0:00

So now we'll turn our attention to the diabetic foot.

0:03

It is kind of, you know, similar.

0:05

We're gonna use this, the same kind of tools

0:08

to figure out whether or not this is, uh, infected or not.

0:12

But oftentimes these are the, uh, cases

0:15

that are scanned right about 4:30 PM finishing right at

0:19

5:00 PM So when you do have to call the clinicians to, uh,

0:23

tell them about acute osteomyelitis, nobody's around

0:27

or somebody else has just taken over

0:28

and has no idea who the patient is.

0:31

So from the radiographic examination, we already know

0:34

that this patient has been through the ringer

0:36

and has had several amputations,

0:39

but we can appreciate the soft tissue air

0:42

that's surrounding the amputated stump of a great toe.

0:45

Not only do we have that, but we have rare faction

0:48

and bone loss involving the first metatarsal head.

0:52

On the axial T one

0:54

and STR sequences, there is this sinus tract

0:57

that extends all the way down

0:59

to the first metatarsal head stump.

1:02

And there is tremendous amounts of soft tissue irregularity,

1:06

as well as a small joint effusion involved, uh,

1:10

at the first metatarsal head.

1:12

These findings are similar on the T one

1:16

and, uh, stir sequences of the, um,

1:19

sagittal sagittal projection.

1:21

But again, if we look carefully,

1:23

you could argue maybe there's a little bit

1:26

of retained marrow signal

1:28

and ty on the T one weighted sequence.

1:30

But remember, look at the adjacent soft tissues, see

1:34

how they're doing, and that's how we're going to try

1:36

to predict whether or not this patient has a high likelihood

1:40

or a low likelihood of osteo uh, myelitis.

1:44

So in this particular case,

1:46

because of a overlying soft tissue ulceration,

1:49

we will put this patient into the high likelihood of

1:53

osteomyelitis category, despite some

1:56

of the T one fat signal intensity being

1:59

relatively maintained.

2:02

So as we go back to thinking about the biomechanics related

2:06

to the diabetic foot, we know that this is primarily an

2:11

outside in phenomenon, whether it is, uh, related

2:16

to ill-fitting shoes

2:18

or some sort of neuropathy that leads to

2:22

an alteration in weightbearing.

2:24

These patients typically will be developing callous

2:27

formation, as we can see in this particular patient

2:32

along the lateral aspect of the foot, um,

2:35

is a very common site, as is the medial aspect

2:38

of the first metatarsal head.

2:41

Look very carefully at your T one weighted sequences

2:45

and use your subcutaneous fat

2:47

to help you find these ulcerations

2:50

because the stir sequence

2:52

or your T two fat suppress sequences will have the signal

2:56

intensity of the fat and the

2:58

Callous about the same.

3:00

So it's going to be nearly impossible

3:02

to find those findings if you're purely looking at a stir

3:06

or a T two fat suppressed sequence.

3:10

So the T one weighted sequence here makes it very easy

3:14

as this hypo intensity along the, um, lateral

3:18

and uh, plantar aspect of the fifth metatarsal head.

3:22

Fortunately for this patient, it has not gotten

3:24

to do the point of, uh, acute osteomyelitis yet

3:28

with spared marrow signal intensity within the

3:31

fifth metatarsal head.

3:35

Here on the other hand is another patient,

3:38

and this is already severe deformities.

3:42

Based on just the sagittal images alone,

3:44

we see septic arthritis involving the metatarsal falon chill

3:49

joint with frank dislocation of the toe, with an overlap

3:53

of the toe with the metatarsal head on the T one

3:58

and T two fat suppress sequences.

3:59

We can see this very large abscess to better advantage

4:04

on the axial T two weighted sequence

4:06

with multiple different pockets

4:08

and areas of thickened synovial enhancement.

4:12

Not only do we do see

4:13

that is the signal alteration on the T one weighted

4:17

sequences compatible with acute osteomyelitis.

4:21

I'll bring your attention to this single axial

4:24

T one fat suppressed sequence here.

4:26

And the reason for this is

4:28

that the intravenous contrast really helps us see not only

4:32

the joint effusion at the site of the dislocation,

4:37

but look at this peripheral rim enhancement

4:39

that extends along the, uh, extensor tendons here.

4:43

So this was additional septic teno synovitis

4:47

of the extensor tendons,

4:49

and this is an important pathway, uh,

4:51

that the infection can extend.

4:54

Um, and it is one of the important things for us

4:58

as radiologists to report such

5:00

that the patient can be treated in a timely manner

5:04

and treated appropriately.

5:05

So if you did a resection, uh, in the, uh,

5:09

the trans metatarsal level here,

5:12

the the patient may still have residual infection more

5:15

proximally and he may not do as well.

5:19

Postoperatively there's one more sinus tract,

5:23

again using the areas, uh, uh,

5:26

that we look at here we have the high signal intensity

5:29

within the T two fat stress sequence,

5:32

the adjacent sinus track here, relatively kind

5:37

of better signal intensity on our T one weighted sequence on

5:40

both the axial and also the sagittal images.

5:43

But know that there's that, that sinus track there.

5:46

So this is another patient that would be, uh, put into

5:50

that higher likelihood of osteomyelitis.

5:53

This is another, uh, case demonstrating some

5:56

Of that septic teno synovitis.

5:58

You've seen one, you've kind of seen them all.

6:01

We see that septic, um,

6:02

arthritis involving the fifth metatarsal phalangeal joint,

6:06

much more difficult to detect on radiographic examination.

6:10

Not only do we have septic teno synovitis of portions

6:13

of the extensor tendon here,

6:14

but we have nearly, um, uh,

6:17

diffuse signal intensity throughout the entirety

6:20

of the flexor tendon as well.

6:23

So if we think back to where the podiatrist

6:26

or the ankle surgeon may have to resect, we could

6:31

tell them mid shaft here.

6:33

However, that would not cover, uh, the debridement

6:37

of this flexor tendon, um, uh, abnormality as well.

6:42

So this is something to report and,

6:45

and make sure that they're made aware of such

6:48

that they can do the appropriate debridement

6:50

and then follow with the antibiotic therapy as well.