Evaluation of the Congenital Deformities of the External and Middle Ear with High Resolution CT

Objective To discuss HRCT features of the congenital deformities of external and middle ear so as to provide accurate information for the diagnosis and treatment.Materials and Methods 35 cases with congenital deformities of external and middle ear diagnosed clinically were performed with HRCT. Axial scans were performed in 5 cases, axial and coronal scans were taken in 30 cases.Results (1) 42 ears of 32 cases with external ear abnormalities were found, these abnormalities included bony external auditory canal atresia in 30 ears, membranous atresia in 5 ears, and external auditory canal stenosis in 7 ears. 1 case with different atresia patterns respectively at two sides and another case with stenosis associated contralateral atresia were found. Atresia plates, which were complete in 26 ears and incomplete in 4 ears, were demonstrated. In bony atresia, associated deformities which included anterior located descending segment of the facial nerve canal in 22 ears, posterior and superior oriented mandibular condyle in 25 ears and anterior located sigmoid sinus in 4 ears were found. In the patients with external ear deformities, small tympanic cavity and dysplasia or absence of auditory ossicles were manly associated with middle ear abnormalities. 1 case with concomitant inner ear dysplasia was confirmed. (2) 6 ears of 3 cases with isolated middle ear deformities were demonstrated. Auditory ossicles abnormalities presented in all these ears. Small tympanic cavity and enlarged eustachian tube and tympanic sinus were found in 1 case respectively.Conclusion HRCT can demonstrate patterns, severity and associated changes of congenital deformities of external and middle ear accurately, which has already become a indispensable imaging modality for microscopical operation of otology.