High-resolution CT of the temporal bone in dysplasia of the auricle and external auditory canal.

PURPOSE: To determine CT findings in the external, middle, and inner ear of patients with microtia and external auditory canal dysplasia. METHODS: We used high-resolution CT, with multiplanar or axial 1-mm continuous sections, coronal or sagittal reformations, or low-dose spiral acquisitions, to examine 184 temporal bones of children with microtia. RESULTS: In cases of minor microtia, auditory canal stenosis was the most common associated abnormality; in those with major microtia, atresia was predominant. Middle ear malformations depended on the severity of the auricular anomalies. Inner ear changes could also be noted. Ossicle dysplasias occurred in 98% of patients (stapes, 72%), absence of the oval window in 36%, labyrinthine malformations in 13%, closed round window in 6%, facial canal displacement in up to 75%, and aberrations of the vascular canal in 38% of patients with third-grade auricular deformity. CONCLUSION: A variety of external, middle, and, less frequently, inner ear changes were detected in connection with microtia.