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Address reprint requests and correspondence: James Y. Chen, MD, Department of Radiology, San Diego VA Medical Center, 3350 La Jolla Village Dr, MC 114, La Jolla, CA 92161.
Affiliations
Department of Radiology, San Diego VA Medical Center, San Diego, CaliforniaDepartment of Radiology, University of California, San Diego, California
Computed tomography (CT) of the temporal bone is an important diagnostic imaging tool. Good CT acquisition and postprocessing technique are critical for depicting pathology and normal anatomy. In this article, we discuss CT acquisition and reformatting technique, as well as normal anatomy on temporal bone CT.
Computed tomography (CT) of the temporal bone has 2 major acquisition techniques: a dual acquisition, including separate direct coronal and direct axial scans or a single axially acquired volume, with coronal and optionally sagittal reformats from the axial source data. In most patients, a single axially acquired volume from a multidetector row CT (MDCT) scanner reformatted in multiple planes will provide adequate diagnostic information while minimizing radiation dose–related and patient-related motion artifact. There are cases, however, in which both direct coronal as well as axial acquisitions may provide superior diagnostic image quality.
Intravenous contrast may be helpful for specific indications, such as evaluating for complications of otomastoiditis, vascular tumors, and vascular abnormalities, but is not typically necessary for routine evaluation of coalescence or destruction of mastoid air cells or hearing loss.
Multidetector row CT
MDCT scanners with 16, 32, 64, 128, 256, and 320 rows have become increasingly common compared with the early single-slice CT scanners. MDCT, with many scanners acquiring isotropic voxels, allows high-resolution imaging and enables high-quality image reconstruction for displaying in different 2-dimensional (2D) planes than the original acquisition. In addition, these data sets may allow various 3D reconstructions, which may aid comprehension of anatomy in complex cases.
This communication will concentrate on standard CT acquisition parameters and 2D reconstructions; the various 3D reconstruction and volume surface–shaded display techniques are numerous and outside the scope of this communication.
There are radiation considerations in MDCT with 4 or more slices, which include overbeaming and overranging.
Overbeaming is the difference between the area of the imaged body region and the total area irradiated by the scanner beam penumbra. Overranging is related to additional scanner rotations required at the beginning and end of a scan to reconstruct the first and last slices of the imaged body region. Each CT scanner may vary in its manufacturer-specific strategies for addressing radiation dose related to overranging and overbeaming. Please refer to their specific documentation for scanner specific recommendations.
Acquisition technique
There are many possible temporal bone CT acquisition protocols, which can vary by manufacturer, specific scanner, and patient's age with different trade-offs in image quality and total radiation dose. These variations are beyond the scope of this article; however, we do describe our imaging protocol.
We prefer our 64 detector scanner (Lightspeed VCT; GE Medical Systems) for temporal bone imaging. We perform a helical acquisition and routinely use a collimation of 0.6 mm. Our pitch is set to 0.531:1 and rotation time of 0.5. Speed is 21.24 mm/s. Scan field of view is set to head. Kilovolt peak and tube current is adjusted according to both size of head and patient's age to balance image quality and total radiation dose. For neonates to 5-year-old children, our recommended low-dose protocol is 80 kV and 90-110 effective mAs. For children between the ages of 5 and 10 years, our protocol suggests 120 kV and 180 effective mAs. For adolescents, our protocol suggests 120 kV and 330 effective mAs. For adults, our protocol suggests 140 kV and 335 effective mAs. Lower radiation doses are possible, but need to balance diagnostic image quality with greater image noise typical in lower dose images.
On scanners that support iterative reconstruction techniques in addition to standard filtered back-projection, lower effective mAs may be used resulting in lower radiation doses without compromising image quality.
For the axial technique, the patient is placed supine and positioned to minimize radiation to the lens. The scan is then planned for acquisition from the lateral scout topogram from the arcuate eminence through the mastoid tip. To limit distortion of reformatted images, axial CT source images may be obtained with a 0° gantry tilt and scan plane parallel to the inferior orbitomeatal line. For best quality of reformatted images in the coronal or sagittal planes, reconstruction of the raw data with submillimeter overlapping sections should be performed.
For direct coronal imaging, the patient is placed in the prone position and the gantry angled perpendicular to the infraorbital-meatal line. The scan is planned for acquisition from the lateral scout from the level of the posterior temporomandibular joint anterior to the bony portion of the external auditory canal through the entire mastoid air cells.
In patients with implanted metallic hardware within the typical scan planes, it may be possible to improve diagnostic image quality with various techniques. Metal in the scan field can result in severe streak artifact directed in the plane of scanning, which can obscure anatomical areas of interest. By performing both direct coronal and axial acquisitions, each acquisition “throws” the artifact into a different plane, and the 2 acquisitions in total may result in a diagnostic scan. On an MDCT, acquiring an axial volume in an obliquity that avoids the metal and then reformatting into standard planes for imaging review, it may be possible to avoid scanning the metal altogether. There are other techniques to reduce the effect of metallic artifact on the postprocessing or reconstruction side, such as using of iterative reconstruction techniques
when available. To reduce metal artifact on the acquisition side, for temporal bone imaging, collimation and slice thickness are typically already at their minimum, but one can still increase kilovolt peak and increase effective mAs to reduce metal artifact at the expense of additional radiation dose. Another acquisition technique that may reduce metal artifact is acquisition on dual-energy energy scanners with reconstructed virtual monochromatic images,
though dual-energy scanners are still relatively rare in most clinical practices.
All images should be reconstructed in bone algorithm. Separate left and right sides may be reconstructed with a magnified smaller field of view in standard axial and coronal planes. For evaluating for superior semicircular canal dehiscence, additional reformats in the Poschl and Stenver planes may be performed. Some practices also choose to reconstruct an additional set of images using soft-tissue algorithm.
At our institution, we reconstruct each side into 0.625-mm thick axial images and effectively magnify them by using a display field of view of 100 mm. The raw data are then reformatted at the CT console or a separate workstation to create standard axial and coronal reformats.
Standard axial and coronal reformats
To create standard axial reformats that will display the anterior and posterior limbs of the lateral semicircular canal in a single section, the raw data of the scan are loaded into the CT console or a workstation and then displayed in 3 orthogonal planes (axial, coronal, and sagittal). The sagittal images are used to identify an image in which the anterior and posterior limbs of the lateral semicircular canals are displayed in cross-section. The axial dataset created by selecting a plane parallel to the lateral semicircular canal in which a reference slice connects the anterior limb to the posterior limb of the lateral semicircular canal (Figure 1). The coronal reformats are then created by selecting a plane perpendicular to the axial images. At our institution, for these reformats, we generate 0.625-mm thick images at 0.5-mm intervals.
Figure 1Sagittal CT image with axial reformatting plane (lines) parallel to the line created by connecting the anterior and posterior limbs (arrows) of the lateral semicircular canal (LSCC).
The Poschl reformat displays the temporal bone such that the superior semicircular canal can be seen en face (Figure 2A). To create the Poschl reformat, one loads the axial reformats already created into the CT console or workstation. An image demonstrating the apex of the superior semicircular canal is chosen and a plane selected that is parallel to the superior semicircular canal (Figure 2B). Images may be generated at the same 0.625-mm thickness and 0.5-mm intervals as the earlier reformats.
Figure 2(A) Poschl-type CT reformat demonstrating the superior semicircular canal (SSCC) en face (in plane), and well demonstrating an intact bony covering. ow, oval window; ISJ, incudostapedial joint. (B) Axial CT image near the apex of the superior semicircular canal demonstrating the reformatting plane (lines) to create a Poschl-type reformat parallel to the superior semicircular canal (SSCC) on the CT console or a separate workstation. (C) Stenver-type CT reformat demonstrating a cross-section of the superior semicircular canal (SSCC) and its bony covering. Also shown are the internal auditory canal (IAC), cochlea (Coch), vestibule (V), and lateral semicircular canal (LSCC). (D) Axial CT image near the apex of the superior semicircular canal demonstrating the reformatting plane (lines) to create a Poschl-type reformat perpendicular to the superior semicircular canal (SSCC) on the CT console or a separate workstation.
The Stenver reformat displays the temporal bone such that the superior semicircular canal and its roof are displayed in cross-section (Figure 2C) and is orthogonal to the Poschl reformat. To create these reformats, one loads the axial reformats already created into the CT console or workstation. An image demonstrating the apex of the superior semicircular canal is chosen, and a plane is selected that is perpendicular to the superior semicircular canal (Figure 2D). Images may be generated at the same 0.625-mm thickness and 0.5-mm intervals as the earlier reformats.
Temporal bone anatomy
The temporal bone is an area of complex anatomy with multiple important structures in close proximity. These include vascular structures, such as the internal carotid and middle meningeal arteries; jugular bulb and sigmoid sinus; fifth, sixth, seventh, and eighth cranial nerves and branches, as well as inner ear structures. Each structure may be affected by various specific pathologies, therefore, it is critical to understand temporal bone anatomy for both appropriate differential diagnosis and for surgical planning. This introduction to temporal bone anatomy concentrates on structures visible on temporal bone CT and draws on several sources; for more detailed description of the anatomy and embryology, please refer to any of the cited references.
For this article, sequential axial, coronal, CT, and sagittal images (Figure 3, Figure 4, Figure 5) are grouped together at the end to demonstrate anatomy in contiguous sections for ease of spatial understanding.
Figure 3Axial CT images from superior to inferior. (A) SSCC, superior semicircular canal; (B) VII tymp, tympanic segment of CN VII; VII lab, labyrinthine segment of CN VII; PSCC, posterior semicircular canal; and SSCC, superior semicircular canal; (C) MH, malleus head; MIJ, malleoincudal joint; LSCC, lateral semicircular canal; and Inc, incus; (D) AER, anterior epitympanic recess; VII tymp, tympanic segment of CN VII; Coch, cochlea; V, vestibule, CC, common crus; PSCC, posterior semicircular canal; LSCC, lateral semicircular canal; AD, aditus ad antrum; Inc, incus; and MH, malleus head; (E) Mall, malleus; Inc long p, incus long process; Coch, cochlea; V, vestibule; PSCC; posterior semicircular canal; LSCC, lateral semicircular canal; and Inc short p, incus short process; (F) Mall handl, malleolar handle; Coch, cochlea; V, vestibule; PSCC, posterior semicircular canal; Vestib aqu, vestibular aqueduct; and Inc lent p, incus lenticular process; and (G) Coch prom, cochlear promontory; Coch bt, cochlea basal turn; Tymp recess, tympanic recess; Pyram Em, pyramidal eminence, and Inc long p, incus long process.
There are 5 osseous major parts of the temporal bones: the squamous, mastoid, petrous, tympanic, and styloid process.
The squamous portion is thin, laterally convex and forms the anterior and upper bone, forming the lateral wall of the middle cranial fossa. It underlies and provides attachment of the temporalis muscle along its convex surface. Along the inner concave surface are grooves along which meningeal arteries run. Within the largest groove runs the middle meningeal artery, a branch of the external carotid artery. The petrosquamous suture, which contains Körner septum, separates the squamous temporal bone from the petrous temporal bone. It runs from the glenoid fossa toward the mastoid tip inferior and lateral to the facial nerve canal.
The mastoid portion contains the mastoid air cells and has an inferior conical projection, the mastoid process, in adults. The mastoid process provides an attachment for the sternocleidomastoid, splenius capitis, and longissimus capitis muscles. The mastoid air cells communicate through the middle ear via the eustachian tube with the nasopharynx. Laterally, the mastoid bone borders the parietal and occipital bones.
The petrous temporal bone forms the majority of the internal temporal bone, extending to the petrous apex along the clivus at the petro-occipital fissure. It contains the inner ear structures, most major nerve and vascular structures, and compartments including the internal auditory canal, carotid canal, and jugular fossa.
The tympanic bone forms the osseous external auditory canal and middle ear. The petrotympanic fissure separates it from the petrous bone anteriorly and internally. From anteriorly and externally, it is separated from the squamous portion by the tympanosquamous suture.
The styloid process is a downward and forward osseous projection just anterior to the stylomastoid foramen.
External auditory canal
The external auditory canal is formed of fibrocartilage laterally and of bone medially with a slight S shape. The osseous portion provides a tunnel through the temporal bone with the rostral border formed by the posterior border of the glenoid fossa. The posterior border is formed by the mastoids. The fibrocartilaginous and osseous segments are lined by a contiguous layer of skin. The medial border is separated from the middle ear cavity by the tympanic membrane.
The tympanic membrane is a thin, transparent membrane with a downward and inward slope. It is composed of the higher, smaller, and thicker pars flaccida and larger and more fibrous pars tensa. Against its transparent membrane, the attachment of the manubrium and short process of the malleus can be seen.
Arterial vasculature is provided by branches of the external carotid artery. This includes the posterior auricular, superficial temporal, and internal maxillary arteries. Venous drainage is primarily into the internal and external jugular veins. There may also be venous drainage through mastoid emissary veins into the sigmoid sinus.
Lymphatic drainage is into all regional nodes, including retroauricular, parotid, and superficial cervical.
Cutaneous innervation is complex and variable because of the complex embryology. There is innervation from the auriculotemporal branch of the mandibular division of the trigeminal nerve and from the greater auricular nerve, from the C2 and C3. There are also additional sensory contributions from the 7th, 9th, and 10th cranial nerves.
Middle ear
The middle ear is an irregular cavity within the petrous portion of the temporal bone. Laterally, it is bounded by the tympanic membrane. Medially, it is bounded by the inner ear. Superiorly it is bounded by the tegmen tympani. Inferiorly, it is bounded by the floor of the hypotympanum. It contains the ossicles, which transmit and amplify vibrations from the tympanic membrane across the normally air-filled chambers to the inner ear. The middle ear is aerated via the eustachian tube, which communicates with the nasopharynx. The tympanic cavity is further divided into 5 parts: 3 in the coronal plane and 3 in the axial plane with 1 overlapping in both planes, accounting for the numeric discrepancy. In the coronal plane, from superior to inferior are the epitympanum, mesotympanum, and hypotympanum. In the axial plane, the middle ear is divided from anterior to posterior into the protympanum, mesotympanum, and posterior tympanum.
The epitympanum
The epitympanum, which is also known as the attic or the epitympanic recess, is superior to the level of the tympanic membrane and communicates with the mastoid air cells via the posterior and superior aditus ad antrum. The anterior wall is formed by the tympanosquamous suture, and the posterior wall is formed by the tympanomastoid suture. The superior wall, which separates the middle ear cavity from the middle cranial fossa, is the tegmen tympani, a thin, bony plate from the petrous bone. The medial wall is formed by the lateral wall of the lateral semicircular canal and the facial nerve canal. The lateral inferior wall of the epitympanum immediately above the tympanic membrane is a medially pointed bony spur, the scutum. Between the scutum and the malleus is the superior recess, Prussak space. Portions of the ossicles that lie within the epitympanum are the head of the malleus as well as the body and short process of the incus.
The hypotympanum
The hypotympanum, which lies below the tympanic membrane, varies in size owing to variations in positioning of the floor of the middle ear. The floor of the middle ear is composed of a platelike bone, the jugular wall, which separates it from the jugular fossa. The thickness of the floor is inversely proportional to the size of the jugular bulb. A high-riding jugular bulb or a dehiscent floor may result in an upward convex floor, reducing the size of the hypotympanum.
The mesotympanum
Between the epitympanum and hypotympanum lies the mesotympanum, the proper tympanic cavity. The cavity is aerated by the eustachian tube, which has an osseous portion and a cartilaginous portion. The bony portion begins along the wall of the carotid canal and angles anteriorly, caudally, and medially to the junction of the squamous and petrous temporal bones. From there, the cartilaginous portion follows a groove between the petrous temporal bone and sphenoid greater wing to the nasopharyngeal opening.
The cavity contains the following multiple structures.
The ossicles and connecting ligaments and muscles
The ossicles transmit and amplify sound vibrations from the tympanic membrane to the oval window.
The malleus has a handle or manubrium, a neck, a head, a lateral process, and an anterior process. The manubrium or handle of the malleus and the lateral process attach to the tympanic membrane via the umbo. The neck projects anteriorly and provides attachment to the tensor tympani muscle and ligaments to the mesotympanum. The head of the malleus articulates via the articular facet with the body of the incus within the epitympanum.
The incus has a body, a short process, and a long process. It articulates with the malleus via its articular facet. The body of the incus is attached to the tegmen tympani via the superior ligament. The short process projects posteriorly in the fossa incudis of the posterior wall and is attached by the posterior incudal ligament. The long process projects inferiorly into the mesotympanum similar in orientation to the malleolar manubrium before it becomes the lenticular process beyond its medial bend. The lenticular process then articulates with the stapes.
The stapes had a head or capitellum, an anterior crus, a posterior crus, and a footplate. The capitellum articulates with the lenticular process of the incus and is the tendon insertion of the stapedius muscle. The stapedius muscle is innervated by the facial nerve and serves to attenuate sound by decreasing the ability of the stapes to vibrate and transmit sound. The anterior and posterior crus of the stapes project medially to hold the footplate, which covers the oval window and is held in place by the annular ligament.
The posterior wall (posterior tympanum or retrotympanum)
The posterior or mastoid wall of middle ear lies posterior to the bony tympanic annulus and includes the aditus ad antrum, pyramidal eminence, facial recess, tympanic recess, and incudal fossa. The aditus ad antrum is an aperture that communicates between the epitympanic recess to the mastoid antrum. The pyramidal eminence lies in front of the vertical segment of the facial nerve canal and behind the oval window. Within its hollow central structure is the stapedius muscle, whose tendon exits through the summit of the pyramidal structure. The stapedius muscle is innervated from a branch of the facial nerve, arising from the mastoid segment.
The pyramidal eminence serves as a boundary between 2 important recesses of the posterior wall, which may harbor otoscopically and surgically occult disease that should be readily demonstrated on CT scans. These 2 recesses are the tympanic recess medially and the facial nerve recess laterally. Preoperative scrutiny of these recesses is necessary for surgical planning, as they may require a different (retrofacial) surgical approach or else they may potentially harbor residual and recurrent mass lesions. The tympanic recess is bounded by the labyrinthine wall laterally and the pyramidal eminence medially, whereas the facial nerve recess is bounded by the pyramidal eminence medially and the bony tympanic annulus laterally.
The aperture for the chorda tympani nerve lies just lateral and usually inferior to the aperture of the stapedius tendon. It leaves the mastoid segment of the facial nerve in the lower portion of the facial canal and then turns superiorly to travel through the canaliculus of the chorda. Then it enters the middle ear cavity, coursing lateral to the long process of the incus, medial to the manubrium before exiting the middle ear cavity.
The anterior wall (protympanum)
The protympanum contains the tympanic orifice of the bony eustachian tube at its floor.
The roof
The tegmen tympani separates the middle ear cavity from the middle cranial fossa and forms the roof for the tensor tympani muscle and the mastoid antrum. Its inferior surface is lined by mucosa and superior surface is lined by dura. Defects in the tegmen tympani can thus result in direct communication of infection or cerebrospinal fluid.
The facial nerve
The facial nerve takes a long and complex course through the temporal bone. After the cisternal segment of the facial nerve courses along the anterior superior quadrant of the internal auditory canal, bounded by Bill’s bar vertically but inferiorly and transversely by the crista falciformis, it exits the apex of the internal auditory canal through the facial or fallopian canal; this segment of the nerve is termed the labyrinthine segment and courses anteriorly and laterally to reach the geniculate ganglion. At the geniculate ganglion, after giving off the greater superficial petrosal nerve anteriorly, the facial nerve makes it anterior genu and then courses posteriorly and laterally along the undersurface of the lateral semicircular canal as the tympanic or horizontal segment. From here, the facial nerve then makes its posterior genu for its mastoid or descending segment to take an inferior vertical course through the mastoid before exiting at the stylomastoid foramen.
Along its course, the facial nerve gives off innervation to the stapedius muscle along its proximal vertical segment behind the pyramidal eminence and the chorda tympani nerve along the distal mastoid segment just proximal to the stylomastoid foramen. The chorda tympani conducts taste sensations for the anterior two-thirds of the tongue.
Inner ear
The inner ear is composed of a bony labyrinth, a membranous labyrinth, as well as perilymphatic spaces. It functions in audition and in balance.
Bony labyrinth
The bony labyrinth consists of the cochlea, vestibule, and semicircular canals.
Vestibular sense organs of the bony labyrinth
The vestibule is an ovoid perilymphatic space that communicates with the cochlea anteriorly and with the semicircular canals posteriorly. There are 2 openings usually visible with current imaging, the oval window that abuts the footplate of the stapes and the vestibular aqueduct. There are smaller openings for nerve branches from the vestibular nerve on the medial walls and floor. The medial wall contains 2 recesses, the elliptical recess posteriorly and superiorly and the spherical recess anteriorly and inferiorly separated by the vestibular crest. The vestibular crest divides posteriorly to bind the cochlear recess that leads to the cochlea.
Combined, the utricle, saccule, and semicircular canals, function in the maintenance of balance and a stable retinal image. Vestibular sensory hair cells are contained with the maculae of the utricle and saccule and in the ampullae of the semicircular canals. The hair cells are accompanied by supporting cells in the epithelium. The cilia of the hair cells can be stimulated by otoliths, which may move from changes in head positioning. Linear acceleration is detected within the macula of the utricle. Angular acceleration is detected in the ampullae of the semicircular canals, the kinetic labyrinth.
The utricle lies within the elliptical recess and receives the semicircular membranous ducts. The endolymphatic duct is connected via the utricular duct. The saccule and utricle communicate through the utriculosaccular duct.
The saccule lies within the spherical recess. It communicates via the saccular duct with the sinus of the endolymphatic duct.
The semicircular canals are perilymphatic canals that communicate with the vestibule. Posteriorly the superior and posterior semicircular canals join at their common crus. Anteriorly each canal has an enlargement, the ampulla.
The lateral semicircular canal is approximately 30° off the horizontal plane, with the anterior limb higher than the posterior limb. The posterior and superior semicircular canals have a vertical orientation and are approximately 90° from each other; the superior semicircular canal is approximately 45° lateral off the sagittal plane and the posterior semicircular canal is approximately 45° posterior from the coronal plane. Overlying the superior semicircular canal is a bony ridge, the arcuate eminence, that serves as an anatomical landmark in infratemporal approach surgery.
The superior and lateral semicircular canals are innervated by the superior vestibular nerve, whereas the posterior semicircular canal is innervated by the inferior vestibular nerve.
Auditory organ of the bony labyrinth
The cochlea is a conical perilymphatic cavity coiled around a central core of the modiolus. It is oriented anteriorly and posteriorly, slightly laterally and downward with the base facing posteriorly. Cochlea takes approximately 2.5 turns from base to apex with each turn separated by the interscalar septum. The lateral bony covering basal turn of the cochlea forms a portion of the medial wall of the tympanic cavity, the cochlear promontory. The spiral lamina emanates from the modiolus across the canal to the outer cochlear wall attaching at the spiral ligament. The spiral lamina encloses the scala media or cochlear duct, containing the organ of Corti and separates the duct from the scala vestibuli and the scala tympani. The scala media is separated from the scala vestibuli by the Reissner vestibular membrane and is separated from the scala tympani by the basilar membrane. The scala vestibule and scala tympani communicate at the apex of the cochlea through the helicotrema. At the base of the modiolus of the cochlea is an aperture for the eighth cranial nerve.
The endolymphatic labyrinth and the perilymphatic labyrinth are contained within the 3 parallel spiral chambers of the scala vestibuli, scala tympani, and scala media. The scala vestibuli and scala tympani contain perilymph, whereas the scala media contains endolymph. The organ of Corti is within the cochlear duct on the basilar membrane.
Sound is transmitted through the ossicles to the oval window of the vestibule by the stapes. From the oval window, the pressure of the induced fluid waves is transmitted through the medial wall of the vestibule through the cochlear recess, which is in direct communication with the scala vestibuli. These perilymphatic fluid waves propagate through the helicotrema to the scala tympani and are dissipated through a flexible membrane at the round window. These fluid waves are also transmitted through the Reissner vestibular membrane to the endolymph of the scala media, resulting in displacement of the basilar membrane and stimulating the organ of Corti.
Vestibular aqueduct and endolymphatic duct system
The vestibular aqueduct is an osseous channel along the posterior petrous surface, originating from the vestibule near the common crus, posteriorly and superiorly. In the adult, it is typically no wider than 1.5 mm.
The endolymphatic duct system is comprised of the endolymphatic duct and sac, which are housed in the vestibular aqueduct. It contains endolymph and is surrounded by perilymph, as well as connective tissue and periosteum. The endolymphatic duct arises from the junction of the utricular and saccular ducts and courses within the vestibular aqueduct to exit along the posterior surface of the petrous bone. The endolymphatic duct terminates as the endolymphatic sac. The sac has both intraosseous and intradural portions.
Conclusion
Temporal bone anatomy is complex, consisting of numerous small, important and anatomically close structures. CT of the temporal bone provides an important diagnostic tool in evaluating bony temporal bone pathologies. Good CT acquisition and reformatting techniques can aid in depicting normal and abnormal anatomy for diagnosis and treatment planning.
References
Reisser C.
Schubert O.
Forsting M.
et al.
Anatomy of the temporal bone: detailed three-dimensional display based on image data from high-resolution helical CT: A preliminary report.
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