The Study Of Multi-slice Computed Tomography Imaging In Infant Congenital Sensorineural Hearing Loss

ObjectiveTo discuss the value of multi-slice computed tomography imaging (MSCT) in infant with congenital sensorineural hearing loss (SNHL) and understand the incidence of malformations of the temporal bone and their distributions in infants with SNHL. At the same time, to provide necessary informations for further treatment.Materials and Methods125 cases of infants with SNHL were studied by a Somatom Sensation 16 ( Siemens, Germany) CT scanner and a Lightspeed 16 (GE, American) CT scanner with following parameters: 120 kV, 120 mAs, 0.75 mm and 0.625 mm collimation, 1 mm reconstruction increment, a pitch factor of 1.0mm and a field of view of 100 mm. The axial images of interested ears were reconstructed with 0.1 mm reconstruction increment, and a field of view of 50 mm. The age ranged from 8 days to 3 years. Axial high-resolution MSCT scan and MPR reconstruction were done in all cases on the Osirix and GE AW4.2 workstation. The 3D reconstructions were done with volume rendering technique (VRT) on the workstation .Results45 patients were congenital inner ear malformations among 125 cases of infants with SNHL . Of the malformations, all the axial, MPR and VRT images can display the site and degree in 85 ears. VRT images were superior to the axial images in displaying the malformations in 11 ears with Mondini malformation. 68 patients(131 ears) were normal and 41 patients (77ears) were congenital inner ear malformations (of which 41 ears accompanied by other malformations) among 104 patients with prespeech deafness : there were 1 case (2 ears) with Common Cavity :cochlear, vestibule and lateral semicircular canal formed a big cavity; 1 case (2 ears) with Incomplete Partition TypeⅠ: cochlea lacks the entire modiolus and interscalar septa, resulting in a cystic appearance; 10 case (20 ears) with Mondini malformation: The cochlea consisted of 1. 5 turns, in which the middle and apical turns coalesced to form a cystic apex. 28case(50 ears) with Vestibule—Lateral Semicircular Canal dysplasia : Cochlea was normal, vestibule dilated, semicircular canals were absent, hypoplastic or enlarged; 18case (36 ears) with large vestibular aqueduct: The vestibular aqueduct was bell-mouthed and the diameter of the duct is greater than that of the adjacent posterior semicircular canal and the vestibular aqueduct connect with the vestibule ;6 case (8 ears) ears with abnormality of the internal auditory canal: internal auditory canal stenosis or enlarged; case (5 ears) with absence of bony external auditory canal: Atresia and formation of an atretic plate are on the external auditory canal ; Among 104 patients with prespeech deafness, 17ears with facial nerve canal dehiscent in the tympanic segment, 33 ears with secretory otitis media. There were 13patients(26 ears) were normal, 4 cases(8 ears)with large vestibular aqueduct syndrome, 4case (8ears) with secretory otitis media in 21 patients with postspeech deafness. Most cases have more than one kind of malformations, the rate Vestibule—Lateral Semicircular Canal dysplasia is high and most accompanied by other malformations, the rate of large vestibular aqueduct and Mondini malformation are also high. The rate of other malformations is few. The rate of congenital inner ear malformations among the patients with prespeech deafness is high(37.0%) and most of them is bony labyrinth malformations, the rate of congenital inner ear malformations among the patients with postspeech deafness is low(19.0%) and most is simple large vestibular aqueduct. The patients with congenital external and middle ear abnormalities seldom have inner ear malformations.Conclusion(1) MSCT allows a comprehensively assessing various congenital ear malformations through high quality MPR and VRT reconstructions. The MSCT scan in axial view with 2D MPR was the choice of the protocols in infant with congenital sensorineural hearing loss. VRT images can display the site and degree of the malformations three-dimensionally and intuitionistic. MSCT plays an important role in diagnosis of infant SNHL.(2) All 115 cases were analyzed and the characteristic of congenital abnormalities of the inner ear is: most cases have more than one kind of malformations, the rate Vestibule—Lateral Semicircular Canal dysplasia is high and most accompanied by other malformations, the rate of large vestibular aqueduct is also high, half of them accompanied by Mondini malformation. The rate of other malformations is few. The rate of congenital inner ear malformations among the patients with prespeech deafness is high and most of them is bony labyrinth malformations, the rate of congenital inner ear malformations among the patients with postspeech deafness is low and most is simple large vestibular aqueduct.The patients with congenital external and middle ear abnormalities seldom have inner ear malformations.(3) MSCT is very useful to the cochlear implantation.