MRI artifacts of metallic stents derived from imaging sequencing and the ferromagnetic nature of materials.

In vitro and in vivo studies were performed to assess the optimum materials and imaging methods for metallic stents by conducting an in vitro investigation of MRI artifacts arising during imaging by several representative imaging methods using various types of stents and by clarifying the differences occurring with different metals and imaging sequences. We also examined the use of MRCP and MRA in evaluating luminal patency within stented biliary tracts and blood vessels in vivo. In vitro study showed either no artifacts or very slight artifacts created by titanium stents, however, marked image distortion was created by a stainless steel stent. Using SE instead of GRE sequences can minimize these artifacts. Echo planar imaging (EPI) produced severe susceptibility artifacts, resulting in unsatisfactory images. In vitro and in vivo studies indicated that MRCP was an effective method for follow-up studies of bile duct stents, but that MRA is quite limited as a method of follow-up study for currently available vascular stents.