

almost 100% of the time,

3:23

they want to know is it acute or chronic

3:24

and should I ramp up my immunologics or

3:28

should I refer this person to a surgeon?

3:31

So we're going to look at some cases trying

3:33

to get you able to answer that question.