Magnetic Resonance Imaging of Bioresorbable Vascular Scaffolds

Bioresorbable vascular scaffolds (BVSs) are a rapidly evolving technique in interventional cardiology. Bioresorption of the scaffolds polylactate backbone takes ≈2 years, leaving behind only the distal and proximal platinum markers used for scaffold localization in fluoroscopy. Recent studies comparing BVS with standard drug eluting stents have suggested potential benefits for the patients including a significant reduction in postprocedural angina, or a trend toward the reduction of revascularization rates.1,2 Multiple large-scale studies are currently ongoing to further clarify the future role of BVS compared with drug eluting stents.Because of the nonmetallic polylactate backbone, BVS therapy might also allow for noninvasive evaluation of coronary arteries by magnetic resonance imaging (MRI), simultaneously yielding information about anatomy and atherosclerotic plaque dynamics. Conventional metallic stents are known to shield off the radio frequency fields during MRI signal excitation and data acquisition, which leads to a severely reduced MRI sensitivity inside the stent. In addition, the closed metallic ring structures can create unwanted field distortions from susceptibility differences and gradient-induced eddy currents.3 Thus, direct MRI of the lumen of a conventional stent is difficult, and an in-stent restenosis or neoatherosclerosis can hardly be detected. In contrast, BVS might allow for an artifact-free imaging of the scaffold lumen, so that the patency of the vessel can be directly assessed in a noninvasive manner. Compared with conventional stents that can be easily identified by their imaging …