Coronary arterial stents: safety and artifacts during MR imaging

To investigate the safety and imaging artifacts with different coronary arterial stents and magnetic resonance (MR) imaging sequences.

The heating, artifacts, and ferromagnetism with different stents were studied with a 1.5-T MR tomograph with ultrafast gradients by using turbo spin-echo, turbo gradient-echo, and echo-planar imaging sequences. Nineteen stents, which were 8-25 mm in length and 3.0-4.5 mm in diameter, were evaluated. Stent deviation induced by the magnetic field and during MR imaging, migration, and heating caused by the radio-frequency pulses were examined. The size of imaging artifacts was measured with all the stents under standardized conditions and with six stents after their implantation into the coronary arteries of freshly explanted pig hearts.

All except two types of stents showed minimal ferromagnetism. No device migration or heating was induced. Turbo spin-echo images had minimal artifacts; larger artifacts were seen on the turbo gradient-echo and echo-planar images. With ultrafast gradients, the artifacts on the echo-planar images were substantially reduced.

The studied coronary stents were not influenced by heating or motion during 1.5-T MR imaging. Artifact size differed according to the type and size of the stent and the MR imaging sequence used. Thus, patients with these stents can be safely examined.