Chapter 4 Flashcards
A-Mode
mode of operation in which the display presents echo amplitude versus depth
Amplification
the process by which small voltages are increased to larger ones
amplifier
a device that accomplished amplification
analog
related to a procedure or system in which data are represented by proportional, continuously variable, physical quantities
analog-to digital converter
a device that converts voltage amplitude to a number. ADC
B mode
mode of operation in which the display presents a spot of appropriate brightness for each echo received by the transducer
B scan
a B-mode image that presents an anatomic cross section through the scanning plane
bandpass filter
see other
beam former
the part of an instrument that accomplishes electronic bean scanning, apodization, steering, focusing, and aperture with arrays.
bistable
having two possible states
Bit
binary digit; one or zero
channel
a single one or two way path for transmitting electric signal, in distinction from other parallel paths
Cine loop
sequential display of all the frames stored in memory at a controllable frame rate
coded excitation
a sophisticated form of transmission in which the driving voltage pulses have intrapulse variations in amplitude, frequency, and or phase
compensation
equalization of received echo amplitude difference cause by different attenuations for different reflector depths
compression
reduction in difference between small and large amplitudes. region of high density and pressure in a compressional wave.
contrast resolution
ability of a gray scale display to distinguish between echoes of slightly different intensities
demodulation
detection
Depth gain compensation
see compensations. DGC
detection
conversion of voltage pulses from radio frequency to video form.
digital
related to a procedure or system in which data are presented by numeric digits
digital to analog converter
a device that converts a number to a proportional voltage amplitude
display
a device that presents a visual image derived from voltages received from an image processor
dynamic range
ration of largest to smallest power that a system can handle, ration of the larges to smallest intensity of echoes encountered.
elastrography
imaging tissue stiffness by tracking movement under mechanical stress
flat-panel display
a back-lighted rectangular matrix of thousands of liquid crystal display elements.
frame
a single image produced by one complete scan of the sound beam
frame rate
number of frames of echo info stored each second
gain
ratio of amplifier output to input electric power
gray scale
range of brightnesses between black and white
image memory
the part of the image processor where echo info is stored in image format
image processor
an electronic device that manipulates and prepares image for visual presentation
lateral gain control
gain controls that enable different gain values to be applies laterally across an image to compensate for differing attenuation values in different anatomic regions
M mode
a B-mode presentation of changing reflector position versus time. (Motion)
panoramic imaging
the extension of the field of view beyond the normal limits of a transducer scan plane
persistence
averaging sequential frame together
PACS
the system provides means for electronically communicating image and associated info to work stations and devices external to the sonographic instrument, the examining room, and even the building in which the scanning is done.
pixel
picture element; the unit into which imaging info is divided for storage and display in a digital instrument
postprocessing
image processing done after storage in the memory
preprocessing
signal and image processing accomplished before storage in the memory
radio frequency
voltages representing echoes in cyclic form
real time
imaging with a rapid frame sequence display
real time display
a display that, which a sufficient frame rate, appears to image moving structures or a changing scan plane continuously.
refresh rate
the number of times each second that info is sent from the image memory to the display.
scan line
a line produced on a display that represents ultrasonic echoes returning from the body.
scanning
the sweeping of a sound beam through the anatomy to produce an image
shear wave
see transverse wave
signal
the physical representation of a message or info
signal processer
an electronic device that manipulates electric signal in preparation for appropriate presentation of info contained in them
spatial compounding
averaging of frames that view the anatomy from diff angles
strain
the increase or decrease of the length of segment of a material, subjected to a stress, divided by its original lengh
stress
a force per unit area applied to a material that compresses or stretches it
temporal resolution
ability to distinguish closely spaced events in time, improves with increased frame rate
TGC
equalization of echo amplitude differences caused by different attenuation for different reflector depths
volume imaging
3D imaging
young’s modulus
a measure of the hardness of a material . is it the ration of applied stress to the resulting strain in a material subjected to the stress.
Freeze-rate
constant display of one of the frames in memory.
