GE Voluson 730 Service Manual page 126

GE M S - K
EDICAL YSTEMS
D 105844, R
IRECTION EVISION
5-2-1 Description of Voluson® 730 Operating Modes
5-2-1-1 B-Mode or 2D-Mode:
B-Mode or 2D-mode is a two-dimensional image of the amplitude of the echo signal. It is used for
location and measurement of anatomical structures and for spatial orientation during operation of other
modes. In 2D-mode, a two-dimensional cross-section of a three-dimensional soft tissue structure such
as the heart is displayed in real time. Ultrasound echoes of different intensities are mapped to different
gray scale or color values in the display. The outline of the 2D cross-section may be a rectangle,
parallelogram, sector or 360-degree circle, depending on the particular transducer used. 2D-mode can
be used in combination with any other mode.
5-2-1-2 M-Mode:
In M-mode, soft tissue structure is presented as scrolling display, with depth on the Y-axis and time on
the X-axis. It is used primarily for cardiac measurements such as value timing on septal wall thickness
when accurate timing information is required. M-mode is also known as T-M mode or time-motion mode.
Ultrasound echoes of different intensities are mapped to different gray scale values in the display.
M-mode displays time motion information of the ultrasound data derived from a stationary beam.
Depth is arranged along the vertical axis with time along the horizontal axis. M-mode is normally used
in conjunction with a 2D image for spatial reference. The 2D image has a graphical line (M-line)
superimposed on the 2D image indicating where the M-mode beam is located.
5-2-1-3 Color Doppler Mode:
Color Doppler is used to detect motion presented as a two-dimensional display.
There are three applications of this technique:
• Color Flow Mode (C) - used to visualize blood flow velocity and direction
• Power Doppler (PD) - used to visualize the spatial distribution of blood
• Tissue Doppler (TD) - used to visualize tissue motion direction and velocity (optional
5-2-1-3-1 Color Flow Mode:
a real-time two-dimensional cross-section image of blood flow is displayed. The 2D cross-section may
be presented as a rectangle, parallelogram, trapezoid, sector, or a full circle, depending on the
particular transducer used. The 2D cross-section is presented as a full color display, with various colors
being used to represent blood flow (velocity, variance, power and/or direction). Often, to provide spatial
orientation, the full color blood flow cross-section is overlaid on top of the grayscale cross-section of soft
tissue structure (2D echo). For each pixel in the overlay, the decision of whether to display color
(Doppler), gray scale (echo) information or a blended combination is based on the relative strength of
return echoes from the soft tissue structures and from the red blood cells. Blood velocity is the primary
parameter used to determine the display colors, but power and variance may also used. A high pass
filter (wall filter) is used to remove the signals from stationary or slowly moving structures. Tissue motion
is discriminated from blood flow by assuming that blood is moving faster than the surrounding tissue,
although additional parameters may also be used to enhance the discrimination. Color flow can be used
in combination with 2D and Spectral Doppler modes.
5-2-1-3-2 Power Doppler:
a real-time two dimensional cross-section of blood flow is displayed. The 2D cross-section may be
presented as a rectangle, parallelogram, trapezoid, sector, or a full circle, depending on the particular
transducer used. The 2D cross-section is presented as a full color display, with various colors being
used to represent the power in blood flow echoes. Often, to provide spatial orientation, the full color
blood flow cross-section is overlaid on top of the gray scale cross-section of soft tissue structure (2D
echo). For each pixel in the overlay, the decision of whether to display color (Doppler power), gray scale
(echo) information or a blended combination is based on the relative strength of return echoes from the
soft-tissue structures and from the red blood cells. A high pass filter (wall filter) is used to remove the
signals from stationary or slowly moving structures.
5-6
U
RETZTECHNIK LTRASOUND
1
Section 5-2 - General Information
V ® 730 S
OLUSON ERVICE
see
M
ANUAL
5-2-5-8)