ABSTRACT
The Doppler principle underlies some of the key aspects of echocardiography, particularly in relation to the assessment of blood flow and the study of myocardial mechanics. This chapter describes the Doppler effect and how this can be used to measure the velocity of blood flow. The modalities of spectral Doppler (continuous wave and pulsed-wave Doppler) and colour Doppler are discussed, together with tissue Doppler imaging. The use of Doppler techniques in the assessment of fluid dynamics is described, together with their application to the calculation of stroke distance and volume, the continuity equation and the evaluation of pressure gradients.
