Spectral Doppler Ultrasound and Pressure Gradients:
©Walter Rasmussen, R.D.C.S.
One of the major roles that spectral Doppler ultrasound plays in Echocardiography is the ability to calculate pressure gradients from the velocity profiles obtained. The simplified Bernoulli Equation states that pressure is equal to four times the velocity squared. It is through the use of this equation that intracardiac pressures can be quickly determined using the analysis software on the ultrasound machine.
A trackball is used to trace the peak and mean pressure gradients.
For Example: If the peak velocity of a jet is 1 meter per second, the peak pressure gradient would be: (1×1)x4= 4mmHg
A peak pressure gradient is obtained by placing the measurement cursor at the peak velocity of a given Doppler recording. A mean pressure gradient is obtained by tracing the edge of the velocity profile from the baseline to the peak and then back to the baseline.