Different intimal changes of the aorta often observed under a scanning electron microscope. (A) Normal-appearance intimal endothelial cells. (B) Intimal surface becomes bulged without monocyte adherence (right area). (C-D) Monocytes are found under split endothelial cells, possibly due to artifacts of the fixation and drying processes. (E-H) Monocyte adherence to the bulged or protruded intima.