A metalworker with a suspected retained intraocular metallic foreign body is referred for imaging. Which investigation is CONTRAINDICATED until the foreign body is excluded radiologically by plain X-ray or CT?
- A Non-contrast orbital CT scan
- B B-scan ultrasonography
- C MRI of the orbits ✓
- D Plain orbital radiography
Correct answer: C. MRI of the orbits
Explanation
MRI is contraindicated when a ferromagnetic intraocular foreign body is suspected because the strong magnetic field can cause movement of the fragment within the eye, producing additional retinal and vitreous damage. Plain X-ray or non-contrast CT must first exclude metallic fragments. CT detects even small metallic IOFBs with high sensitivity, and C-scan is useful for non-metallic bodies but requires gentle contact, so it follows imaging confirmation.
Reference: Khurana Comprehensive Ophthalmology, 7th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
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