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Lesson
Inner Ear
49 topics, 3 hr. 16 min.
Inner Ear Preview
2 m.Inner Ear – Introduction
2 m.Anatomy of the Internal Auditory Canal (IAC)
8 m.Coronal Anatomy of the Inner Ear
4 m.Axial IAC Anatomy and Otospongiosis/Otosclerosis
6 m.Coronal IAC Anatomy and Facial Nerve Segments
6 m.MRI imaging techniques and cochlea aplasia
7 m.IAC Congenital Lesions & Syndromes - Summary
7 m.Cochlear Hypoplasia
8 m.Cochlear Nerve Deficiency, Pontine Tegmental Cap Dysplasia
5 m.Bilateral Cochlea Nerve Deficiency
5 m.Labyrinthine Dysplasia/Syndromes - Summary
10 m.Incomplete Partition Type 1
3 m.Incomplete Partition Type 2 – Summary
3 m.Bilateral Incomplete Partition Type 2
3 m.Mondini Malformation, Incomplete Partition Type II
2 m.Incomplete Partition Type II, Mondini Malformation, Semicircular Canal Abnormality
3 m.Vestibular Malformation
3 m.Enlarged Endolymphatic Sac
2 m.Incomplete Partition Type III – Summary
4 m.Down Syndrome – Summary
6 m.Down Syndrome, Semicircular Canal Deformity, Cochlear Aperture Stenosis
6 m.Down Syndrome, Aperture Stenosis
6 m.Cochlear Hypoplasia and Aperture Stenosis - Summary
4 m.Semicircular Canal (SCC) Dehiscence – Summary
4 m.Semicircular Canal (SCC) Dehiscence
3 m.Semicircular Canal (SCC) – Oblique Reformat
2 m.Inflammatory/Infectious Lesions of the Inner Ear - Summary
7 m.Labyrinthitis, Secondary to Otomastoiditis
3 m.Labyrinthine Fistula Mastoidectomy and Cochlea implant
3 m.Viral Labyrinthitis
3 m.Otospongiosis (Otosclerosis) - Summary
10 m.Bilateral Otospongiosis (Otosclerosis)
5 m.Bilateral Retrofenestral Otospongiosis
4 m.Bilateral Otospongiosis and SCC Dehiscence
3 m.Otospongiosis, Left Stapedectomy
3 m.Labyrinthitis Ossificans – Summary
11 m.Post Traumatic Labyrinthitis Ossificans
3 m.Labyrinthitis Ossificans, Cochlear Turn
2 m.Labyrinthitis Ossificans, Superior SCC
2 m.Unilateral Labyrinthine Ossificans
2 m.Petrous Apex Lesions
8 m.Right Cholesterol Granuloma
5 m.Intravestibular/Labyrinthine schwannoma
3 m.Labyrinthine Schwannoma
4 m.Left Side Labyrinthine/Vestibule Schwannoma
2 m.Endolymphatic Sac Tumor (ELST) – Summary
4 m.Endolymphatic Sac Tumor and VHL
4 m.Inner Ear Malignant Neoplasm and Trauma Closing Points
6 m.0:01
As I mentioned,
0:02
the enlarged vestibular aqueduct syndrome, or EVAS,
0:08
on CT, is analogous to the enlarged endolymphatic
0:12
sac. You actually see the sac on the MRI scan,
0:15
and this is the most frequent finding in general
0:18
sensorineural hearing loss. Now,
0:20
we've seen examples in the incomplete
0:22
partition type two,
0:24
where it is so associated with abnormal
0:26
malformation of the cochlea. However,
0:29
it may be an isolated finding,
0:32
and it is an abnormality,
0:33
which is typically bilateral, we say,
0:35
in 90% of cases and occurs in
0:39
females more so than males.
0:41
So isolated endolymphatic sac enlargement is an
0:46
anomaly that may be associated with congenital
0:49
sensorineural hearing loss,
0:50
but it also may be seen in conjunction with abnormal
0:53
development of the cochlea in our incomplete
0:56
partition type 2. Here's a CT scan,
0:59
bilateral involvement with enlargement
1:02
of the vestibular aqueduct.
1:04
Here is what we might see on MRI scan.
1:07
On the MRI scan in this individual,
1:10
you see that there is a high signal intensity
1:13
abnormality on our T2 CISS image,
1:17
and this represents the enlarged vestibular
1:20
aqueduct, or endolymphatic sac.
1:22
So we're actually seeing the sac.
1:23
Again, the aqueduct we usually refer to in the CT,
1:27
whereas in MR we're seeing the sac,
1:29
the endolymphatic sac. And these are dilated.
1:32
How do we know they're dilated?
1:33
They're larger in caliber than the semicircular
1:35
canals when we compare to them.
Enlarged Endolymphatic Sac
HIDEInteractive Transcript
0:01
As I mentioned,
0:02
the enlarged vestibular aqueduct syndrome, or EVAS,
0:08
on CT, is analogous to the enlarged endolymphatic
0:12
sac. You actually see the sac on the MRI scan,
0:15
and this is the most frequent finding in general
0:18
sensorineural hearing loss. Now,
0:20
we've seen examples in the incomplete
0:22
partition type two,
0:24
where it is so associated with abnormal
0:26
malformation of the cochlea. However,
0:29
it may be an isolated finding,
0:32
and it is an abnormality,
0:33
which is typically bilateral, we say,
0:35
in 90% of cases and occurs in
0:39
females more so than males.
0:41
So isolated endolymphatic sac enlargement is an
0:46
anomaly that may be associated with congenital
0:49
sensorineural hearing loss,
0:50
but it also may be seen in conjunction with abnormal
0:53
development of the cochlea in our incomplete
0:56
partition type 2. Here's a CT scan,
0:59
bilateral involvement with enlargement
1:02
of the vestibular aqueduct.
1:04
Here is what we might see on MRI scan.
1:07
On the MRI scan in this individual,
1:10
you see that there is a high signal intensity
1:13
abnormality on our T2 CISS image,
1:17
and this represents the enlarged vestibular
1:20
aqueduct, or endolymphatic sac.
1:22
So we're actually seeing the sac.
1:23
Again, the aqueduct we usually refer to in the CT,
1:27
whereas in MR we're seeing the sac,
1:29
the endolymphatic sac. And these are dilated.
1:32
How do we know they're dilated?
1:33
They're larger in caliber than the semicircular
1:35
canals when we compare to them.
Report
Description
Faculty
David M Yousem, MD, MBA
Professor of Radiology, Vice Chairman and Associate Dean
Johns Hopkins University
Tags
Temporal bone
Neuroradiology
MRI
Head and Neck
Congenital
CT
Brain
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