Chapter 2 Review Flashcards
What is the basic concept of ultrasound?
detect structures and measure distance
adjusts or amplifies the brightness of all of the pixels on the system monitor
overall gain
Is overall gain a pre or post processing function?
post
This control is used when the overall appearance of the image is too bright or too dark
overall gain
When adjusting the overall gain, a high setting introduces “noise” which decreases the _____ and _____ resolution.
contrast
spatial
As sound travels through tissue, there is a waveform amplitude reduction because of _______
attenuation
3 reasons for reduction in ultrasound energy through a tissue
absorption
scattering
reflection
Attenuation from lowest to highest .
water, fluid, fat, soft tissue, muscle, bone, and air
time gain compensation is also called
depth gain compensation
allows the adjustment of darker or brighter areas
TGC
the separation of structures perpendicular to the transmit beeam
lateral resolution
Lateral resolution is highest within ______
focal zone
If using multiple zones, you may see a decrease in _____
frame rate
The operating frequency relates directly to _______
thickness of the piezoelectric element
In ______ imaging, higher frequencies increase both aliasing and scatter artifacts
Doppler
allows adjustment of the amount of anatomy displayed in the image
image depth
the number of lines used in an image
line density
Narrowing sector width _____ frame rate
increases
Narrowing sector width, _____ lateral resolution
increases
the range of grays displayed in the B-mode image, M-mode tracing, or spectral Doppler tracing
Dynamic range
tint overlay to increase structure visualization
tint/colorize
temporal averaging of multiple sequential ultrasound images or frames
persistence/frame averaging
determines the number of frames used to create the final image
persistence
helps decrease the noise within an image because of the averaging of the data across multiple frames
persistence
What resolution decreases with persistence?
temporal
Increasing persistence, _____ frames
decreases
changes the gray assignment of each pixel based on the received ultrasound signal to increase image contrast
maps/curves
adjusts the brightness of the grays rather than the number of displayed shades
maps/curves
allows for manual adjustment of the acoustic output of the transducer per unit of time
transmit power
an indicator of the potential damage to tissue with the passing wave
mechanical index
displays the thermal index in bone
TIB
the soft-tissue thermal index
TIS
the cranial thermal index
TIC
allows the ultrasound system to use two signals to help create the image
tissue harmonic imaging
uses multiple, averaged transmit beams at different angles and frequencies to increase image detail
compound imaging
_____ angle of incidence creates the optimal reflection
90 degree
Compound imaging ______ axial, lateral, and contrast resolution.
increases
allows visualization of anatomy posterior to a strongly reflecting structure
compound imaging
provide a graphic display of structure in relation to time
M-mode (motion mode)
adjusts the scrolling speed or time of the M-mode
sweep speed
involves the addition of color over the grayscale ultrasound image to indicate movement
color flow imaging
The color above Color flow imaging bar represents:
color flow toward the transducer or positive Doppler shifts
The color below Color flow imaging bar represents:
flow away from the transducer or negative Doppler shifts
BART
blue away
red toward
The color white commonly represents:
increase in blood velocity
Darker colors represent:
slower velocities
green colors represent:
flow disturbances
Mixture of colors represents:
turbulence
ROI should have an angle of incidence of less than ____ degrees
60
Color shadings become darker as the angle of insonation approaches __ degrees
90
Optimal ROI
longer ROI
The wider the gate, the ____ scan lines are required.
more
Increasing or decreasing the scale adjust the ____.
PRF
allows adjustment of the displayed flow to accomodate the vessel flow type and to show true aliasing
PRF
adjusts the spatial averaging for flow between color frames
smooth
adjusts the range of flow velocities displayed above and below the baseline through the movement of the baseline up or down
baseline
to detect slow flow, _____ the persistence
increase
Increased persistence _____ temporal resistance
decreases
allows ability to select a processing curve that assigns the velocity or variance range with color Doppler
Maps
allow ability to display an image with more 2D information, a balance between color and gray scale, or prioritize the color
color priority
adjusts the amount of color or grayscale information each image pixel contains
color priority
reverses the color display
invert
calculates the amplitude within the ROI instead of the mean Doppler frequency shift
Power Doppler
The power Doppler scale calculation includes the ____, ____, and _____ of the signal
intensity
power
amplitude
hybrid of color and power Doppler imaging
directional color Doppler