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All right, so for the first images we're going to

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review, we're going to go through each sequence

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and talk about some technical pieces about how

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we perform the sequence, as well as some ways

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to approach evaluating these sequences as a

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general rule for these MR enterography cases.

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And for all these cases, and

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for all this, this technical detail,

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10 00:00:20,675 --> 00:00:22,195 we're assuming that the indication is

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Crohn's disease, which is certainly the most

0:24

common indication for doing MR enterography.

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And so, to start off, a key to imaging with MR enterography

0:31

is getting high-quality T2 sequences.

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And to do this, we do this in multiple planes, and

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we also do it without and with fat saturation.

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So here we have axial T2 HASTE images at

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the top, and I'll make that larger for you.

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So here you see that we have the bright

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fat, so this is without fat saturation,

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and we do this in the axial plane.

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One thing you'll also notice is this patient is

0:53

prone, and so the top of the abdomen is flat,

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that's because they're laying on their stomach

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and then after the fact, the technologist flips it

1:00

and so it shows up on our PACS series like

1:02

this and that work is done by the technologist.

1:05

The reason we do a prone position is twofold.

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One is that it actually keeps the

1:11

bowel from moving to a certain extent.

1:13

And the other is that it decreases the AP diameter.

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So if you look from the anterior abdomen to the sacrum,

1:19

the distance is a lot less if the patient is prone.

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And that allows you to get better

1:23

coverage with your coronal images.

1:25

And so when patients are able to do prone

1:27

imaging, we prefer it, and that's what we try to do.

1:30

Now, it's not a necessity.

1:31

You can get high-quality imaging without doing a prone.

1:34

And so anyone with any difficulty or

1:36

inability to sit still in the prone position,

1:38

we certainly lay those patients supine.

1:41

So, for this T2 sequence, what you'll see is that

1:45

we make sure we cover, we don't even get all the way

1:47

through the liver, but we cover all the bowel.

1:49

And we go all the way down, and we'd

1:51

like to go all the way through the anus.

1:52

I actually would prefer if this was a couple more

1:54

cuts because this is a sequence that I think we try

1:56

to cover all the way through the anus to look for

1:59

perianal disease in these patients with Crohn's.

2:01

Additionally, this is a great overview

2:04

sequence to look at the bowel wall.

2:06

And you can look for things

2:08

like wall thickening and edema.

2:10

And it's a good first sequence to look

2:12

at your standard T2 sequence.

2:15

Now we do T2 imaging without fat saturation

2:17

in both the axial and coronal planes.

2:19

I think it's important to do it this

2:21

way because it's easier to see things

2:23

in two dimensions on this sequence.

2:25

And I think it is a critical sequence.

2:26

So doing it in two planes is important.

2:29

One thing you'll notice is that there's a lot

2:31

of artifact within the bowel on these sequences,

2:33

and that's because of bowel peristalsis.

2:35

So you actually get these apparent filling

2:37

defects, and that's just fluid moving

2:39

in and out of the plane of imaging.

2:42

And so that's one drawback of the sequence.

2:44

We'll show you the remedy for that as

2:45

we move through the other sequences.

2:47

So this is the T2 without fat saturation.

2:50

Those are the main components that I think

2:53

are important for everyone to consider.

2:54

And next we'll move to the other T2 sequences.