45 year old with chronic bilateral hearing loss for cochlear implant assessment
CT axial noncontrast bone windows
CT coronal reconstructions noncontrast bone windows
T2 axials
Findings:
CT: Subtle
demineralization surrounding both the
right and left cochlea, worse on
the right side
MRI: Increased T2 signal surrounding the cochlea bilaterally
DDX:
Cochlear otosclerosis
Diagnosis:
Cochlear otosclerosis
Discussion:
Cochlear otosclerosis is an uncommon cause of mixed and sensorineural
hearing loss. It has a characteristic appearance on CT, producing
a distinctive pericochlear hypodense double ring. However, its
appearance on MRI is not as readily appreciated, producing a
ring of intermediate signal in the pericochlear and perilabyrinthine
regions on T2 and T1 weighted images sometimes with enhancement.
Submitted by Hari Challa, MD, UW Neuroradiology Fellow
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