0:00

<v ->Well rheumatologists became very interested in MR imaging,

0:04

although they always liked plain films,

0:06

and they still order plain films,

0:08

but they became interested in MR imaging quite a while ago.

0:13

And in fact, what I'm showing you at the bottom

0:15

of this slide is the search that I did in 2009,

0:20

MRI in rheumatoid arthritis and spondyloarthropathy.

0:25

This being, what, 13 years ago,

0:27

there were 18,000 results at that time.

0:30

I'm showing you three of those results

0:32

to point out some of the early things

0:34

that were suggested with regard to the advantages

0:38

of MR over conventional radiography.

0:41

MR detects bone erosions in early RA

0:45

when conventional radiography is negative.

0:48

Number two, MRI in fact detects bone erosions

0:51

one year earlier than conventional radiography.

0:55

And number three, MR finding

0:59

of marrow edema is a strong predictor

1:02

of the subsequent development of bone erosions.

1:05

So look at the excitement that all of this,

1:07

I mean here you have a technique,

1:09

we don't have to wait for the bone erosions.

1:11

We're gonna see changes on MR.

1:14

We're gonna perhaps see marrow edema.

1:16

So after this, so many articles appeared,

1:19

I'm sure we're dealing with hundreds of thousands

1:22

of articles dealing with MRI and rheumatoid arthritis.

1:27

If I had to try to summarize what we currently know

1:30

about the role of MRI, generally accepted,

1:34

I've listed here five things.

1:37

MRI is more sensitive than the clinical examination

1:40

for identifying synovitis.

1:42

MRI can predict progression to RA when you're dealing

1:46

with an undifferentiated inflammatory arthritis.

1:50

Subclinical synovitis

1:52

detected by MRI predicts subsequent flare

1:56

even when clinical remission is present.

1:59

MRI may be used to predict treatment response.

2:03

All right, and I think that's a very important one.

2:06

And then the bottom one I've highlighted.

2:08

MRI can allow detection of bone marrow edema,

2:12

which is a strong predictor

2:14

of subsequent radiographic progression in early RA.

2:19

Edema before bone erosion.

2:22

Now ultrasonography can also be used

2:25

for many of these same factors.

2:27

And as you know, rheumatologists are very interested

2:30

in ultrasonography as well.

2:33

So we look at a typical example, and you know,

2:35

a lot of people believe the earliest target site

2:38

of rheumatoid is not the hand, it's not the wrist,

2:41

certainly not the knee or large joint.

2:44

It's the foot, and in the foot classically

2:47

it's the metatarsal heads

2:48

and the metatarsal phalangeal joints

2:51

that are involved early on.

2:52

And the earliest findings occur in the medial aspect

2:55

of those metatarsal heads as osteopenia

2:59

and a subtle dot-dash disruption

3:03

of the subchondral bone plate,

3:04

with the exception of the fifth metatarsal

3:07

where an erosion may occur here.

3:09

Well in this particular case, you could argue

3:11

whether or not you see anything

3:13

that tells you you're dealing with rheumatoid arthritis,

3:16

but when you deal with MR in the same pace,

3:19

you begin to see that it is clearly more sensitive.

3:24

Part of that relates to it's a tomographic technique.

3:27

We're looking at sections rather than a composite image.

3:31

But here we see the marrow edema,

3:33

and we can see areas of erosion,

3:35

again, typically on the medial aspect

3:38

of that metatarsal head.

3:41

Now not everything is golden

3:42

when we talk about MRI and rheumatoid arthritis.

3:45

There are diagnostic problems.

3:48

Early on when I first started to do studies

3:51

in patients with rheumatoid using MR,

3:54

we would have a time slot of four or five hours

3:58

because we didn't know what to do.

4:01

I mean, how many joints?

4:03

Both sides, perhaps?

4:04

Hands and wrists separately?

4:06

Throw in the feet?

4:07

Perhaps the hips and knees?

4:09

I mean then do we have to use gadolinium before and after?

4:14

Do we have to use all three imaging planes?

4:16

You add all that up, you can understand

4:18

why studies might take five or six hours.

4:22

Here one of our earlier studies

4:24

just showing you rheumatoid arthritis MR imaging,

4:28

including an IV gad, which we were using early on.

4:32

And you can see clearly changes of rheumatoid,

4:35

both in the right hand and left hand,

4:37

areas of erosion, synovitis, soft tissue involvement,

4:41

very, very dramatic.

4:43

Well of course, protocols were established

4:47

by some of the national organizations.

4:51

And basically what is considered

4:54

that if you're using MR for rheumatoid,

4:56

typically you image in two planes,

4:59

you use T1-weighted images

5:01

before and after intravenous gadolinium.

5:04

Whether or not you need fat suppressed images is not clear.

5:08

And then you need a T2-weighted fat suppressed

5:12

or a spin echo or STIR sequence.

5:16

So I show you an example here

5:18

of the T1-weighted fast spin echo image,

5:21

a T2 fat suppressed fast spin echo image,

5:25

and a gadolinium image.

5:26

And clearly we can see some signal,

5:29

this could be fluid or synovitis,

5:33

but with the gadolinium we can see

5:35

there's still some enhancement,

5:36

so presumably that is synovial inflammation.

5:41

But therein lies the second problem.

5:44

I mean isn't enhancement of synovium considered normal

5:47

up to a certain extent?

5:49

Synovium is vascular.

5:51

So how much enhancement, how thick the synovium,

5:54

how widespread the abnormality must it be to be certain?

5:59

And this is not clear, and it would vary

6:01

from one joint to another.

6:03

There are studies that have proven this,

6:05

for example this one

6:07

where they looked at contrast-enhanced MR imaging findings

6:10

of the knee in healthy children.

6:12

And look at the highlighting here,

6:15

following gadolinium.

6:18

Well is that too thick?

6:19

We don't have measurements.

6:21

And I don't think we can be certain.

6:23

And early on, we decided to do a study,

6:25

and our study was to look at what might be seen

6:29

about the odontoid process.

6:31

As I'll talk about later, rheumatoid targets this site.

6:34

So it's a good one to look at.

6:36

So we took those patients undergoing brain MR

6:39

who were getting contrast agents with no arthritis,

6:43

and we looked at their C1 C2 articulations,

6:46

and here arrows point out areas of synovial enhancement

6:51

about the odontoid.

6:52

So indeed synovium, normal synovium enhances.

6:57

How do you tell it's pathologic?

6:59

And then there's another diagnostic problem.

7:02

And that is it's easy to mistake surface irregularities

7:06

as erosions when normal contour alterations may be seen.

7:12

And this is a particular problem at the metacarpal heads

7:15

and the metatarsal heads, as shown here.

7:19

And these are areas of normal grooves

7:21

and flattened areas and irregularities that are normal.

7:25

Now you might say, gee, that doesn't look too bad.

7:28

They don't look like erosions.

7:29

But look at this example.

7:31

Here on the left, normal metatarsal head.

7:34

All right, well normal, but boy, oh, boy,

7:37

that kinda looks like an erosion.

7:39

On your right, a patient with rheumatoid.

7:42

Clearly different, but you can see

7:44

there might be diagnostic problems that arise

7:47

telling normal contour alterations

7:51

from areas of bone erosion.

7:53

What is clear in my view, however, is the role of MR

7:57

in following patients during treatment.

8:00

You start with an early image, here one before treatment.

8:04

You get a second image, identical parameters,

8:07

identical imaging technique.

8:10

You compare the two, there may still be abnormalities,

8:13

as in this case, but as you look at the two images,

8:16

certainly it looks like there has been some improvement

8:19

on the right 12 months during or after the treatment.