IVOCT imaging artifacts of coronary stents

Coronary stent placement is a routine treatment of coronary artery disease, the leading cause of death worldwide. Intravascular Optical Coherence Tomography (IVOCT) is a superior imaging assessment technique in coronary stenting. To characterize IVOCT artifacts, phantom blood vessels were constructed and metallic and bioabsorable coronary stents were deployed with and without phantom neointima. High resolution Micro-CT images of the stent strut were recorded as a gold standard and utilized to create a three-dimensional representation of a strut that was imported into computer optical simulations. Simulated IVOCT images were computed that include the IVOCT catheter, light reflection from stent struts with varying neointimal thickness and scattering in the vessel lumen. The simulation results along with IVOCT images of the phantom vessels were utilized to elucidate the mechanisms underlying the “sunflower effect”, bending of stent struts toward the imaging catheter and “merry-go-round” effect, variable apparent strut size of metallic stents. Atomic force microscopy was used to examine surface properties of metallic and bioabsorbale stents, revealing sources of the distinctive appearance of bioabsorable stents in IVOCT images. The model formed a basis to develop a correction algorithm to remove stent artifacts in clinical IVOCT images.