
Dopplers use high-frequency sound waves to measure the amount of blood flow through arteries and veins in your legs, arms, and neck. Dopplers can show reduced or blocked blood flow in vessels of the neck that could cause a stroke. Dopplers could also show blood clots (Deep Vein Thrombosis or DVT) that may break loose and block blood flow to the lungs (Pulmonary Embolism or PE).