Answer:
COCHLEAR /RETROFENESTRAL OTOSCLEROSIS
Findings:
Foci of demineralization or low density seen anterior to oval window in both sides . Demineralization medial to basal turn is noted- Fourth turn of Cochlea (Double ring sign)
Discussion:
In cochlear or retrofenestral otosclerosis, demineralization of the cochlear capsule is greater than that seen in fenestral otosclerosis. Area just anterior to the oval window is almost always involved. Double ring or fourth turn sign - low-density demineralized enchondral defect around the cochlea.
Contributed By: Dr. Babu Peter MD. DNB
Associate Professor, Barnard Institute of Radiology, Chennai
Senior Consultant Radiologist, Aarthi Scans, Chennai
COCHLEAR /RETROFENESTRAL OTOSCLEROSIS
Findings:
Foci of demineralization or low density seen anterior to oval window in both sides . Demineralization medial to basal turn is noted- Fourth turn of Cochlea (Double ring sign)
Discussion:
In cochlear or retrofenestral otosclerosis, demineralization of the cochlear capsule is greater than that seen in fenestral otosclerosis. Area just anterior to the oval window is almost always involved. Double ring or fourth turn sign - low-density demineralized enchondral defect around the cochlea.
Contributed By: Dr. Babu Peter MD. DNB
Associate Professor, Barnard Institute of Radiology, Chennai
Senior Consultant Radiologist, Aarthi Scans, Chennai