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Let's talk arthrography MRI.

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Please feel free to go to the axial projection

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for discussion of technique in the axial vignette.

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But I'm going to talk primarily about some of the

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observational and pitfalls that occur in coronal

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evaluation, and also what I like and why I like it.

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So I've given you a, a menu.

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On the far left is a T1 fat

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suppression using 2D technique, 3.

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5 millimeter cuts.

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It's really, really dark, isn't it?

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The bones are dark, the muscles are dark, the

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fat is dark, everything's dark except the fluid.

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So this is what I call the black and white image.

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The whites are white, the darks are

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dark, kind of like Tide, the detergent.

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Now the reason that's good is you get exquisite

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contrast interfaces between ligaments,

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fibrocartilage, and intraarticular fluid.

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The reason it's potentially bad is because

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it can be very confusing and confusing.

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If you have multiple abnormalities and edema in

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multiple territories and trying to figure out

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which is the territory that really dominates.

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So for that reason, um, it's not the sequence that

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I would use all by itself in the coronal projection.

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If you've looked at the axial vignette, you know

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that we showed you a very exquisite 3D gradient

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echo with about a one millimeter series of cuts.

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Where everything was black in the bones, black

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in the fat, dark in the muscles, and bright in

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the joint as well, but with a thinner slice.

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So another potential disadvantage of this

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T1 fat suppression technique is that the

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spatial detail is not going to be as high.

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Three and a half millimeters versus one

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millimeter for through-plane resolution.

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On the other hand, most scanners can do it.

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So if you have an older scanner, that's 10, 15, 20

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years old, you can do a T1 with fat suppression.

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So it has some, some technical versatility.

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Spinecho, any scanner can do it.

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Any scanner.

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Low field, high field, older scanners, newer scanners.

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So it has that advantage.

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It also has the advantage of showing

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you something other than fluid.

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In other words, you're looking at gadolinium.

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So, if there were fluid out here, you wouldn't know

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if that fluid was extravasated, or whether that fluid

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was from a rotator cuff tear, or it might be a

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little difficult, might be a little more challenging.

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The same thing down here, you had a little tear

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down here, is it extravasation, or was it a

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technical issue, or is it truly a hole with water

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going through the axillary portion of the IGHL?

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Whereas if it's gadolinium Based T1

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shortening, right on T1, and it's out here.

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It can really pretty much only be from extravasation.

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Unless you punctured it.

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Unless you punctured that spot.

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And as I said, my preferred locus for injecting is with

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the patient prone, in the back, in the posterior interval.

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So if you stay away from this area, and gadolinium

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is out here, the odds are, it's not edema, it's,

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it's actually extravasation of the gadolinium itself.

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So this has a great deal of specificity

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with regards to geography of the contrast.

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Now on the far right, I've got a PD fat suppression.

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This has, this has the advantage of being

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highly sensitive to all things water.

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It has the disadvantage of being

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highly sensitive to all things water.

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We have water here, but what if we had water here?

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We got a little water here, what if we had water

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here, and here, and here, what would it mean?

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It, in some ways, because of its sensitivity,

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diminishes the specificity of what the water

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means once you put contrast in the joint.

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So this has some advantages and

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some disadvantages, they all do.

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Now if I was going to choose, I would probably

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choose the T1 with contrast, without fat suppression,

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and then I would choose this one to the far right.

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But, you know, it's dealer's choice.

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Some of you may like the blackness of the bone marrow

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and the blackness of the fibrocartilage up against

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the whiteness of the contrast intraarticularly.

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And if you're new to the game, why not all three?

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You know, take your time.

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Few pitfalls.

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As you're scrolling back and forth, no, that's not a tear.

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That is simply a recess between the biceps and the SGHL,

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the superior glenohumeral ligament that's coming at you.

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That is not abnormal.

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You'll see hyaline interposition right here at the base

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of the biceps and right against and underneath the SGHL.

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Now what's this structure?

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There's another recess between the biceps

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and the coracohumeral ligament which forms

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the deepest layer of the rotator cuff.

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So we have multiple bands.

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CHL, coracohumeral ligament,

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recess, biceps and labral anchor.

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And then the SGHL and its recess.

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So those are some potential pitfalls in

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analysis of the superior labral area.

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Now we're not technically talking superior labrum

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and SLAP lesions, but it is part of the instability,

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microinstability spectrum, so I've thrown it in.

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What about down low?

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You know, the coronal projection

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is all about up high and down low.

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Because of your position.

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You're orthogonal to these areas.

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And you're perpendicular to them.

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So down low You've got the labral ligamentous complex.

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Now I like to see the axis of my labrum.

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Not my SGHL, but my labrum point this way.

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Somewhere around 60 degrees.

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So if this is the horizontal, this is about 60 degrees.

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45 degrees, okay.

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65 degrees, okay.

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When I start to see my labrum tilt.

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So when I start to see my labrum do this.

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Tilt downward, like that.

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Or I start to see my labrum medialize.

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Or move this way, relative.

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to the glenoid cup.

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In other words, the labrum is now over here.

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Now I know I've got a detachment.

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And some form of anteroaxillary labral shift.

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On the other hand, when you distend the joint, let's

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pull down the axial for a minute, when you distend

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the joint, look how medial a normal capsule can be.

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I'm gonna make it a little smaller so you can see it better.

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It's really medial, almost to the anterior scapular ridge.

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So it's not surprising that you

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get a lot of distension here.

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So don't confuse this medialized collection of

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fluid with stripping or periosteal separation.

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That can be and frequently is normal, especially

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in athletes who have stretched out their capsule.

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Also, do not be put off by the fact that the axillary band

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of the IGHL doesn't take off at the apex of the labrum.

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It usually takes off right at the junction.

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of the labrum and the bone, right there.

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So it comes almost straight down

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and then starts to curl over.

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That is also a potential source of confusion

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for most newbies and youngins to MRI.

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Also pay very careful attention to the

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insertion, posteriorly, of the IGHL.

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Tears of this area frequently scar back down.

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So you want to look at the shape.

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Is it very smooth, even though it's attached?

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Is it smooth, or is it lumpy,

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bumpy, and lobulated, and irregular?

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of the IGHL and have a look at it.

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Most of these tears occur right here in the middle.

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And then go to the front.

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Then go all the way to the front of the IGHL, right

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there, and look for a potential haggle or a B haggle.

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So this is a very important area for assessment, sometimes

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you can tear here, sometimes you can tear here, sometimes

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you can tear in both places, in which case you get an igle.

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And remember these axes that we've

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talked about in the coronal projection.