Optical coherence tomography (OCT) is a light-based, high resolution, imaging modality for intra coronary assessment of tissue and implants. Currently two CE-marked OCT systems are used in clinical practice in (Illumien OPTIS, St. Jude Medical , Minnesota, USA and Lunawave, Terumo , Tokyo, Japan). It is a common assumption that the scanning images for the two systems are similar and are interpreted the same way.