Kreamkau Chapter 4 - Key Terms 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
Amplifer
a device that accomplishes amplification
Analog
related to a procedure or system in which data are represented by proportional continuous wave
Analog-to-digital converter (ADC)
A device that converts voltage amplitude to a number
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 represents an anatomic cross-section through the scanning plane
Bandpass filter
Function of the signal processor. Filter that passes a range of frequencies (its bandwidth) and rejects those above and below the acceptance bandwidth
Beam former
The part of an instrument that accomplishes electronic beam scanning, apodization, steering, focusing, and aperture with arrays
Bistable
Having two possible states (e.g., on or off, white or black, one or zero)
Bit
Bit Binary digit; one or zero
Channel
A single one- or two-way path for transmitting electric signals, in distinction from other parallel paths; an independent transmission delay line and transducer element path; an independent reception transducer element, amplifier, analog-to-digital converter, and delay line path
Cine loop
Sequential display of all the frames stored in memory at a controllable frame rate
Coed excitation
A sophisticated form of transmission in which the driving voltage pulses have intrapulse variations in amplitude, frequency, and/or pulse
Comensation
Equalization of received echo amplitude differences caused by different attenuations for different reflector depths
Compression
Reduction in differences 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
Equalization of received echo amplitude differences caused by different attenuations for different reflector depths
Detection
Conversion of voltage pulses from radio frequency to video form
Digital
Digital Related to a procedure or system in which data are represented 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
Ratio (in decibels) of largest to smallest power that a system can handle; ratio of the largest to smallest intensity of echoes encountered
Elastography
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 information stored each second
Freeze-frame
Constant display of one of the frames in memory
Gain
Ratio (in decibels) of amplifier output to input electric power
Gray scale
Range of brightnesses (gray levels) between white and black
Image memory
The part of the image processor where echo information is stored in image format
Image Processor
An electronic device that manipulates and prepares images for visual presentation
Lateral gain control
Gain controls that enable different gain values to be applied laterally across an image to compensate for differing attenuation values in different anatomic regions
M Mode
A B-mode presentation of changing reflector position (motion) vs time
Panoramic imaging
The extension of the field of view beyond the normal limits of a transducer scan plane
Persistence
Averaging sequential frames together
Picture archiving and communications systems (PACS)
The system provides means for electronically communicating images and associated information 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 information 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 (RF)
Voltages representing echoes in cyclic form
Real-time
Imaging with a rapid frame sequence display
Real-time display
A display that, with a sufficient frame rate, appears to image moving structures or a changing scan plane continuously
Refresh rate
The number of times each second that information is sent from the image memory to the display. The number of times per second that a computer monitor redraws the information found in the memory`
Scan line
A line produced on a display that represents ultrasonic echoes returning from the body. A sonographic image is composed of many such lines
Scanning
The sweeping of a sound beam through the anatomy to produce an image
Shear wave (transverse wave)
A sound wave in which the particle motion is perpendicular to the direction of wave travel
Signal
Information-bearing voltages in an electric circuit; an acoustic, visual, electric, or other conveyance of information. The physical representation of a message or information
Signal processor
An electronic device that manipulates electric signals in preparation for appropriate presentation of information contained in them
Spatial compounding
Averaging of frames that view the anatomy from different angles
Strain
The increase or decrease of the length of a segment of a material, subjected to a stress, divided by its original length
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 attenuations for different reflector depths
Volume imaging
Three-dimensional imaging
Young’s modulus
A measure of the hardness (stiffness) of a material. It is the ratio of the applied stress to the resulting strain in a material subjected to the stress
