0:01

There are different causes of labyrinthitis.

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The most common actually is secondary

0:05

spread from a middle ear infection.

0:09

I'm showing you the post-contrast fat suppression scan of

0:13

a patient who is being evaluated for

0:15

hearing loss on the left side.

0:17

We immediately see that there is opacification and

0:21

enhancement of the mastoid air cells on the

0:25

left side, and also into the middle ear cavity.

0:30

On the post-gadolinium enhanced scans,

0:32

where I'd like to stop is on this image

0:35

and demonstrate the pathology as it relates to

0:39

the inner ear spread of middle ear infection.

0:43

I have to admit that at 3 Tesla,

0:46

evaluating the cochlear and vestibule and semicircular

0:49

canals for enhancement is a little bit problematic

0:51

because they naturally look a little bit brighter

0:55

than the adjacent soft tissues.

0:57

So if we look on the right side,

1:01

we have the cochlear basal turn, we have the vestibule,

1:04

we have the lateral semicircular canal.

1:06

So vestibule, cochlea, lateral semicircular canal.

1:10

And here is the apical turn of the cochlea.

1:15

Although there is slight hyperintensity to the basal

1:18

turn of the cochlea and the vestibule

1:20

and the lateral semicircular canal,

1:23

those are normal phenomena on a post-gad three

1:26

tesla fat-suppressed scan. However,

1:29

if we look on the contralateral side,

1:31

I think that you can see pretty strikingly that the

1:33

basal turn of the cochlea on the left side is enhancing

1:39

much more so than its contralateral normal and the

1:44

anatomic structure. So let's just erase some of this

1:47

so it's a little easier to see the areas of enhancement.

1:52

Not only that,

1:53

but you can also see that the vestibule

1:58

is also showing abnormal enhancement compared

2:02

to the contralateral vestibule.

2:04

So let me erase everything so you can sort of look at

2:07

this on your own. And hopefully, you can see that there is

2:11

abnormal enhancement here,

2:12

an abnormal enhancement here.

2:13

Here's the lateral semicircular canal on the left side,

2:17

and that is secondary to spread of this infection from

2:20

the middle ear structures to the inner ear structures.

2:24

And this is what we would call labyrinthine enhancement,

2:26

secondary to labyrinthitis,

2:28

secondary to otomastoiditis.