0:00

The next case is a 44-year-old woman with shoulder pain

0:06

after falling on the ice. Right now, it's summer here; we're

0:10

having heat waves everywhere, so there isn't a lot of ice.

0:15

Okay, so let's go with a differential. So, falling on the ice,

0:24

you know, the first thing you would think of would be a fracture.

0:27

What else might you think of? A bone contusion, a soft

0:31

tissue contusion, a dislocation of the shoulder.

0:38

And, you know, rarely, if you fall down

0:40

and you grab something, you might get a SLAP lesion

0:43

or a rotator cuff tear when your arm jerks upward.

0:47

But that would be a much less common thing.

0:48

So it helps to think about what the diagnosis

0:52

might be, you know, prior to getting into the case.

0:56

One of my dear friends who's no longer with us

0:59

used to say, you know, if you know what you're

1:01

looking for, you're a lot more likely to find it.

1:04

So when I, when I'm hunting for say a fracture

1:08

I don't rely very heavily on the gradient echo.

1:10

The gradient echo is for labra.

1:12

The gradient echo is for hyaline cartilage.

1:14

The gradient echo is for the joint

1:17

space, looking for loose bodies.

1:19

Looking for hydroxyapatite deposition disease, for calcium,

1:23

for blood, for iron, for metal, for susceptibility effect.

1:28

And none of those are present here.

1:31

It is not very good for looking at the skeleton, although

1:34

there is a suggestion right here that something is happening

1:38

in the skeleton, but, but it's not all that clear.

1:42

But when I put up the proton density fat suppression image,

1:45

and I put it up next to my beloved T1 weighted image.

1:49

And I know many of you use proton density in place of T1.

1:53

I would urge you not to do that.

1:55

A lot of you do it for menisci and for cartilage,

1:58

but the reason not to do it is because you you

2:01

lose your ability to quantify marrow injuries.

2:05

And as we scroll,

2:07

we can see that there is a marrow injury and we see it best

2:11

on the T1 weighted image.

2:14

And the edema from this marrow insult from the

2:18

fall is apparent, much more apparent on the proton

2:21

density fat suppression than on the gradient echo.

2:24

Now, I said I don't like proton density for the marrow.

2:29

I didn't say I didn't like proton density fat suppression.

2:32

Simple proton density without fat suppression is a marrow buster.

2:36

It does not show marrow pathology very well

2:39

and you must be aware of this.

2:41

If you're going to use PD without T1, which

2:44

I know has been a common practice in Australia.

2:48

So now let's talk about the grades of bone injury.

2:53

I like to lump them into if it's not a fracture.

2:56

I like to call them microtrabecular

2:58

bone injuries, and then I will parse out

3:02

what type of microtrabecular bone injury I have.

3:04

For instance, if it's very ill-defined without any lines

3:08

and it's only on a water-weighted image, kind of like

3:11

this, I call it a contusion, a low-grade contusion.

3:15

If I were to see something kind of ill-defined, wax on, wax

3:18

off appearance like Karate Kid and no lines and no cortical

3:24

communication, it's on the T1, it's on the water-weighted

3:27

image, I'm going to call it a high-grade bone contusion.

3:31

If I see spidery lines like this, I'm going

3:34

to call it a microtrabecular intramedullary

3:37

fracture, kind of like this one right here.

3:40

And I'm going to say in my report, unlikely

3:43

to be seen on conventional radiography.

3:47

Now, if you wanted to call it a medullary

3:49

bone fracture, an incondylar bone fracture.

3:54

or microtrabecular fracture.

3:56

I wouldn't object to that either.

3:58

As long as you make clear there's no cortical communication.

4:01

Now, this one is different.

4:03

This one has a microtrabecular component.

4:06

This one has a bone contusive

4:08

component, but it also has a step-off.

4:11

There's the step-off.

4:12

It has depression.

4:14

It has clear cortical communication.

4:16

So this is a fracture now because plain radiography may

4:20

hide this, you know, it's not all the way from front to back.

4:23

You may have good bone in the front that good

4:25

bone in the back of the fracture in the middle,

4:27

you may or may not see it on a radiograph.

4:31

This is so much easier on an MRI than

4:34

it is with a conventional radiograph.

4:37

And in fact, in the United States, people that come into

4:40

the ER with hip pain after a fall a little old lady in some

4:44

acute distress, a so-called lull in sad, we don't put her in

4:48

the x-ray machine and do a frog leg views and judo views.

4:53

We stick her right in the MRI.

4:54

We do a T1 and a gradient echo image

4:57

in three to four minutes and we're done.

4:59

We got the answer with 100 percent accuracy.

5:03

Let's take a look at the sagittal just for

5:04

giggles and see what our injury looks like.

5:09

This is actually a T2, which is not as

5:12

sensitive as the proton density fat suppression

5:15

and picking up the character of the fracture.

5:18

Nor is it as specific as the T1 in

5:21

telling what grade of bone injury it is.

5:24

And again, the grades are low-grade contusion, high-

5:27

grade contusion, microtrabecular fracture, fracture.

5:31

And then when you get into fracture, you do everything you do on

5:34

radiography, depression, displacement, comminution, angulation.

5:39

Rotation, gapping, dogs and cats living together, 10

5:43

days of darkness, the plague and mass hysteria, all

5:46

your knowledge of conventional radiography should be

5:49

poured into your identification of the fracture on MRI.

5:54

There is one other interesting, very minor finding,

5:58

and that is there's a small injury to the periosteum

6:02

of the inferior glenoid.

6:03

That's kind of tiki-tac, but I thought I'd show it to you

6:06

and you're not going to see this on any other sequence.

6:09

You certainly don't see it on T1.

6:11

You're not going to see it on any other sequence other

6:13

than the proton density fat suppression sequence.

6:17

So for fractures, PD fat set and T1 are your friend.

6:22

If you know what you're looking for

6:23

going in, it's going to help you a lot.

6:26

One of you suggested that there was a tear of the IGHL.

6:30

Here is the IGHL in the back posterior, or it is in the axillary.

6:34

Here it is thick in the anterior.

6:36

Yes, there is a periosteal injury

6:38

but there is not rupture of the IGHL.

6:40

G.

6:41

H.

6:41

L.

6:42

Some of you suggested that there was a

6:44

partial thickness tear of the subscapularis.

6:48

I like to look at the subscapularis and

6:49

the sagittal and it looks just peachy.

6:52

It looks fine right there.

6:54

The subscapularis is intact.

6:56

There's a little fluid above it in the rotator interval.

6:58

There's your biceps.

6:59

Here is your C.

7:01

H.

7:01

L.

7:01

Your coracohumeral ligament is right here and the

7:07

little hammock that supports The underbelly of

7:11

the rotator interval is the SGHL it's right here.

7:15

So a little bit of extra anatomy at no additional charge.

7:18

Some of you suggested that there

7:20

was a reverse Hill-Sachs lesion.

7:24

Let's go to the axial water-weighted image.

7:28

There's an axial water-weighted gradient echo

7:31

image and a reverse Hill-Sachs would be over

7:34

here in the lesser tuberosity, not there.

7:37

So it's in the wrong place that would not be a consideration.

7:41

Somebody suggested borderline AC joint widening you know whenever

7:45

I hear the term borderline could be maybe thought to be possibly.

7:50

I know the reader is not confident.

7:53

In their descriptor, or in the finding.

7:56

Yeah, there is a little bit of tissue thickening I think

7:58

widening is a little strong because it suggests an AC

8:01

joint separation, there's no swelling here to speak of.

8:04

There is no AC joint separation, and in a patient of

8:08

this age it's not uncommon to have a little thickening.

8:11

Of the capsule in this region.

8:13

The AC joint actually is never normal after the age of 15.

8:17

It's kind of one of those joints that wasn't meant to last.

8:22

There was no bony bankers, and somebody also suggested a hill

8:27

sacks by the way, not, not a great location for a hill sacks

8:32

abnormality, a hill sacks abnormality is posterior as this is,

8:36

but it tends to be slightly off the apex of the humoral head.

8:41

For instance, over here at about the 11 o'clock position

8:45

or on the other shoulder at the one o'clock position.

8:48

And it, it, it's also nice for me to show you

8:51

the labrum, given the query about the hill sacks.

8:54

The labrum is absolutely normal.

8:57

The labrum is a little grayer on gradient echo imaging

9:00

down low because it's a labral ligamentous complex and

9:03

you get a little magic angle effect associated with it.

9:06

So this patient has not had.

9:08

A dislocation and the answer is a slightly comminuted,

9:14

slightly depressed fracture of the humerus.

9:17

Greater tuberosity with a minor

9:21

periosteal injury of the inferior glenoid.

9:24

This high signal intensity of the rotator cuff is

9:28

nothing more than a cuff contusion, which commonly

9:31

accompanies a fracture of the greater tuberosity.

9:35

Shall we move on?