Spectral doppler measurements
Echocardiography Textbook
Vmax and Vmid
Vmax - Maximum flow velocity.
Vmid (Average Flow Velocity) - The sum of the flow velocities measured every 2 seconds, divided by the number of measurements.
PGmax and PGmid
The movement of blood between the chambers of the heart depends on the pressure difference between the chambers. Doppler echocardiography allows determining the pressure gradient between the chambers. The pressure gradient can be determined using the simplified Bernoulli formula:
V - flow velosity.
PGmax - Maximum flow gradient, measured at the maximum point of velocity.
PGmid (Average Gradient) - The sum of the gradients measured every 2 seconds, divided by the number of measurements.
VTI
VTI (Velocity Time Integral) is calculated by the formula:
ET (Ejection Time) - The time from opening to closing the valve.
PHT
Pressure half-time (PHT) is defined as the time interval in milliseconds between the maximum gradient in and the time point where the gradient is half the maximum initial value.
Spectral Doppler measurements (Vmax, Vmid, PGmax, PGmid, VTI, PHT) will be done by ultrasound device automatically when user will select (trace) the appropriate spectrogram.
Spectral doppler measurements. V max, V mid, PG max, PG mid, VTI and PHT. Simulation By Echocardiography Online Simulator MyEchocardiography.com
Using the Transmitral diastolic and LVOT flows spectrogram the following parameters can be measured and calculated:
- AT (Acceleration Time) - The time from the opening of the mitral valve to the peak flow.
- DT (Deceleration Time) - the time from the Peak to Baseline.
- ET (Ejection Time) - The time from opening to closing the mitral valve.
- Vmid (Average Flow Velocity) - The sum of the flow velocities measured every 2 seconds, divided by the number of measurements.
- VTI (Velocity Time Integral) - VTI = Vmid x ET
- Vmax - Maximum flow velocity.
- IVRT - Isovolumetric relaxation time.
- IVST - Isovolumetric contraction time.
How to Simulate spectral doppler measurments? >>>