0:01

<v ->Now there are other things that don't tell you

0:05

whether or not these are reversible or irreversible.

0:10

Including confluent regions of intense

0:13

edema-like alterations in the subchondral bone

0:17

with or without a linear or band-like alteration.

0:22

So you look at this example here

0:25

early on there is band-like marrow edema

0:29

and a, what looks to be, a subchondral stress fracture

0:34

but without collapse of the subchondral bone plate.

0:38

Remember that is irreversible,

0:40

if the bone plate is collapsed.

0:43

But if you see the fracture and marrow edema

0:47

without collapse, that can be reversible.

0:50

And here in this case, you can see

0:53

that it pretty much has cleared up four months later.

0:57

Now, finally, there's some other patterns of alterations

1:01

in marrow signal that are irreversible

1:05

because they're diagnostic of conditions

1:08

that are persistent.

1:09

Paget's Disease is one of these.

1:11

We all recognize it radiographically

1:14

as thickening of the trabecular pattern.

1:17

You can have areas of altered marrow signal.

1:20

Typically in Paget's, fat signal

1:23

may be maintained until late

1:26

and indeed the absence of fat signal

1:28

can sometimes indicate a complication of Paget's Disease.

1:34

Similarly, just in hemangioma,

1:36

we can see the altered trabecular pattern

1:40

characteristic of hemangioma,

1:42

with some increased fat signal in that particular area.

1:46

Typically this too is irreversible.

1:50

So what I've tried to do in my third lecture

1:53

is to give you an idea of what may be the link

1:56

between transient painful osteoporosis marrow edema,

2:01

insufficiency fractures, and osteonecrosis

2:05

because there are important links

2:08

among those three conditions.

2:11

Let's stop now and go ahead

2:13

and get our third case review from Abdula.