A worker is suspected of having a retained intraocular metallic foreign body after a grinding wheel injury. Which imaging investigation is BOTH the most appropriate initial study AND mandatory to exclude before any magnetic resonance imaging is contemplated?
- A Orbital ultrasonography
- B Plain orbital radiograph in two views
- C Non-contrast computed tomography of the orbits ✓
- D Magnetic resonance imaging with gradient echo sequences
Correct answer: C. Non-contrast computed tomography of the orbits
Explanation
Thin-section non-contrast CT is the investigation of choice for suspected intraocular foreign body because it detects even small metallic fragments, localises them relative to ocular coats, and avoids globe manipulation. MRI is absolutely contraindicated until a ferromagnetic foreign body is excluded, since movement of the fragment can destroy the eye, which is exactly what makes option D wrong.
Reference: Parsons' Diseases of the Eye, 23rd ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.