0:01

Let's chat technique,

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arthrography, axial arthrography first.

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Now, how do you get into the joint?

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You can get into the joint by poking it down here,

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using fluoroscopy or CT, or if you're really talented

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and done a lot of them, you can even do it by feel.

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Um, you know, using, using the position

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of the needle and the free flow of the

0:23

needle when you make just gentle injection.

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But the more easy technique is to put the patient

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prone, uh, have the patient, uh, slightly.

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Either RPO or LPO so that the injected shoulder is

0:37

slightly elevated compared to the non-injected shoulder

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and go through the posterior interval of the shoulder.

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If you don't know where the posterior interval

0:44

of the shoulder is, I suggest you Google it.

0:47

Make you do a little work.

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So now that we've talked about

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where to go, um, what do you put in?

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I think it's a good idea to dilute

0:55

at least one to 200 with gadolinium.

0:58

If, if you are any more concentrated than that, then

1:01

your contrast is gonna be black and you don't want that.

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You want your contrast to be nice and white on T one.

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And you also want it to look water-like on

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any fat-suppressed water-weighted images.

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So, not too much concentration.

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What will the shoulder take?

1:18

Well, some shoulders, like my own, when I was 19

1:21

and I received one of these, it only took 9 cc's.

1:24

And at 9 cc's, it was the most painful

1:26

thing that's ever happened to me.

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They overextended my shoulder with 9 cc's.

1:30

But I have had elderly patients in here and

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athletes in here that have taken up to 25 cc's.

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So there is a very broad range of

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what the capsule will accommodate.

1:40

Although, people with plastic injuries, Capsular

1:42

deformation and stretching are more prone to instability.

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Now in terms of, uh, identifying whether you're

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in, the easiest way to identify is, is by feel.

1:56

You will feel free flow of your injected material.

2:01

And I'll use normal saline, uh, mixed with a 1 to

2:05

gadolinium, and a little bit of iodinated contrast.

2:09

You can use a concentration of 300 or 350.

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Just so you can see under CT or fluoro, if you're

2:16

in, especially if you are new to this or a novice.

2:21

And then I have the patient exercise for

2:23

about 5 or 10 minutes, move the arm around,

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and then I put them in the MR scanner.

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So I've got two axial projections here.

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A T1 spin echo, where the gadolinium is doing

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its thing, it's making the contrast bright.

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And a water-weighted image.

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Now, why have both?

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Well, the water-weighted image tends to be a little

2:43

more sensitive in detecting subtle labral pathology.

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But there's a drawback.

2:48

There's a yin and a yang to everything.

2:50

And what's that drawback?

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If you've got swelling, if you've got a cyst, if you've

2:56

got, if you have a demo that is pointing to an area of major

3:00

pathology, It may be tough for you to tell whether you're

3:03

looking at extravasation of your contrast that you put in.

3:08

Maybe you over-distended the joint, or

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maybe you didn't get all the way in.

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So in some respects, you potentially can hide pathology.

3:15

And it is not uncommon for younger radiologists,

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when they're doing an anterior stick, to

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put the needle close to the labrum complex.

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And then you have a little fissure or a little dot inside

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the labrum, and now you're not sure whether you did it.

3:32

Or the resident did it, or the fellow

3:34

did it, or it's real pathology.

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Now, the T1 weighted image is helpful in that

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if you have contrast outside the capsule, the

3:45

character of the contrast usually helps you a lot.

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Because if the contrast is, is well-defined

3:52

within the bursal space, nothing is extravasated

3:54

here, then you know you have extravasation.

3:57

Whereas if the contrast is kind of wavy and ill

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defined and irregular, the odds are that you either

4:03

over-distended the joint or you didn't get fully in.

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You might say, well, why isn't that

4:07

true on the water-weighted image?

4:09

Well, on the water-weighted image, fuzzy signal

4:12

outside the capsule could be extravasation.

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It could be that you didn't get all the way in.

4:17

Or it could be part of the injury.

4:20

Because injuries are typically edematous.

4:23

So, in some respects, this can help you.

4:26

And it can hurt you.

4:29

Now, how often do I do arthrography for macro

4:34

instability and micro instability cases?

4:36

Less than 1 percent of the time.

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My primary reason for doing

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arthrography is the clinician wants it.

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But, for people starting out in MRI, it may

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be a little easier for you anatomically,

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if you have contrast in the joint.

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Frequently, people with instability or

4:54

dislocators have innate, inherent contrast.

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In other words, they have a joint effusion.

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Or they have a hemarthrosis, you don't

5:01

need to put contrast in the joint.

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If you've got a hemarthrosis, it's like

5:05

having gadolinium inside the joint.

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So that is not going to be, that is not going

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to be a necessary process in most cases.

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Now typically, when I'm looking at an arthrographic

5:19

study, I like to have a pre and a post.

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Most people will do post only.

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And I have gravitated to post only as I've gotten

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older, because I've gotten comfortable with it

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over time, and speed has become very important.

5:35

Table time in MRI has become very important.

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So if you're good at doing post only, it

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saves you a tremendous amount of time.

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On the other hand, if you are a newbie, If you're

5:44

young and new to MRI, you're going to get confused

5:48

between extravasation and edema, and you're going to

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have trouble finding the areas of most significant

5:55

pathology based on their high water-weighted signal

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because you've obscured it by injecting the joint.

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So if you don't have a pre, that may make it a

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little more challenging for you to figure out

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what is the finding of greatest importance.

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Now let's scroll up and down.

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on our T1 weighted image first with gadolinium inside.

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And we see a few key structures like

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the superior glenohumeral ligament.

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This is not an anatomy lesson.

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Here is the coracohumeral ligament,

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the intra-articular portion.

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Here's the middle glenohumeral ligament.

6:30

And more curved and thicker is the

6:32

inferior glenohumeral ligament.

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And these are studied, uh, very judiciously

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and with high quality using MR arthrography.

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Now sometimes I'll externally rotate

6:43

the shoulder to make this taut.

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Sometimes I'll go in the Heber position to put the

6:49

arm behind the head, the so-called Dion Sanders

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touchdown position, to also try and stretch this

6:56

out or pull on it, and also tug on the labrum.

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The capsule will tug on the labrum, and if

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there's any partial rim tears of the labrum,

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then they may be brought forth by externally

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rotating the shoulder, or by the Heber view.

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So I'll put the arm behind the back, with a thumb up and

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then I'll put the arm behind the back with the thumb down.

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And what that does is it'll curl the labrum in and out.

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It'll curl, curl the labrum in, it'll curl the labrum out.

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And sometimes the labrum is hypermobile in people

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with what I call functional microinstability.

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They'll feel a click or a clunk or a sense of giving way.

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And the only way to bring that forth is with

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some of these views, arm behind the back, thumb

7:42

up, thumb down, or a Burr view, abduction.

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External

7:47

rotation.

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Now you can also see the same

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thing on the water-weighted image.

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And, um, on the water-weighted image, I'm

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going to make it just a little bit smaller.

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This particular water-weighted image is not

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as motion-affected as our T1-weighted image.

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The T1 took a little bit longer, but this is a 3D.

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So another variation in axial imaging that

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you have available to you is you can do very,

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very thin section imaging, which this is.

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This is a 3D GRE with exquisite fat suppression.

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So the blacks are very black, and the

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whites are very white, and the muscles are

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grey, and the fat is really, really dark.

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But remember, that's all you're getting.

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You are only getting labrum to capsule,

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labrum to bone, and hyaline cartilage.

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Period.

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So let's scroll up and down, and look how exquisite

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we see the hyaline cartilage on both sides.

8:44

The humeral side and the glenoid side.

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And then look at the, look at the glenoid

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and the relationship of the hyaline cartilage

8:52

right there, and to the fibrocartilage.

8:55

So the fibrocartilage, as we said in other

8:58

vignettes, gets bigger, it gets badder,

9:02

it gets more pointed, it gets blacker.

9:05

It is bigger than the posterior labrum as you

9:07

go down, and that is characteristic of everyone.

9:11

The capsule is usually more medial

9:13

in the front than it is in the back.

9:16

As you go really far down, the IGHL anterior band, inferior

9:22

glenohumeral ligament, anterior band, becomes one, it unites

9:27

with the labrum, so we have a labroligamentous complex.

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And there is often a small recess or notch, especially

9:36

in athletes who have a lot of plasticity down low.

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That notch is smooth, it's round, it's not jagged,

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there's no edema, there's no periosteal elevation,

9:48

there's no bleeding, the glenoid shape is normal.

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This is a source of potential confusion for some imagers.

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What are these things right here?

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Well, these are two bands of the labral ligamentous complex.

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It can split into two bands, three bands.

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You may sometimes see one major bundle and several

10:10

synchiae next to it that are much thinner.

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Not in this particular case.

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So, this is how you use the axial

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projection arthrographically.

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I've also seen it done with simple T1

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spin echo 2D imaging with fat suppression.

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That's a fine way to do it, too.

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I don't like it as well as 3D gradient echo.

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But if you're gonna do that, it's probably a

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good idea to have a pre-arthrographic T1 with

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fat suppression so you can compare the pre-T1

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fat set with the post-arthrographic T1 fat set.

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Let's move on to arthrographic analysis.

10:48

Arthrographic analysis.

10:49

Of the coronal projection, shall we?