In the diagnosis of heart diseases the Doppler echocardiography makes it possible to distinguish physiological and pathological blood flow and thus to prove and judge valve defects in a noninvasive way. The color Doppler gives a survey about place and direction of the streams. The exact analysis and quantification of the stream speed results from the spectral Doppler.
Valve stenosis is characterized by a flow acceleration on the level of the stenosis.
The increased speed is used for estimation of the severity of the stenosis. Valve insufficiency is recognized by a reflux of blood to the ventricle or atrium, respectively. The extent of the insufficiency can be evaluated semiquantitatively.