Terason t3000, Руководство пользователя

Страница: 27 / 421

Chapter 1 - About the Terason Ultrasound System About Ultrasound Modes
Terason t3000 / Echo Ultrasound System User Guide 27
Example Directional Power Doppler Scan
For more information on using Directional Power Doppler, see:
• Acquiring Images on page 63
• Using Color and Power Doppler Image Controls on page 118
Pulsed-Wave Doppler
A Pulsed-Wave Doppler (PWD) scan produces a series of pulses used to study the motion
of blood flow in a small region along a desired ultrasound cursor, called the sample
volume or sample gate.
The X-axis of the graph represents time, and the Y-axis represents Doppler frequency
shift. The shift in frequency between successive ultrasound pulses, caused mainly by
moving red blood cells, can be converted into velocity and flow if an appropriate angle
between the insonating beam and blood flow is known.
Shades of gray in the spectral display represent the strength of the signal. The thickness of
the spectral signal is indicative of laminar or turbulent flow (laminar flow typically shows
a narrow band of blood flow information).
In the Terason Ultrasound System, Pulsed-Wave Doppler and 2D are shown together in a
mixed-mode display. This combination lets you monitor the exact location of the sample
volume on the 2D image in the 2D Image Display window, while acquiring Pulsed-Wave
Doppler data in the Time Series window.