IMAGING OF THE TEMPORAL BONE
-MAJOR MODALITIES USED INCLUDE CT, MRI, AND ANGIOGRAPHY
-80% OF DISEASES REQUIRE ONLY ONE IMAGING STUDY
PLAIN FILMS    -CAN USE TO CHECK PNEUMATIZATION OF THE MASTOID AND PETROUS APEX
-CAN USE TO CHECK INTEGRITY OF COCHLEAR IMPLANT LEADS
CT SCAN        -DELINEATES INTRATEMPORAL PATHOLOGY WELL ESPECIALLY WITH CHL OR MIXED HL
-DYNAMIC SCANNING CAN HELP DIFFERENTIATE VASCULAR STRUCTURES
MRI        -DELINEATES LESIONS EXTENDING OUT OF THE TEMPORAL BONE OR ORIGINATING AT THE CP ANGLE          OR PETROUS APEX
-DELINEATES CENTRAL AUDITORY AND VESTIBULAR PATHWAYS
-T1 AND T2 IMAGES CAN HELP DIFFERENTIATE DIFFERENT DISEASE PROCESSES THAT AFFECT THE SAME          AREA
ANGIOGRAPHY    -IMPORTANT IN PRE-OP EVALUATION OF VASCULAR TUMORS FOR LOCATION OF FEEDING VESSELS AND          POSSIBLE EMBOLIZATION
ANATOMIC VARIATIONS ARE IMPORTANT TO LOOK FOR ON ALL SCANS
-PNEUMATIZATION OF THE MASTOID OR PETROUS APEX
-LOCATION OF THE TEGMEN
-LOCATION OF THE JUGULAR BULB
-DEHISCENT FACIAL CANAL
PATHOLOGY OF THE MASTOID  – USE CT SCAN
-ACUTE MASTOIDITIS    -FLUID FILLED AIR CELLS WITH DESTRUCTION OF BONY TRABECULAE                      DESTRUCTION, MAY HAVE ASSOCIATED ABSCESSES
-CHRONIC MASTOIDITIS    -THICKENED TRABECULAE AND NONHOMOGENEOUS CLOUDING OF THE AIR CELLS
PATHOLOGY OF EXTERNAL AUDITORY CANAL  – USE CT SCAN
-CONGENITAL        -CAN SHOW COMPLETE AGENESIS, A THIN OBSTRUCTING PLATE, OR STENOSIS OF                   EAC; MAY SHOW MALFORMED AND FUSED OSSICLES; MICROTIA AND                      INAPPROPRIATE ALIGNMENT OF EXTERNAL EAR TO EAC AND ME
-TRAUMA        -POST/SUPERIOR WALL FX LINE ASS. WITH LONGITUDINAL FX
-ANT WALL FX ASS. WITH MANDIBULAR TRAUMA
-COMMINUTED FX SEEN WITH PROJECTILES
-MALIGNANT EXT. OTITIS    -BONY EROSION OF THE EAC USUALLY ALONG THE FLOOR WITH ASSOCIATED SOFT                  TISSUE SWELLING
-EXT. CANAL CHOLESTEATOMA    -OPEN EAC BUT LOCALIZED BONY DESTRUCTION USUALLY NEXT TO                      TYMPANIC MEMBRANE
-KERATOSIS OBTURANS/OBLITERANS    -STENOTIC EAC WITH DEBRIS AND BONY DESTRUCTION MEDIAL TO                      STENOSIS
-CARCINOMA         -SOFT TISSUE SWELLING WITH BONY DESTRUCTION OF VARIABLE EXTENT
PATHOLOGY OF THE MIDDLE EAR AND OSSICULAR CHAIN  – USE CT SCAN
-CONGENITAL    -VARY FROM MINIMAL HYPOPLASIA TO AGENESIS OF ME CLEFT; OSSICLE ARE USUALLY              PRESENT BUT ARE USUALLY FUSED IF NOT SEVERALLY ATRETIC
-TRAUMA    -USUALLY AFFECTED BY THE LONGITUDINAL FX WITH OSSICULAR DISCONTINUITY AND              TEGMEN FX
-ACUTE OM    -HOMOGENOUS FLUID FILLED ME CLEFT AND MASTOID BUT MAY PROGRESS TO TRABECULAR              LOSS AND/OR ABSCESS FORMATION
-CHRONIC OM    -ME SPACE CLOUDED DUE TO THICKENED ME MUCOSA OR GRANULATION TISSUE; OSSICULAR              EROSION OR TYMPANOSCLEROTIC PLAGUES MAY BE PRESENT
-CHOLESTEATOMA-CONGENITAL- WELL DEFINED ME SOFT TISSUE MASS
-ACQUIRED – SOFT TISSUE MASS THAT MAY BE ASS. WITH SCUTAL EROSION AND LATERAL TO              OSSICLES IF ATTIC ORIGIN; SOFT TISSUE MASS MEDIAL TO OSSICLES IF PARS TENSA ORIGIN;              MAY HAVE OSSICULAR EROSION, TEGMEN DEFECT, OR LAT. SCC FISTULA, ISODENSE TO CSF,              NONENHANCING
-TUMORS    -OSTEOMAS, GLOMUS, MALIGNANCY
-OTOSCLEROSIS    -USEFUL FOR PERSISTENT POST-OP COMPLAINTS TO CHECK PROSTHESIS PLACEMENT
PATHOLOGY OF THE INNER EAR  – USE CT SCAN
-CONGENITAL     -MONDINI – LOSS OF COCHLEAR TURNS
-MICHEL – COMPLETE AGENESIS
-TRAUMA    -TRANSVERSE SKULL FX WITH FX LINE THROUGH IAC AND LABYRINTH
-OBLITERATIVE LABYRINTHITIS
PATHOLOGY OF PETROUS APEX  – COMBINATION OF CT AND MRI MAY BE NEEDED
-GLOMUS JUGULARE- CT SHOWS ENLARGED JUGULAR BULB WITH SOFT TISSUE MASS SHOWING WASHOUT; MRI                  SHOWS MEDIUM INTENSITY LESION ON BOTH T1 AND T2 WITH POSSIBLE SIGNAL VOID
-CONGENITAL CHOLESTEATOMA VS CHOLESTEROL GRANULOMAS
-CT SCAN SHOWS BOTH TO BE CYSTIC WITH NO OR FAINT PERIPHERAL ENHANCEMENT
-MRI -CONG. CHOL. – HIGH INTENSITY ON T2 AND LOW INTENSITY T1
-CHOL. GRAN. – HIGH INTENSITY ON BOTH T1 AND T2 IMAGES
-MENINGIOMA    -CT SHOWS HYPEROSTOSIS OF INVOLVED BONE
-MRI SHOWS MENINGEAL EXTENSION ON CONTRASTED T1 IMAGES
-PAGET’S DZ     -CT SCAN SHOWS WASHED OUT APPEARANCE OF PETROUS APEX

PATHOLOGY OF FACIAL NERVE  – USE CT TO EVALUATE CANAL AND MRI TO EVALUATE NERVE
-CONGENITAL    -CT TO LOOK FOR ABNL COURSE OF NERVE
-TRAUMA    -CT TO LOOK FOR DISRUPTION OF CANAL
-BELL’S PALSY    -MRI SHOWS INCREASED INTENSITY OF NERVE ON CONTRASTED T1 IMAGES
-TUMOR        -MRI PRECONTRAST WILL SHOW LOW INTENSITY T1 AND INTERMEDIATE INTENSITY T2 AND              POSTCONTRAST T1 WILL BE HIGH INTENSITY
PATHOLOGY OF CP ANGLE  – USE MRI
-ACOUSTIC     -T1 ISODENSE TO GRAY MATTER AND BRIGHTER THAN CSF; T2 ISODENSE TO CSF AND              BRIGHTER THAN GRAY MATTER; ENHANCES ON T1 CONTRASTED STUDY
-MENINGIOMA