Chapter 4 Kremkau final review Flashcards
mode of operation in which the display presents echo amplitude versus depth
A mode
the process by which small voltages are increased to larger one
amplification
a device that accomplishes amplification
amplifier
related to a procedure or system in which data are represented by proportional, continuously variable, physical quantities
analog
a device that converts voltage amplitude to a number
analog-to-digital converter
Mode of operation in which the display presents a spot of appropriate brightness for each echo received by the transducer.
B mode
A B-mode image that represents an anatomic cross section through the scanning plane
B scan
arrangement of electronic components that allows only those electric waves lying within a certain range, or band, of frequencies to pass and blocks all other
bandpass filter
the part of an instrument that accomplishes electronic beam scanning, apodization, steering, focusing, and aperture with arrays
beam former
having two possible states
bistable
binary digit; one or zero
bit
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
channel
sequential display of all the frames stored in memory at a controllable frame rate
cine loop
a sophisticated form of transmission in which the driving voltage pulses have intrapulse variations in amplitude, frequency, and/or phase
coded excitation
equalization of received echo amplitude differences caused by different attenuations for different reflector depths
compensation
reduction in differences between small and large amplitudes. Region of high density and pressure in a compressional wave
compression
ability of a gray-scale display to distinguish between echoes of slightly different intensities
contrast resolution
detection
demodulation
compensation
depth gain compensation
detection
conversion of voltage pulses from radio frequency to video form
related to a procedure or system in which data are represented by numberic digits
digital
a device that converts a number to a proportional voltage amplitude
digital-to-analog converter
a device that presents a visual image derived from voltages received from an image processor
display
ratio (in decibels) of largest to smallest power that a system can handle; ratio of the largest to smallest intensity of echoes encountered
dynamic range
imaging tissue stiffness by tracking movement under mechanical stress
elastography
a backlighted rectangular matrix of thousands of liquid-crystal display elements
flat-panel display
a single image produced by one complete scan of the sound beam
frame
number of frames of echo information stored each second
frame rate
constant display of one of the frames in memory
freeze
ratio (in decibels) of amplifier output to input electric power
gain
range of brightness (gray levels) between white and black
Gray-scale
the part of the image processor where echo information is stored in image format
image memory
an electronic device that manipulates and prepares images for visual presentation
image processor
gain controls that enable different gain values to be applied laterally across an image to compensate for differing attenuation values in different anatomic regions
lateral gain control
A B-mode presentation of changing reflector position (motion) versus time
M mode
the extension of the field of view beyond the normal limits of a transducer scan plane
panoramic imaging
averaging sequential frames together
persistence
a beam of light
physical beam
the system provides means for electronically communicating images and associated information to workstations and devices external to the sonographic instrument, the examining room, and even the building in which the scanning is done
picture archiving and communications system
picture element; the unit into which imaging information is divided for a storage and display in a digital instrument
pixel
imaging processing done after storage in the memory
postprocessing
signal and image processing accomplished before storage in the memory
preprocessing
the high frequency generator generates short waves
pulse-echo principle
voltages representing echoes in cyclic form
radio frequency
imaging with a rapid frame sequence display
real-time
a display that, with a sufficient frame rate, appears to image moving structures or a changing scan plane continuously
real-time display
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
refresh rate
a line produced on a display that represents ultrasonic echoes returning from the body. A sonographic image is composed of many such lines.
scan line
the sweeping of a sound beam through the anatomy to produce an image
scanning
transverse wave
shear wave
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
an electronic device that manipulates electric signals in preparation for appropriate presentation of information contained in them
signal processor
averaging of frames that view the anatomy from different angles
spatial compounding
the increase or decrease of the length of a segment of a material, subjected to a stress, divided by its original length
strain
a force per unit area applied to a material that compresses or stretches it
stress
ability to distinguish closely spaced events in time; improves with increased frame rate
temporal resolution
equalization of echo amplitude differences caused by different attenuations for different reflector depths
time gain compensation
an imaginary beam that describes the result of retrospective, computed beam forming.
virtual beam
three-dimensional imaging
volume imaging
a measure of the hardness of a material. It is the ratio of the applied stress to the resulting strain in a material subjected to the stress
Young’s modulus
The ultrasound PRF is equal to the voltage ______ repetition frequency of the pulser.
pulse
Increased voltage amplitude produced by the pulser increases the ______ and _______ of ultrasound pulses produced by the transducer.
amplitude, intensity
If a 6 MHz transducer images to a depth of 10 cm, to avoid range ambiguity, the maximum PRF permitted is ______.
7.7 kHz
Functions performed by the signal processor include ______, _______, and _______.
filtering, detection, compression
If the input voltage to an amplifier is 1 mV and the output voltage is 10 mV, the voltage amplication ratio is ______. The power ratio is ______. The gain is _____ dB.
10, 100 20
An amplifier with a gain of 60 dB has 1 uW of power applied to the input. The output power is ______ W.
1
An amplifier with a gain of 60 dB has 10 uV of voltage applied to the input. The output voltage is ______.
10
Time gain compensation is accomplished in the
beam former
Compensation takes into account reflector _____.
depth
Compensation amplifies echoes differently, according to their arrival ______.
times
Compression decreases the ______ range to a range that the _____ and human _____ can handle.
dynamic, display, vision
If a display has a dynamic range of 20 dB and the smallest voltage it can handle is 200 mV, then the largest voltage it can handle is _____ V.
2.0
Detection converts voltage pulses from ______ form to ______ form.
radio frequency, amplitude
Filtering widens bandwidth
false
Filtering is accomplished in the
signal processor
The compression or dynamic range control reduces the range of echo amplitudes displayed by reducing the weakest to _____ and/or the strongest ones to the ______ value and assigning the others to increasing values. This produces a(n) _______ contrast image with elimination of weakest and maximizing of strongest echoes.
zero, maximum, higher
An amplifier has a power output of 100 mW when the input power is 0.1 mW. The amplifier gain is _____.
30
If the beam-former output to the transducer is reduced by 3, 6, or 9 dB, the ultrasound pulse output intensity is reduced by _____%, _____%, or _____%, respectively.
50, 75, 87.5
One watt is _____ dB below 100 W.
20
One watt is ______ dB above 100 mW.
10
If the input power is 1 mW and the output is 10,000 mW, the gain is _____ dB.
40
If an amplifier has a gain of 15 dB, the ratio of output power to input power is ______.
32
If the output of a 22-dB gain amplifier is connected to the input of a 23-dB gain amplifier, the total gain is _____ dB. The overall power ratio is _____.
45, 32,000
If a 17-dB electric attenuator is connected to a 15-dB amplifier, the net gain is _____ dB. The net attentuation is _____ dB. The net attenuation is _____ dB. For a 1-W input, the output is _____ W.
-2,2,0.63
The contrast resolution for an instrument that has an echo dynamic range of 43 dB and 32 shades is ____ dB per shade.
1.3
The contrast resolution for an instrument that has a 6-bit memory and a 45-dB echo dynamic range is _____ dB per shade.
0.7
Typical image pixel dimensions are _____.
512 x 384
_____ total memory elements are required for a 100 x 100 pixel, 5-bit digital memory.
50,000
Memories of _____ bits per pixel are common in ultrasound today.
6 to 8
Digital memories store _____.
numbers
______ is commonly controllable by the operator.
postprocessing
In binary numbers, how many symbols are used?
2
The term binary digit is commonly shortened into the single word _____.
bit
Each binary digit in a binary number is represented in the memory by a memory element, which, at any time, is in one of _____ states that are ______ or ______.
2, on, off
The binary number 10110 represents zero 1, one 2, one 4, zero 8, and one 16; that is, the decimal number 0+2+4+0+16=22. What decimal number does the binary number 11001 represent?
25
The decimal number 13 is made up of one 1, zero 2, one 4, and one 8 (8+4+0+1=13). The number therefore is represented by the binary number
1101
The primary formats of image presentation are called _____ mode, ______ mode, and _____ mode. They are used in _____, ______, and ______ types of clinical imaging, respectively
B (brightness), M (motion), A (amplitude), all, cardiac, ophthalmic
_____ mode is used for studying the motion of a structure such as a heart valve.
M
A B scan presents a cross section through the _____ plane.
scan
A display that shows various echo strengths as different brightnesses is called a ______ - ______ or _______ display.
gray-scale, B mode
The ______ stores the gray-scale image and allows it to be displayed on a computer monitor.
image memory
If the PRF of an instrument is 1 kHz and it displays (single focus) 25 frames per second, there are ____ lines per frame.
40
The PRF is _____ Hz if 30 frames (40 lines each) are displayed per second (single focus).
1200
Imaging involving 10-cm penetration, a single focus, 100 scan lines per frame, and 30 frames per second can be accomplished without range ambiguity.
true
The maximum frame rate permitted for 15-cm penetration, 3 foci, and 200 scan lines per frame is _____.
8.5
