HRCT Measurements Of Normal Inner Ear Structures And The Temporal Bone Findings In Sensorineural Hearing Loss Children

Part One: HRCT measurements of normal inner ear structuresObjective:To reconstruct the image of inner ear using multi-planar reformation (MPR) of high resolution computed tomography (HRCT), and to establish normative HRCT measurement of inner ear structures.Patients and methods:One-hundred and fifty inner ears of 75 volunteers, with normal hearing and without any diseases in the inner ear, underwent HRCT scanning. All the images were transferred to an online workstation, analyze software was used for image post-processing. All the structures of inner ear were measured including the cochlear, vestibular, internal auditory cannel (IAC), the LSCC bony island width.Results:All the structures of inner ear and internal auditory cannel could be visualized clearly by HRCT, Using analysis of variance, there was no age, side or race-related differences in other inner ear measurements, except the differences of IAC length.Conclusion:The HRCT measurement criterion of inner ear structures is established. Except the IAC length, there was no difference between children and adults inner ear structures. Part Two: Temporal bone high resolution computed tomography findings insensorineural hearing loss childrenObjectiveTo describe the imaging findings of the high resolution CT in children with sensorineural hearing loss and measure some of inner ear structures.Patients and methodsFifty (mean age 4.5years) with clinical signs of sensorineural hearing loss underwent HRCT scanning of the temporal bone. HRCT was performed in the axial plane with a section thickness of 1.0 mm using a high-resolution bone window-level setting. The inner ear, internal auditory were evaluated for abnormal morphology. Prospective measurements of the inner ear were performed on MPR images. The measurements were similar with Part One, all the measurements data were compared with Part One.ResultsThough the HRCT measurements, twenty-one patients showed no abnormalities on CT scanning. Congenital abnormalities were found in 29 of these patients, and (1)Michel deformity(2 ears): There was complete absence of all cochlear and vestibular structures . (2) Common Cavity(2 ears): the cochlear, vestibule and lateral semicircular canal formed a big cavity; (3)Incomplete partition I (IP-I, 2 ears): The cochlea was lacking the entire modiolus and cribriform area, resulting in a cystic appearance. This was accompanied by a large cystic vestibule. (4)Incomplete partition II(IP-II, Mondini deformity, 7 ears): The cochlea consists of 1.5 turns, in which the midge and apical turns coalesce to form a cystic apex, accompanied by a dilated vestibule and enlarged VA. (5)Vestibular and semicircular canal malformations (10 ears): The cochlea is normal. Vestibule and the Lateral semicircular canal coalesce of the latter is small. (6) Vestibule aqueduct dilate(27 ears, of which 4 ears accompanied by other malformations): The dimension of the midisthmus of VA was more than 1.5mm. (7)Internal auditory canal malformations (3 ears): The internal auditory canal was narrowed or dilated.ConclusionThe congenital inner ear malformations is the common reason for the sensorineural hearing loss in children, HRCT with measurements of the inner ear are very useful to diagnosis the malformations. Vestibule aqueduct dilate is the most common malformation.