0:00

Now, what are the available techniques that we can use

0:03

as imagers to evaluate this particular region?

0:07

Conventional radiography is what I grew up with.

0:10

That's what I learned about

0:11

and I think it is insensitive

0:14

for the early inflammatory stage of sacroiliitis.

0:18

When you use conventional radiography, in addition

0:21

to the AP pelvis view, there is a Ferguson view,

0:24

and I remember this one very well.

0:27

It's an AP radiograph of the pelvis with the beam,

0:30

the x-ray beam angled toward the head.

0:33

Some people reverse that with a patient pro

0:36

and angle the beam toward the feet.

0:38

I like that view. It elongates the S sacroiliac joints.

0:42

Here you can see some patchy sclerosis

0:44

involving both of them.

0:47

CT is the most sensitive method in my view,

0:50

for detecting morphologic abnormalities.

0:53

By that I mean bone sclerosis, bone erosions.

0:57

The nature of the interosseous space,

1:00

is it narrowed, is it widened?

1:02

And in fact, is there bone ankylosis?

1:05

Where MR is useful is it's the most sensitive mass

1:09

for detection of active or quiescent inflammation.

1:13

You're gonna see marrow edema in the active stages related

1:17

to inflammation

1:18

and later on you will see in fact fat abnormal collections

1:23

of fat in the quiescent stage of sacroiliitis.

1:28

Just to give you some images to prove the points

1:31

that I've just mentioned, the role of CT scanning

1:35

shown here in two examples.

1:38

Bone erosions, cartilage loss and intraarticular ankylos.

1:42

And indeed you can see even small erosions very, very well

1:46

with CT scan.

1:49

With regard to MR imaging, the typical wave

1:51

that we will in fact program are

1:55

sequences is using a true coronal sequence

1:58

or sequences along the length of the uh, uh,

2:03

sacrum here and sacroiliac joint.

2:05

And then in addition, transverse images at right angles

2:09

for the long axis.

2:11

This is what it might look like in an example.

2:14

Here's what it would look like.

2:16

And typically in both of these planes, we include

2:20

non-flu sensitive

2:21

and fluid sensitive sequences, including sometimes

2:24

and often stir, stir sequences.

2:27

Now, there are scoring systems that have been, uh,

2:31

described in the literature for evaluation of sacroiliitis.

2:36

These can be done in the coronal plane

2:40

or in the transverse plane or in both planes.

2:44

We don't use them in our practice,

2:47

but indeed some people do.

2:49

And indeed you can go, uh, judge whether

2:52

or not there are abnormalities present or not.

2:55

And if there are present,

2:56

you can judge the degree of involvement

2:58

With a number of morphologic features including bone

3:02

erosions, fatty backfill,

3:05

fatty metaplasia, and the presence.

3:07

And we'll talk about it of joint fluid.

3:11

To give you an idea of what Mr.

3:13

Imaging and CT look like, uh, as we put images next

3:17

to each other with in two cases

3:20

this taken from the literature.

3:22

Again, I would emphasize that I think MR Imaging is superior

3:26

for the detection of inflammation

3:29

and not for the detection of erosive abnormalities.

3:32

Now, in these two cases,

3:33

yes we can see surface irregularity involving both the ileum

3:38

and sacrum, but I would maintain that it is the CT images

3:42

that show that surface irregularity

3:45

and the bone erosions to better advantage.