Head and NeckLive data

CT Temporal Bones

High-resolution CT of the temporal bones provides sub-millimetre isotropic imaging of the middle and inner ear structures. Reconstructed with a sharp bone algorithm and multiplanar reformats, it is the primary modality for cholesteatoma, otosclerosis, ossicular pathology, temporal bone trauma and congenital anomalies.

Indications

Suspected acquired cholesteatoma with conductive hearing loss or otorrhoea
Conductive hearing loss for ossicular chain and otosclerosis evaluation
Sensorineural or mixed hearing loss with suspected otic capsule or inner ear anomaly
Temporal bone trauma with suspected fracture, ossicular disruption or CSF leak
Congenital hearing loss and cochlear implant candidacy assessment

Contraindications & Cautions

No absolute contraindication; ionising radiation dose considerations in children
Routine intravenous contrast is not required and generally not administered
MRI is preferred for retrocochlear pathology and residual/recurrent cholesteatoma characterisation

Patient Preparation

No specific patient preparation required
Remove earrings and metallic hair accessories to reduce artefact
Ensure head immobilisation to preserve high spatial resolution
Clarify laterality and specific clinical question before acquisition

Technique & Parameters

Non-contrast helical acquisition with ≤0.6 mm collimation and isotropic voxels
Reconstruction with a high-spatial-frequency (bone/sharp) kernel
Multiplanar reformats in axial and coronal planes at ~0.5-0.6 mm
Oblique Poschl (superior semicircular canal) and Stenvers reformats when indicated
Small field of view centred on each temporal bone for maximal detail

Systematic Review

Assess external auditory canal, tympanic membrane region and scutum
Evaluate ossicular chain (malleus, incus, stapes) integrity and alignment
Inspect the otic capsule, oval and round windows for lucency or fixation
Trace the facial nerve canal (labyrinthine, tympanic, mastoid segments)
Review tegmen tympani, mastoid air cells and semicircular canals

Key Findings & Significance

Cholesteatoma: non-dependent soft tissue in Prussak space with scutum erosion and ossicular destruction
Otosclerosis: lucency at the fissula ante fenestram (fenestral) and pericochlear otospongiosis (retrofenestral)
Ossicular disruption or dislocation, often incudostapedial, following trauma
Temporal bone fracture (otic-capsule sparing versus violating) and tegmen dehiscence
Semicircular canal dehiscence and congenital inner ear malformations (e.g. incomplete partition)

Differential Considerations

Cholesteatoma versus middle ear effusion, granulation tissue or cholesterol granuloma
Otosclerosis versus other causes of otic capsule lucency (e.g. osteogenesis imperfecta, Paget disease)
Glomus tympanicum/jugulare versus other middle ear soft-tissue masses
Traumatic ossicular disruption versus congenital ossicular anomaly
Automastoiditis with coalescence versus neoplastic mastoid involvement

Pearls & Pitfalls

Pars flaccida (attic) cholesteatoma classically erodes the scutum and displaces ossicles medially
A soft-tissue density eroding the lateral semicircular canal or facial nerve canal raises complication risk
Non-echo-planar diffusion-weighted MRI is complementary for detecting residual cholesteatoma
Distinguish otic-capsule-violating from otic-capsule-sparing fractures given prognostic implications

Structured Report

State laterality and correlate with audiometric and otoscopic findings
Describe soft-tissue location, ossicular integrity and bony erosion (scutum, tegmen, canals)
Report otosclerosis site (fenestral versus retrofenestral) when present
For trauma, classify fracture and note ossicular and facial canal involvement
Comment on surgically relevant anatomy (facial nerve course, tegmen dehiscence, sigmoid sinus position)

References

ACR-ASNR-SPR Practice Parameter for the Performance of CT of the Extracranial Head and Neck
Radiographics: Baráth K et al. Neuroradiology of Cholesteatomas
Radiographics: Purohit B et al. Imaging in Otosclerosis
Radiographics: Juliano AF et al. Imaging Review of the Temporal Bone

Educational clinical decision support only. Protocols vary by institution and equipment; always confirm with a qualified radiologist and local guidelines before clinical use.

CT Temporal Bones

📋 Indications

⛔ Contraindications & Cautions

🧑‍⚕️ Patient Preparation

⚙️ Technique & Parameters

🔎 Systematic Review

🩻 Key Findings & Significance

🧠 Differential Considerations

💡 Pearls & Pitfalls

📝 Structured Report

📚 References