Visual inspection of the surface takes place after stent expansion to the nominal diameter with a stereomicroscope in connection with a video camera system with an adjusted magnification of 10x. Particularly selected areas (connecting posts, deformation zones) are examined with a magnification of 70x.
Surface defects and particularly cracks at the filaments due to the expansion procedure are to be identified. In addition, surface examination can be performed by scanning electron microscopy (SEM). SEM provides more detailed information about the suface, and is recommended in particular for coated implants.