0:00

We have a couple of our questions,

0:02

and I also, I wanted to ask you, uh, to both, uh, you

0:06

and Karen, uh, for you, uh, Rodrigo,

0:08

there is a question that came in.

0:10

Just curious, how does the FSIS growth plate protect the

0:14

epiphysis from being involved in a Brody's abscess?

0:18

Is there an established pathophysiologic etiology?

0:23

Oh, yeah. Uh, what, uh, the vessels, they go

0:28

until the, the growth plate,

0:30

and they don't, uh, they don't trespass,

0:33

they don't go to the epiphysis.

0:34

They, uh, the vessels go to the go growth plate

0:38

and they return to the metaphysis.

0:40

So it functions as a barrier.

0:43

So the, the germs, they just stop at the metaphysis

0:48

and they, and they don't go further, uh,

0:50

through the growth growth plate.

0:52

So that's the, the, the way that they protect the epiphysis

0:56

and the, and the joints.

0:58

Yeah. And I would just make one point about

1:00

that particular case.

1:02

I love it. It's the most common place we see Brody's

1:04

absences in the distal tibia,

1:07

and many of 'em, as you mentioned, are elongated,

1:10

and they have little tracks,

1:11

and your case showed that track,

1:13

which extended down into the joint leading

1:16

to the septic arthritis.

1:18

Sometimes the tracks extend to the surface

1:22

of the bone as well.

1:23

That's another direction. So that is very useful.

1:26

Um, I have a question, um, for, uh, Karen, if she's there.

1:31

Yeah. And maybe for both of you, my first question is

1:35

what are the percentage of cases

1:37

of osteomyelitis in the diabetic foot

1:39

that there is not a foot ulcer nearby?

1:44

How often do you see that?

1:46

Pretty? I like almost never.

1:49

Yeah. So that to me is always, you know, something that I,

1:54

I look for because I'm sure there are examples.

1:57

Maybe some have calloused because the ulcer has healed.

2:01

But that's, to me, you look for a nearby ulcer,

2:04

because I think, as you say, in the vast majority of cases,

2:08

there will be an ulcer, a nearby.

2:11

Um, I wonder if, uh, Karen, you

2:14

or Rodrigo have used what has been described

2:18

as a so-called ghost sign on the T one weighted images.

2:22

Let me tell you what it is. Okay.

2:24

And that is that when you're trying to differentiate

2:28

neuropathic disease from osteomyelitis

2:31

or both, it has been suggested

2:34

that when you look at the T one weighted images,

2:36

and that's why I bring it up to your case, Rodrigo,

2:39

when you look at the T one weighted images in infection,

2:43

the surfaces of the bones are ill-defined.

2:46

Okay? When you look at it in neuropathic disease, again,

2:50

you can get fragmentation,

2:51

but the surfaces of the bone are well-defined.

2:55

So the go sign means an ill-defined surface to the bone,

2:59

and people have reported it as being very suggestive

3:02

of infection alone

3:04

or infection combined with neuropathic disease.

3:08

I don't know if either one of you, uh, Karen

3:10

or Rodrigo have used that or have heard of that.

3:14

Uh, is that something you can comment on or not?

3:16

I don't know.

3:18

I had the one slide that, um, showed the recurrence of,

3:22

uh, the reappearance of the surface of the bone on, um,

3:26

after the administration

3:27

of intravenous contrast on T one fat suppressed sequences.

3:31

But I really liked Rodrigo's case

3:34

because it nicely showed the crisp outlines in the setting

3:39

of neuropathic osteoarthropathy.

3:40

It can look like a big mess, right?

3:43

Cystic changes, erosive changes,

3:46

sometimes even like really tiny bony fragments.

3:50

Um, but I think what you're, they're referring

3:52

to is a ghost sign and,

3:54

and that it, uh, kind of dis the,

4:00

it becomes more clear on T one.

4:02

Is that what you're referring to?

4:03

Oh, no, they, they, oh, no, because more, more fuzzy.

4:06

Yeah. Neuropathic it is sharp edges to the fragmented bone

4:10

as opposed to it'll define ghosting

4:13

that you see an infection.

4:15

I, I've read the articles.

4:17

I, I don't see a lot of cases in my teleradiology

4:20

of diabetic feet, so I don't know if it's a useful finding.

4:24

I, I think it is actually useful

4:26

because they talk about this, you know,

4:28

bacteria when it's super infected,

4:30

that there is a bacterial lio that

4:33

is going on in that midfoot.

4:36

And I think of it in a very simplistic level

4:39

as a bacteria going to town

4:40

and eating up the little bony fragments so

4:43

that then you're gonna have, you know,

4:46

a much more ill-defined appearance, bony fragments

4:49

that were there before that are small enough to be

4:54

resorbed by this bacteria involvement, um,

4:57

are gonna disappear.

4:59

They talk about also the disappearance

5:01

of those cystic changes in the midfoot as well.

5:04

So if you have 'em before and then you don't have them

5:08

after, that's high clinical suspicion

5:11

that there is a super infection going on.

5:13

Yeah. About the Dose.

5:14

And one other question for Rodrigo, the CRMO, which is part

5:19

of SO, how do,

5:21

how do you make the diagnosis if there aren't pustules on

5:24

the hands and feet?

5:26

I mean, I would think it would be difficult exclusion,

5:30

Exclusion criteria.

5:31

It's like, it's not infection, it's not a tumor.

5:34

Sometimes we do whole body MRI with other areas

5:38

that are compromised and it help us.

5:41

But, uh, there's no some, there's no laboratory test

5:45

that help us, uh, to do this diagnosis.

5:48

Sometimes when is, uh, when you focal lesion, uh,

5:54

they have to, they biopsy if there is a suspicion,

5:58

maybe infection or a tumor,

6:00

but it's a diagnostic of exclusion.

6:04

Okay. And then also, sorry,

6:07

Go ahead. What?

6:07

Go ahead. And also, very rarely, I think if you send it

6:10

for, um, bacterial analysis

6:12

or p bacterial PCR, sometimes you can, um, uh,

6:17

sometimes it'll come back with either what used

6:20

to be called prop, no prop nodes, you know, I can't say it

6:24

acnes or now cutie bacterium acnes.

6:27

Which is why I think they changed the name.

6:29

Yeah. Which was felt to be a contaminant

6:32

and yeah, no, I agree with that.

6:33

There's one further question.

6:35

Uh, do you ever see for me, fat globules in the bone marrow

6:40

and fat necrosis where they become hypo at tense on non-fat,

6:43

fat images in the chronic setting?

6:46

I have not, uh, I would ask the person

6:49

who is sending this in, I see the name,

6:51

I'd love to see the case.

6:53

My email's dresnick@ucsd.edu.

6:57

So if you have a case like that, please send it to me

7:00

and I'll, I'll make a comment about it.

7:03

I just threw up the M mss KI rads, uh, um, table here.

7:06

And I find it a little bit messy.

7:09

Uh, this is the answer to the other question.

7:11

Um, I think that was in the chat,

7:13

but, um, what I don't like about it is like how wordy it is.

7:18

But a lot of times, you know,

7:19

we're gonna be talking about these things, you know,

7:21

how a highly success suggestive bit of osteomyelitis

7:25

and you know, where it's involving.

7:28

Um, the part I don't like is

7:30

where we start making recommendations about, um,

7:34

what, what should be done.

7:35

Um, so I myself, I am gonna stay in my lane

7:39

and stay as a radiologist on the diagnostic side,

7:42

not recommend treatments.

7:44

So that's what the MSKI RADS is.