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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