0:01

So we have our discitis,

0:02

osteomyelitis infection and we have discussed some of

0:07

the complications of those spinal infections,

0:10

those including phlegmons,

0:12

where we don't see a central low density

0:16

but it is bright on T2-weighted scanning.

0:18

The abscess where we see central load

0:21

signal intensity in the rim of a gadolinium-enhanced collection,

0:25

and again, fluid signal intensity on T2-weighted scanning.

0:29

The surgeons are much more likely to go in to drain an

0:31

abscess than they are to deal with a phlegmon

0:34

because it's not as well defined.

0:36

But both of them can lead to that severe complication I

0:40

mentioned of phlebitis of the veins that affect the

0:44

spinal canal, which could lead to cord ischemia.

0:47

Tuberculosis is one of the causes of a spine infections,

0:52

spondyloarthritis, that is relatively unique.

0:56

It's unique because in certain cases,

0:59

the disc may not show enhancement.

1:02

You can have lesions in multiple locations in the spinal canal.

1:07

Sometimes it may even involve the posterior

1:09

elements predominantly.

1:11

And the signal intensity on T2-weighted scan may not

1:14

be as bright as we typically expect

1:17

on T2-weighted imaging.

1:19

This is a patient who has tuberculous spondylitis.

1:23

On the STIR imaging,

1:25

we see a lesion that is affecting the vertebral

1:29

bodies and the intervertebral disc.

1:31

However, it's relatively dark in signal intensity on

1:35

T2-weighted imaging. Not only that,

1:38

but we also see that it is extending under

1:42

the anterior longitudinal ligament.

1:45

This is one of the features that is,

1:47

if not pathognomonic,

1:49

very typical of tuberculous spondylitis.

1:53

It does have an epidural component that is compressing

1:56

the spinal cord, as you see here.

1:59

Axial scans are very helpful with regard to tuberculous

2:02

spondylitis because it is the bacterial agent that

2:06

has the highest rate of creating psoas abscesses.

2:11

And in point of fact,

2:12

even after the infection has resolved,

2:16

you may see focal calcifications from the previous

2:19

infection, associated with tuberculous spondylitis.

2:23

So here we just see diffuse enhancement in the epidural

2:27

tissue in this case of tuberculous spondylitis.

2:31

Here is a more gross case in the lumbar spine, where we

2:37

basically have destruction of the vertebral body and

2:41

infiltration massively into the psoas muscles.

2:44

Frankly, on this T1-weighted post-gadolinium

2:47

enhanced scan, for some of you,

2:49

it may be impossible to even see where the thecal sac is.

2:52

But this is the area of the thecal sac being displaced

2:56

by a small area where there was some

3:00

metal artifact associated with the previous surgery.

3:02

So the thecal sac is narrowed.

3:04

And what is it narrowed by?

3:06

You have infection that is involving the facet joints.

3:09

You have infection that's involving the vertebral body.

3:13

Here's our vertebral body outlined here.

3:15

And then we have these massively enlarged psoas muscles

3:20

showing areas of necrosis within the muscle for

3:24

the psoas abscess. On T2-weighted scanning,

3:28

you'll note that this inflammatory process in the

3:32

psoas muscle is not very bright on T2,

3:37

which is very unusual.

3:39

So either this is old tuberculous spondylitis

3:42

with calcified psoas muscle,

3:44

or it's just the normal tuberculous signal intensity,

3:49

which may not be as bright as typical pyogenic mycobacteria.

3:55

In this case,

3:56

because of the appearance on the T1-weighted scan,

3:59

we know that this active tuberculosis affecting the spinal canal.