A stroke occurs when there is delayed or reduced blood flow to the brain, either permanently or temporarily, which can cause cell death. Diagnosis involves Doppler ultrasound to locate any obstructions. Strokes are sometimes called "silent killers" as they can be caused by atherosclerosis thickening and hardening of blood vessel linings. Treatment focuses on increasing narrowed blood vessel openings with stents, monitoring blood pressure, diet, and exercise, and maintaining a healthy lifestyle of eating to live rather than living to eat.