Doppler ultrasound of an artery

Courtesy of Intermountain Medical Imaging, Boise, Idaho.

Figure 1 shows an ultrasound of blood flowing through a normal artery. Figure 2 shows an artery narrowed by the buildup of calcium and fat (cholesterol) in the inner lining of the artery, called plaque, which leads to "hardening of the arteries" (atherosclerosis).