The intima is the innermost layer of an artery or vein wall, consisting of a single layer of endothelial cells and a thin layer of connective tissue. It is the layer that is in direct contact with the flowing blood and is the site where atherosclerosis begins. On high-frequency ultrasound, particularly during carotid imaging, the intima can be seen as a thin, echogenic line on the inner surface of the vessel wall. Atherosclerotic plaque develops within the intimal layer, and the earliest detectable sign of atherosclerosis on ultrasound is an increase in the combined thickness of the intima and the adjacent media layer, known as the intima-media thickness.
Sonography Term