Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
THE ROLE OF HIGH RESOLUTION COMPUTED TOMOGRAPHY (HRCT) IN EVALUATION OF CHRONIC SUPPURATIVE OTITIS MEDIA WITH CHOLESTEATOMA; RADIOSURGICAL CORRELATION By *Adel MS Mohsen, **Yehia MS El-Kashif. Departments of *Radiodiagnosis & **ENT - El-Minia Faculty of Medicine ABSTRACT: Objective and aim of the work: Chronic otitis media and its complications need clinical effort for proper diagnosis. Early diagnosis and management can avoid permanent hearing loss which is common sequelae. The advent of HRCT facilitates diagnosis of temporal bone, mastoid and inner ear pathologies. The study aimed to study the value of HRCT in diagnosis of chronic suppurative otitis media with cholesteatoma, its complications and matching the results surgical findings. Subjects & methods: The present work included 32 patients within the period from September 2001 to December 2003. They were randomly selected from the Radiology and ENT Departments in El MINIA University hospital. Their ages ranged from 10 to 65 years (24.88 + 14.3). All patients presented with clinical picture of suppurative otitis media such as ear discharge, conductive hearing loss with or without signs of increased intracranial pressure and facial palsy. Thorough ENT clinical and otoscopic examinations at the ENT Department were done. Patients presented with vertigo are examined for the presence of labyrinthine fistula by fistula test. HRCT examinations were done to all patients using (GE CT/ PROSPEED PLUS Ver.04.00 Scanner, with 512 elements, 256 x 256 matrix. Scanning was done in the direct axial and coronal planes for optimal demonstration of temporal bone structures. HRCT images were interpreted to define (1) the nature of inflammatory ear disease; localization and possible complications (2) To give anatomical and pathological changes needed for surgical planning and define neoplastic changes (3) To detect the normal variant important to the surgeon and (4) To evaluate the ear following surgery for the detection of possible residual, recurrence or post operative complications. Results: Combined pars flaccida and pars tensa cholesteatomas was the most common type detected in (37.5%). The attic cholesteatoma was most frequently site seen (31.25%). The scutum, lateral attic wall erosion & eroded Korner’s septum were the most common findings seen in (56.3%). Complete erosion of ossicles was seen in (56.3%), involvement of sinus tympani (Hidden areas) was seen in (34.4%) and sclerotic mastoid cells in (56.3%).Labyrinthine fistula was seen in (18.8%) of cases and eroded facial nerve canal in 25% of cases. Diseased other ear was seen in 10 cases (31.3%) with cholesteatoma seen in (6.3%) of such cases. Temporal bone complications were the most prevalent complications (50%) with conductive hearing loss was manifested in 46.9% of cases, meanwhile intracranial complications were seen only in 4 cases (12.5%). HRCT showed 100% sensitivity in diagnosis of soft tissue mass, bony erosion, labyrinthine fistula, dehiscent facial nerve canal and intracranial complications. It showed less accuracy in diagnosis of eroded facial canal (96.4%), incus erosion (96.4%) and tegmen erosion (94.4%). Conclusion: HRCT is unique in its ability to display not only the internal bone architecture of middle ear and mastoid but also presence of soft tissue mass; that a negative scan effectively excludes possibility of cholesteatoma. It is also valuable in visualization of hidden areas such as sinus tympani and facial recess beyond otoscopic examination which is important before decision of surgical strategy. HRCT provides the surgeon about 1 possibility of normal anatomic variation that may be present such as overriding jugular bulb; alerting him before start surgery, hence avoid intra-operative problems. Early use of HRCT in cases of chronic suppurative otitis media can save hearing and improve morbidity. KEY WORDS: - History of previous middle ear operation-if present- was also taken. - Thorough ENT clinical and otoscopic examinations at the ENT Department were done. Patients presented with vertigo are examined for the presence of labyrinthine fistula by fistula test (Nystagmus elicited by the application of positive or negative pressure to the external canal in positive cases). INTRODUCTION: Otitis media and resultant hearing loss remain a significant international health problem in terms of prevalence, economics and sequelae. Short and long-term sequelae of otitis media may be devastating. It can be avoided if recognized early and probably treated.1,2 Aim of the work: The aim of this work is to emphasize the role, value and impact of HRCT in diagnosis of chronic suppurative otitis media with cholesteatoma, its complications as well as correlation with operative data. HRCT examination: The study was done to all patients using (GE CT / PROSPEED PLUS Ver.04.00 Scanner) with 512 elements, 256 x 256 matrix. Zooming and magnification were done for the petrous bone on each side and for the diseased side. The HRCT scan protocol includes the following factors: Patient position: supine for the axial scanning, prone or supine with hyper extended neck for coronal scanning. KV…………………120 MA……………….…200 Scan time…………..1.5 Sec Slice thickness…… 1 mm Section spacing (Interval) 1mm Field of view (small) 25cm Mode……………Bone Algorithm. Window width (extended) 4000 HU. Window level …3000 Collimation……1.5mm Pixels…………0.25mm2 Scanning was done in the direct axial and coronal planes for optimal demonstration of temporal bone structures. (a) Axial (Horizontal projection): The patient lies supine with the neck slightly extended (the cantho-meatal line is perpendicular to the table top). PATIENTS AND METHODS: Patients: This work included 32 patients within the period from September 2001 to December 2003. They were randomly selected from the Radiology and ENT departments in El MINIA University hospital. Fifteen were males and 17 were females, their ages ranged from 10 to 65 years (24.88 + 14.3). All patients presented with clinical picture of suppurative otitis media such as ear discharge, conductive hearing loss with or without signs of increased intracranial pressure and facial palsy. Methods: Every patient was subjected to the following studies: - Full history taking including history of chronic ear discharge, conductive hearing loss, symptoms of increased intracranial tension (Fever, headache, vomiting) and facial palsy. 2 Scout view was obtained and sections were performed parallel to the anthropologic line (plane intersecting the inferior orbital rim and the superior margin of the external auditory canal). The sections were taken at 1mm increments beginning at the level of the floor of the hypo-tympanum and jugular fossa and extending cephaliccally to the level of the arcuate eminence using line for localization. (b) Coronal (frontal) projection: The patient lies in the prone position with the neck fully extended. A lateral scout view was performed and sections performed nearly parallel to the ramus of the mandible. The gantry of the scanner was tilted 15٥-20٥ to compensate for an incomplete extension of the neck. Sections were taken from the bony Eustachian tube anteriorly, extended posteriorly to the posterior wall of the mastoid bone. The coronal projection was not done in patients suffering from head trauma and obese patient with short neck. The coronal scanning also can be done with the patient supine with hyperextended neck. the normal variant important to the surgeon (e.g. laterally placed sigmoid sinus, high riding jugular bulb, thick Körner’s septum, deep sinus tympani and prominent cochlear aqueduct. (4) To evaluate the ear following surgery for the detection of possible residual, recurrence or post operative complications. Contrast enhancement: No contrast enhancement was used, unless there was suspected vascular mass or suspected intracranial complications. Intravenous injection of 50 ml Urovideo 75% was given. Scanning of the brain in these cases was done pre and post intravenous contrast media. Sagittal reformat: Sagittal reformatting was done in some cases to define the mastoid segment, facial nerve canal and stylomastoid foramen. The hallmarks of cholesteatoma on CT are based primarily on the presences of one or more of the following criteria; (1) A non-dependent soft tissue density mass (2) Typical location in (attic, mesotympanum or antrum), associated with (3) bony erosion of the middle ear bony walls (i.e. Scutum, lateral attic wall, anterior tympanic wall, tegmen, sigmoid sinus plate, Korner’s septum, posterior and superior metal wall), erosion of the ossicles, scalloping of the mastoid, erosion of the semicircular canal and facial nerve canal (tympanic and mastoid segments) may be present.3, 4, 5, 6 A routine study of the cooperative patient takes 15-20 minutes. The window width and settings were adjusted to a long gray scale to allow best visualization of the temporal bone structures. Images were photographed to an extended window level +3500-4000 HU and window width 250 to 300. When soft tissue structures were of interest images were displayed at window widths of approximately 100-300 HU. RESULTS: This study included 32 (15 males &17 females) patients having chronic suppurative otitis media with cholesteatoma. The high age incidences were in the 3rd & 4th decades, while the low incidence was in 2nd and 6th decades. Females (53.1%) were more affected HRCT images were interpreted in details to define (1) the nature of inflammatory ear disease; localization and possible complications (2) To give anatomic and pathological changes needed for surgical planning and define neoplastic changes (3) To detect 3 than males (46.9%). The Age and sex distribution of patients are presented in table I. The clinical presentations of these patients are presented in table II. Chronic ear discharge with partial or complete conductive hearing loss was the main clinical presentation and representing (53.1%) followed by chronic discharge (15.6), chronic discharge with signs of increased intracranial tension (12.5%) and those with vertigo and sensorineural hearing loss.(12.5%) Table (I): Age & sex distribution of chronic suppurative otitis media with cholesteatoma: Age in Sex Total years Male Female No. % No. % No. % 101 6.67 1 5.9 2 6.25 203 20.0 8 47.1 11 34.4 304 26.7 5 29.4 9 28.1 403 20.0 1 5.9 4 12.5 503 20.0 1 5.9 4 12.5 601 6.67 1 5.9 2 6.25 15 17 32 100 Total Table (II): Clinical presentations of the studied patients with cholesteatoma: Clinical presentation Chronic ear discharge without hearing loss Chronic discharge with hearing loss Chronic discharge with signs of increased I.C.T Chronic discharge with facial paresis Chronic discharge with vertigo and SNHL Recurrent cholesteatoma Total SNHL: Sensorineural hearing loss No. of patients 5 % 15.63 17 4 53.1 12.5 2 4 6.25 12.5 2 6.25 32 100 I.C.T: Intracranial tension. Location & extent of cholesteatoma (table IV). The attic cholesteatoma was most frequently seen (31.25%) then extensive holo-tympanic acquired cholesteatoma (28.1%) followed by attico-antral cholesteatoma in (25 %). Figs. III→ V HRCT criteria of the studied group: The HRCT findings are presented in tables from table III to table XII. Type of cholesteatoma: (table III). Combined pars flaccida and pars tensa cholesteatomas were the mostly encountered type detected in (37.5%) and then both pars flaccida & pars tensa cholesteatomas in (31.25%). See Fig. (I & II). Bony erosions of the middle ear bony walls: (Fig. III, IV) (table V). The scutum and lateral attic wall erosion 4 was the most common finding in (56.3%) and eroded Korner’s septum (56.3%) followed by thinning tegmen (31.3%) and the least common is the eroded sigmoid sinus plate (12.5%). mastoid wall fistula (18.8%) and mastoid abscess was detected in (9.4%) cases with infected cholesteatoma. (Fig. VI) The labyrinth: (table IX) The lateral semicircular canal fistula was the most common finding encountered in (18.8%), eroded whole structures in (3.1%), and eroded canal in (9.4%). (Fig. VI, VIII) Integrity of the ossicular chain: (table VI). The ossicles was absent or completely eroded in (56.3%), the incus was the most commonly affected (21.9%), followed by malleus erosion (9.4%). The ossicles were displaced without erosion only in (12.5%). (Fig. IV) Integrity of the facial nerve canal: (table X). The facial nerve canal was intact in (68.8%), eroded in (25%) and dehiscent in (6.3%) of cases. The whole segments were equally affected (6.25%). Fig. VI. Involvement of hidden area (Fig. V), (table VII). The involvement of the sinus tympani was detected in (34.4%) and the facial recess involvement was encountered in (31.3%). Condition of the other ear: (table XI). The other ear was normal in (68.8%) and diseased in (31.3%), chronic suppurative otitis was encountered in (25.0%) and bilateral cholesteatoma in (6.3%). Mastoid air cell system: (table VIII). The sclerotic mastoid was the most common finding encountered in (56.3%) of cases. Automastoiectomy was encountered in (31.3%), lateral Table (III): Type of cholesteatomas: Type of cholesteatoma No. of patients 10 10 12 32 Pars flaccida cholesteatoma Pars tensa cholesteatoma Combined cholesteatoma Total % 31.25 31.25 37.5 100 Table (1V): Location & extent of cholesteatoma: Location & extension No. of % patient Attic 10 31.25 Attico-antral 8 25.0 Mesotympanum 5 15.6 Extensive (holotympanic) extended to mastoid antrum 9 28.1 Total 32 100 5 (A) (B) Figure I: Early cholesteatoma pars flaccida (A) Axial epitympanic and (B) Coronal anterior tympanic sections through the left petrous bone showed localized tissue density mass (arrow) filling the Prussak’s space lateral to head and neck of malleus and medial to the blunted scutum. The ossicular chain is displaced medially. Normally aerated remaining left middle ear cavity. EAC (external auditory canal) (A) (B) Figure II: Early Cholesteatoma pars tensa (A) Axial midtympanic section of the left petrous bone showed localized tissue density mass seen filling the facial recess and overlying the pyramidal eminence. Labeled structures include; PE= pyramidal eminence, ST= sinus tympani, BT= basal turn of the cochlea, V= vestibule, RWN= round window niche, CA= cochlear aqueduct (B) Coronal midtympanic section showing a soft tissue density mass mostly involving the pars tensa of the tympanic membrane, eroding the incus lenticular process (arrow). Note the opacified meso-tympanum and intact incus body. Labeled structures include; TM= tympanic membrane, IB=incus body, SSC= superior and LSC= lateral semicircular canal, IAC = internal auditory canal. Table (V): Middle ear bony wall erosion: Bony wall erosion* No. of % patients Blunted scutum 5 15.6 Eroded scutum & lateral attic wall 18 56.3 Eroded tegmen 5 15.6 Thinning of the tegmen 10 31.3 Eroded sigmoid sinus plate 4 12.5 Eroded superior & posterior meatal wall 5 15.6 Eroded Körner’s septum 18 56.3 *More than one finding may be present in the same patient 6 Table (VI): Integrity of the ossicular chain Integrity of the ossicles No. of patient 18 3 7 4 32 Completely eroded (no ossicles) Eroded malleus only Eroded incus only Displaced intact ossicles Total (A) % 56.3 9.4 21.9 12.5 100.0 (B) (C) (D) Figure III. Attic Cholesteatoma. (A) Axial section IAC level, (B) Axial section lateral semicircular canal level, (C) Coronal anterior tympanic and (D) Coronal midtympanic level of the right petrous bone showing a well defined, rounded tissue density mass filling the anterior part of the attic extended to midtympanic region. The lesion erodes the scutum and malleus head and neck. Note the normal appearance of the aditus denoting that the lesion is localized within the attic with no antral extension. Labeled structures in (A) include; Mass= cholesteatoma mass, PE=pyramidal eminence, ST=sinus tympani and IAC=internal auditory. Labeled structures in (B) include, EPIT C= epitympanic cavity, ADITUS= aditus ad antrum, MA= Mastoid antrum, LSC= lateral semicircular canal and VA= vestibular aqueduct. Labeled structures in (C) include; Mass= cholesteatoma mass, TT= tegmen tympani, GG= geniculate ganglion, COCH= cochlea and CC= carotid canal (vertical segment). Labeled structures in (D) include; M=mass, EAC=external auditory canal, IAC=internal auditory canal and TT= tegmen tympani. 7 (A) (B) Figure IV. Right attico-antral cholesteatoma pars flaccida (A) Axial section lateral semicircular canal level and (B) Coronal midtympanic section through the right petrous bone showing a well defined, soft tissue density mass filling the attic, widen the aditus and extended to the mastoid antrum. The mass erodes the scutum and supero-posterior meatal wall, Korner’s septum and sigmoid sinus plate. The tympanic membrane is thickened and retracted. Note that the cholesteatoma mass abutting the anterior limb of the lateral semicircular canal, which is seen intact in axial section. Labeled structures in (A) includes; C= cholesteatoma mass and SSP= eroded sigmoid sinus plate. Labeled structures in (B) include; EC= posterior part of the epitympanic cavity, TM= the thickened retracted tympanic membrane and LSC= lateral semicircular canal. Table (VII): The involvement of hidden areas (anterior & posterior tympanum): Hidden area involved Posterior tympanum Sinus tympani Facial recess Anterior tympanum No. of patients % 11 10 6 34.4 31.3 18.8 Table (VIII): Integrity of mastoid air cell system: Mastoid state* No. of % patients Sclerotic 18 56.3 Auto-mastoidectomy 10 31.3 Lateral mastoid wall bony fistula 6 18.8 Mastoid abscess 3 9.4 *More than one finding may be present in the same patient 8 (A) (B) Figure V. Extensive cholesteatoma invading the anterior epi-tympanum (hidden area) (A) Coronal anterior tympanic and (B) Coronal mid-tympanic oval widow level through the left petrous bone. A large cholesteatoma mass fills the middle ear cavity involving the anterior attic with erosion of the lateral attic wall, tegmen tympani and the posterosuperior meatal wall. The labeled structures include; COCH= cochlea, VCC= vertical segment of the carotid canal and the cholesteatomas, SSC and LSC= superior and lateral semicircular canal, TT= eroded tegmen tympani, IAC= internal auditory canal and EAC P= external auditory canal polyp. Table (IX): Integrity of the inner ear: Inner ear state No. of patients Intact inner ear structures 23 Lateral semicircular canal (LSC) fistula 6 Eroded inner ear structures (cochlea, 1 vestibule & semicircular canals) Eroded Internal Auditory Canal (IAC) 3 % 71.9 18.8 3.1 9.4 Table (X): Integrity of the facial nerve canal: Facial Nerve Canal state (FNC) Intact FNC Dehiscent FNC Eroded FNC: Proximal tympanic segment Distal tympanic segment All tympanic (horizontal) segment Vertical segment Total 9 No. of patients 22 2 8 2 2 2 2 32 % 68.8 6.3 25.0 6.25 6.25 6.25 6.25 100.0 Table (XI): The condition of the other ear: Other ear No. of patients 22 10 8 2 32 Normal other ear Diseased Chronic suppurative otitis media Bilateral Cholesteatoma Total (A) % 68.8 31.3 25.0 6.3 100 (B) Figure VI. Extensive cholesteatoma. (A) Axial lateral semicircular canal section (B) Coronal jugular foramen and posterior middle ear sections through the right petrous bone. A large cholesteatoma mass fills the whole middle ear cavity eroding the lateral semicircular canal with subsequent labyrinthine fistula and the mastoid air cells with subsequent automastoidectomy. Labeled structures include; C= cholesteatoma mass, LSC F= lateral semicircular canal fistula, V= vestibule, IAC= internal auditory canal, PSC=posterior semicircular canal, MA= mastoid antrum, DFNC= descending facial nerve canal and the JF= jugular foramen. labyrinthine fistula (18.8%), post auricular abscess (18.8%), sigmoid Complications of chronic sinus plate erosion (15.6%) and the suppurative otitis media with Cholesteatoma: (see table XII). least complication was the Temporal bone complications were sensorineural hearing loss (6.52%). Regarding intracranial complications, prevalent more than those of the cerebellar, cerebral extradural intracranial complications. The abscesses and otitic hydrocephalus ossicular destruction was the mostly were equally encountered in (3.1%) of encountered complication (50%), cases. followed by conductive hearing loss (46.9%), auto-mastoidectomy (31.3%), Table XII: Temporal bone and intracranial complications in 32 patients with Cholesteatoma: 10 Complications* No. patients of % Temporal bone complications Complete ossicular destruction 16 50.00 Automastoidectomy 10 31.3 Mastoid wall fistula 6 18.8 Conductive hearing loss 15 46.9 Total hearing loss 2 6.52 LSC fistula 6 18.75 Mastoid abscess 1 3.1 Post auricular & zygomatic 6 18.8 abscess 5 15.6 Eroded sigmoid sinus plate Intracranial complications Cerebellar abscess 1 3.1 Cerebral abscess 1 3.1 Extradural abscess 1 3.1 Otitic hydrocephalus 1 3.1 *More than one finding may be present in the same patient (A) (B) Figure VII. Infected cholesteatoma with abscess formation (A) Axial lateral and superior semicircular canal sections through the right petrous bone showing diffuse soft tissue density mass filling the mastoid antrum (MA) and eroding the sigmoid sinus plate (SSP). (B) Axial enhanced CT section of the brain showing extradural abscess (EDA) and zygomatic abscess (ZA). (A) (B) 11 (C) Figure VIII. Extensive cholesteatoma eroding the petrous pyramid and osseous labyrinth (A) Axial inferior tympanic section and (B) Coronal anterior tympanic section of the right petrous bone showed middle ear cavity tissue density mass eroding the lateral attic wall, scutum and ossicles and bony labyrinth (long white & black arrows), the tegmen is thinned (short black arrow).The lesion erodes the labyrinthine and tympanic segments of the facial nerve canal. The attic, aditus and mastoid antrum are opacified with tissue density and the mastoid air cells are sclerotic.(C) Axial section through the posterior fossa in the same patient with contrast showed right cerebellar abscess. were demonstrated with CT scan and the preoperative CT scans agreed with surgical findings of incus erosion in 25 patients (96.4%). Of 18 patients with Correlation between HRCT findings and operative features: (table XIII) HRCT scans showed the presence of a non dependent tissue mass in 26 out of 32 patients with cholesteatoma (92.8%), the location of the pathology on the scan was typical for cholesteatoma in 27 patients (96.4%) and in 28 patients (100%) there was radiological evidence of erosion or destruction of the bony walls of the middle ear, mastoid antrum or ossicles. All patients had at least one of the above radiological features, and 26 (92.8%) patients showed all 3 features. Based on these features 27 ears with cholesteatoma (96.4%) were accurately diagnosed by the HRCT scans. This revealed that the accuracy and sensitivity was excellent regarding malleus erosion, lateral semicircular canal fistula, sigmoid sinus plate erosion and intracranial complications, very good correlation regarding incus erosion and the tegmen tympani erosion and good for the facial nerve canal. State of the ossicles: Out of the 26 patients with incus erosion found at surgery, 25 patients eroded malleus, 18 were seen by the scan with accuracy (100%). The stapes is not visualized consistently by CT scan and not analyzed in this study. Semicircular canal fistula: There were 6 patients with surgically confirmed labyrinthine fistula. Preoperative CT scan diagnosed all the 6 patients of lateral semicircular canal fistulas accurately. In the remaining cases, there were no false positive radiographic interpretations, and thus complete agreement was obtained. Erosion of the tegmen tympani: The tegmen is visualized in coronal sections, appears as a thin bony plate overlying the epitympanum and antrum. There was agreement in (94.4 %) between the preoperative CT scan and operative features. One case was diagnosed as eroded tegmen and the operative features showed only dehiscence of the tegmen with no dural exposure. Integrity of the facial nerve canal: 12 In this study, CT scans found agreement about facial nerve canal integrity in 22 patients (68.8%) and surgery. Out of 8 patients with surgical confirmation of eroded facial nerve canal, CT could detect 7 patients in the present study. CT is agreed with operative features regarding 2 patients with facial canal dehiscence. Integrity of the sigmoid sinus plate: Four patients of sigmoid sinus plate erosion were diagnosed accurately by preoperative CT scans. Intracranial complications: Five patients with intracranial complications including cerebellar cerebral, extradural abscesses and otitic hydrocephalus were diagnosed accurately be preoperative CT scans. Table XIII. Correlation between CT findings and operative features: Features Tissue mass Typical location Bony erosions Incus erosion Malleus erosion LSC fistula Tegmen erosion Facial canal Intact Eroded Dehiscent Eroded SSP Eroded KS Intracranial complications LSC: lateral KS: Finding in CT 26 27 Operative Features 26 27 False Negative 0 0 False Positive 0 0 Accuracy Sensitivity 100 100 100 100 32 25 18 32 26 18 0 1 0 0 0 0 100 96.4 100 100 96.1 100 6 5 6 4 0 0 0 1 100 94.4 100 100 22 8 2 5 18 4 22 9 2 5 18 4 0 1 0 0 0 0 0 0 0 0 0 0 100 96.4 100 100 100 100 100 83.3 100 100 100 100 semicircular canal Korner’s The incidence of the petrous bone 13 SSP: Sigmoid sinus plate. septum anatomical normal variations: (Table XIV) Dehiscent jugular fossa (Fig. IX) was the mostly encountered normal variant (9 cases) followed by laterally placed sigmoid sinus (4 cases), high riding jugular bulb (3 cases), (Fig.X), deep sinus tympani (2 cases), high riding non dehiscent jugular bulb with diverticulum (one case). Table XIV: The incidence of petrous bone normal variants in studied patients: (A) Normal variant Patients' No. jugular 9 % Dehiscent fossa High riding jugular bulb High riding jugular bulb with diverticulum Anteriorly & laterally placed sigmoid sinus Deep sinus tympani Total 2.9 3 0.96 1 0.32 4 1.28 2 0.64 19 6.08 (B) Figure IX. Dehiscent jugular fossa with post-inflammatory ossicular fixation right (A) Axial inferior tympanic section and (B) Coronal section oval window level of the right petrous bone showing dehiscent jugular fossa, normally aerated middle ear cavity with sclerotic mastoid. Note the fibrous tissue extending from the thickened tympanic membrane to the oval window making a post inflammatory ossicular fixation. Labeled structures include DJF= dehiscent jugular fossa and FTF= Fibrous tissue fixation. (A) (B) (B) 14 Figure X. High riding jugular bulb with diverticulum (A) Axial midtympanic section and (B) Coronal jugular foramen level section of the left petrous bone showing high riding jugular bulb with superior diverticulum. Labeled structures include; HRJ= high riding jugular bulb and JD= jugular bulb diverticulum. DISCUSSION Chronic suppurative otitis media is divided into 2 main clinical types. The first variety tends to follow a benign clinical course where there is a persistent perforation of the tympanic membrane; chronic suppurative otitis media without cholesteatoma or tubotympanic type. The other type is more aggressive and follows a dangerous course of destruction of the middle ear, mastoid antrum and termed chronic suppurative otitis media with cholesteatoma or tympano-mastoid variety.(7) High-resolution CT is ideal for the evaluation of middle-ear pathology. Contrast-enhanced CT is useful if an intracranial complication is suspected and if brain hernia (encephalocele) is present in revision surgery. HRCT offers high-resolution images that allow good visualization of the anatomy of the bones, ossicles, and inner ear. (8 & 9) Acquired cholesteatoma divided into primary acquired (no history of otitis media, usually pars flaccida) and secondary acquired (positive history for previous infection). Primary acquired cholesteatomas arise as a result of tympanic membrane retraction. Secondary acquired cholesteatomas occur as a direct consequence of injury to the tympanic membrane. This injury can be a perforation that has arisen as a result of acute otitis media or trauma, or it may be due to surgical manipulation of the drum. (4, 5, 10) In HRCT the axial projection allows visualization of most of temporal bone anatomy, delineating the sinus tympani, facial recess, lateral semicircular canal, Körner’s septum, incudo-malleolar and incudo-stapedial articulations, horizontal segment of the facial nerve canal, internal auditory canal, vestibular aqueduct, oval and round windows and temporal ear pathology. Coronal scans is valuable in evaluating scutum, Prussak’s space, roof of the tympanic cavity (tegmen), geniculate ganglion, oval window, stapes, ossicles heads (malleus and stapes), oval window, jugular fossa, internal auditory canal, vestibule and the vertical segment of the facial nerve canal. Axial images should include top of the petrous apex to the inferior tip of mastoid, and coronal images should be obtained from the anterior margin of petrous apex to the posterior margin of the mastoid. (11) In adults, aural polyps often represent an irritative response to chronic otitis media but may herald the presence of cholesteatoma.(13) Gliklich et al., 1993 (14) and Chakeres; et al., 1985(15) concluded that patients with primary aural polyps unresponsive to medical therapy should undergo the performance of audiogram and CT 15 scan of the temporal bone prior to surgical intervention. The presence of temporal bone erosion on CT heightens the concern of severe underlying abnormality (malignancy or cholesteatoma). In the present study; the high incidence of cholesteatoma was in the 3rd decade of age with a history of recurrent chronic otitis media, tympanic membrane perforation and Eustachian tube dysfunction, while the low incidence was in 6th decade. David White 1997(16) stated that acquired cholesteatoma are more common in patients < 30 years. In a study of Kemppainen et al., 1999(10) the mean annual incidence was 9.2 per 100,000 inhabitants and the incidence was higher among males < age of 50 years. In the present study, tympanostomy was carried out in 10.2% and adenoidectomy or adeno-tonsillectomy in 15.9% of cholesteatoma ears prior to surgery. HRCT features of cholesteatoma of the studied patients: In the present study, and according to the criteria of (3, 4, 5, 6), we found that secondary acquired cholesteatoma were most often localized to the attic and antrum, some extended to the meso-tympanum and some are holotympanic. Attic cholesteatoma was detected in 10 patients (31.25%), attico-antral cholesteatoma in 8 patients (25%), meso-tympanic cholesteatoma detected in 5 patients (15.6%) and extensive holo-tympanic cholesteatoma in 9 patients (28.1%). Regarding the type of cholesteatoma, 10 patients out of 32 patients showed CT features of pars flaccida cholesteatoma (31.25%), 10 patients out of 32 were of pars tensa cholesteatoma (3.25%) and combined types cholesteatomas in 12 patients (37.5%). If Prussak’s space is clear and there is no pars flaccida retraction, we presumed cholesteatoma to arise from the pars tensa. Liu and Bergeron 1989(6) stated that CT is a unique in its ability to display not only the internal bony architecture of the temporal bone but also to evaluate the soft tissue components associated with a pathologic process. Therefore; one of its major contributions to the otologist dealing with cholesteatoma is the preoperative localization of the cholesteatomatous sac, a detail not only determine the type of surgical approach but may also alert the surgeon to possible intraoperative as well postoperative complications. HRCT can early detect cholesteatoma associated with subtle bony erosion or ossicular displacement. This early detection by HRCT with the use of simple non invasive surgical technique (as delivery or atticotomy) will preserve hearing. In the current study, small attic and meso-tympanic cholesteatoma were demonstrated in 10 patients out of 32 patients. Early Prussak’s space cholesteatoma was detected in 2 patients as a localized small soft tissue density mass slightly eroding the scutum in one patient and displaces the ossicles medially in the other patient. Early meso-tympanic cholesteatoma extending from a postero-superior retraction related to the facial recess and sinus tympani detected in 3 patients associated with slightly eroded incus long and lenticular process. The remaining 2 patients showed localized attic cholesteatoma associated with erosion of the scutum, malleus head and neck with slight extension towards the aditus. Phelps and Lloyd 1990(17) stated that, demonstration of small cholesteatoma in the middle ear cavity by CT depends on two factors: the first is the bone erosion of lateral attic wall and scutum and/or displacement of the ossicles and the second factor is the morphology of 16 a soft tissue mass, which is typically seen in the attic and extends down to the isthmus of the middle ear. The ossicular chain is normally equidistant from the medial and lateral walls of the epi-tympanum. The ossicular displacement in either direction often is an early sign of cholesteatoma. Pars flaccida cholesteatomas usually displace the ossicular chain medially, and pars tensa cholesteatoma displace it laterally.(18) Mafee et al 1988(18) and David et al 1989(19) described the criteria indicating cholesteatoma in the attic as follows: destruction of the lateral spur of bone formed by the junction of the lateral attic wall and roof of the external auditory canal (scutum). Blunting of the scutum’s (normally sharp tip) is the earliest sign of attic cholesteatoma. Erosion of the anterior tympanic spine (which is best seen in sagittal scans), is another sign indicating cholesteatoma in the attic. Bone destruction of the lateral attic wall causing widening of the aditus with loss of the “figure-of-eight” pattern (formed by narrow isthmus of the aditus between the radiolucencies of the epitympanum and antrum) usually signifies that cholesteatoma has extends into the antrum. Dehiscence of the tegmen and erosion of the medial attic wall are less common than lateral wall erosion and may lead to involvement of the facial nerve canal with paralysis and invasion of the lateral semicircular canal with vertigo or sudden sensorineural hearing loss. Cholesteatoma in the mastoid antrum is characterized by a smooth cavity that is usually larger than normal owing to bone erosion. When the air cells appear cloudy but maintain their irregular trabecullar pattern or whenever there is obliteration of the mastoid antrum and peripheral air cells by reactive new bone formation, chronic mastoiditis without cholesteatoma is indicated. Another sign of cholesteatoma in the antrum is erosion or absence of the bony partition known as Körner’s septum. So, it is mandatory to compare both ears, because of the normal anatomic variations among individuals. Destruction and scalloping of the mastoid air cells (automastoidectomy), dehiscence or erosion of the sigmoid sinus plate with or without venous sinus thrombosis represents the complications of antral cholesteatoma.(18) Hidden cholesteatoma: The anatomy of the posterior tympanum is quite complex. The pyramidal eminence from which the stapedial tendon arises is the most prominent structures on the posterior tympanic wall. It is bordered medially by the sinus tympani and laterally by the facial recess. They are important in that, cholesteatoma material may lie within and be hidden from view during surgery. Detection of hidden cholesteatoma within the posterior or the anterior tympanum by HRCT makes it the method of choice.(20) In the present study; CT scan demonstrate the involvement of posterior tympanic recesses (sinus tympani and facial recess) by cholesteatoma mass in 21 out of 32 patients (65.6%), the anterior tympanum involved in 6 patients (18.8%). This is consistent with results of Hasso et al., 1988 (21&22) and Mafee 1988(18) who mentioned that CT could demonstrate cholesteatomas in hidden areas such as the posterior tympanic recesses, which could not be detected by the otologic examination. Evaluation of these recesses of the tympanic cavity is essential prior to surgery since the surgical approach may be altered by the presence of inflammatory disease medial to ossicular chain. The anterior epitympanum corresponds to the ossicular space and is very difficult to view with 17 patients. Sadé et al 1982 (27) concluded that ossicular chain erosion occurs in 30% of patient with cholesteatoma. Erosion of the lenticular process and stapes superstructure may produce a conductive hearing loss. Combined sensorineural and conductive hearing loss detected in two patients having extensive cholesteatoma eroding the middle ear structures and invading the osseous labyrinth. The presence of sensorineural hearing loss may indicate involvement of the labyrinth.(27) Labyrinthine fistula: It is encountered in 6 of patients with cholesteatoma. One of these patients presented with vertigo and sensorineural hearing loss as well as positive fistula test. The other 5 patients were discovered accidentally by HRCT scan with no symptoms of labyrinthine fistula. Silver et al., 1987 (28) stated that patients with vertigo and chronic middle ear disease may have a cholesteatoma with a "fistula" between the middle and inner ear. Although the fistula usually involves the lateral semicircular canal, the cholesteatoma may invade the oval window. Palva 1990(29) concluded that the labyrinthine fistula may occur in 10% of patients with cholesteatoma. A fistula should be suspected in patients with longstanding disease and have sensorineural hearing loss and/or vertigo induced by noise or pressure changes in the middle ear. HRCT scan of the temporal bone should be obtained to confirm the diagnosis. Facial nerve paresis was detected in two patients with cholesteatoma eroding the horizontal portion of the facial nerve canal. The paresis developed slowly from chronic expansion of the cholesteatoma. HRCT of the temporal bone helps to localize the site of involvement. Intra-cranial complications: In the present study intracranial complications were encountered in 4 operating microscope even after removal of the head of malleus. These described hidden areas give a bad reputation of recurrence of cholesteatoma. Extensive holo-tympanic cholesteatoma: In this study 9 patients out of 32 (28.1%) presented with extensive cholesteatoma that filling the whole tympanic cavity and extended to mastoid antrum. The diagnosis depends on that, the cholesteatoma had a propensity for bony erosions of the middle ear bony boundaries and mastoid and did not gravitate (non dependent) in axial and coronal sections. These features are consistent with, Voorhees et al.,1983 (23) and Jackler et al., 1984 (24) who depended mainly on the bony erosion not the CT numbers in the diagnosis of holotympanic cholesteatoma. Sara, 1991(25) and Mafee et al., 1988(18) reported that whereas CT scan produces excellent soft tissue resolution, the differentiation of pathological processes on the bases of CT numbers proved to be unsuccessful, because acquired cholesteatoma, granulation tissue and middle ear effusion, all share similar CT numbers. Therefore; secondary findings and clinical information must be relied upon to make a definitive diagnosis. Complications of cholesteatoma: Virtually all complications of the cholesteatoma are related to osseous destruction. The ability to destroy bone may lead to serious intracranial complications. Although these complications may produce obvious signs and symptoms, they may be subtle and unrecognized without CT scan.(5, 26) Intra-temporal complications: In the present study; conductive hearing loss is a common complication of cholesteatoma as ossicular chain erosion occurred in as many as 50 % of 18 patients (14.28%).The cerebellar abscess was a sequel of invasive cholesteatoma eroding the sigmoid sinus plate. The extradural abscesses were detected in one patient having infected cholesteatoma eroding sigmoid sinus plate and the tegmen mastoidium. Otitic hydrocephalus was detected in one patient complaining of intermittent headache. CT scan excludes the presence of cerebral abscess and showed attenuated ventricular system. EL-Essawy et al 1992 (30) in a series of (32 cases) concluded that, the temporal bone complications including bone erosion and cavity formation were seen in all patients with cholesteatoma (100%), sclerosis of the mastoid and ossicular destruction in 30 patients (93.8%).The intracranial complications represented in (21.7%) in the 32 ears due to negligence of treatment and delayed operative interference in addition to un-awareness of the value of CT in detection of these complications. Value of preoperative HRCT in patients with cholesteatoma: The absolute indications for preoperative HRCT in chronic otitis media were described by Falcioni et al.,2002 (31) which include: doubtful diagnosis, suspected malformations, difficult microscopy evaluation, suspected petrous apex cholesteatoma, suspected intracranial complications, and review of cases that did mastoidectomy before. The scan aids in alerting surgeon to the presence of anatomical variations (such as a high riding jugular bulb, prominent laterally placed sigmoid sinus, aberrant carotid artery), and potential surgical hazards that may arise from destructive nature of the disease (such as labyrinthine dehiscence).(32) Correlation between HRCT findings and operative data: HRCT findings of labyrinthine fistula were compared with operative features and fistula test. CT findings were coincident with operative data for all studied parameters and the least one is the integrity of the facial nerve canal. Thirty one patients out of 32 with cholesteatoma accurately diagnosed with HRCT scan (96.4%), only one patient with diffuse tissue density in the attic and meso-tympanum associated with eroded incus long process was diagnosed as acquired mesotympanic cholesteatoma, but the surgery showed diffuse granulation tissue with eroded incus long process. This coincides with Mafee et al 1988 (18) who reported that (96%) of cases were diagnosed correctly with the preoperative CT scan. Chee &Tan, 2001(32) concluded that (94.4%) of cases had at least 2 of the 3 criteria of CT features of cholesteatoma. Both Jackler et al., 1984 (24) and O’Donoghue et al., 1987 (33) , found cholesteatoma presents in 80% of the cases explored. O’Reilly et al 1991(34) detected 23 out of 29 cases (79%) of cholesteatoma. HRCT images may influence the decision and timing of surgical exploration. CT scan evidence of cholesteatoma with significant bony destruction or other complications could prompt the surgeon to operate earlier, particularly if polyps or a tortuous bony canal obscures visualization of the tympanic membrane and hinders clinical diagnosis.(32) Ossicular chain erosion: Bone resorption of the ossicles depends on the origin and mode of spread of cholesteatoma.(4,5,32) In the present study, radio-surgical correlation for the middle ear ossicular erosion was (96.4%) for the incus erosion and (100%) for the malleus erosion. These features are matched with a study made by Chee &Tan, 2001(32) who found that, out of 31 19 incus, found at surgery to be eroded; 30 were demonstrated by CT scan with accuracy (96.8%) and out of the 15 malleus, 14 were seen by the scan with accuracy (96.8%). In a study done by Mafee et al., 1988(18) the radio-surgical correlation was (94%) for the incus and (89%) for the malleus erosions. Hassman et al., 2003 (35) in a series of 60 ears operated between 1988-2001 reported that there is good correlation between CT finding and operative features in cholesteatoma for most middle ear structures except for the integrity of incus long process. On the other hand, O’Reilly et al., 1991 (34) were able to correctly predict an intact ossicular chain in only (50%) of cases. O’Donoghue et al., 1987 (33) reported that erosion of the long process of the incus detected in (67%) of the scanned cases. Phelps and Wright 1990 (36) stated that the error in all cases to demonstrate the ossicular chain reliability was due to the combination of partial volume averaging and tissue silhouetting. While prior knowledge of the state of the ossicles is not critical as the operative risk is concerned, it has bearing on the likelihood of hearing preservation that can be achieved after surgery. For example, the hearing outcomes in patients with an intact stapes tend to be better than those where the stapes super-structure is absent. Pre-surgical knowledge of the status of the ossicular chain would allow the surgeon to better advise the patient on the degree of hearing attainable after surgery.(37) Labyrinthine fistula: In the present study only 6 patients with lateral semicircular canal fistulas, were diagnosed. The HRCT findings were correlated with fistula tests as well as operative data. A labyrinthine fistula is caused by resorption of the bone of the otic capsule by the action of enzymes associated with cholesteatoma or chronic active suppurative osteitis. The most common site for a fistula is the lateral semicircular canal. However, any of the canals may be involved and a cochlear fistula may occur in the middle ear or epi-tympanum. These results were in agreement with those of Mafee et al (1988) and Chee &Tan (2001) (32). Busaba,19 99 (38) mentioned that the labyrinthine fistula was detected radiologically in 42% of patients. He concluded that in chronic otitis media, labyrinthine fistulas occurred almost exclusively in the presence of cholesteatoma and the postoperative hearing outcome correlated with the size of the fistula and the presence of granulation tissue invading the labyrinth. Menif et al., 2000 (39) stated that; HRCT scan assessment of osseous labyrinthine fistula coincided with the surgical findings (14 cases of labyrinthine fistula suspected by CT was surgically confirmed). Phelps and Wright 1990 (36) advocated scanning in both axial and coronal planes when vestibular symptoms were present. Mafee et al., (18) stated that, axial sections may give a false impression of lateral semicircular fistula and another plane (coronal or sagittal) should be obtained. Jackler et al.,1984 (24) reported that the most common canal affected by fistula is the lateral semicircular canal and reliance on coronal sections alone may lead to a (50%) false positives rate of dehiscence due to the artifact of partial volume averaging. Even with the addition of axial scans, minute fistula may still be missed and the careful dissection of the cholesteatoma matrix over the dome of the lateral semicircular canal revealed a tiny bony canal fistula. The axial scans are more satisfactory because they depicted the lateral 20 semicircular canal in its entirety and were less like to produce false positives, but useful information could be gained from the coronal scans. We recommended both planes for accurate diagnosis. Walshe et al., 2002 (40) stated that, there may be a medico-legal role for routine CT before mastoid surgery. For example, erosion of the lateral semicircular canal by cholesteatoma in the absence of vertigo is presumably due to cholesteatoma sealing the defect. When removed at mastoidectomy, such a patient may well become vertiginous. With evidence of erosion in the preoperative HRCT, any accusation of iatrogenic damage could be refuted. Tegmen erosion: Tegmen tympani represent the roof of the middle ear cavity. Erosion of the tegmen is well seen on coronal imaging. In this study tegmen erosion was detected in 5 patients with accuracy 94.4%. One case was diagnosed as eroded tegmen and the operative features showed only dehiscence of the tegmen with no dural exposure. Mafee et al., 1988(18) had similar results as CT findings matched with operative data regarding tegmen erosion were seen in 94% of cases. Also the accuracy in a study made by Chee & Tan (32) was 94.5%. Facial canal integrity: Out of 9 patients with surgically confirmed facial canal erosion, 8 patients detected by CT with accuracy (96.4%) and sensitivity (83.3%). In a study made by Mafee et al 1988,(18) they diagnosed normal facial canal in 41 patients (85%). They also reported that to fully visualize the vertical segment of the canal, one must utilize the sagittal plane, which is not available in all CT scanners. When the middle ear is normal, the thin lateral bony wall of the fallopian canal is easy to visualize on CT scans against its black radiolucent background. But when pathologic soft tissue abuts the tympanic portion of the canal, it may be difficult to determine whether cholesteatoma has eroded the canal or merely lies adjacent to congenital defect.(18) The problem with partial volume averaging artifact is evident as the fallopian canal can be so thin even in non-pathological ears to appear dehiscence in CT scan. Also visualizing the tympanic portion of the facial canal is difficult when there is an adjacent pathologic soft tissue mass in the meso-tympanum.(24,18) Recurrent chronic suppurative otitis media in postoperative ear: The postoperative radiographic evaluation requires information about; the pathology for which the surgery performed, the type of surgery, the clinical and otoscopic findings that make further CT studies necessary. (3,41) Ideally, whenever the surgeon feels that at the end of surgery there is residual disease, he should secure a postoperative study, which can serves as a baseline for subsequent evaluations.(42) The diagnosis of recurrent cholesteatoma depends on the presence of new bone erosion not detected in the preoperative evaluation, the presence of tissue density mass with well defined borders and an air space between the mass and walls of the tympanic cavity noted, expansion of the mastoidectomy cavity and thinning of its walls. Residual cholesteatoma is considered if the cholesteatoma matrix or sac is retained over exposed dura, lateral sinus, facial nerve or labyrinthine fistula. .(42) The present study showed that 2 patients had localized middle ear tissue density mass with well-defined margin. One of them was diagnosed as recurrent cholesteatoma and the other as residual cholesteatoma sac left 21 around the oval window. The diagnosis of recurrent cholesteatoma depends on the bone erosions in the form of eroded tegmen and anterior epi-tympanic wall, which were not detected in preoperative CT and operative data. This finding is coincides with Gristwood &Venables 1990 (43) who stated that the incidence of recurrent or residual cholesteatoma in patients have undergone mastoidectomy ranges from 5% to 51%. In another study made by Lino et al.,1998(44) the rate of residual / recurrent cholesteatoma after an average of 10 years from the initial surgery (canal wall down) varied from 6% to 38%. The risk factors documented are poor cavity ventilation and associated otitis media with effusion.(44) Tierney et al., 1999(45) revealed that the sensitivity of CT scan in diagnosing residual or recurrent cholesteatoma was 42.9% with a specificity of 48.3% and a predictive value of 28.6%. These results explained by the fact that it is radiologically difficult to differentiate between recurrence, scar tissue or fluid with HRCT scan. Mukherji et al., 1994(46) stated that because of its superior visualization of bone detail, compared with that of MRI, CT commonly used in patient who have had otomastoid surgry or other form of temporal bone surgery. Swartz JD et al.,(47) recommend HRCT scan in cases where there is a high risk of recurrent disease at approximately three-months post-surgery following resolution of acute postoperative changes to establish a baseline for further examination. HRCT of the post mastoidectomy ear provides information about the status of the bony margin of the mastoid bowel and the amount of soft tissue density debris in the middle ear cavity proper. The surgeon must be cautioned in presence of tegmen defects to the possibility of an accompanying meningocele or meningo-encphalocele. It is also worth noting that the surgeon may be unable to elicit from the patient or past medical records the exact type of mastoid surgery performed. HRCT can provide information in this respect, which is often not immediately apparent upon inspection of the cavity. Primary petrous apex cholesteatoma was suggested by the site and expanding nature as well as the extension of the lesion through the petrous pyramid and these findings aided by clinical presentation (facial palsy). HRCT scan could not differentiate between primary petrous apex cholesteatoma and the possible petrous apex granuloma, so MRI is recommended to solve the problem. These findings are matched with results of Valvassori, 1993 (48) who stated that the first sign of primary petrous apex cholesteatoma is often facial paralysis of slow onset followed by sensorineural hearing loss caused by erosion of the labyrinth while the middle ear cavity may be normal. HRCT showed expansile lesion in the apex. Normal anatomical variations: The pre-operative knowledge of normal anatomic variants is very valuable to the otologic surgeon. The important normal anatomical variations include; anteriorly and laterally placed sigmoid sinus which may lies within the mastoid antrum, which would obviously make surgery more complicated particularly if a post auricular approach is planned. A dehiscent jugular fossa may have similar implications, the jugular fossa may be separated by only a thin bony plate from the hypo-tympanum, the jugular vein may extends into the hypo-tympanum and in other cases the jugular bulb may fill the hypotympanum and meso-tympanum. The 22 importance of sinus tympani is exaggerated if it is unusually deep. In cases with thick Korner’s septum the surgeon may believe that the entire antrum has been explored when indeed the more medial aspect has not.(4,20) The large cochlear aqueduct is significant if surgery is planned around the oval window. In these patients there is a higher incidence of cerebrospinal fluid leak (satpes gusher) due to low-lying middle cranial fossa dura. It occurs due to absence of tegmental pneumatization. The dehiscence of horizontal portion of the facial nerve canal can be diagnosed by HRCT. This has obvious implications when surgery is planned in the oval window region.(20) The incidence of normal anatomical variations encountered in this study seen in 19 patients. Dehiscent jugular fossa was the mostly encountered normal variant (9 patients) followed by laterally placed sigmoid sinus (4 patients), high riding jugular bulb (3 patients), and deep sinus tympani (2 patients). A study made by Tomura et al., 1995 (49) in a series of 325 patients, six groups of variants were evaluated on HRCT scan. These include; an incomplete bony covering of a high position jugular bulb (2.4%),severe asymmetry of the jugular foramen (4%),an anteriorly located sigmoid sinus (1.6%),deep sinus tympani (5.9%), large internal auditory canal (2.3%) and large cochlear aqueduct (3%). Virapongse et al., 1986 (50) stated that CT is valuable in the demonstration of Korner’s septum. Because thick septum on CT can be mistaken for the medial mastoid wall during surgery, therefore is helpful in the preoperative surgical planning of the temporal bone and skull base. A high riding jugular bulb projecting into the middle ear is a vascular anomaly, which may present with conductive deafness and tinnitus. In this condition a blue or pink mass is seen arising out of the hypotympanum.(51) The aberrant internal carotid artery passing through the middle ear giving a similar appearance. In undetected cases tympanotomy and biopsy have been associated with severe hemorrhage or even death.(52) Conclusion: HRCT is unique in its ability to display not only the internal bone architecture of middle ear and mastoid but also presence of soft tissue mass; that a negative scan effectively excludes possibility of cholesteatoma. It is also valuable in visualization of hidden areas such as sinus tympani and facial recess beyond otoscopic examination which is important before decision of surgical strategy. HRCT provides the surgeon about possibility of normal anatomic variation that may be present such as overriding jugular bulb; alerting him before start surgery hence avoids intra-operative problems. Early use of HRCT in cases of chronic suppurative otitis media can save hearing and improve morbidity. REFERENCES: (1)Beaumont GD: "Radiology in the management of chronic suppurative otitis media." Australia Radiol (1980); 24:238-245. (2)Paparella MM, Goycoolea MV.; "Clinical problems in otitis media and Innovations in Surgical Otolgy. Ear Clinics International volume II. WILLIAMS & WILKINS Baltimore/ London; (1982), Chapter 15:95-102. (3)Valvassori GE, Buckingham RA, Carter BL, Hanafee WN, Mafee MF (eds.) "Radiology of the temporal bone". In: Head and Neck Imaging. Thieme Medical Publishers Inc, New York, (1988); 1-172. (4)Swartz JD: 23 "Imaging of the temporal bone. A text/Atlas. Thiem Medical Publishers Inc, New York, (1986); 1-172 (5)Swartz JD.; "Cholesteatoma of the middle ear: Diagnosis, etiology and complications." Rad. Clin. North. Am. (1984); 22:1536. (6)Liu DPC and Bergeron RT.; "Contemporary radiolgic imaging in the evaluation of middle ear-attico antral complex cholesteatoma. Otolaryngol. Clin. North Am.(1989); 22:897. (7)Maran AGD.; "Disease of Throat, Nose and Ear" 10th ed, WRIGHT (1988), ch. 3.8: 304-316. (8)Swartz JD, Harnsberger HR: "The middle ear and mastoid." in Imaging of the temporal bone. 3rd edition. Thieme (1998); 47-169. (9)Savic D, Jsovic A, Djeric D.; The value of computed tomography (CT) in the evaluation of the anatomic structures of the attic. J. Laryngol. Otology (1987); 101:1118-1124. (10)Kemppainen HO, Puhakka HJ, Laippala PJ: "Epidemiology and etiology of middle ear cholesteatoma." Acta Otolaryngol, (1999); 119(5): 56872. (11)Banerjee A, Flood LM, Yates P, Clifford K.; "Computed tomography in suppurative ear disease: Does it influence management?." J Laryngol Otol (2003) June; 117(6): 454-8. (12)Veitch D, Brockbank M, Whittet H.; "Aural polyps & cholesteatoma." Clin. Otolaryngol. (1988); 13:395:397. (13)Williams SR, Robinson PJ, Brightwell AP. "Management of the inflammatory aural polyp." J. Laryngol. Otol.(1989); 103:10401042. (14)Gliklich RE, Cunningham MJ & Roland D.; "The cause of aural polyp in children." Arch Otolaryngol.(1993);119:669671. (15)Chakeres DW, Kapila A & La Masters D. "Soft tissue abnormalities of the external auditory canal: Subject review of CT findings." Radiology (1985); 156:105-109. (16)David White presentation: Acquired middle ear cholesteatoma complicated by ossicular erosion and LSSC fistula. Wilford Hall Medical Central Resource, 4/9/1997. (17)Phelps PD, Lloyd GAS.; "Diagnostic imaging of the ear". 2nd edition London Berlin Heidelberg New York 1990. (18)Mafee MF, Levin BC, Applebaum EL, Campos M and James CF.; "Cholesteatoma of the middle ear and mastoid. A comparison of CT scan and operative findings" Otolaryngol. Clin North Am. (1988); 21, No.2: 256-293. (19)David P.C, Thomas R. Bergeron M.; "Contemporary radiologic imaging in the evaluation of middle ear attic-antral complex cholesteatomas." Otolaryngol. Clin. North Am.(1989); 22:897-909. (20)Swartz JD; "High resolution computed tomography of the Middle Ear and Mastoid." Part 1: Normal anatomy including normal variations. Radiology, (1983); 148:449-54. (21)Hasso AN, Vignaud J., De Smedt E. "Normal anatomy of the temporal bone and mastoid. In Newton TH, Hasso AN, Dilon WP (eds): Computed tomography of the head and neck. Raven Press, New York. (1988, a); Chap.4: 1-23. (22)Hasso AN, Vignaud LJ and Bird CR., "Pathology of the temporal bone and mastoid. In Newton TH, Hasso AN, Dillon WP (eds): Computed 24 tomography of the Head and Neck. Rave Press, New York. (1988 b); Chap.5: 1-45. (23)Voorhees R, Johnson D Lufkin R, et al.; "High resolution CT scanning for detection of cholesteatoma and complications in post operative Ear." Laryngoscope, (1983); 93:598-595. (24)Jackler RK., Dillon WP., Schindler RA., "Computed tomography in suppurative ear disease: a correlation of surgical and radiographic findings." Laryngoscope (1984); 94:746-752. (25) Sara T.; "Computerized Tomography: its role in the assessment of ear disease." Radiography today May (1991); 57:22-26. (26)Samuel, J. et al., "Otogenic complications with an intact tympanic membrane," Laryngocope, November, (1995), 1387-1390. (27) Sade`J, Berco E, Buyanover D. et al.; "Ossicular damage in chronic middle ear inflammation." In Sade J (ed). Cholesteatoma and mastoid surgery. Amsterdam, Kugler Publications Co., (1982); 347: 358. (28) Silver AJ, Wazen J, Hilal S, Rutledge JN.; "Complicated Cholesteatoma: CT findings in inner ear complications of middle ear cholesteatomas." Radiology (1987); 164:47-51. (29) Palva T.; “The pathogenesis and treatment of cholesteatoma”. Acta Otolaryngol. (1990); 109: 323330. (30) El-Essawy S, El-Nahas M, ElShewahy H, Ghoniem MR.; "Complicated middle ear cholesteatoma, A CT study." Egyp. J. Radiol.& Nucl. Med., (1992); 23 (1): 161-170. (31) Falcioni M., Taibah A., De Donato G., "Preoperative imaging in chronic otitis surgery." Acta Otorhinolaryngol Ital.)2002) ; 22 (1): 19-27. (32) Chee NWC and Tan TY.; "The Value of Preoperative High Resolution CT Scans in Cholesteatoma Surgery." Singapore Med J, (2001); Vol. 42(4)155-159. (33) O’Donoghue GM, Bates GJ, Anslow P, Rothera MP.; "The predictive value of high resolution computerized tomography in chronic suppurative ear disease." Clinical Otolaryngology, (1987); 12; 89-96. (34) O’Reilly BJ, Wylie I, Thakker C, Butter P, Sathanathan N and Kenyon GS.; "The value of scanning in chronic suppurative otitis media." J. Laryngol & Otology,(1991); 105:990-994. (35) Hassman EP, Goscik E, Shotnicka B.; "Computerized Tomography in preoperative imaging of the middle ear cholesteatoma." Otolaryngol Pol.(2003); 57:243-9. (36) Phelps PD, Wright A.; "Imaging cholesteatoma." Clinical Radiology, (1990); 41:156162. (37) Cook JA, Krishnan S, Fagan PA.; "Hearing result following modified radical versus canal wall up mastoidectomy." Ann Otol. Rhinol Laryngol (1996); 105 (5): 379-83. (38) Busaba NY.; "Clinical presentation and management of labyrinthine fistula caused by chronic otitis media." Ann Otol Rhinol Laryngol (1999); 435439. (39) Menif E, Hemaied E, Baccar A, Kamoun S, Ben Messaoud M, Slim 25 reconstruction, and other cochlear R, Besbes G, Hachicha S. "Preoperative CT and MR evaluation implantation. " of trans-labyrinthine invasive Am. J. Roentog., (1994); 163:1467cholesteatoma." (2000); Tunis / TN. 1471. (40) Walshe P, Walsh R, Brennan P, (47) Swartz JD, Goodman RS, Walsh M.; Russell KB, Ladenheim SE and "The role of computerized tomography Wolfson RJ.; in the preoperative assessment of "High resolution Computed chronic suppurative otitis media." Tomography of the Middle Ear and Clin. Otolaryngol. (2002); 27:95-97. Mastoid. Part III Surgically Altered Anatomy & pathology." (41) Sade J.; "Surgical planning of the treatment of Radiology, August (1983); 148:461cholesteatoma and postoperative 464. follow up." (48) Valvassori GE.; Ann Otol Rhinol Laryngol (2000); 109: "Imaging Studies of the Temporal 372-376. Bone. Head and Neck Surgery". Otolaryngology, edited by Byron J. (42) De la Cruz A, Fayad JN.; "Detection and management of Bailey. J.B. Lippincott Company, childhood cholesteatoma." Philadelphia, (1993). Pediatr. Ann, (1999); Jun; 28(6): 370(49) Tomura N, Sashi R, Kobayasa 3. M, Hirano H, Hashimoto M, (43) Gristwood RE, Venables WN.; Watarai J.; "Factors influencing the probability of Normal variations of the temporal bone residual cholesteatoma." on high-resolution CT: Their incidence Ann Otol Rhinol Laryngol (1990); and clinical significance. (1995). 99:120-123. (50) Virapongse C, Kirchner JC, (44) Lino Y, Imamura Y, Kojima C, Sasaki & Shapiro M.; Takegoshi S, "Risk factors for "Computed tomography of the recurrent and residual cholesteatoma in Korner's septum and petrosquamosal children determined by second stage suture." operation." Arch Otolaryngol. (1986); 112:81-87. Int J Pediatr Otorhinolaryngol (1998); (51) Lloyd TV, Van Aman M and 46-65. Johnson JC. "Aberrant jugular bulb presenting as a middle ear mass." (45) Tierney PA, Pracy P, Blaney Radiology (1979); 131:139-141. SP:; "An assessment of the value of the (52) Pickles JM, Tucker AG, Cowie preoperative computed tomography JW. "Computed tomography of scans prior to otoendoscopic 'second vascular middle ear masses." look' in intact canal wall mastoid J. Laryngol. & Otology( 1986); surgery." 100:405-410. Clin Otolaryngol (1999); Aug; 24(4): 274-6. (46) Mukherji SK, Mancuso AA, Kotzur IM, Slattery WH, Swartz JD, Tart RP and Nall A.; "CT of temporal bone; Findings after mastoidectomy, Ossicular الملخص العربي 26 " دور األشعة المقطعية بالكمبيوتر( عالية التميز) فى تقييم حاالت التهاب األذن الوسطى المزمن المتقيح المصحوب بالورم الزهمي (كوليستياتوما) ومضاعفاته مع مقارنة الدراسة بالجراحة" *-د.عادل محمد سامي -د.يحيي الكاشف** *قسم األشعة التشخيصية**-قسم األنف واألذن والحنجرة مستشفي المنيا الجامعي يعتبر التهاب األذن الوسطى المزمن من األمراض الشائعة فى العالم بشكل عام و فى بالدنا بشكل خاص ما زال يمثل مشكلة لدى الفئة العمرية من 01إلى 01عاما ,حيث يؤدى التهاب األذن الوسطى المزمن مع وجود كوليستياتوما (الو رم الزهمى ) إلى تدمير ملحوظ لعظام األذن الوسطى مما يؤدى إلى فقد ميكانيكية السمع و كذلك التأثير المباشر على األذن الداخلية و العصب السابع و فى بعض الحاالت تكوين خراج داخل المخ. وكان الهدف من هذا البحث تقييم دور األشعة المقطعية بالكمبيوتر( عالية التميز) فى تشخيص وتقييم حاالت التهاب األذن الوسطى المزمن المصاحب بالورم الزهمى "كوليستياتوما" ومتابعة الحاالت بعد العمليات الجراحية لمعرفة التغيرات المصاحبة ومقارنة نتائج األشعة المقطعية مع نتائج العمليات الجراحية. و قد أجريت هذه الدراسة فى الفترة من سبتمبر 1110حتى ديسمبر 1110فى وحدة األشعة المقطعية بالكمبيوتر بمستشفى المنيا الجامعى وقد اشتمل هذا البحث على 01مريض تم اختيارهم من الحاالت المحولة من قسم األنف واألذن والحنجرة بالمستشفى الجامعى تراوحت أعمارهم ما بين عشرة الى خمسة وستين عام , وكان من بين هؤالء خمسة عشرة مريضا من الذكور وسبعة عشرة من اإلناث .وقد تم فحص جميع الحاالت فحصا إكلينيكيا كامال شمل األعراض المصاحبة لحاالت التهاب األذن الوسطى مثل الصديد المزمن ,الفقد الجزئى أو الكلى للسمع التوصيلى ,ارتفاع درجة حرارة المريض مع شعوره بالصداع الشديد المصاحب اللتهاب األذن الوسطى أو أعراض شلل العصب السابع. تم أجراء األشعة المقطعية عالية التميز على العظم الصدغى لجميع الحاالت فى الوضع المحورى والتاجى عن طريق أخذ مقاطع متجاورة سمك المقطع 0ملليمتر باإلضافة الى فحص المخ لبيان المضاعفات المصاحبة, وقد أستخدم وسيط التباين فى بعض الحاالت المصحوبة بالمضاعفات وكذلك فى األورام .وقد أثبتت هذه الدراسة أهمية استخدام الوضعين ,المحورى والتاجى. أكدت هذه الدراسة على النتائج التالية-: لألشعة المقطعية بالكمبيوتر دورا رئيسيا ال غنى عنه فى تشخيص حاالت التهاب األذن الوسطى ومضاعفاته وذلك على أن يتم الفحص فى وضعين مختلفين على األقل (مثل الوضع التاجى والمحورى). معرفة الوصف التشريحى الطبيعى باألشعة المقطعية للعظم الصدغى شامال العظم الصخرى يساعد فى التشخيص الدقيق واالستفادة األكبر من الفحص. فى حاالت التهاب األذن الوسطى المزمن المصحوب بالورم الزهمى "كوليستياتوما" أثبتت األشعة المق طعية أنها الفحص الفريد فى تقييم تلك الحاالت بدقة متناهية وكشف اإلصابة المبكرة وكذلك توضيح وجود الورم الزهمى فى الجزء الخلفى من األذن الوسطى بالفجوات والدهاليز الخلفية بعيدا عن مجال الرؤية بمنظار األذن و كذلك أظهرت األشعة المقطعية مكان اإلصابة بدقة وطريق ومدى انتشارها .وأثبتت هذه الدراسة التناسق الرائع بين تقييم األشعة المقطعية لحاالت الورم الزهمى "كوليستياتوما" قبل أجراء الجراحة والتقييم الجراحى لتلك الحاالت .كما لألشعة المقطعية دورا هاما فى رسم الطريقة المثلى للجراحة المناسبة للمريض و لها أيضا دورا ال غن ى عنه فى تقييم الحاالت بعد إجراء الجراحة لمعرفة التغيرات المصاحبة والكشف عن بقايا أو ارتجاع الورم الزهمى وكذلك المضاعفات المصاحبة للجراحة. استطاعت األشعة المقطعية بالكمبيوتر أن تميز بين الورم الزهمى (الكوليستياتوما) واألورام األخرى التى تصيب العظم الصدغى مثل األورام الدموية التى كانت تلزم أخذ عينة جراحية لمعرفتها مما يعرض المريض لمضاعفات خطيرة مثل النزيف الحاد . و أظهرت األشعة المقطعية بالكمبيوتر االختالفات الطبيعية للعظم الصدغى التى تمثل أهمية قصوى لجراحى األنف واإلذن مما يفيد فى اختيار األسلوب المناسب للمريض وعدم تعرضه لمخاطر تهدد حياته. 27