The Diagnostic Value Of MRI In Sensorineural Hearing Loss Of Children

ObjectiveTo explore the characteristics of magnetic resonance imaging (MRI) in sensorineural hearing loss (SNHL) and the value of MRI in the diagnosis of SNHLMaterials and methods1. Materials:52cases of pediatric patients clinically diagnosed as binaural SNHL and24cases of normal children without hearing loss (control group) were examined by Philips Achieva1.5T superconducting MRI scanner. Conventional brain scan and3D/T2WI/TSE axial scan of inner ear were performed by use of the head orthogonal coil. Informed consents were sighed with parents before checking up. One can not keep quiet breathing in children were given oral chloral hydrate for sedation before the scanning.2. Methods:MR pulse sequences included transverse T1WI, T2WI, T2-FLAIR, DWI and T2-DRIVE-HR SENSE sequence. In order to obtain the precise structure of the inner ear anatomy and its positional relationship, the line of positioning into the bed travelled through the same location of the bilateral auricular (the angular ear line) as far as possible, then positioned the scanned inner ear on T2WI as location center for high-resolution three-dimensional fast spin echo (T2WI/3D/DRIVE) axial scan with accurately scanning range of inner ear structure. Vestibular maximum diameter, diameter of the vestibular vertical, the height of the three semicircular, diameter of three semicircular canals and cochlear height were measured under the reformations of MPR and MIP, parts of the original images were reformatted3. Statistical analysis:SPSS17.0statistical package was used to process the data, Two Sample t’ Test or Two Sample t Test or Two Sample u Test was selected. P<0.05means a statistically significant difference. Meanwhile calculate95%double side medical reference value range of the normal inner ears measured on MRI.Results:1. MRI scan can clearly show brain structure and detect the brain lesions. Detail anatomy structures of internal auditory canal and membranous labyrinth of inner ear could be showed clearly by T2-DRIVE-HR SENSE sequences and multi planar reformation (MPR), even minimal lesions, clear and overall three-dimensional images of membranous labyrinth could be shown through maximum signal intensity projection (MIP) reformation.2.19cases of abnormality were found in52children with SNHL (the positive rate was36.5%). Among these abnormal cases,8cases had bilateral white matter disease,1case had bilateral white matter disease with the right hemisphere dysplasia,6cases showed bilateral large vestibular aqueduct syndrome (LVAS),2cases presented semicircular canals dorsally and stunted growth of both ears (one case was with large vestibular aqueduct and large vestibular),2case had Mondini malformation (1.5circular cochlear companied with small vestibular and semicircular dysplasia).According to the measurements above before MRI examination,52cases with SNHL were divided into4groups:brain white matter lesions group (9cases,18ears), large vestibular aqueduct syndrome (LVAS) group (6cases,12ears), complicated deformation of the inner ear group (4cases,8ears), MRI negative group (33cases,66ears)3. On the images of MIP reformation:According to95%double side medical reference value range of the normal inner ears measured on MRI, more than half measures of each inner ears’ anatomical structure of the brain white matter lesions group and LVAS group located in the range, and more than half of the all structures’ measures excepted the vestibular vertical diameter of the group, which had no positive performance or cerebellopontine area lesions, exceeded the range, meanwhile measures of the complicated inner ear deformation group rarely were in the range. There were statistical significant difference of the vestibular maximum diameter, the vestibular vertical diameter, the largest diameter(tube height) and tube diameter of posterior semicircular canal and level semicircular tube,the cochlear height between SNHL children and control group; statistical significant differences of the vestibular maximum diameter, the vestibular vertical diameter, the tube height and diameter of posterior semicircular canal, the tube diameter of the level semicircular and cochlear height between brain white matter lesions group and control group; statistical significant differences of the vestibular maximum diameter, the tube height of posterior semicircular canal, the tube height of level semicircular canal and cochlear height between LVAS group and control group;statistical significant differences of the vestibular maximum diameter and vertical diameter, the tube height and diameter of superior semicircular, the tube height of posterior and level semicircular canal, the cochlear height between MRI negative group and control group.Conclusion:1. The inner ear MR hydrography sequences could clearly show the membranous labyrinth of inner ear, the internal auditory nerves and parts of the small blood vessels, to make up for the lack of only showing bony labyrinth with CT, it is also important for detecting LVAS and complicated inner deformation.2. MRI brain scan has a great value in ruling out brain lesions such as brain white matter lesions besides subtle structures of inner ear. Routine sequences including conventional brain scan and inner ear MR hydrography have a great clinical value for diagnosis of pediatric SNHL. They are necessary examinations in children with SNHL before cochlear implant surgery.3. Compared with the healthy control group, MRI negative group had statistical mean value difference in measures of the different inner ears’ structure on MRI, it needed further study for the etiology correlation between the statistical mean value difference and SNHL.