Doppler Ultrasound

In the typical 2-D echocardiographic image, blood flow is not imaged (cavities and vessels are black; the exception being the spontaneous echo contrast in low flow states). The reason is that the red blood cells are very small and do not offer a reflective surface; instead, they scatter the ultrasound, like the fog is scattering the light. Imaging of blood flow is possible with Doppler ultrasound. The clinical applications of Doppler ultrasound are numerous and very important for the understanding of the circulation physiology and for the evaluation of cardiovascular hemodynamics.