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1989, The British Journal of Radiology , 62 , 107-113VOLUME 62 NUMBER 734 FEBRUARY 1989The British Journal of RadiologyRadiological evaluation of temporal bone disease: high-resolution computed tomography versus conventional X-raydiagnosisBy P. Fritz, MD, K. Rieden, MD, *T. Lenarz, MD, *J. Haels, MD, and K. zum Winkel, MDDepartments of Radiology and *Otolaryngology, University of Heidelberg, D-6900 Heidelberg, FederalRepublic of Germany(Received April 1988 and in revised form July 1988)Abstract . Sixty-two patients with different temporal bone lesions were prospectively examined by high-resolution computedtomography (CT) and conventional plain radiography, including pluridirectional tomography. High-resolution CT enabled aclear diagnosis in 80% of cases, conventional radiology in 6 3% ; 1.6-times more bone information was recorded by high-resolutionCT which is clearly superior for imaging cholesteatomas, metatastases and inflammatory processes and for evaluating osseousdestruction. With regard to pathological soft tissue or effusions filling the tympanic cavities, conventional radiology shows poorsensitivity (0.61). High-resolution CT is the most sensitive method for the imaging and classification of temporal bone fractures,including labyrinthine damage and ossicular chain injuries. Only in cases of atypical fractures with an unfavourable relationship tothe CT planes, can carefully directed tomography be more effective. In most cases high-resolution CT replaces conventionalradiology and should be the method of choice for comprehensive radiological examination of the temporal bone.Radiological evaluation of the petrous bone is difficultowing to the complicated anatomical structure of themiddle and inner ear. Because of different spatialarrangements of the anatomical structures, multiplanarviews are required.The topography as well as the smallness of manystructures limit the imaging possibilities. Radiologicalimaging of the petrous bone m ust meet high standards oftopographic representation and spatial resolution. Inconventional radiological procedures, there exist anumber of special projections for optimal representationof particular structures but they are often diagnosticallyinsufficient and additional tomographs in one or moreplanes are necessary.Thin-section, high-resolution computed tomography(CT) with modern equipment allows, by means of specialalgorithms, imaging of osseous structures up to a spatialresolution of 0.45-0.65 mm. However, withoutadditional equipment, CT cannot reproduce the variousprojections of conventional radiological procedures. Inroutine diagnosis, CT is limited to standard axial andcoronal images. However, high-resolution CT has theadvantage of excellent topographic visualization, devoidof artefacts from superimposition of structures. Allrelevant parts of the petrous bone are represented withhigh sensitivity and there is considerably less skin andeye lens exposure than with conventional tomography(Chakeres & Spiegel, 1983; Koster & Ewen, 1986; Fritz etal, 1987).Numerous CT studies deal with the identification ofanatomical details and the appearance of various lesionsAddress correspondence to: Dr P. Fritz, RadiologischeUniversitatsklinik, Kopfklinikum, Im Neuenheimer Feld 400,D-6900 Heidelberg, Federal Republic of Germany.

of the petrous bone (Chakeres & Spiegel, 1983; Swartz etal, 1983a, b; Zonneveld, 1983; Zonneveld et al, 1983,1984; Damsm a et al, 1984; Koster e t al, 1984; von Konig& Kurtz, 1984; De Groot et al, 1985; Mafee et al,1985a, b; Koster & Straehler-Pohl, 1986; Welleschick &Salomonowitz, 1986; Fritz et al, 1987) but there are fewpublished studies comparing conventional radiologicalprocedures with CT. Brunner et al (1986) consider plainradiographs and tomographs sufficient for assessment ofchronic otitis media, malformations and fractures. Imhofet al (1986) see the need for CT mainly in theinvestigation of malignant disease and in the pre-operative evaluation of cholesteatoma. In the case ofpetrous bone fractures, CT should be performed only if acomplication is suspected. According to Virapongse et al(1983), bone destruction by cholesteatoma was morereadily diagnosed by conventional tomography. Thelatter and CT were of equal value in diagnosing fractureswith or without dislocation of the middle ear ossicles.There is agreement on the superiority of CT in thevisualization of soft-tissue structures and of fluidcollections.Most studies regard the main role of CT as an adjunctto conventional radiology and the conflictingconclusions probably reflect the different techniquesemployed and the small number of patients examined.This paper will contribute to the discussion of thevalue of conventional and computed tomographicprocedures in middle and inner ear diagnosis.Mater ia l s and methodsSixty-two patients with different petrous bone lesionswere prospectively examined (Table I). Only patientswith a firm clinical diagnosis established through casehistory, otological examination and audiometry were

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P. Fritz, K. Rieden, T. Lenarz, J. Haels and K. zum WinkelTable I. Number of patients and clinical diagnosesDiagnosisFracturesCholesteatomaMetastasesOtosclerosisInflammatory processesChronic otitis mediaChronic mastoiditisLabyrinthine osteomyelitisDysplasia of the externalauditory meatusTotal

(4)(1)(1)

n2312127

6

262

tested by CT. Petrous bone fractures were mostcommon, followed by metastatic deposits andcholesteatomas. High-resolution CT as well asconventional plain radiographs and tomograms wereobtained in all patients.Computed tomographyComputed tomography was performed in astandardized manner with a GE 8800 unit using 120 kVand 320 mA. To minimize the radiation exposure, nooverlapping or contiguous slices were performed but allpatients were examined in both axial and coronal planes.The distance between slices was 2 mm; the thickness ofeach slice was 1.5 mm. In the axial plane, an average of12 slices was taken parallel to the orbitomeatal; in thecoronal plane, an average of 13 sections was taken. Toobtain coronal slices free of motion artefacts, weexamined the patients prone with the head fully flexed bymeans of a special head support. Image reconstructionwas done primarily with a 1.5 magnifying factor on theprospective target mode of the GE high-resolution bonealgorithm. With this method the spatial resolution of theCT image is 0.65 mm. The images were recorded at awindow of 4000 Hounsfield units (HU) and a levelbetween 1000 and 2000 HU.Table II. Fractures of the temporal bone ( = 23)

Figure 1. Stenvers' view of pluridirectional tomo graphy .Atypical transverse fracture of the base of the temporal boneextending to the vestibule and the mastoid (arrowheads).Neither axial nor co ronal CT planes demonstrated the fractureline.Conventional X-ray diagnosisIn conventional imaging, at least two views, eitherStenvers, Schuller or M ayer, were taken and, in addition,tomograms in lateral, modified lateral or antero-posterior (AP) projections (coronal plane). The abovepluridirectional tomography was performed withhypocycloid technique using a 2 mm distance betweenlayers a t 65 kV and 75 mA.The CT scans and conventional radiographs wereexamined separately by two independent observers.ResultsFractures (TableII)A fracture was diagnosed by CT in 18% more casesthan by conventional radiology. Of the 16conventionally diagnosed fractures, 15 were also

Diagnosis of fractureClassification of fractureLabyrinthine injuryOssicular disarticulationInjury to facial canalHaemotympanum (n = 10)/cerebrospinal fluid leak (n = 2)

C T20/23 (87%)( l fn )20/20 (100%)*

8/7 (114%)(1 fp?)1/2 (50%)( l fn )1/1 (100%)

12/12 (100%)

Conventional radiology16/23 (69%)8/16 (50%)( 1 03/7 (42%)0/2 (0%)(2fn)1/1 (100%)

13/12 (108%)(2fp)

Reference methods"23/23

7/232/231/23

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fn = false negative; fp = false positive; f = false classification when comp ared with CT and reference m ethod s."Reference methods: case h istory, clinicalfindings,audiometry, surgery (n = 4). *CTfindings:12 longitudinal fractures, fivetransverse fractures,fivecombined fractures, one atypical fracture.108 The British Journal of Radiology, February 1989


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Radiological evaluation of temporal bone disease

Figure 2. High-resolution CTscan shows a transverse fracturewith labyrinthine damage(arrowheads). The fracture wasnot diagnosed by conventionalmeans .confirmed by CT. In one case, the fracture line wasevident only in the Stenvers tomogram (Fig. 1). It wasimpossible to recognize the atypical fracture on eitheraxial or coronal CT scans. Fractures diagnosed by CTwere always clearly classifiable whereas by conventionalmeans the fracture type could be clearly defined in onlyhalf of the diagnosed cases. The diagnosis of combinedfractures was difficult by conventional techniques andone of the conventionally diagnosed fractures wasincorrectly described when com pared with the CT image.Lesions of the labyrinth or ossicular chain were moreclearly demonstrated by CT as shown by comparisonwith the audiometric findings (Fig. 2). Out of eightpatients with labyrinth lesions demonstrated by CT,seven had audiometric findings (sensory impairment ofhearing up to deafness and/or disturbance of vestibularfunction). This group included those patients whoselabyrinth lesions were diagnosed by conventionalradiology. In one case, CT showed a fracture line in thearea of the anterior semicircular canal although therewas no loss of vestibular function. A lesion of theossicular chain was diagnosed by audiometry in twopatients and later confirmed at operation. In anothercase, there was rupture of the ossicular chainarticulations with dislocation of the incus, which had

been correctly diagnosed by CT but not by conventionalradiology (Fig. 3). In this case there was also a stapesfracture which was diagnosed neither by CT norconventional radiology. In a case of primary, partialparalysis of the facial nerve, the fracture line runningthrough the internal auditory meatus was recognized inthe CT image as well as in the conventional tomogram.An important advantage of CT is the correctrepresentation of liquids and soft-tissue masses. Twelvepatients presented clinically with haemotympanum,among these two patients with cerebrospinal fluid loss.The accumulated fluid was correctly identified by CT inall cases. By conventional means, fluid accumulation inthe middle ear was diagnosed 13 times. However, two ofthe findings were false positive and six were falsenegative.Cholesteatoma (TableHI)The low sensitivity of conventional radiology withregard to pathological fluid accumulations and soft-tissue structures limits the value of this procedure,especially in the case of cholesteatoma. In eight out of 12cholesteatoma patients, the diagnosis was confirmed bysurgery. The clinicalfindingswere obvious in four of thepatients. A typical, localized, soft-tissue lesion was

(a )Figure 3. High-resolution CT scans, (a) transverse and (b) coronal planes, showing a transverse fracture with discontinuity of theossicular chain and complete dislocation of the incus due to rupture of the incudomalleolar and incudostapedial joint. The longprocess of the incus is displaced into the epitympanum (arrowhead). Body of the malleus (^-) and incus (^).

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P. Fritz, K. Rieden, T. Lenarz, J. Haels and K. zum WinkelTable III. Cholesteatomas ( =

Soft-tissue tumourBony destructionOssicular erosion

12)C T12/12 (100%)5/8 (62%)"4/6 (66%)"

Conventional radiology7/12 (58%)2/8 (25%) tp3/6 (50%) tp

Reference methods"12/12 (100%)8/8 (I00%) r6/8 (75%)'

"Reference meth ods : clinical findings, surgery. Tr u e p ositive. "Surgical findings (n = 8) .

Figure 4. High-resolution CT scans, (a) axial and (b) coronal planes, showing attic cholesteatoma (X), remnants of the ossiclewalled in (-^) and erosion of the antrum and destruction of the external auditory canal and the tegmen tympani (-*).

recognized by CT in all patients (Fig. 4). Five falsenegative diagnoses were made by conventionalprocedure.Computed tomography was also superior in assessingbone erosions. Cholesteatoma masses next to the lateralsemicircular canal may lead to a closed fistula of thecanal, which may be opened during surgical procedures,leading to serious complications. The prediction of thepossibility of afistulaof the lateral semicircular canal hasa decisive influence on the choice of operative approach.

Figure 5. High-resolution CT scan (coronal plane) showingmetastasis in the temporal bone from bronchial carcinoma anddestruction of the clivus, internal auditory canal and the middleear wall (arrowheads). Tumour masses are sealing the tympaniccavity.

Computed tomography is also able to visualize thespatial relationship to the lateral semicircular canal.Petrous bone metastasesIn metastatic osteolysis and sclerosis, CT showed asuperior detection rate of 83% as opposed to 67% byconventional means (Fig. 5; Table IV).Otosclerosis (Table V)The possibility of otosclerosis was diagnosedconventionally more often than by CT, by virtue ofincreased opacification or of seeming resorption zones inthe labyrinth area. Sclerosis in the area of the footplateof the stapes was diagnosed neither by conventionalmeans no r by C T. In one case the radiological diagnosiswas examined at operation, turning out to be falsenegative. The higher percentage of positive findings bypluridirectional tomography could be explained byartefacts. Conventional tomography is influenced byopacification artefacts and the centring of the X-raybeam. Faulty positioning of the apparatus which is notcentred exactly can lead to a seeming difference in densityof the petrous bone images.Table IV. Metastases ( = 12)

CT ConventionalradiologyOsteolytic/osteoblasticSoft-tissue tumour 10/12 (83% ) 8/12 (67% )3/12 (25% ) 4/12 (33%) (1 fp)Reference methods: clinical findings, follow-up bone scan;fp = false positive when compared with CT.

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Radiological evaluation of temporal bone diseaseTable V. Otosclerosis ( = 7)

Qualitative bone change(lucent/sclerotic areas)Fenestral sclerosisOpacification(soft-tissue/effusion)

CT

1/70/7 (1 fn)0/7

Convent ionalradiology3/70/7 (1 fn)*2/7 (2 fp)

Reference methods: case history, audiometry, *surgery(n = 1).fn = false negative; fp = false positive when compared withCT.Table VI. Inflammatory processes (n = 6)

CT ConventionalradiologyResorption zones/sclerosisOpacification(soft-tissue/effusion)

3/65/6

1/63/6 (3 fp)

Reference methods: clinical findings, bone scan,fp = false positive when compared with CT.InflammationComputed tomography resulted in more diagnosescompared with conventional radiology, confirmed byclinical and nuclear medicinefindings(Fig. 6; Table VI).Stenosis of the external auditory meatusOsseous stenosis was diagnosed by both CT andconventional radiography. An additional obstructivesoft-tissue membrane in one of the two cases wasdiagnosed only by C T (Table VII).

Figure 6. High-resolution CT scan (axial plane) showingosteomyelitis of the petrous bone; CT clearly shows areas ofbone resorption in the lateral semicircular canal capsule(arrowheads). No abnormality was discovered on conventionaltomography.

Table VII. Dysplasia of the external auditory canal (n = 2)CT Conven tional Referenceradiology methods

Osseous stenosisSoft-tissue stenosis 2/21/2 2/20/2 (1 fn) 2/21/2Reference methods: surgery (n = 2), clinical findings.

The value of conventional radiology to determinepathological soft-tissue structures or fluid accumulationsin the external auditory m eatus, tympanic cavity and themastoid air cells was also investigated. Sealing of the air-filled cavities of the petrous bone can be diagnosed withcertainty by CT. However, a clear differentiationbetween solid masses or liquids by means of densitymeasurements is not always possible. The smalldimensions of the air-filled cavities only allow for smallregions of interest with correspondingly poor countstatistics and high standard deviation. In addition,adjacent osseous structures lead to partial volume effectswhich can falsify density measurements considerably.However, it can always be determined whether the air-filled cavities are open or closed. Hence, CT can serve asa reference standard for conventionally diagnosedopacifications. In 29 out of 62 patients (47%),opacification was diagnosed by conventional radiology.Compared with CT, eight of these were false positive(27%). Thirteen of 33 negative diagnoses were falsenegative (39%). Sensitivity of conventional radiologywith regard to soft tissue or effusions filling the tym paniccavities was 0.61, specificity 0.71 and accuracy 0.66.DiscussionThe majority of basic otological diagnoses can bemade by clinical and audiometric testing. Radiologicalprocedures are used to confirm the clinical diagnosis andto provide a more thorough pre-operative evaluation.An exact radiological diagnosis is of particularimportance in the prediction of complications and thetopographic representation of petrous bone lesionsbefore surgery. Computed tomography is clearlysuperior in the imaging and classifying of temporal bonefractures. Only in cases of uncomplicated petrous bonefractures is conventional radiology sufficient, providedthat the fracture can be identified on the plainradiograph.Conventional tomography should be used as requiredif doubt still exists after CT. This can be the case withatypical fractures, where the spatial relationship isunfavourable to the CT imaging planes. In the case ofcerebrospinal fluid loss, the exact identification of thefracture line determines the operative approach. In manycases it is possible to determine the location of thecerebrospinal fluid leak by CT cysternography(Valavanis et al, 1986).The demonstration of a fracture through the facialcanal facilitates the decision to undertake adecompression opera tion which might preserve function.If a post-traum atic conductive hearing loss of more than

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30 dB persists longer than 2 months, damage to themiddle ear bones must be considered (Bellucci, 1983;Swartz et al, 1985). Radiological evidence of such traumawill be the deciding factor in planning a reconstructiveoperation of the ossicular chain. Injury of this kindmostly involves the incus (Wright, 1974) and usuallyleads to rupture of the incudostapedial joint (Goodwin,1983). Ossicular chain dislocation and injuries of theinner ear can be visualized better by CT thanconventional tomography. Stapes fractures are mainlysecondary to dislocation of the incus (Bellucci, 1983) andgenerally cannot be recognized by radiological meansbecause anatomical details of the stapes normally cannotbe determined by high-resolution CT (Miller et al, 1985;Fritz et al, 1987). Radiological evidence of labyrinthinedamage determines the prognosis of post-traumaticsensorineural hearing loss (Zonneveld, 1983).In cases of cholesteatoma, determination of the exactextent of the tumour mass, including bony erosions, isonly possible through high-resolution CT.Cholesteatoma masses in contact with the lateralsemicircular canal threaten the possibility offistulaandinfluence the operative approach. Similarly, CT isindispensable when there are metastases within thepetrous bone. In these circumstances, CT is not onlymore sensitive but visualizes the extent of the tumourbetter than conventional radiology and also provides abasis for the planning of radiation therapy. Computedtomography is clearly superior in imaging pathologicalsoft-tissue and tympanic effusions and therefore shouldbe the method of choice for evaluation of obscureinflammatory processes.The possibility of opacification and centring artefactsproduced through conventional tomography should betaken into consideration if otosclerosis of thelabyrinthine capsule is suspected. In fenestralotosclerosis, we believe that the spatial resolution of bothhigh-resolution CT and conventional tomography is stilltoo limited to give clear answers about the status of thefootplate and the oval window niche. The aboverequirement m akes clear the need for accurate and exactradiographic diagnosis. At present, CT is the mosteffective means. In our total series, 1.6-times more bonefindings were recorded by high-resolution CT. Whencompared with CT, conventional radiology shows poorsensitivity for evaluation of soft-tissue processes andeffusions. Computed tomography enabled a cleardiagnosis in 80% of the cases, conventional radiology in63% of the cases. Conventional radiological pro-cedures, including pluridirectional tomography, werenot only less informative but also often led to wronginterpretation.Lower radiation exposure as well as the savings in timeare additional advantages of CT. We believe high-resolution CT performed in a standardized manner withboth axial and coronal planes and 2 mm increments at1.5 mm thickness will be sufficient for the majority ofclinical circumstances. Inaccuracy might occur withregard to very small, particular structures of the innerear, like the stapes. In our opinion, contiguous or

P. Fritz, K. Rieden, T. Lenarz, J. Haels and K. zum Winkeloverlapping slices should be reserved for additional, verydetailed examinations. We conclude that, if available,high-resolution CT is the method of choice for acomprehensive radiological examination of the temporalbone and should replace conventional X-ray diagnosis.ReferencesBELLUCCI, R. J., 1983. Traumatic injuries of the middle ear.Otolaryngologic Clinics of North America, 16, 633-650.BRU N N E R, E., T U R K , R., S W O BO D A , H. , IMHOF, H. & SCHRATTER,M., 1986. Die Bedeutung der Computertomographie fur dieMit telohrdiagnose. Laryngologie Rhinologie Otologie, 65,327-330.CHAKERES, D. W. & SPIEGEL, M. D ., 1983. A systematictechnique for comprehensive evaluation of the temporal boneby computed tomography. Radiology, 146, 97-106.D A M S M A , H., DE G R O O T , J. A. M., Z O N N E V E L D , F. W., VAN

W A E S , P. F. G. M. & H U I Z I N G , E. H., 1984. CT of cochlearotosclerosis (otospongiosis). Radiologic Clinics of NorthAmerica, 22, 37-43.F R I T Z , P., L E N A R Z , T. , H A E L S , J. & F E H RE N T Z , D., 1987.Feins trukturanalyse des Felsenbeines mittels

hochauflosender Dunnschicht-Computertomographie Teil 1:Sensitivitat de r Feinstrukturdarstellung bei einerstandardisierten Untersuchungstechnik. Fortschritte auf demGebiete der Rontgenstrahlen und der Nuklearmedizin, 147,266-271.GOODWIN, W. J., 1983. Temporal bone fractures.Otolaryngologic Clinics of North America, 16, 651-659.DE G R O O T , J. A. M., H U I Z I N G , E. H., Z O N N E V E L D , F. W.,

D A M S M A , H. & V A N W A E S , P. F. G. M., 1985. Labyrinthineotosclerosis studied with a new computed tomographytechnique. Annals of Otology, Rhinology and Laryngology, 94,223-225.IMHOF, H., SALOMONOWITZ, E., K U M P A N , W., CANIGIANI, G. ,

SCHRATTER, M., Z R U N E K , M . & T U R K , G., 1986. CT undkonventionelle Schlafenbeindiagnostik-Wertigkeit undEinsatzfolge. In Digitate Bildgebende Verfahren. IntegrierteDigitale Radiologie, Grazer Radiologisches Symposium, 3- 5October, ed. by E. Vogler & G. H. Schneider (Schering,Berlin), pp. 270-277.K O N I G , H. VON & K U R T Z , B., 1984. HochauflosendeComp utertomographie der Felsenbeine. Fortschritte auf demGebiete der Rontgenstrahlen und der Nuklearmedizin, 141,129-135.K O S T E R, O., BO CK L E R, R. , L A CK N E R, K. & K O C H , U., 1984. Diehochauflosende Computertomographie des Mittel-undInnenohrs . Laryngologie Rhinologie Otolaryngologic 63, 4 8 8 -493.K O S T E R, O. & E W E N , K., 1986. Zu r Strahlen belastu ng bei derhochauflosenden Computertomographie des Felsenbeines.

Digitale Bilddiagnostik, 6, 176-180.K O S T E R, O. & S T RA E H L E R-P O H L , H. J., 1986. Diehochauflosende Computertomographie in der Abklarungknochendestruierender Prozesse des auBeren Ohres.Fortschritte auf dem Gebiete der Rontgenstrahlen und de rNuklearmedizin, 145, 651-656.M A F E E , M. F., VALVASSORI, G. E., D E I T C H , R. L., N O R O U Z I , P. ,

H E N RIK S O N , G . C , C A P E K , V. & A P P L E BA U M , E. L., 1985a.Use of CT in the evaluation of cochlear otosclerosis.Radiology, 156, 703-708.M A F E E , M. F., H E N RIK S O N , G. C , D E I T C H , R. L., N O R O U Z I , P. ,

K U M A R , A. , K R I Z , R. & VALVASSORI, G. E., 1985b. Use of CTin stapedial otosclerosis. Radiology, 156, 709-714.M I L L E R , D., D A W E S , A. T. & C O W I E , J. W., 1985.Routineuntersuchungen des Felsenbeines unter Verwendung

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Radiological evaluation of temporal bone diseasehochauflosender multiplanarer Rekon struktionsverfah ren.Electromedica, 53, 12-15.

S W A RT Z , J. D., G O O D M A N , R. S., RUSSEL, K. B., LADENHEIM, S.E. & WOLFSON, R. J., 1983a. High-resolution computedtomography of the middle ear and mastoid. Part HI:Surgically altered anatomy and pathology. Radiology, 148,4 6 1 ^ 6 4 .S W A RT Z , J. D., G O O D M A N , R. S., RUSSEL, K. B., M A R L O W E , F.

E. & WOLFSON, R. F., 1983b. High-resolution computedtomography of the middle ear and mastoid. Part II :Tubotympanic disease. Radiology, 148, 455-459.S W A RT Z , J. D., S W A R T Z , N. G., H A M P E L , A. , K O RS V IK , H.,

RONIS, M. L., W O L F S O N , R. J. & L O W E R Y , L. D., 1985.Computerized tomographic evaluation of the middle ear andmastoid for post-traumatic hearing loss. Annals of Otology,Rhinology and Laryngology, 94, 263-266.VALAVANIS, A. , SCHUBINGER, O. , S T U CK M A N N , G. &

ANTONUCCI, F., 1986. CT-Diagnostik traumatischerLasionen des Felsenbeines. Radiologe, 26, 85-90.VIRAPONGSE, C , S A RW A R, M., K I E R , E. L., SASAKI, C. &

PILLSBURY, H., 1983. Temporal bone disease: a comparisonbetween high resolution computed tomography andpluridirectional tomography. Radiology, 147, 743-748.WELLESCHICK, B. & S A L O M O N O W IT Z , E., 1986. InnenohrmiB-bi ldung. Otol iquorrhoe bei Stapedektomie. LaryngologieRhinologie Otologie, 65, 688-690.WRIGHT, J. W., 1974. Trauma of the ear. Radiologic Clinics ofNorth America, 12, 527-532.Z O N N E V E L D , F. W., VAN W A E S , P. F. G. M., D A M S M A , H.,

RABISCHONG, P. & VIGNAUD, J., 1983. Direct multiplanarcomputed tomography of the petrous bone. Radiographics, 3,400-^49.ZONNEVELD, F. W., 1983. The value of non-reconstructivemult iplanar CT for the evaluation of the petrous bone.Neuroradiology, 25, 1-10.Z O N N E V E L D , F. W., DE G R O O T , J. A. M., D A M S M A , H., VAN

W A E S , P. F. G. M. & H U I Z I N G , E. H., 1984. DieAnwendbarkei t der hochauflosenden CT zur Darstellung desAquaeductus vestibuli (Meniere) und der Otospongiosis desLabyrinths . Radiologe, 24, 508-515.

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