-
What type of medium has has the highest absorption coefficient? (air, bone, or soft tissue(water)
Bone
-
The propagation speed is fastest in? (soft tissue, bone or air)?
Soft tissue
-
For soft tissue, if the path length is doubled, total attenuation will:
Double
-
If the attenuation coefficient for muscle is 5.0 dB at 3MHz, what is the attenuation coefficient at 6MHz?
10
-
The portion of sound energy redirected towards the sound source is called:
Reflected
-
If the acoustic output is set at 0 dB, this indicates:
Reference intensity level
-
If the half value layer thickness for muscle is 4cm at 2MHz, the HVL thickness at 4MHz is ___cm.
2
-
If the amplitude is increased by a factor of 2, intensity:
Increases by a factor of 4
-
The maximum pressure variation that occurs in a cycle is termed:
Amplitude
-
An ultrasound field in soft tissue experiences an intensity reduction of 9 dB. This is equivalent to ____ Half Intensity Depth(s).
3
-
The tissue property that determines the amount of refraction at an interface is:
Velocity
-
If the reflection intensity coefficient at an interface is 25%, what is the transmission intensity coefficient?
75
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Acoustic impedance is equal to:
Density x velocity
-
The propagation speed through the medium is NOT dependent on:
Frequency
-
If the initial intensity is reduced to 25%, this is equivalent to ____ dB.
6
-
Which of the following is an example of a specular reflector?
Diaphragm
-
If the acoustic power is doubled, intensity will:
Double
-
If the wavelength is decreased by 1/4 , the frequency will:
increase by 4
-
What is the typical transmission coefficient at a soft tissue/air interface?
0.1
-
As the temperature decreases, the propagation speed in tissues would:
Decrease
-
If the total attenuation at 2 MHZ = 20 dB, the total attenuation at 4 MHz is ____ dB.
40
-
Which of the following accounts for the greatest portion of the attenuation rate at an air/soft tissue interface?
Reflection
-
Which of the following types of media would have the highest characteristic acoustic impedance value?
soft tissue/air (99.9% reflected back)
-
Decreasing the beam area to 1/6 of the original will result in:
increasing intensity
-
Which of the following conditions is most likely to produce the greatest amount of refraction? (0 degrees = normal incidence)
Muscle/bone interface - 20 degree incidence
-
If the wavelength for a sound field = 2 mm, which of the following interfaces would most likely behave as a specular reflector?
4.0 mm
-
If the wavelength for a sound field is 1 mm, which of the following reflectors would behave as a non-specular reflector?
0.5 mm
-
If the transmission coefficient is 60% at an interface, the reflection coefficient is:
40
-
Which of the following would have the lowest absorption coefficient?
Water
-
Which of the following mediums would have the largest half intensity depth in cm?
soft tissue
-
The sonographic pattern displayed distal to a region with a low attenuation rate is termed:
Enhancement
-
What is the typical per cent reflection at a muscle/bone interface?
50
-
Which of the following factors accounts for the greatest portion of the attenuation rate in soft tissue?
Absorption
-
If the acoustic output is increased by 9 dB, the resulting intensity has increased by a factor of:
8
-
The theory/principle that relates the angle of incidence to the angle of refraction is:
Snell's law
-
A large amplitude pulse (voltage) from the pulser results in:
Increasing transmit intensity
-
Which control changes the intensity of the transmitted pulse?
Acoustic power
-
Increasing the pulse repetition frequency will:
Decrease the maximum imaging depth
-
The primary method that the sonographer uses to control frame rate during real time imaging is:
Imaging depth
-
The initial amplitude is determined by :
Acoustic power control
-
According to the range equation, which of the following are required to calculate the distance to the reflector?
Propagation speed and round trip time
-
The signal processing function that eliminates the negative component of the signal is termed:
Rectification
-
The System Gain function is performed in the:
Beam former
-
Reflector B is twice the distance from the transducer as reflector A. It takes ______ times as long for an echo to arrive from reflector B as from reflector A.
2
-
The sonographer has increased the size of the sector width to image a large mass. What can the sonographer do to maintain the same temporal resolution before this adjustment?
Decrease the number of focal zones.
-
Increasing the number of scan lines per frame improves:
Detail resolution
-
If the gain is increased by 9 dB, the power has been increased by a factor of:
8
-
Adjusting the TGC controls affects the settings in the:
Beam former
-
Which of the following transducer arrays utilizes electronic beam steering?
Sector
-
On an A-Mode display, the height of the spike represents:
The echo intensity
-
The computer parameter that limits the number of gray levels available to display on the image matrix is:
Number of bits in computer word
-
Which of the following system components generates the signals to focus and steer the sound field?
Beam former
-
The pulse repetition period is the reciprocal of:
Pulse repetition frequency
-
In cardiac imaging, reducing the size of the sector angle will:
Increase the frame rate
-
The ability to distinguish between adjacent structures producing echo amplitudes of similar amplitude is termed:
Contrast resolution
-
The typical dynamic range in the amplifier is:
60-100
-
What is the maximum number of displayed shades of gray in a 7-bit processor?
128
-
Which of the following digital scan converters would display the best contrast resolution?
8 bit
-
In which of the following modes is time the unit of measurement on one axis?
M-mode
-
How many levels of information can a single bit represent?
2
-
Preprocessing programs are performed in the:
Image processor
-
Postprocessing programs are performed in the:
Display
-
The use of cine loop will primarily improve _________ resolution
Temporal
-
During real time imaging, if the scan line density is reduced to 1/4, the maximum frame rate is:
Increased by a factor of 4
-
In clinical applications, maximum reflection amplitude occurs with:
Normal incidence
-
At a muscle/fat boundary, the percentage of sound energy reflected will be:
60 %
-
As sound propagates through the medium, amplitude:
Decreases
-
As frequency increases, half intensity depth:
Decreases
-
Propagation speed is determined by the:
Medium
-
By altering the imaging depth, the period of the wave:
Remains unchanged
-
At a soft tissue/air interface, the percentage of sound transmitted will be:
0.1%
-
Determine the power if the amplitude of the wave is 4.
- 16 = 42
- Power = amplitude2
-
The _______ is a unit of measurement used to express the difference or ratio between two variables.
decibel
-
The sonographer can change the sound field intensity by manipulating:
Transmit power
-
For soft tissue, which of the following would most likely be used to represent a 50% reduction in intensity?
-3 dB
-
The total attenuation for a 10 MHz sound field in soft tissue at 2 cm is _____ dB.
10dB
-
Increasing intensity increases
Propagation speed
-
At soft tissue interfaces, the percentage of ultrasound energy transmitted is approximately _____ %,
99
-
Which of the following has an average propagation speed of 1.54 mm/µs?
Muscle, soft tissue
-
As sound propagates through the medium, intensity:
Decreases
-
Frequency is determined by the:
Piezoelectric element
-
The best example of a Rayleigh scatterer is:
Red blood cell
-
The initial amplitude is determined by :
Acoustic power control
-
As propagation speed and density values increase, acoustic impedance:
Increases
-
Determine the attenuation coefficient in dB/cm for a 10 MHz sound field in soft tissue.
10dB/cm
-
The attenuation rate will increase if there is an increase in:
frequency
-
A region of high pressure, high density is:
Compression
-
Wavelength is determined by the:
- Frequency
- (increase frequency to decrease wavelength)
-
To maximize reflection from a specular reflector, the sonographer should strike the interface at ______ degrees.
90
-
This artifact cannot occur at perpendicular incidence
Refraction
-
As sound propagates through a medium, power:
Decreases
-
A sound beam's wavelength is 0.5 mm. Which of the following would be an example of a nonspecular reflector?
0.4 mm
-
Impedance is equal to:
c x p
-
For an unfocused circular soundfield, the crystal diameter is 30 mm. What is the beam diameter in mm at a depth equal to twice the near field length?
30
-
Elevational resolution is related to:
Beam width
-
The intensity of a focused beam is generally:
Highest in the focal zone
-
The product of the period and the number of cycles in the pulse is:
Pulse duration
-
Axial resolution can be improved by using:
Higher frequency transducers
-
The type of real-time transducer that employs a combination of electronic focusing and mechanical steering is:
Vector array
-
The reverse piezoelectric effect is best described as:
Mechanical deformation resulting from high voltage applied on crystal faces, generating ultrasound
-
Which of the following transducers would be most useful for imaging superficial structures?
5 MHz, superficial focus
-
Lateral resolution is equal to:
Beam area
-
The unit of measurement for the duty factor is:
Percent
-
Increasing the pulse repetition period:
Increases the maximum imaging depth that can be imaged
-
For an unfocused sound field utilizing a 10 mm crystal diameter, the sound field diameter at the end of the near field will be ____ mm.
5
-
Grating lobes in electronic array systems:
Are controlled with a process called subdicing
-
As frequency increases, the beam width will:
Decrease
-
The principle that states that all points on a wavefront can be considered as point sources for the production of spherical secondary wavelets was postulated by:
Huygen
-
The ____ relates the bandwidth to operating frequency
Quality factor
-
For an unfocused circular sound field, the crystal diameter is 40 mm. What is the beam diameter 1cm from the crystal surface in mm?
40
-
The piezoelectric properties of the transducer will be lost if the crystal is heated above the:
Curie point
-
What is the most commonly used material for ultrasound transducer crystal elements?
Lead zirconate titanate
-
A decreased pulse duration produces:
Better axial resolution
-
The beam of an unfocused transducer diverges where?
- In the Fraunhofer zone
- Far Field
-
The amount of divergence in the far field can be decreased by:
Increasing the frequency or a larger crystal diameter
-
The near field length of an unfocused transducer depends on:
Frequency and diameter
-
Extraneous sound energy emitted from a linear sequenced array are called:
- Grating Lobes
- Corrected by subdicing
-
The spatial pulse length:
Decreases with increasing frequency
-
Transmit delay focusing in a linear array transducer will improve:
Lateral resolution
-
Axial resolution depends on the ______
wavelength/frequency (higher frequency/shorter wavelength)
-
The damping material will improve
Increase damping material>>shorter pulse>>wider bandwidth>>better axial resolution
-
For a given sound field, which of the following would demonstrate the lowest intensity value?
SATA
-
What type of tissue is most susceptible to the effects of cavitation?
- Aerated lung tissue
- Air in GI tract
-
With all other parameters constant, increasing the acoustic output will:
Increase intensity
-
Which artifact is associated with reverberation and resonance in a small gas bubble or surgical staple?
Comet tail
-
Which control changes the intensity of the transmitted pulse?
Acoustic power
-
Increasing the number of scan lines per frame improves:
Detail resolution
-
The use of cine loop will primarily improve _________ resolution
Temporal
-
What system component generates the signals to focus and steer the sound field?
Beam former
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