LTE uses two different radio links for downlink and uplink, that is, from tower to device, and vice versa. For the downlink, LTE uses an OFDMA (orthogonal frequency division multiple access), which requires MIMO.
What you are referring to is called plaque, and it's a hallmark of atherosclerosis or arteriosclerosis (they both mean the same thing). Basically, cholesterol deposits end up lining the interior walls (lumen, intima) of the arteries narrowing the opening.
Atherosclerosis is a medical condition in which a fatty substance called plaque builds up on the inside walls of blood vessels, which can slow or eventually block the flow of blood. When this occurs in the coronary arteries, it is termed coronary artery disease, or CAD. To learn more about atherosclerosis and CAD, watch this animation.