# Introduction he Mastoid air cells are open spaces containing air that are located throughout the mastoid bone, the prominent bone located behind the ear that projects from the temporal bone of the skull. The air cells are connected to a cavity in the upper part of the bone, which is in turn connected to the middle ear. Mastoid air cells considered to be an important contributor to the physiology of middle ear function. the mastoid air cell system served as an reservoir of air and serves as buffer system to replace air in the middle ear cavity temporarily in case of Eustachian tube dysfunction. The mean volume of air in the mastoid air cell system could be about 5-8 ml. CT scan evaluation of temporal bone is considered to be the best modality to assess mastoid air cell system (1). problem) and then subsequently involve the mastoid air cells -since they are anatomically connected. Severe cases of the disease may lead to meningitis, which is an infection of the membranes surrounding the brain. Mastoid air cell disease is often diagnosed these days by CT scanning -which shows opacification (e.g. fluid accumulation) in the air cells. (1) A computerized tomography (CT) scan of the mastoid process reveals the air cells as small, dark spaces separated by lighter areas of dense bone cells. Inflamed or infected cells will appear as gray or white areas on the scan where the darkened spaces would be expected to be located. When these abnormal looking cells are present, they are called mastoid cell opacification (2). Helical CT has become the method of choice for many routine and new clinical applications. It provides good image quality for body imaging applications at table advancement per rotation of 1 to 2 times the x-ray beam collimation (3&4). Using 3D, multiplanar reformation ~MPR! Or maximum intensity projection ~MIP! Techniques would be benefited by improved volume coverage speed performance (3&4). Recent advances in 32, 64 and now 128-slice CT scanners allow the acquisition of high-resolution, volumetric data that allows image reconstruction in any plane. The advent of high-resolution CT scanning in the 1980s has revolutionized diagnostic imaging of the temporal bone. CT scanning offers the greatest structural definition of any currently available imaging modality (5&6). Temporal bone is a complex structure which contains organs for hearing and balance. Large vessels and nerves pass through temporal bone. Because of its complex anatomic structure and functional properties temporal bone is one of the most challenging organs for radiologists to detect diagnostic findings. It is obligatory to have a good knowledge of its anatomy and functions in order to accomplish optimal radiological evaluation (7). CT is a standard examination technique in diagnosing and treatment of temporal bone diseases (7&8) Slices in different planes can be obtained by CT and it is possible to understand the complex relationship of ana¬tomical structures. Its capability of obtaining slices less than 1 mm and the development of specific examination techniques for restricted density regions increased the imaging rate of detailed examinations. With the advent of multislice CT after gaining axial 3D volumetric scan¬ning coronal and sagittal reformatted slices can be ob¬tained. By this technique total radiation dose can be decreased using 0.5 mm slice thickness. A CT with a sub-milimetric spatial resolution, slice thickness of 2 mm or less, wide window settings, bony detail reconstruction algorithm, having target reconstruction and high quality image reformatting programs is very efficient in evalua¬tion of inflammatory middle ear pathologies (9 &10). The most important advantage of spiral CT in temporal bone imaging is its perfect visualization of the contrast between bony structures and the air in the middle ear. In addition to detailed evaluation of the bony structures it also permits assessment of soft tissue components as well. (8 &11). This study aimed to study the mastoid air cells diseases and their complications using spiral CT, it was conducted in Alfaisal Specialized hospital and Ibn Elhaitham Diagnostic center. II. # Materials & Methods were therefore obtained with the neck flexed such that the infra-orbito-meatal line was parallel to the scanning plane when obtaining images in the axial plane. A zero degree gantry tilt when obtaining such images ensured no distortion of the post-processed 3D images. Volumerendered 3D images were generated from the original 2D data with different soft tissue and bone All post-processed images, axial scans and coronal MPR were studied by senior technologist and diagnosed by radiologist. # ii. Data Analysis The data were collected by using questionnaire and medical reports and were analyzed by using statistical package of social science (SPSS). III. # Results This study carried out in 100 patients their ages between (15 to 70) years old, whom suspected of mastoid air cells pathologies using 4 MDSCT (Toshiba medical system), the study was done according to gender, clinical diagnosis, side of lesion, signs & symptoms, anatomical variations and CT diagnosis and the results obtained as following. were then reconstructed at 2 mm intervals. All studies a) Materials i. Machine Toshiba (4 multi slice detector) Spiral CT scanner which is not different in external appearance from conventional CT scanner However, there are significant differences in several major equipment components # Discussion This study was performed in 100 patients (58 female & 42 male) their ages between (15 -70 years) whom suspected of mastoid air cells pathologies and they were referred to CT department centers for CT scan of the temporal bones using 4 MDSCT (Toshiba Medical System) and the results as the following: The gender distribution was 58 female & 42% male as explained in figure (4.1). 41% of them were diagnosed clinically as having CSOM (figure 4.2) while by CT 28% of them were diagnosed of having chronic mastoiditis & CSOM , 8% were diagnosed of having CSOM, 2% having chronic mastoiditis and 2% having cholesteatoma &CSOM as shown in table(4.1) & figure (4.14). 44 % of patients were diagnosed clinically as having chronic infection (figure 4.2), while by CT, 19% of them were diagnosed as having chronic mastoiditis &CSOM, 14% as having chronic mastoiditis,7% as having cholesteatoma & CSOM and 4% as normal. 10% of patients were diagnosed clinically as having chronic mastoiditis, while by CT they were diagnosed as follows; 6 % of them having chronic mastoiditis & CSOM and 4% of them having chronic mastoiditis, figure (4.14). 5% of patients were diagnosed clinically as having cholesteatoma (figure 4.2), also by CT they were diagnosed as having cholesteatoma (figure 4 This study also relative to (Keskin 2011) who detect 35 patients of scutum erosion by helical CT, 28 patients of them were confirm by surgery. The tegmen timpani erosion were detected in only 2% of patients as shown in table (4.9) & fig (4.22). Also this result was compared with (Keskin2011), there were no tegmen erosion in surgery among 11 patients whom diagnosed as having tegmen erosion by CT, but no tegmen erosion detected by surgery or CT among 44 patients. Inner ear and external ear structures changes were very low (2% of patients & 6% of patients) respectively, table (4.10) & (4.11) figure (4.23 & 4.24). These results indicate that the middle ear structures were affected more than the inner and external ear structures, thus there was correlation between middle ear diseases and mastoid air cells diseases. V. # Conclusions Spiral CT is an effective imaging modality in studying mastoid air cells diseases and their complications. The diseases of mastoiditis with CSOM had higher frequency and also their complications (ossicular erosion, scutum erosion, and loss of hearing). There was correlation between mastoid air cells diseases and middle ear diseases, and with the help of spiral CT it is possible to acquire multiple slices and understand the complex relationships of anatomic structures. CT with a spatial resolution below 1 mm, ? 2 mm slice thickness, wide window, having bone -detail reconstruction program, target reconstruction and high quality image reconstruction programs is very efficient in studing of mastoid air cells and middle ear pathologies. Using 3D, multi-planar reformation ~MPR! Techniques would be benefited to detect and diagnosed the complications of mastoid air cells diseases. The advent of high-resolution CT scanning has revolutionized diagnostic imaging of the temporal bone. Spiral CT scanning offers the greatest structural definition of any currently available imaging modality. 4![Figure (4.1) : Shows gender distribution](image-2.png "Figure ( 4") 46494![Figure (4.3) : Shows signs &symptoms frequency](image-3.png "Figure ( 4 . 6 )FFigure ( 4 . 9 )Figure ( 4") 4444![Figure (4.15) : Shows CT diagnosis & signs and symptoms cross tabulationTable (4.3) : Demonstrates CT diagnosis * Side of lesion Cross tabulation CT diagnosis Side of lesion Total Bilateral Rt side Lt side Chronic mastodities 10 3 7 20 CSOM 4 5 1 10 Chronic mastoditis & CSOM](image-4.png "Figure ( 4 Figure ( 4 .Figure ( 4 .Figure ( 4 .") 4![Figure (4.21) : Shows CT diagnosis & scutum changes Cross tabulation](image-5.png "FFigure ( 4 .") 4![Figure (4.24) : Shows CT diagnosis &external ear structure changes Cross tabulation](image-6.png "Figure ( 4 .F") (External ear structure changesNormal Unremarkable6%94%0 10 20 30 40 50 60 Figure (4.14) : Shows CT diagnosis & clinical diagnosis Cross tabulations 53 20 10 6 2 4 5 Frequency Table (4.2) : Demonstrates CT diagnosis * signs & symptoms Cross tabulationCT diagnosis Chronic mastoditiesChronic Ear pain & mastodities swelling 4CSOM Ear pin & Chronic mastoiditis & ? Signs & amp; symptoms Cholesteatoma Chronic CSOM & chlesteatoma discharge Ear discharge Eear Normal discharge & swelling mastoidites & ? 5 7 2Ear pain & loss of hearing 2Total 20CSOM22CT diagnosis 32110Chronic mastoditis8131751053&CSOMCholestetoma100056cholesteatoma Chronic mastoidites &4.1) : Demonstrates CT diagnosis * Clinical diagnosis Cross tabulation 0 0 0 0 22CSOM & cholesteatoma100034NormalCT diagnosis Total0 16CSOMClinical diagnosis 0 Chronic Infection 5 Cholesteatoma 0 25 27 90 mastoiditis Chronic 23Total5 100Chronic mastodities214020CSOM82010Chronic mastoditis& CSOM2819053Cholesteatoma0246Chronic mastoidites &1102cholesteatomaCSOM & chlesteatoma1214Normal1405Total4144510100 (Table (4.7) : Demonstrates CT diagnosis * Ossicular changes Cross tabulationCT diagnosisOssicular changes Normal ErosionChronic mastodities18220CSOM046mastoid air cells Abcent 10Chronic mastodities Chronicmastoiditis &CSOM CSOM Chronic mastoiditis & CSOM Cholesteatoma Cholesteatoma Chronic mastoidites & cholesteatoma CSOM & cholesteatoma Normal TotalChronic mastoidites &cholesteatoma40 2 0 2 5 CSOM & cholesteatoma 71Normal13 4 2 2 0 29pnematization mastoid air cells Decreased pnematization mastoid air cells Normal 53 6 2 4 5 100CT diagnosis4.6) : Demonstrates CT diagnosis & middle ear cavity changes cross tabulationCT diagnosisMiddle ear cavity changes Obacified NormalTotalChronic mastodities51520CSOM9110Chronic mastoiditis&CSOM53053Cholesteatoma606Chronic mastoidites &112cholesteatomaCSOM & cholesteatoma404Normal055Total78221000 10 60 Figure (4.20) : Shows CT diagnosis & ossicular changes Cross tabulation 50 40 30 20 Table (4.8) : Demonstrates CT diagnosis * scutum changes Cross tabulationChronic mastodities CT diagnosis Chronic sup otitis Chronic mastodities COM Chronic mastoiditis &CSOM media Cholesteatoma cholesteatoma Chronic mastoidites &Chronicmastoiditis&CSOMCholesteatoma Normal Chronic mastoidites & 19 10 50 0 0cholesteatomaNormal Scutum changes middle ear cavity Obacified middle ear cavity Normal Total Partial erosion Total erosion 0 1 20 0 0 10 2 1 53 3 3 6 CSOM & chlesteatoma 2 0 2CSOM & chlesteatoma Normal0 CT diagnosis 51 03 04 5Total8488100Figure (4.19) : Shows CT diagnosis & middle ear cavity changes Cross tabulation The ossicular changes were detected in 29% ofpatients, 14% of them with partial erosion, while 15% ofthem with total erosion as shown in figure (4.8).21 patients of them were diagnosed by CT as having013chronic mastoiditis & CSOM while 8patients of them were diagnosed as having cholesteatoma. (Table 4.7 & fig 4.20).2 Yearstudy of (in diagnosing mastoid air cells diseases. The signs & symptoms was; 77% of patients were having ear pain, discharge & swelling (figure4.3), all of them were diagnosed by CT as having chronic mastoiditis & CSOM, 23% of patients were having ear pain & loss ofVolume XIII Issue III Version Ihearing, most of them (13patients) were diagnosed as having chronic mastoditis &CSOM and the others (10( D D D D ) Fpatients) were diagnosed as having cholesteatoma(table 4.2 & fig 4.15).The side of lesions in 49% of patients wasbilateral (fig 4.4), most of them were diagnosed by CTas chronic mastoiditis & CSOM (table 4.3&fig 4.15), 26%of them at the right side and 25% at the left one.The pathological changes on the mastoid bonewas explained as 13patients with mastoid bonesclerosis (fig 4.5) all of them were diagnosed by CT ashaving chronic mastoiditis & CSOM , 6 patients withmastoid bone erosion 4 of them were diagnosed by CTas having cholesteatoma & 81 patients with normalmastoid bones ,as shown in table (4.4 & fig 4.17).The mastoid air cells changes as follows; 61%of patients were absent pnematization (figure 4.6), 53patients of them were diagnosed by CT as havingchronic mastoiditis & CSOM while 8 patients werediagnosed as having cholesteatoma, 32% of patientswith decreased pnemataization, 29 patients of themwere diagnosed by CT as having chronic mastoiditis &CSOM while 3 patients were diagnosed as havingcholesteatoma and 7 patients with normal pnematizationas shown in table (4.5 & figer 4.18)). This result indicatethat the helical CT had effective role in diagnosing© 2013 Global Journals Inc. (US) © 2013 Global Journals Inc. (US) ( ) ( ) F Study of Mastoid Air Cells Diseases using Spiral CT ( ) * The Nature and vicissitudes of the Accessory Air Spaces of the Middle Ear ATumarkin J the Nature and Significance of Tumarkin A 71 1957 * Otitis and Size of the MDiamant Air Cell System. ActaRadiol (Stockh) 21 1940 * Spiral CT: Decreased Spatial Resolution In vivo due to Broadening of Section-Sensitivity Profile Brink Radiology 185 1992 * Helical CT: Principles and Technical Considerations Brink 1994 14 * Temporal Bone Anatomy: Correlation of Multiplanar Reconstruction Sections and three-dimensional Computed Tomography images NFujii Jpn J Radiol 28 9 2010 * Comparison of 128-Section Single-Shot Technique with Conventional Spiral Multisection CT for Imaging of the Temporal Bone SASchwab 2011 * High Resolution Computed Tomography of the Temporal Bone CVirapogse 1983 4 * High Resolution Computed Tomography of the Middle Ear and Mastoid JDSwartz Radiology 148 1982 * Computed Tomography of the Petrous Bone in Otosclerosis and Meniere's disease JAM 8 1 2011 * HAkan 2008 * MN Medical-Nobel 2 104 * Computed Tomography of the Middle Ear in the Evaluation of Cholesteatomas and other Soft Tissue Masses: Comparison with pluridirectional tomography MFMafee Radiology 148 1983