DOPPLER ECHOCARDIOGRAPHY-ECHOCARDIOGRAPHY

DOPPLER ECHOCARDIOGRAPHY-ECHOCARDIOGRAPHY

Doppler echocardiography includes pulse wave continuous wave and colour flow doppler.Doppler principle is applied to blood flow within the heart and the direction and velocity of blood flow can be determined by examining the movement of red blood cells by the ultrasound beam.



Doppler effect is a change in the observed frequency of sound that results from the motion of the source or target. Doppler ultrasound equipment detects a frequency shift and determines the velocity and direction of red blood cells flow concerning the ultrasound beam

doppler effect
doppler effect


By convention the velocity of RBC moving towards the transducer is displayed above the zero baselines and moving away from the transducer is displayed below the zero baseline

Echocardiography
Echocardiography


Normal Doppler velocity is less than 1 meter per second for tricuspid and pulmonary valves and maybe up to 1.6 for the ascending and descending aortas.

Coming to the modes of doppler echocardiography pulsed doppler transducers have only 1 crystal for transmitting and receiving the ultrasound. Advantage of this signal is it can obtain doppler signal from a specific area of cardiovascular system example mitral valve.

Pulse wave doppler
Pulse wave doppler

In continuous wave doppler, there are 2 crystals, one is for transmitting and another one is for receiving the signal. The major limitation is this doppler is lack of discrimination of the many blood velocity components returning to the transducer, for example measuring Lvot velocity.

Continuous wave doppler
Continuous wave doppler


Coming to the colour flow doppler the ultrasound beam is rotated through an arc and recording of Doppler shift frequency are made throughout the arc. A colour coded doppler provides the images of the direction and disturbance of blood flow superimposed on the echo structural image.

Red is used to indicate flow towards the transducer and blue indicates flow away from the transducer. The turbulent beam is colour-coded as green or yellow

colour flow doppler
Colour flow doppler

Information that can be obtained from Doppler spectrum is the velocity of blood through a sample volume- example pulse wave and along entire beam path using continuous-wave and doppler also provides the direction of flow relative to transducer and timing of flow events during a cardiac cycle.

You can also refer the topic in the link

https://www.youtube.com/channel/UCRrYRylZdS67_kbATQrLQqA


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