CT Grading of Otosclerosis

Abstract

BACKGROUND AND PURPOSE:The CT grading system for otosclerosis was proposed by Symons and Fanning in 2005. The purpose of this study was to determine if this CT grading system has high interobserver and intraobserver agreement.

Diagnostic efficacy and therapeutic impact of computed tomography in the evaluation of clinically suspected otosclerosis

“…The distribution and extent of otosclerotic changes demonstrated on CT has been previously graded by a number of authors [2,6,8,[11][12][13][14][15][16], and its clinical utility has been investigated, particularly with respect to impact on pre-and post-operative audiometry. In particular, the extent of otic capsule involvement on CT has been shown to predict the degree of SNHL [3,6,12] and hearing outcomes following stapedectomy.…”

Imaging Review of the Temporal Bone: Part II. Traumatic, Postoperative, and Noninflammatory Nonneoplastic Conditions

“…As the disease progresses or becomes inactive, the "spongy" areas recalcify, becoming less vascular and more sclerotic (50). The most common location to be involved in otosclerosis early on is around the em bryologic fissula ante fenestram, a thin fold of embryonic cartilage and con nective tissue in a small cleft just ante rior to the oval window (51,52). When disease is limited to this area near the oval window, it is referred to as fenes tral otosclerosis.…”

Imaging of the Temporal Bone

“…26 Otosclerosis is an idiopathic disease characterized by spongiotic change of the otic capsule that can result in conductive, mixed, or sensorineural hearing loss. 27 The mildest form of otosclerosis is the fenestral form, which presents with conductive hearing loss and manifests as a lucency in the fissula ante fenestram, a small segment of bone located just anterior to the oval window (Fig. 26).…”