Effect of beam size and catheter position on the apparent size and apposition of metallic stent struts in IVOCT images were examined. Micro-CT data was employed to determine light -stent strut interactions. Simulated results suggest that location of the reflecting regions depend on relative orientation and position of stent struts to the IVOCT beam. Erroneous stent apposition measurements can occur when the IVOCT catheter is at an eccentric position. A method that mitigates stent strut apposition measurement errors is proposed. Coherence Tomography (IWG-IVOCT), "Consensus standards for acquisition, measurement, and reporting of intravascular optical coherence tomography studies: a report from the International working group for intravascular optical coherence tomography standardization and validation," J. Am.