Interactive Transcript
0:01
This is the second case of otomastoiditis
0:05
and I want to show one of the potential
0:08
complications of otomastoiditis on this case.
0:12
So, once again, as we scroll through the images,
0:16
we come to the external auditory canal with its
0:20
cartilaginous portion and bony portion.
0:22
Immediately, we start to see that there is opacity within
0:26
the middle ear cavity medial to the tympanic
0:29
membrane. And we see this soft tissue here,
0:32
which is extending from the middle ear cavity into
0:35
the round window niche on the left side.
0:39
You notice also that there is some opacification of
0:41
mastoid air cells and you have the normal variation
0:45
in the size of the mastoid air cells on the
0:47
normal side as well as the left side.
0:51
So looking at this,
0:52
we come to the middle ear ossicles and we see again
0:55
that there is not aeration around the middle ear
0:58
ossicles the way there is on the right side,
1:00
but soft tissue which is also extending
1:04
into the anterior epitympanic space.
1:06
And this is the horizontal portion or tympanic
1:09
portion of the facial nerve coursing right
1:11
by just adjacent to that inflammation.
1:15
So in looking at this, this patient, we would say,
1:18
has evidence of otomastoiditis with middle ear
1:23
cavity opacification and mastoid fluid with a
1:27
fluid level on the left side in the mastoid.
1:30
So it's not until we see erosion of the ossicles or
1:33
displacement of the ossicles or areas of dehiscence
1:36
that we would even raise the specter
1:38
of cholesteatoma. Now,
1:41
cholesteatoma as well as otitis media and otomastoiditis
1:46
usually cause a conductive hearing loss
1:49
because of the fluid that is damping down,
1:53
the ability of the stapes to
1:55
shake or the ossicles to move
1:58
and cause that wave to enter the cochlea.
2:05
So this patient, however,
2:07
had a sensorineural hearing loss.
2:10
So that's unusual for an explanation
2:13
with just otomastoiditis.
2:15
And because of the sensorineural hearing loss,
2:19
the patient also got an MRI scan.
2:23
So I want to show the MRI scan at this juncture,
2:26
the MRI scan was done with both a skull base
2:30
protocol as well as post gadolinium
2:34
enhanced sequences.
2:36
So we'll put this on 2-1-1.
2:39
I'll drag down the CT image as well as
2:45
the post gadolinium enhanced scan.
2:47
So on the post gadolinium enhanced scan,
2:50
and I must admit that this is one month later
2:53
on the post gadolinium axial fat-sat scan,
2:57
you see an awful lot of,
3:00
and enhancement of the mastoid air cells as well
3:04
as extending into the middle ear cavity.
3:07
And some of this mastoid looks more eroded.
3:12
So there's probably an element now of coalescent
3:15
mastoiditis but more importantly on the
3:18
post gadolinium enhanced scan we can see abnormal
3:22
enhancement in the basal turn of the cochlea.
3:26
So here we have the middle and apical turns of the
3:29
cochlea and here we have enhancement in the basal
3:32
turn of the cochlea as well as in the vestibule and
3:37
this is the enhancement in the middle ear cavity
3:40
just adjacent to this and you may actually
3:46
see sometimes enhancement avid enhancement
3:49
of the facial nerve as well.
3:51
So the semicircular canals, little bit worried about
3:54
this posterior crus of the superior semicircular
3:58
canal enhancing more than the anterior crus but
4:02
pretty clearly basal turn of cochlea and the
4:06
vestibule. If we look on the CT image,
4:10
what we're actually looking for is a difference in
4:13
the signal intensity of the CSF between the
4:18
right and left side in the cochlea.
4:20
And this is pretty obvious when we look at the
4:25
right and left side on the same slice.
4:29
So here we have the cochlea with
4:31
its modiolus or mediolus,
4:33
that's the internal skeleton of the cochlea
4:36
with the apical and middle turn and
4:40
basal turn here. And as we look on the left side,
4:45
you see you never have that bright signal intensity
4:48
of CSF-like signal intensity in the basal turn.
4:51
And in point of fact,
4:52
even in the middle turn it is not as bright and
4:57
that's because there's purulent material in there
5:00
and the same thing is true with the vestibule.
5:03
So the vestibule looks nice and bright here and
5:05
clean on the left affected side
5:08
it's kind of grayish.
5:10
It should be all this bright signal intensity but
5:13
doesn't have that same signal intensity and that
5:16
would be indicative on the CT image of the
5:19
inflammation that's occurring in there.
5:21
Much clearly seen on the post gadolinium
5:25
enhanced fat-suppressed scan.
5:27
So we have what looked like on the CT
5:31
scan as otomastoiditis. However,
5:34
upon review of the MRI with post gad fatsat images,
5:38
we now see the patient developed coalescent
5:42
mastoiditis as well as spread to the inner ear
5:45
structures, the basal turn of the cochlea,
5:47
the vestibule, and possibly the one of the ampullae
5:53
of the superior semicircular canal, identifying this as
5:57
labyrinthitis. So inflammation of the internal ear,
6:01
the inner ear structures would be called labyrinthitis,
6:04
and that's one of the complications of
6:08
otomastoiditis, and we'll talk about
6:11
other ones in just a moment.
© 2024 MRI Online. All Rights Reserved.