PRINCIPLES OF DOPPLER

摘要

Doppler ultrasonography provides functional information regarding blood flow. It is used to detect the presence of blood flow and to quantify the presence, direction, speed, and character of flow in vessels. It is commonly used to differentiate between blood vessels and nonvascular tubular structures (e.g., bile ducts or renal diverticula) and is useful in assessment of thromboses. Doppler is used extensively in cardiac applications to characterize valvular insufficiencies, stenosis, and septal defects. Accurate blood flow velocity determined by Doppler ultrasound is used to as a noninvasive method to calculate blood flow and pressure.