GE Voluson E10 Training Manual
© 2017 Conquest Imaging
Power Doppler
Power Doppler is the same as Color Doppler except that it uses the
amplitude of the signal to detect movement. The power in the
remaining signal after wall filtering is then averaged over time to
present a steady state image of blood flow distribution. It is
independent of velocity and direction of flow, so there is no signal
aliasing. It is independent of angle allowing the detection of smaller
velocities than Color Doppler, making it easier to detect indistinct
ischemic areas as well as evaluate tiny low-flow vessels. Power
Doppler can be used in combination with 2D (B-Mode) (B-Mode) and
Spectral Doppler modes as well as with 4D mode.
Pulsed (PW) Doppler
PW Doppler processing is one of two spectral Doppler modes, the
other being CW Doppler. In spectral Doppler, blood flow is presented
as a scrolling display, with flow velocity on the Y-axis and time on the
X-axis. The presence of spectral broadening indicates turbulent flow,
while the absence of spectral broadening indicates laminar flow. PW
Doppler provides real time spectral analysis of pulsed Doppler signals.
PW Doppler can be used alone but is normally used in conjunction
with a 2D (B-Mode) (B-Mode) image with an M-line and sample
volume marker superimposed on the 2-D image indicating the
position of the Doppler sample volume. The sample volume size and
location are specified by the operator. Sample volume can be overlaid
by a flow direction cursor which is aligned, by the operator, with the
direction of flow in the vessel, thus determining the Doppler angle.
This allows the spectral display to be calibrated in flow velocity
(m/sec.) as well as frequency (Hz). PW PW Doppler can be used in
combination with 2D (B-Mode) (B-Mode) and Color Flow modes.
Continuous Wave (CW) Doppler
Continuous Wave Doppler systems use two crystals, one to send and
one to receive the echoes. The transmitter inputs a continuous
sinusoidal wave. The receiver detects the shift. An audible sound is
created and recorded by either an analog recorder or spectral
analyzer. Spectral analysis separates the signal into individual
components and assigns a relative importance.
CW Doppler is optional on
the Voluson E10 systems.
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