lesson 6 Flashcards
- The earliest ultrasound mode showed a returning
echoes in a one-dimensional - used to measure the distance between, or thickness of tissues
A-MODE (Amplitude Mode)
- The most common mode of operation utilized.
- BLANKs produce a two-dimensional image of the underlying tissue
- a linear an array of transducers simultaneously scans a plane through the body that can be viewed as
a two-dimensional image on the screen
B-MODE (Brightness Mode)
Uses a stationary transducer with a moving
recording device. Detects all motion down a line drawn through the tissues
M-MODE (Motion Mode)
check for blood vessel conditions that affect the amount, speed, and direction of blood flow
DOPPLER ULTRASOUND
Discovered by Christian Johann Doppler
Doppler effect
- enables ultrasound to be
used to detect blood flow and to quantify vascular disease
The machine can assign different colors depending
on the flow direction, also known as phase shift. This is traditionally assigned as red for flow towards the transducer or blue for flow away from the transducer.
COLOR DOPPLER/ COLOR FLOW IMAGING
Encodes the power of the ultrasound signal rather than velocity and direction. It is sensitive to movement in any direction. It is a single
color and appears red or red-orange
POWER DOPPLER
By sending short and quick pulses of sound, it
becomes possible to measure the accurately
velocity of blood in a precise location and in
real time. This is accomplished by using the
same piezoelectric crystals to send and analyze sound waves.
PULSED WAVE
- Ultrasound waves are continuously emitted
from the transducer and the reflections of
These waves are analyzed continuously. - This is possible by using two different sets of
piezoelectric crystals; one set for sending ultrasound and the other for analyzing reflected sound waves.
CONTINUOUS WAVE DOPPLER
Increases the amplitude of the return signal, expressed on the screen by brightness of the corresponding pixels
GAIN
It is a control on an ultrasound machine that allows the operator to pause the real-time display of the image on the screen. It is typically used to take a closer look at a specific area of the image or to record or print a still image
FREEZE BUTTON
Controlled by a vertical row of toggles. Allows the gain to be adjusted differently at different depths
TIME GAIN COMPENSATION (TGC)
- The focal point of an ultrasound signal is the
the narrowest part of the beam - allows the focus of the signal to be adjusted in the near field on structures of interest
FOCUS
Adjusting the BLANK will make deeper structures appear clearer and more defined; however, shallower
structures will appear smaller
DEPTH
allows the sonographer to
see a structure in detail. It does not change the resolution of the image, so structures. may appear more grainy.
ZOOM
save a still image and will
show you a thumbnail of this picture.You can also choose to ‘Save Cine’. Cine clips are very popular with clients (moving images)
SAVE BUTTON
allows the operator to
generate a physical hard copy of the displayed
ultrasound image
PRINT BUTTON
