Magnetic resonance imaging and computed tomography in the detection and localization of intraocular foreign bodies.

In this experimental study, various foreign bodies were inserted into fresh bovine eyes, in different localizations. Twenty-one magnetic and non-magnetic foreign bodies, dimensions of which varied from 1.5 x 1.5 x 2 mm to 3.5 x 6 x 7 mm, were tried to detect by computed tomography (CT) and magnetic resonance imaging (MRI) scanning. In addition, further dissections were applied to check the ocular damage attributable to movement of the foreign bodies. Ferromagnetic foreign bodies have been shown to move in the eye and the risk of torsional forces being applied to the ferromagnetic foreign body seemed to cause intraocular complications during MRI scanning. All of the foreign bodies that were implanted in bovine eyes were recognized on CT scanning, except intraocular lenses. As a general rule, metallic foreign bodies produced beam-hardening artifacts, but these artifacts did not cause any problem in detecting the localizations of foreign bodies.