Tissue Doppler echocardiography

Tissue Doppler echocardiography (TDE) is a medical ultrasound technology, specifically a form of echocardiography that measures the velocity of the heart muscle (myocardium) through the phases of one or more heartbeats by the Doppler effect (frequency shift) of the reflected ultrasound. The technique is the same as for flow Doppler echocardiography measuring flow velocities. Tissue signals, however, have higher amplitude and lower velocities, and the signals are extracted by using different filter and gain settings. The terms tissue Doppler imaging (TDI) and tissue velocity imaging (TVI) are usually synonymous with TDE because echocardiography is the main use of tissue Doppler. Tissue Doppler echocardiography (TDE) is a medical ultrasound technology, specifically a form of echocardiography that measures the velocity of the heart muscle (myocardium) through the phases of one or more heartbeats by the Doppler effect (frequency shift) of the reflected ultrasound. The technique is the same as for flow Doppler echocardiography measuring flow velocities. Tissue signals, however, have higher amplitude and lower velocities, and the signals are extracted by using different filter and gain settings. The terms tissue Doppler imaging (TDI) and tissue velocity imaging (TVI) are usually synonymous with TDE because echocardiography is the main use of tissue Doppler. Like Doppler flow, tissue Doppler can be acquired both by spectral analysis (spectral density estimation) as pulsed Doppler and by the autocorrelation technique as colour tissue Doppler (duplex ultrasonography). While pulsed Doppler only acquires the velocity at one point at a time, colour Doppler can acquire simultaneous pixel velocity values across the whole imaging field. Pulsed Doppler on the other hand, is more robust against noise, as peak values are measured on top of the spectrum, and are unaffected of the presence of clutter (stationary reverberation noise). This has become a major echocardiographic tool for assessment of both systolic and diastolic ventricular function. However, as this is a spectral technique, it is important to realise that measurement of peak values is dependent on the width of the spectrum, which again is a function of gain setting. Pulsed wave spectral tissue Doppler has become a universal tool that is part of the general echocardiographic examination. Like any other echocardiographic measurement, measures by tissue Doppler should be interpreted in the context of the whole examination. The velocity curves are in general taken from the base of the mitral annulus at the insertion of the mitral leaflets, in the septal and lateral points of the four chamber view, and eventually the anterior and inferior points of the two-chamber views. For the right ventricle it is customary to use the lateral point of the tricuspid annulus only. Averaging peak velocities from the septal and lateral point has become common, although it has been shown that averaging all four points mentioned above, gives significantly less variability