RadteraCT Orbits (With and Without Contrast)
CT+ ContrastHead & Neck
Indications
- Orbital trauma — fracture, foreign body, globe injury (non-contrast)
- Suspected orbital cellulitis/abscess, subperiosteal abscess (with contrast)
- Orbital or optic nerve sheath mass, thyroid eye disease (Graves orbitopathy)
- Proptosis, vision loss, painful ophthalmoplegia evaluation
- Metallic foreign body screening prior to MRI
Patient prep
- For contrast study: screen eGFR, IV access, document allergy/premedicate if needed
- Remove glasses, earrings, metallic objects
- Supine head-first; instruct patient to keep eyes still / fixed gaze to reduce motion
- Non-contrast for trauma/foreign body; contrast for infection/mass
Contrast
Agentiodinated (e.g. iohexol 350 or iopamidol 370)
RouteIV
Dose≈70-100 mL at 2-3 mL/s
Timing~60-70 s soft-tissue phase; omit contrast entirely for pure trauma/foreign body
Technique
- Supine, head first; thin-section helical volume from orbital roof through orbital floor (frontal sinus to maxillary sinus)
- Dedicated small field of view over orbits; 120 kV, mAs per scanner with AEC
- Reconstruct thin (0.5-1 mm) soft-tissue kernel; reformat direct/oblique coronal and sagittal aligned to optic nerve
- Bone kernel series for fractures/foreign body
- Eyes-open fixed gaze to limit motion; no breath-hold
Series / Sequences
| # | Series / Sequence | Plane | Thickness | Notes |
|---|---|---|---|---|
| 1 | Axial soft tissue | axial | 0.625-1.5 mm | Globe, optic nerve, extraocular muscles; review with and without contrast as indicated |
| 2 | Coronal reformat (soft tissue) | coronal | 1-2 mm | Extraocular muscle size (thyroid eye disease), orbital floor |
| 3 | Sagittal reformat | sagittal | 1-2 mm | Along optic nerve |
| 4 | Axial/coronal bone | axial | 0.625-1 mm | Fractures, radiopaque foreign body |
Key points
- Non-contrast suffices for trauma/foreign body and FB-clearance before MRI; add contrast for infection, inflammation, and mass
- Coronal reformats best demonstrate extraocular muscle enlargement (Graves: inferior > medial > superior > lateral rectus, sparing tendons)
- Look for subperiosteal abscess and orbital extension of sinus disease in cellulitis
- Keep dose ALARA given lens sensitivity; thin sections essential for small foreign bodies
References
• ACR–ASNR–SPR Practice Parameter for the Performance of CT of the Extracranial Head and Neck
• ACR Appropriateness Criteria: Orbits Vision and Visual Loss
• Radiopaedia: CT orbits (protocol) link
• RadioGraphics: Imaging of Orbital Trauma and Infection
• ACR Appropriateness Criteria: Orbits Vision and Visual Loss
• Radiopaedia: CT orbits (protocol) link
• RadioGraphics: Imaging of Orbital Trauma and Infection
Source: Researched — verify against your institution
Reference template — verify and adapt to your scanner, vendor and institution before clinical use. Not a substitute for clinical judgment.