| ObjectiveTo analyse the auditory ossicle changes images of axial and the MPR reconstruction of 64-Slice Spiral Computed Tomography in chronic otitis media with cholesteatoma,which were checked against with surgical operation,and to inquire into the MSCT performance and its application value;To evaluate the correlation between the destruction of ossicles and the loss of hearing,and to compare preoperative hearing with postoperative hearing,the purpose is to explain the important value of ossicular chain remodeling operation.Materials and methodsExperimental object:Thirty patients with chronic otitis media with cholesteatoma underwent 64-Slice Spiral Computed Tomography before surgery,during January of 2007 to October of 2007,all cases were confirmed by pathology,totally thirty examples (n=30).The patient clinical signs and hearing were recorded in detail.Equipments:Philips Brilliance 64-Slice Spiral Computed Tomography;Denmark Madsen Orbiter 922 acoumeter.Method of CT:The sufferer lied on the back,sweeping first to position an impress, then setting up the plan.Sweeping base line parallel to palatum durum.Scaned the scope from the upper edge of petrous bone to mastoidale.Scanning layer thick: 0.67mm～0.9mm,pitch:0.875mm,reconstruction partition was equal to half of layer thick.,window width of malleus and incus:4095HU,window level:600HU,window width of stapes:3000HU,window level:200HU,matrix:1024×1024 with a 80mm field of view.All cases were adopted the axial scan,then a multiplaner reconstruction (MPR).The ossicular chain was divided into seven parts:malleus head,malleus handle,long crus of incus,short crus of incus,stapes,malleus and incus joint,incus and stapes joint.The appearance of auditory ossicle of MSCT was divided into disappearance(all or part),invasion(include the low density and the vague rim), displacement,joint confluence or dislocation.All the bone changes were wrote down compared with the normal side,the surgical operation were thought as gold standard. Ossicular chain changes founded in the surgical operation were also to be recorded after surgical operation.After that,the statistic methods were used to evaluate the results.Method of acoumetry:The patient hearing were measured in the acoustic chamber, background noise was 30dB,after ISO standard zero was adjusted,Denmark Madsen Orbiter 922 acoumeter was used to measure patients hearing.First measuring air conduction hearing,then bone conduction hearing.The mean of air conduction hearing at 500Hz,1000Hz,2000Hz,4000Hz were noted as preoperative hearing.Twenty-two patients of conductive deafness were picked out from all patients based on the results of Audiometry.Their hearing and ossicular chain were graded by degree of damage, Spearman rank correlation were used to evaluate the results.The patients hearing after ossicular chain remodeling operation were recorded at three months,Matched t-test were used to compare preoperative hearing with postoperative hearing.ResultsThe method of MPR was better than axial image in diagnosing malleus and incus, especially malleus and long crus of incus,the sensitivity,specificity,positive predictive value,negative predictive value and accuracy rating were all 100%.For stapes manifestation,MPR is no better than axial image,the five statistics index are 82.4%,66.7%,82.4%,66.7%,76.2%in turn.All disappearance parts of auditory ossicle was 84 units.Fourteen patients were discovered to have all three ossicles disappeared,five patients of them were combined deafness,it's about 83.3%(5/6)in proportion to all combined deafness patients.All invasion parts of ossicles were nine units.Other ossicles changes is five units.The degree of ossicles destruction is direct correlation to the loss of hearing(rs'=0.7213,P＜0.01).Sixteen follow-up patients hearing had apparent increase as compared to preoperative hearing(P＜0.001),there was significant difference in statistics. Conclusion(1)64-Slice Spiral Computed Tomography can make accurate manifestation for auditory ossicle changes of chronic otitis media with cholesteatoma,especially MPR, which has a great value in manifesting ossicles in the same plane and evaluating changes of malleus and incus.To show the stapes changes,the axial image is better.(2)The destruction degree of ossicular chain is closely correlate to the loss of hearing.Ossicles reconstruction during operation is a great significance in recovery of hearing.(3)The main auditory ossicle changes of chronic otitis media with cholesteatoma is all three ossicles destroyed,especially discovered in the patients who are combined deafness.(4)64-Slice Spiral Computed Tomography can be used to guide the treatment and judge the future. |
