Ultrasound Physics Flashcards
Thermally induced bio effects should be preventable by avoiding a local tissue temperature increase exceeding
A) 1 degrees
B) 4 degrees
C) 10 degrees
D) None
A) 1 degrees
Which intensity descriptor has the lowest numeric value for the characterization of a pulsed-wave Doppler.
A) SATA
B) SPTA
C) SATP
D) SPTP
A) SATA
What does the mechanical index & thermal index indicate on an ultrasound machine
The likelihood of cavitation during an ultrasound exam - mechanical
Estimated temperature increase in tissue
What should you limit when the thermal index exceeds 1
A) overall gain
B) TGC
C) exposure time
D) all of the above
C) exposure time
Which operator control most directly adjusts the intensity of the transmitted pulse
A) receiver gain
B) depth of scanning
C) acoustic output (transmit) power
D) TGC
E) pulse repetition frequency
C)acoustic output (transmit) power
Which of the following would show the highest intensity value
A) SATP
B) SATA
C) Im
D) SPPA
E) SPTP
E) SPTP
Which intensity parameter is not applicable for continuous-wave Doppler
A) SATA
B) SPTA
C) SPPA
D) SAPA
E) SPPA SAPA
Which of the following would most likely have the highest SPTA value
A) CW Doppler
B) B-mode real-time scanners
C) Static B-mode scanners
D) PW Doppler
D) PW Doppler
What does a hydrophone measure
Duty factor, pressure amplitude
You are preforming a ultrasound and notice that the thermal index is greater than 1. Any increase in temperature would be greatest in
A) Liver
B) Lung
C) Kidney
D) Bone
D) Bone
When scanning with PW Doppler, you would affect the acoustic exposure by changing which of the following
A) Doppler gain
B) High pass filter
C) Pulse repetition frequency
D) Baseline position
E) Doppler angle
C) Pulse repetition frequency
When you change the transmit frequency, which of the following is altered
A) displacement amplitude of the particles in the medium
B) speed at which the sound wave propagates through the medium
C) number of cycles per second
D) pulses transmitted per second
E) number of electric impulses applied to the transducer per second.
C) number of cycles per second
In sound wave propagation, a region of elevated pressure is termed
compression
When you switch from a 2.5 MHz to a 5.0 MHz transducer, the sound wavelength
A) doubles
B) quadruples
C) halves
D) quarters
E) is unaffected
C) Halves
Wavelength depends on what two factors
frequency and propagation speed
Which of the following factors does NOT affect impedance
A) stiffness
B) density
C) propagation speed
D) frequency
E) all of the above
D) frequency
You are imaging a structure containing two media having the same acoustic impedance. What will occur at the boundary of the two structures
A) all the sound will be transmitted
B) all the sound will be reflected
C) some of the sound will be reflected
D) some of the sound would be reflected and some would be transmitted
E) most of the sound will be absorbed at the media boundary
A) all the sound will be transmitted
The unit of impedance is
A) Joule
B) Rayl
C) Watts/cm
D) Newton
B) Rayl
While imaging a cyst, you notice shadowing posterior to each lateral border of the cyst. What is the source of the shadows
A) redirection of the sound bean at an interface with different propagation speeds and a curved surface
B) bending of the sound bean due to different media propagation speeds
C) increased attenuation of the sound beam a the boarders of the cyst
D) lateral misregistration of the cyst due to a multipath artifact
E) diffraction of the sound beam resulting in a weakened signal at the lateral borders of the cyst
E) diffraction of the sound beam resulting in a weakened signal at the lateral borders of the cyst
In order to display a structure on your screen, the sound beam must be reflected at the interface. what is required for sound reflection at the interface of two structures
A) oblique incidence at the interface boundary
B) temperature differences between the two media
C) a difference in the acoustic impedance of the media
D) different media diameters
E) different attenuation coefficients
C) a difference in the acoustic impedance of the media
What system control can you adjust to compensate for the effect of sound attenuation in the body
A) TGC
B) Dynamic range
C) Frame averaging (persistence)
D) Depth
E) Line density
A) TGC
The algebraic summation of waves leading to patterns of minima and maxima is called
A) scattering
B) interference
C) absorption
D) refraction
E) diffusion
B) interference
What sound parameter is determined only be the medium
A) frequency
B) period
C) intensity
D) propagation speed
E) none of the above
D) propagation speed
Snell’s law describes
A) the percentage of reflection at an interface with normal incidence and different densities
B) the angle of sound transmission at an interface between media having different propagation speeds
C) the amount of attenuation of sound in tissue with depth
D) the amount of backscatter from a diffuse reflector
E) the angle of sound reflection at an interface with oblique incidence and nonspecular reflection
B) the angle of sound transmission at an interface between media having different propagation speeds
You may observe sound attenuation by all of the following EXCEPT
A) reflection
B) scattering
C) conversion of sound to heat
D) absorption
E) compression
E) compression
During an ultrasound you would be most likely to encounter refraction in this view
A) specular reflector
B) curved interface
C) perpendicular incidence
D) Rayleigh scattering
B) curved interface
What occurs when you image a structure with oblique incidence
angle of reflection will be orientated ___ from the transducer resulting in __ visuakization of the structure
The angle of reflection will be orientated away from the transducer resulting in decreased visualization of the structure
An echo from which one of the following sound reflectors is most dependent on the angle of incidence
A) Rayleigh scatterer
B) diffuse reflector
C) specular reflector
D) acoustic scatterer
E) nonspecular reflector
C) specular reflector
What determines acoustic impedance
density and propagation speed of the medium
According to Snell’s Law, the angle of transmission is related to the incident beam angle and
A) the amount of acoustic impedance mismatch at an interface
B) the change in frequency that occurs at an interface
C) one half the angle of incidence
D) the relative speeds of sound in the two media
D) the relative speeds of sound in the two media
what interactions of sound and tissue decreases the intensity of the transmitted beam
absorption, reflection, scattering, conversion of sound to heat
What is the relationship of frequency and absorption
if frequency is doubled, absorption is doubled
what term is used to describe the reduction in the intensity of sound as it propagates through tissue
attenuation
Another term for nonspecular reflection is
A) destructive interference
B) refraction
C) diffraction
D) scattering
D) scattering
what two conditions must be present to cause refraction of a sound wave
___indidence & diffrent media ___
oblique incidence and different media propagation speeds
when the sound beam is refracted during a sonographic examination which of the following might you detect on the ultrasound image
A) axial misregistration
B) lateral misregistration
C) reverberations posterior to a reflector
D) enhancement of a reflector
B) lateral misregistration
what can you do to enhance the visibility of a specular reflector
scan with perpendicular angle
what interaction of ultrasound and tissue is primarily responsible for imaging the internal structure of organs
scattering
what sound-tissue interaction is necessary to form an ultrasound image
reflection
for soft tissue, one of the factors responsible for determining acoustic impedance is
density
when you image a structure that is a specular reflector, the strength of the received signal depends on what two factors
difference in ___ & ___
difference in acoustic impedance and angle of incidence
when imaging a rounded mass with irregular boarders the mass has much slower propagation speed than surrounding tissue, what sound tissue interaction will be encountered.
A) refraction
B) reflection
C) absorption
D) scattering
E) all of the above
E) all of the above
when imaging a structure that is highly attenuating what imaging effect do you expect to encounter
A) enhancement
B) increasing penetration
C) shadowing
D) refraction
C) shadowing
you have increased the transmit power while preforming an ultrasound this action increases which of the following
A) penetration
B) acoustic power
C) imaging brightness
D) voltage applied to the transducer
E) all of the above
E) all of the above
for pulsed ultrasound, which of the following factors determines the frequency of the sound wave
A) pulse repetition frequency
B) transmitter frequency
C) area of the transducer elements
D) pressure applied to the transducer
B) transmitter frequency
You have decreased the acoustic power by -3dB which of the following most accurately describes this adjustment
A) the intensity has been quadrupled
B) the intensity has been quartered
C) the intensity has been increased 10 times
D) the intensity has been halved
D) the intensity has been halved
which of the following frequeinces is in the audible range
A) 100 MHz
B) 10 kHz
C) 10,000 MHz
D) 10 Hz
B) 10 kHZ
the maximum cyclical change in a quantity is known as
A) amplitude
B) pressure
C) power
D) intensity
A) amplitude
bulk modulus is closely related to which of the following qualities
A) attenuation
B) pressure
C) power
D) volume
E) stiffness
E) stiffness
what term denotes the time it takes for one cycle to occur
period
If the number of cycles in a pulse is increased but the wavelength remains the same which of the following is true
A) the frequency is increased
B) the propagation speed is increased
C) the pulse duration is increased
D) the period is decreased
C) the pulse duration is increased
which if the following is most likely also to decrease beam intensity
A) increasing acoustic output
B) decreasing receiver gain
C) increase focusing
D) increasing beam area
E) increasing amplitude
D) increasing beam area
the regions of low pressure and density that are formed during sound propagation are termed
A) mechanical longitudinal wave
B) radioactive wave
C) transverse rarefactional wave
D) electromagnetic wavy
A) mechanical longitudinal wave
the regions of low pressure and density that are formed during sound propagation are termed
A) compressions
B) shear waves
C) rarefactions
D) cavitation
A) compressions
which of the following increases as frequency increases
A) absorption
B) scattering
C) attenuation
D) A & C only
E) all of the above
E) all of the above
terms used to describe the strength of the sound beam include
A) amplitude & impedance
B) amplitude & wavelength
C) amplitude & intensity
D) intensity and impedance
C) amplitude & intensity
ultrasound propagation velocity depends on
A) amplitude and frequency
B) impedance and attenuation
C) density and compressibility
D) impedance and density
C) density and compressibility
acoustic impedance
A) is independent of the speed of sound
B) is inversely proportional to the density
C) is greater in gas than in metal
D) equals density time the propagation speed
D) equal density time the propagation speed
what determines the speed of sound
A) frequency of sound wave
B) intensity of sound wave
C) attenuation of sound wave
D) reflection of the sound beam
E) medium through which sound wave passes
E) medium through which sound wave passess
you will NOT see refraction in the ultrasound image if
A) the sound strikes an interface at an angle of great 45 degrees
B) the sound beam is perpendicular to the interface
C) the sound beam is 45 degrees to the interface
D) the sound beam changes propagation speed at the interface
B) the sound beam in perpendicular to the interface
when using Doppler the frequency of the transmitted signal is determined by
A) backing material
B) attenuation factor of tissue
C) bandwidth
D) the frequency of the electric signal applied to the transducer
D) the frequency of the electric signal applied to the transducer
power divided by the beam area is equal to the
A) probe angle
B) speed of sound
C) intensity
D) amplitude
C) intensity
axial resolution is determined by
A) beam width
B) transducer diameter
C) pulse duration
D) attenuation coefficient
C) pulse duration
what are two benefits of tissue harmonic imaging
A) grating lobe artifacts are reduced and lateral resolution is improved
B) axial and lateral resolution is improved
C) contrast and axial resolutions are improved
D)penetration is improved and axial resolution is improved
A) grating lobe artifacts are reduced and lateral resolution is improved
acoustic impedance increases with which of the following
A) increases tissue density
B) increased propgation speed
C) increased transducer frequency
D) A & B
E) all of the above
D) A & B
when you adjust the pulse repetition frequency you are changing
A) the number of pulses per line
B) the number of pulses per frame
C) the number of pulses per second
D) the number of wave lengths per pulse
C) the number of pulses per second
The length of space over one cycle occurs is known as the
A) duty factor
B) spatial pulse length
C) wavelength
D) pulse repetition frequency
C) wavelength
which of the following would increase the spatial pulse length
A) increased PRF
B) decreased number of transmit pulses per frame
C) increased number of transmit pulses per second
D) increased number of transmit pulses per line
E) increased number of cycles per pulse
E) increased number of cycles per pulse
the tie that it takes for one pulse to occur us know n as the
A) duty factor
B) spatial pulse length
C) wave length
D) pulse repetition frequency
E) pulse duration
E) pulse duration
bandwidth refers to
A) number of cycles per pulse
B) range of frequencies in a pulse
C) rate of pulse repetition frequency
D) range of pulses in a frame
B) ranges of frequencies in a pulse
when sound strikes a specular reflector at an oblique angle, the angle of reflection is
A) equal to the angle of indacene
B) greater than the angle of incidence
C) less than the angle of indacene
D) twice that of the angle of incidence
A) equal to the angle of incidence
interference patterns of reflected waves cause
A) acoustic speckle
B) acoustic enhancement
C) rarefaction
D) all of the above
A) acoustic speckle
attenuation of the sound bream is affected by
A) absorption
B) scattering
C) reflection
D) propagation speed
E) A, B, & C
E) A, B, C
you are preforming a ultrasound with a wide-bandwidth transducer. the advantage with this transducer compared to a narrower bandwidth transducer is
A) decreased acoustic power output
B) improve axial resolution
C) improved lateral resolution
D) improved focusing
B) improved axial resolution
which of the following transducers creates a rectangular image
A) linear array
B) phased array
C) annular array
D) curved array
A) linear array
for a linear array transducer what method is most used to focus the beam in the elevational direction
A) transmit focusing
B) dynamic receive focusing
C) aperture focusing
D) mechanical focusing
D) mechanical focusing
what type of transducer could you choose to produce a beam that is symmetric about the beam axis
A) annular array
B) linear sequenced array
C) phased array
D) curved array
A) annular array
which of the following will NOT improve axial resolution
A) increased damping
B) increased transducer frequency
C) increased bandwidth
D) increased pulse length
E) increased focusing
E) increased focusing
an ultrasound image has a sector display format that narrows to a point at the transducer surface, what kind of transducer produces this image
A) linear array
B) phased array
C) curved array
D) annular array
B) phased array
what is the main advantage of using a 1.5D or multirow array transducer
A) narrow slice thickness over a large part of the scanned volume
B) increased penetration
C) improved axial resolution
D) faster frame rates
A) narrow slice thickness over a large part of the scanned volume
what benefit would you obtain by choosing a transducer having a large diameter compared to one having a smaller diameter
A) it can focus at greater depths
B) it increases frequency
C) it increases the beam diameter in the far field
D) all of the above
A) it can focus at greater depths
What type of transducer has the same measurement for elevational and lateral resolution
A) convex linear array
B) phased linear array
C) annular array
D) mechanical sector
C) annular array
with a 1D linear array where in the out-of-plane dimension is the dimension of the sound beam the narrowest
A) it is at the point of mechanical focusing
B) it is the point of electronic focusing
C) the beam is same width through the image
D) it is in the far field
A) it is the point of mechanical focusing
another name for axial resolution is
A) transverse resolution
B) azimuthal resolution
C) angular resolution
D) range resolution
D) range resolution
dynamic apodization is a method employed to
A) focus the beam at multiple depths on transmit
B) focus the beam at multiple depths on receive
C) reduce side lobes
D) steer the beam
C) reduce side lobes
which statement is most accurate regarding resolution with a standard one-dimensional linear array transducer
A) axial resolution is the worst measure of resolution with this transducer
B) lateral resolution is the worst measure of resolution with this transducer
C) elevational resolution is the worst measure of resolution with this transducer
D) isotropic spatial resolution
C) elevational resolution is the worst measure with this transducer
during an ultrasound you notice lateral splaying of the echo’s in the far field what can you do to improve the image
A) use maximum acoustic power
B) use lowest line density setting
C) increase the number of transmit focal zones and optimize their location
D) decrease scanning depth
C) increase the number of transmit focal zones and optimize their location
you suspect that there is a calcification but shadowing is not present how do you optimize to demonstrate a shadow
A) move the focal zone well below the hyperechoic focus
B) increase transducer frequency
C) increase acoustic power
D) increase dynamic range
B) increase transducer frequency
when an electric signal is applied to a piezoelectric element, what happens to the element
A) changes temperature
B) expands and contracts
C) produces an electrical signal of opposite polarity
D) emits electromagnetic radiation
B) expands and contracts
you are scanning a phantom containing multiple rows of identical 5 mm spherical fluid filled structures embedded in a tissue mimicking material. what type of resolution is best elevated with this phantom
A) axial
B) lateral
C) contrast
D) elevational
D) elevational
Which statement is NOT true about lateral resolution
A) it is equal to beam width
B) it is improved by focusing
C) it is known as azimuthal resolution
D) it remains constant throughout scanning depth
D) it remains constant throughout scanning depth
Which type of transducer should you select to produce the narrowest slice thickness throughout the image plane
A) 1.5D multirow array
B) phased array with small foot print
C) tightly curved curvilinear array
D) mechanical sector
A) 1.5D multirow array
If you choose a lower frequency transducer to image highly attenuating structures, what trade off are you making
A) decreased penetration for increased resolution
B) decreased beam intensity for longer wavelengths
C) decreased spatial resolution for improved penetration
D) increased beam refraction for higher sound speed
C) decreased spatial resolution for improved penetration
dynamic receive focusing uses
A) mechanical means to focus the beam
B) time delays to excite array elements
C) variable number of elements to form the transmitted beam
D) time delays before echo signals from array elements are combined
D) time delays before echo signals from array elements are combined
varying the excitation voltage to each element in the group used to form the ultrasound pulse is called
A) apodization
B) dynamic aperture
C) interelement isolation
D) rectification
A) apodization
which of the following describes a phased array transducer
A) electronically focused in 2 dimensions and mechanically steered
B) electronically focused along the length of the array, mechanically focused along the elevational dimension (width) and electronically steered
C) electronically focused along the elevational dimension of the array mechanically focused along the length of the of the array, unsteered
D) mechanically focused in two dimensions and mechanically steered
B) electronically focused along the length of the array, mechanically focused along the elevational dimension (width) and electronically steered
resolution of two structures at different depths along the path of the sound beam is termed
A) contrast resolution
B) temporal resolution
C) axial resolution
D) lateral resolution
C) axial resolution
which transducer has the same distance between the scan line’s in both near and far field
A) convex array
B) phased array
C) curvilinear array
D) linear array
D) linear array
which of the following minimizes the degree to which beam width varies with depth
A) apodization
B) dynamic aperture
C) frame averaging (persistence)
D) rectification
B) dynamic aperture
The sound beam can be focused by all of the following except
A) acoustic mirror
B) acoustic lens
C) curved crystal
D) matching layer
E) electronic phasing
D) matching layer
For a single transducer to offer multiple frequency selections for scanning it must have
A) large dynamic range
B) wide bandwidth
C) dynamic aperture
D) electronic steering capability
B) wide bandwidth
what type of focusing decreases the frame rate
A) mechanical focusing
B) dynamic receive focusing
C) dynamic aperture focusing
D) multiple transmit focusing
D) multiple transmit focusing
the ability to distinguish between adjacent structures that produce echo’s of similar amplitude is termed
A) spatial resolution
B) axial resolution
C) lateral resolution
D) temporal resolution
E) contrast resolution
E) contrast resolution
when you increase the scan line density in the B-mode image you improve
A) temporal resolution
B) contrast resolution
C) axial resolution
D) lateral resolution
D) lateral resolution
electronic focusing in the transmit mode is accomplished using
A) curved crystal elements
B) receive time delays
C) time delays to excite transducer elements
D) high pulse repetition frequency
C) time delays to excite transducer elements
what is an advantage of single crystal or pure wave crystal transducers
A) wide bandwidth
B) lower frequencies at higher resolution
C) higher frame rates
D) greater steering angles
A) wide bandwidth
Increasing the number of transmit focal zones to improve spatial resolution involves the following trade off
A) lateral vs axial resolution
B) lateral vs temporal resolution
C) spatial vs contrast resolution
D) contrast resolution vs frame rate
B) lateral vs temporal resolution
which of the following is not associated with a low Q transducer
A) wide bandwidth
B) multifrequency selection
C) long pulse length
D) diagnostic pulsed wave - ultrasound
C) long pulse length
if the number of cycles in the transmitted pulse is increased
A) axial resolution is degraded
B) lateral resolution is degraded
C) spatial pulse is length becomes shorter
D) penetration is decreased
A) axial resolution is degraded
if the frame rate is too slow for adequate temporal resolution what action could you take to improve frame rate
A) reduce the number of transmit focal zones
B) increase the scan line density
C) increase the scanning depth
D) decrease dynamic range
A) reduce the number of transmit focal zones
spatial resolution consists of
A) contrast and temporal resolution
B) temporal and axial resolution
C) contrast and lateral resolution
D) lateral and axial resolution
D) lateral and axial resolution
what type of resolution is affected most by pulse duration
A) lateral resolution
B) contrast resolution
C) temporal resolution
D) axial resolution
D) axial resolution
with a standard one dimensional linear array transducer, what type of resolution is affected most by electronic focusing and dynamic aperture
A) lateral resolution
B) contrast resolution
C) temporal resolution
D) axial resolution
A) lateral resolution
what type of resolution is most affected by the mechanical focus on a linear array transducer
A) lateral
B) axial
C) temporal
D) elevational
D) elevational
a method for imporving frame rates with multizone electronic focusing is
A) apodization
B) parallel processing
C) use of low Q transducer
D) none of the above
B) parallel processing
if you wish to use an array transducer that allows you to control transmit focal depth what type would you select
A) linear array
B) convex array
C) phased array
D) annular array
E) any of the above
E) any of the above
for a non-focused transducer, the region between trhe transducer and the point at which the sound beam is narrowest is called
A) far field
B) Fraunhofer zone
C) near - zone length
D) focal distance
C) near - zone length
axial resolution is determined by
A) beam width
B) transducer diameter
C) pulse duration
D) frame rate
C) pulse duration
what term describes the ability of an imaging device to separate closely spaced objects
A) resolution
B) penetration
C) duty factor
D) interference
A) resolution
what array transducer fires all of the elements for each acoustic scan line using small time delays to steer the beam
A) linear segment array
B) convex array
C) annular array
D) phased array
D) phased array
if you are using a transducer with poor elevational resolution which of the following problems are you most likely to occur
A) inability to resolve 2 structures that lie close together and parallel to the path of the beam
B) inability to penetrate through dense tissue
C) inability to clearly demonstrate small cystic structure
D) inability to demonstrate moving structures accurately
C) inability to clearly demonstrate small cystic structure
what can you do to achive a higher frame rate
A) decrease the number of focal zones
B) decrease the line density
C) decrease sector size
D) all of the above
D) all of the above
what can you do to improve contrast resolution
A) increase sector width
B) decrease the number of focal zones
C) use a 2D or matrix array transducer
D) use a phased array transducer
C) use a 2D or matrix array transducer
increasing which if the following will result in improved axial resolution
A) pulse duration
B) pulse length
C) frequency
D) period
C) frequency
which of the following produces side lobes or grating lobes
A) mechanical sector
B) linear sequential array
C) phased array
D) convex array
E) all of the above
E) all of the above
which of the following can not be evaluated with a tissue equivalent phantom
A) axial resolution
B) lateral resolution
C) contrast resolution
D) temporal resolution
D) temporal resolution
you notice a loss of detail in the lateral dimension of the ultrasound image what can you do to improve this
A) decrease the number of focal zones
B) increase the scan line density
C) decrease the transducer frequency
D) increase dynamic range
B) increase the scan line density
which transducer would have a lower line density in there far field compared to the near field
A) linear array
B) curved array
C) tightly curved array
D) phased array
B, C, D
axial resolution is improved with
A) increased bandwidth
B) shorter pulse length
C) shorter wave length
D) B & C
E) all of the above
E) all of the above
what is a side lobe
A) uneven transducer element
B) accessory pulse used for electronic steering
C) sound beam emitted from the transducer that travels in a different direction from the main beam
D) nonlinear propagation of the sound beam
C) sound beam emitted from the transducer that travels in a different direction from the main beam
what is the purpose of curving the transducer elements or applying a lens
A) to provide focusing in the elevational direction
B) reduce acoustic impedance mismatch between crystal and skin
C) reduce crystal ringing and improve axial resolution
D) help reduce electronic inference
A) to provide focusing in the elevational direction
in order to focus a sound beam relatively far away from the transducer, it is advantageous to
A) increase the thickness of the element
B) increase the diameter of the element
C) decrease the width of the element
D) decrease the frequency of the element
B) increase the diameter of the element
what is the disadvantage of using multiple transmit focal zones
A) decreased lateral resolution
B) decreased temporal resolution
C) decreased elevational resolution
D) decreased axial resolution
B) decreased temporal resolution
what is the advantage of using multiple transmit focal zones
A) increased lateral resolution
B) increased temporal resolution
C) increased elevational resolution
D) increased axial resolution
A) increased lateral resolution
which factor least influences axial resolution
A) damping
B) beam width
C) frequency
D) pulse duration
B) beam width
what factor least influences lateral resolution
A) frequency
B) focus depth
C) beam width
D) damping
D) damping
what system control determines the amount of amplification that occurs in the receiver
A) gain
B) acoustic power
C) dynamic range
D) rectification
A) gain
when you adjust the output power control you affect the following system
A) pulser
B) beam former
C) scan converter
D) receiver
A) pulser
what system control do you adjust to equalize the differences in echo amplitudes received from similar structures situated at different depths
A) dynamic range or compression
B) rectification
C) TGC
D) rejection
C) TGC
electronic noise is reduced in the ultrasound system by
A) demodulation
B) compensation
C) amplification
D) rejection
D) rejection
what term below describes the rate at which the transmitter applies electronic voltage pulses to the transducer
A) period
B) pulse repetition frequency
C) demodulation
D) depth gain compensation
B) pulse repetition frequency
pulsing of the transmitted sound wave is necessary for real time imaging because
A) the depth of the interface from which the echo originated can be determined
B) lateral resolution is improved by pulsed transmission
C) temporal resolution is improved by pulsed transmission
A) the depth of the interface from which the echo originated can be determined
the receiver function is responsible for decreasing the difference between the smallest and largest received signal amplitudes
A) amplification
B) compensation
C) compression
D) demodulation
C) compression
what receiver function is not operator adjustable
A) amplification
B) compensation
C) demodulation
D) rejection
C) demodulation
what part of the sonographic instrument is responsible for apodization, beam steering and aperture control
A) beam former
B) receiver
C) memory
D) pulse
A) beam former
which control would you adjust to alter dynamic range of the displayed echoes
A) compression
B) transmit power
C) TGC
D) focusing
A) compression
the technique of frame averaging (persistence) during real time acquisition is designed to
A) reduce random noise
B) decrease pixel size
C) increase frame rate
D) enhance spatial resolution
A) reduce random noise
when performing an ultrasound you select the tissue harmonics operating mode, what advantage will you obtain over conventional imaging
A) improved contrast resolution
B) improved penetration
C) increased bandwidth
D) improved temporal resolution
A) improved contrast resolution
you have decreased the scan line density what technique will be employed to fill in the empty data between the scan lines
A) interpolation
B) rejection
C) compression
D) demodulation
A) interpolation
to generate an ultrasound image what is the order in which the following system components are activated
A) pulser, receiver, display, beam former, memory
B) pulser, beam former, receiver, memory, display
C) beam former, pulser, memory, display, receiver
D) memory, beam former, pulser, receiver, display
B) pulser, beam former, receiver, memory, display
what control could you adjust to improve the signal to noise ratio on the image
A) dynamic range
B) frame averaging (persistence)
C) gray scale map
D) receiver gain
B) frame averaging (persistence)
the ratio of the largest to the smallest signal that a system can handle is termed
A) apodization
B) compression
C) PRF
D) dynamic range
D) dynamic range
duty factor is defined as
A) the fraction of time the transducer is actively transmitting sound
B) the fraction of time the transducer is actively receiving
C) the fraction of time between the transmitted and received sound pulse
D) the fraction of time between transmitted sound pulses
A) the fraction of time the transducer is actively transmitting sound
If you increase the PRF and leave all other controls unchanged what will happen
A) lateral resolution will improve
B) frame rate will be increased
C) frame rate will decrease
D) axial resolution will improve
B) frame rate will be increased
if you increase PRF to a level too great for the depth of field, the result will be
A) increased side lobes
B) increased grating lobes
C) range ambiguity
D) decreased frame rate
C) range ambiguity
what effect will you see in the image if you increase the reject level
A) increase # of shades of gray
B) decrease low-level echo’s
C) decrease frame rates
D) decreased scanning depth
B) decrease low-level echo’s
the term signal to noise ratio denotes
A) the ratio of the electronic noise to the radiofrequency noise
B) the ratio of the system power to the weakest detectable signal
C) the relative amplitude of the signal compared to the amplitude of the noise
D) the ratio of the largest to the smallest signal that the system can display
C) the relative amplitude of the signal compared to the amplitude of the noise
what receiver function converts the negative portion of the RF signal to positive
A) compression
B) demodulation
C) rectification
D) amplification
C) rectification
increasing the dynamic range setting affects the image by
A) increasing image brightness
B) decreasing image contrast
C) improving spatial resolution
D) improving signal to noise ratio
B) decreasing image contrast
when you adjust TGC what component of the ultrasound system implements the changes
A) pulser
B) receiver
C) monitor
D) scan converter
B) receiver
what system component determines the PRF
A) pulser
B) receiver
C) memory
D) display
A) pulser
what function of the receiver converts electric signals from radiofrequency to video form
A) amplification
B) compensation
C) compression
D) demodulation
D) demodulation
the incoming raw echo signals must be compressed into a smaller dynamic range because
A) a wide dynamic range results in an increased display of electronic noise
B) a wide dynamic range does not allow differentiation between echo’s arriving from different depths
C) the display cannot accommodate the wide dynamic range of the incoming signals
D) a wide dynamic range compromises spatial resolution
C) the display cannot accommodate the wide dynamic range of the incoming signals
which of the following is not a function of the receiver
A) amplification
B) RF to video conversion
C) demodulation
D) dynamic aperture
D) dynamic aperture
what system function is limited by the speed of sound in tissue
A) demodulation
B) PRF
C) voltage amplitude
D) TGC
B) PRF
what control should you adjust to modify the image if the attenuation coefficient of the tissue is very high
A) dynamic range
B) rejection
C) threshold
D) compensation
D) compensation
what can you do to improve the temporal resolution while scanning
A) increase number of focal zones
B) increase the depth
C) increase sector width
D) decrease the acoustic scan line density
D) decrease the acoustic scan line density
you made changes to the following controls during an exam which adjustment increased the duty factor
A) increasing receiver gain
B) increasing output power
C) increasing PRF
D) increasing TGC
C) increasing PRF
the number of images displayed per second in real time imaging is termed
A) PRF
B) PRP
C) frame rate
D) pulse duration
C) frame rate
electronic steering is most commonly applied to which if the following real-time transducer
A) annular array
B) mechanical sector
C) phased array
D) segmental linear array
C) phased array
while preforming a an ultrasound you increase both imaging depth and scan line density these result in
A) reduced contrast resolution
B) reduced temporal resolution
C) improved axial resolution
D) reduced lateral resolution
B) reduced temporal resolution
increasing the number of acoustic scan lines in one frame improves whic if the following
A) temporal resolution
B) axial resolution
C) elevational resolution
D) lateral resolution
D) lateral resolution
what system control converts the numbers stored in memory to proportional voltages that control the brightness on a cathode ray tube monitor
A) analog to digital converter
B) digital to analog converter
C) cathode ray tube
D) pulser
B) digital to analog converter
the spatial resolution of the scan converter is determined by
A) # of pixels in the scan converter matrix
B) # of bits per pixel
C) the post processing settings
D) interpolation scheme
A) # of pixels in the scan converter matrix
where are the images stored in in the ultrasound system
A) pulser
B) receiver
C) beam former
D) scan converter
D) scan converter
what system control is responsible for transmit focusing
A) receiver
B) monitor
C) beam former
D) preprocessing
C) beam former
which of the following describes an analog signal
A) values are discrete
B) there are fixed steps between values
C) continuous variation of the signal is possible
D) levels are determined by bits
C) continuous variation of the signal is possible
digital to analog conversion of the ultrasound signal must occur at what part of the imaging process\
A) between transducer and receiver
B) between beam former and transducer
C) between receiver and scan converter
D) between scan converter and display
D) between scan converter and display
what type of resolution is determined by the number of pixels in the scan converter
A) temporal
B) contrast
C) spatial
D) elevational
C) spatial
what can you improve by changing the gray-scale map
A) axial resolution
B) lateral resolution
C) contrast resolution
D) temporal resolution
C) contrast resolution
what is the order in which the signal travels in the ultrasound system
A) transducer, receiver, display, scan converter
B) scan converter, transducer, receiver, display
C) scan converter, receiver, transducer, display
D) transducer, receiver, scan converter, display
D) transducer, receiver, scan converter, display
which is the best choice to help you demonstrate tissue boundaries that are not perpendicular to the sound beam
A) speckle-reducing algorithm
B) spatial compounding
C) persistence
D) TGC
B) spatial compounding
which of the following artifacts may result in both axial and lateral displacement of a reflector on ann ultrasound
A) refraction
B) side-lobe
C) multipath
D) enhancement
B) side-lobe
the range equation describes the relationship between
A) acoustic impedance of two media
B) side lobe intensity between 2 crystals
C) round trip pulse travel time and distance to the reflector
D) bandwidth and transducer frequency
C) round trip pulse travel time and distance to the reflector
which imaging technique may increase visualization of the reflections from blood flow on the real time ultrasound image
A) compound imaging
B) tissue harmonic imaging
C) 3D imaging
D) speckle reduction imaging
B) tissue harmonic imaging
which of the following artifacts is the result of reverberation
A) comet tail
B) acoustic speckle
C) beam-width
D) refraction
A) comet tail
propagation speed error results in which appearance
A) improper lateral position of an echo
B) improper axial position of an echo
C) shadowing behind an echo
D) enhancement
B) improper axial position of an echo
when you select harmonic imaging, which artifact is less likely to be observed
A) refraction
B) shadowing
C) ring down
D) grating lobes
D) grating lobes
when you select spatial compound imaging which artifact is less likely to be observed
A) refraction
B) shadowing
C) enhancement
D) acoustic speckle
all of the above
selective reception of echo’s generated within the body by non-linear propagation describes
A) compound imaging
B) tissue harmonic imaging
C) speckle reduction imaging
D) 3D imaging
B) tissue harmonic imaging
what can you do to improve visualization of distal acoustic shadowing from calcification
A) compound imaging
B) tissue harmonic imaging
C) speckle reduction
D) 3D imaging
B) tissue harmonic imaging
which of the following help to improve the axial resolution in a B-mode image
A) increased aperture
B) increased bandwidth
C) increasing dynamic range
D) beam steering
B) increased bandwidth
which of the following helps to improve lateral resolution on B-mode imaging
A) increased aperture
B) increased bandwidth
C) focusing with a lens
D) beam steering
A) increased aperture
which of the following helps improve elevational resolution
A) increased transmit power
B) increased bandwidth
C) focusing with an acoustic lens
D) beam steering
C) focusing with an acoustic lens
which artifact is related to the sound beam traveling through a structure with low attenuation
A) comet tail
B) aliasing
C) enhancement
D) side lobe
C) enhancement
what type of imaging results in selective reception of frequencies that are two times that of the transmitted frequency
A) colour Doppler
B) pulsed Doppler
C) tissue Doppler
D) tissue harmonic imaging
D) tissue harmonic imaging
