Learning objectives
To study the imaging findings of the inner ear abnormalities on Computed tomography (CT) and magnetic resonance imaging (MRI).
To learn exactly which information an implant surgeon wants from reporting radiologist.
Background
Congenital deafness is present in approximately 1 in 1000 births,
while the incidence of profound hearing loss in infants may be as high as 1 in 250 (1).
Of these,
it has been estimated that half are due to a hereditary cause.
Mutations in the gene GJB2,
with a carrier frequency of approximately 3% to 4%,
have been established as the most common cause of nonsyndromic hearing loss,
responsible for up to 20% of cases of childhood deafness (2).
Impairment of hair cell function induces...
Findings and procedure details
All the patients (n=72) with bilateral SNHL underwent HRCT (16-slice) & high-field MRI (1.5T).
The age range of study population varied between 6 months to 20 years.
HRCT of temporal bone aws performed with the following parameters:
1.
0.75-mm collimation,
0.625-mm section thickness,
140 kVp,
120 mAs,
pitch of 0.8,
a 15-cm field of view,
and a 512 x 512 matrix.
The initial data sets were then reconstructed at 0.1-mm intervals.
MR scanning was performed with following sequences.
1.
3D FIESTA(Fast Imaging Employing...
Conclusion
Certain abnormalities of inner ear are better depicted on CT,
while others are better seen on MRI.
Hence,
neither HRCT nor MRI of the brain and temporal bones appears to be adequate as a single imaging modality but they are complementary to each other for pre-operative imaging of cochlear implantation.
Personal information
Department of Radio-diagnosis and Imaging,
Kasturba Medical College,
Manipal
University,
Manipal/IN.
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