Study On Diffusion Tensor Imaging And MRI About Sensorineural Hearing Loss

Part 1 The value of diffusion tensor imaging in the diagnosis of bilateral sensorineural hearing lossObjectiveUsing DTI to explore the difference of auditory pathway between normal children and the patient with different level bilateral sensorineural hearing loss,and observing the relationship of auditory pathway and age.Material and Methods21 patients(42 ears)of BSNHL diagnosed by audiological examination and 24 healthy children(48 ears)underwent DTI on Siemens 3.0T MRI,at the same time,they underwent inner ear water imaging to find out if there were inner ear malformation.Patient,s age in experimental group were from 2 to 12 months old,and the average age were 6.3±3.2 months old;the children,s age in control group were from 2 to 14 months old,and the average age were 8.5±3.6 months old,all children in this group were through audiological examination on their 3 days and 42 days old.We divided patients with BSNHL into three groups as hearing threshold.Minor BSNHL was defined as a hearing threshold greater than 26 d B and less than 40 d B;moderate BSNHL was defined as a hearing threshold greater than 41 d B and less than 60 d B;severe BSNHL was defined as a hearing threshold greater than 61 d B.Two regions of interest(ROIs)were drawn at the medial geniculate body(MGB)and the inferior colliculus(IC).We measured fractional anisotropy(FA)of both ROIs in all subjects.Result1 There was no significant difference in FA between minor group and control group at the MGB and the IC(P>0.05).2 There was significant difference in FA between moderate,severe group and control group at the MGB and the IC(P<0.05),and the FA value of moderate and severe group was less than control group.3 The FA value at the MGB and the IC grew with age in control groups.Conclusion1 The reducing of FA value at the MGB and the IC in the moderate and severe group showing that there were myelination damage.2 There is low value in differentiating normal person and minor BSNHL patients by FA.3 The FA value at the MGB and the IC grew with age in control groups and it showing that myelination is progressing with age.Part 2 The value of MRI in cochlear implantation ObjectiveCochlear implants is the most effective treatment for patients with severe and very severe sensoineural hearing loss.But Michel malformation ? Mondini malformation and cochlear aplasia are absolute contraindications of cochlear implants,and different kinds of malformation has different influence to operation window position.Doctors are very easy to make mistake if they did not know the structure of inner ear and increase the difficulty to the surgery.The purpose of this experiment is to explore the value of MRI in cochlear implantation by retrospective analysis and to find out the advantage of MRI compared with CT.Material and MethodsWe have collected 150 BSNHL cases(a total of 300 ears)diagnosed by audiological examination in our hospital who took preoperative screening of cochlear implant and wanted to underwent cochlear implant from March 2014 to December 2016,and there were 98 males and 52 females,and their age were from 8 months old to 5 years old(the average age :2.1±0.8 years old).All patients has underwent temporal bone CT scan and post-reconstruction,MRI brain scan,inner ear water imaging and inner ear three-dimensional reconstruction.Result1 The finding rate of MRI is higher than CT in the diagnosis of Mondini malformation,Michle malformation,common cavity and Semicircular canal malformation(P<0.05).2 We found 14 cases with white matter disease,and the rate is 9.3%.Conclusion1 MRI in the detection of the Mondini malformation,Michle malformation,common cavity and Semicircular canal malformation is better than CT.2 MRI helps to find white matter lesions.