Abstract
Purpose: :
To evaluate the effects of 1.5 Tesla MRI on the MEDPOR ATTRACTOR® screw that is used in the MEDPOR ATTRACTOR® Magnetic Coupling System (Porex Surgical, Newnan, GA).
Methods: :
This experimental study measured the effects of a 1.5T MRI magnetic field on a MEDPOR ATTRACTOR screw. The four main outcomes measured were translational and rotational forces on the screw, surface temperature of the screw, and MR scan image artifact induced by the screw.
Results: :
The force exerted by the MRI magnet on the screw was 38 times the force of gravity. The screw displayed significant torque when placed in the MRI system. The temperature of the screw did not change significantly. All MRI images with the screw showed considerable artifact.
Conclusions: :
An appropriately placed MEDPOR ATTRACTOR screw is deeply embedded into a porous polyethylene implant within the anophthalmic socket. This study showed that the screw displayed considerable translational and rotational forces when placed in an MRI magnetic field. Therefore, by following the guidelines of the American Society of Testing and Materials, we conclude that it is not safe for a patient with an embedded MEDPOR ATTRACTOR screw to undergo an MRI procedure. In addition, the screw causes substantial image artifact, which could significantly alter the utility of a medically necessary periorbital scan.
Keywords: imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • orbit