{"id":110916,"date":"2023-07-28T14:50:07","date_gmt":"2023-07-28T14:50:07","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=110916"},"modified":"2023-07-28T14:50:14","modified_gmt":"2023-07-28T14:50:14","slug":"ardms-spi-exam-latest-2023-2024-real-exam-150-questions-and-correct-answersagrade","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2023\/07\/28\/ardms-spi-exam-latest-2023-2024-real-exam-150-questions-and-correct-answersagrade\/","title":{"rendered":"ARDMS SPI EXAM LATEST 2023-2024 REAL EXAM 150 QUESTIONS AND CORRECT ANSWERS|AGRADE"},"content":{"rendered":"\n

Which gain will increase the risk of bioeffects?
a. transmit
b. receive
c. gain
d. overall gain
a. transmit<\/p>\n\n\n\n

Which of the following is considered the memory of an ultrasound instrument?
a. pulser
b. transducer
c. receiver
d. beam former
e. digital scan converter
f. display monitor
e. digital scan converter<\/p>\n\n\n\n

Spectral broadening suggest:
a. laminar flow
b. turbulent flow
c. flow away from the transducer
d. flow towards the transducer
b. turbulent flow<\/p>\n\n\n\n

With pulse wave Doppler axial resolution:
degrades<\/p>\n\n\n\n

What color is usually use in color flow Doppler variance map to indicate turbulent flow?
green<\/p>\n\n\n\n

Doppler high pass filter eliminates:
high amplitude signals; low velocity flow<\/p>\n\n\n\n

The Doppler wall filter is considered a:
high pass filter<\/p>\n\n\n\n

The Nyquist Limit is equal to:
a. propagation speed x frequency
b. propagation speed\/ wavelength
c. PRF\/2
d. 4xV^2
c. PRF\/2<\/p>\n\n\n\n

Multiple echoes, equally spaced originating from a gas bubble is called:
a. comet tail
b. ring down
c. slice thickness artifact
d. multipath
b. ring down<\/p>\n\n\n\n

An increase in red blood cell velocity will_____ the Doppler Shift:
a. increase
b. decrease
c. not change
d. cannot be predicted
a. increase<\/p>\n\n\n\n

The primary advantage of CW Doppler is:
a. range resolution
b. range discrimination
c. range ambiguity
d. range gating
e. absence of sampling rate
e. absence of sampling rate<\/p>\n\n\n\n

The range for ultrasound begins:
a. 20 Hz
b. 20,000 Hz
c. 2 MHz
d. 15 MHz
b. 20,000 Hz (useful frequency range for clinical imaging is 2MHz-10MHz)<\/p>\n\n\n\n

Which instrument control affects the amplitude (dB) of the outgoing signal:
a. gain
b. receiver gain
c. TGC
d. transmit gain
e. overall gain
d. transmit gain; amplitude can be affected by the sonographer<\/p>\n\n\n\n

Which of the following is used to convert Doppler shift information into color:
a. high PRF
b. fast Fourier transform
c. autocorrelation
d. time interval histogram
c. autocorrelation
b is incorrect because fast Fourier transform is the method used to process conventional Doppler shift information but is too slow a method for color Doppler<\/p>\n\n\n\n

Pulse repetition frequency
Number of pulses that an ultrasound system transmits into the body each second. Hz. Typically 4-15 KHz. PRF and depth of a view are inversely related: When system is imaging deeper, the pulse repetition frequency is lower.
Also the number of pulses created each second<\/p>\n\n\n\n

The best way to increase the near field length of an ultrasound beam is to:
increase transducer diameter<\/p>\n\n\n\n

The range of frequencies produced by a damped PZT element is called:
a. fundamental frequencies
b. Q Factor
c. near field
d. bandwith
d. bandwidth<\/p>\n\n\n\n

The percentage of time that the ultrasound instrument is emitting ultrasound is called:
a. PRF
b. pulse duration
c. pulse repetition period
d. duty factor
d. duty factor; the maximum value is 1, the minimum is 0<\/p>\n\n\n\n

The unit of duty factor is:
a. Hz
b. mm
c. ms
d. unitless
d. unitless<\/p>\n\n\n\n

Quality Factor= Fundamental frequency\/ bandwidth
This allows doses of different types of radiation to be compared for their biological effects.<\/p>\n\n\n\n

Clinical imaging transducers are:
wide bandwidth; low q factor<\/p>\n\n\n\n

Power\/area=
Intensity<\/p>\n\n\n\n

Increasing wavelength will _<\/strong><\/em><\/strong> frequency.
a. increase
b. decrease
c. not change
d. cannot be predicted.
b. decrease<\/p>\n\n\n\n

All of the following directly affect frame rate except:
a. depth of penetration
b. field of view
c. number of focuses
d. line density
e. beam width
e. beam width<\/p>\n\n\n\n

A reflection will occur at the boundary of two media if the acoustic impedences of the two media are:
a. equal
b. different
c. unchanged
d. cannot be predicted
b. different<\/p>\n\n\n\n

A mechanical transducer utilizes:
a. transmit focus
b. receive focus
c. fixed focus
d. dynamic aperture focusing
c. fixed focus; sonographer cannot determine the location of # of foci. mechanical transducer uses cross sectional imaging, rotating wheel, wobbler, oscillating mirror<\/p>\n\n\n\n

The transducer frequency is primarily determined by the transducer element:
a. diameter
b. thickness
c. propagation speed
d. type
b. thickness<\/p>\n\n\n\n

A strongly focused transducer implies a:
a. short focal length; decreased beam divergence
b. medium focal length; increased beam divergence
c. long focal length; no beam divergenc
d. short focal length; increased beam divergence
d. short focal length; increased beam divergence<\/p>\n\n\n\n

B-mode displays reflector:
a. amplitude and distance
b. amplitude and velocity
c. power and direction
d. depth and speed
a. amplitude and distance<\/p>\n\n\n\n

An increase in the number of pixels on the display will improve:
detail resolution<\/p>\n\n\n\n

Propagation speed is determined by:
a. frequency
b. harmonics
c. bandwidth
d. bulk modulus
d. bulk modulus<\/p>\n\n\n\n

Increasing transmit gain increases everything except:
frequency<\/p>\n\n\n\n

The correct depth placement of reflectors depends primarily upon:
a. frequency
b. period
c. power
d. propagation speed
d. propagation speed<\/p>\n\n\n\n

Which of the following will increase the color flow jet area displayed?
a. increase color gain
b. increase velocity scale
c. increase frequency
a. increase color gain<\/p>\n\n\n\n

Increasing propagation speed:
air, soft tissue, bone<\/p>\n\n\n\n

The most common type of transducer used in echo is:
sector phased array<\/p>\n\n\n\n

Decibels are the units for all of the following except:
a. amplitude
b. transmit gain
c. gain
d. attenuation
e. TGC
f. dynamic range
e. intensity
e. intensity= mW\/cm2<\/p>\n\n\n\n

What are the four acoustic variables:<\/p>\n\n\n\n

    \n
  1. temperature, density, particle motion, pressure<\/li>\n<\/ol>\n\n\n\n

    Frequency is
    Cycles per second (Hz)
    not affected by sonographer
    increase frequency; decrease depth<\/p>\n\n\n\n

    Pulse duration
    period (ms) x # of cycles in a pulse<\/p>\n\n\n\n

    Wavelength
    the length of one cycle
    wavelength= propagation speed\/ frequency
    1.54\/3MHz= .5mm<\/p>\n\n\n\n

    An increase in packet size will _<\/em><\/strong> the frame rate
    Decrease<\/p>\n\n\n\n

    The range for audible sound is:
    20 Hz- 20kHz<\/p>\n\n\n\n

    The wavelength of a 1MHz transducer is:
    1.54\/1= 1.54mm<\/p>\n\n\n\n

    The average speed of sound in soft tissue is:
    1540m\/s; 1.54km\/s; 1.54mm\/us<\/p>\n\n\n\n

    An increase in overall gain will result in all of the following except:
    a. increase in image brightness
    b. increase in output power
    c. increase in amplification of the returning signal
    d. decrease risk in bioeffects
    b. increase in power<\/p>\n\n\n\n

    Reject eliminates:
    low amplitude signals<\/p>\n\n\n\n

    There have been no proven biological effects for unfocused transducers for intensities below:
    100mW\/cm2 SPTA<\/p>\n\n\n\n

    The primary cause of attenuation of ultrasound in soft tissue is caused by:
    absorption<\/p>\n\n\n\n

    Resolution artifact
    When two structures parallel to the ultrasound beam are displayed as one reflector.<\/p>\n\n\n\n

    Damping does not decrease:
    bandwidth<\/p>\n\n\n\n

    Spectral Broadening
    The widening of the doppler shift spectrum. Meaning the increase of the range of doppler shift frequencies present, owing to a broader range of flow speeds encountered by the sound beam.<\/p>\n\n\n\n

    Refraction
    Change in direction of a wave when it changs speed as in travels from one material to another. The change in the direction of sound as it crosses a boundary.<\/p>\n\n\n\n

    autocorrelation
    used to convert Doppler shift information into color.<\/p>\n\n\n\n

    PRF
    Pulse Repetition Frequency. The rate at which pulses are transmitted, given in hertz or pulses per second; reciprocal of pulse-repetition time.<\/p>\n\n\n\n

    Period
    the time per cycle
    1-10usec<\/p>\n\n\n\n

    Period Calculation
    1\/frequency
    1\/5MHz= .2<\/p>\n\n\n\n

    How do you decrease period?
    Increase frequency<\/p>\n\n\n\n

    Impedance
    the opposition of sound propagation<\/p>\n\n\n\n

    The unit for impedance?
    Rayls<\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    What is dynamic aperture?
    A.aperture that varies with transmit frequency
    B.aperture that decreases as a function of time
    C.aperture that increases with increasing focal length
    D.aperture that changes as a function of frame rate<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    to which acoustic variable is penetration depth inversely related?
    A.frequency
    B.wavelength
    C.period
    D.propagation speed<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    which imaging mode requires a broadband transducer?
    A.continuous wave doppler
    B.Pulsed wave doppler
    C.color flow imaging
    D.harmonic imaging<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    what is the doppler shift frequency?
    A.recieved ultrasound frequency multiplied by the transmitted ultrasound frequency
    B.difference between the transmitted ultrasound frequency and the received ultrasound frequency
    C.sum of the transmitted and received ultrasound frequencies
    D.ratio of the transmitted ultrasound frequency to the received ultrasound frequency<\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    what is the potential effect of increasing the pulse repetition frequency(PRF)?
    A.Depth ambiguity
    B.Decreased frame rate
    C.Poor spatial resolution
    D.Decreased penetration<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    what is an advantage of using pulsed wave doppler compared to continuous wave doppler?
    A.higher echo sensitivity
    B.ability to select sample depth
    C.decreased display of aliasing
    D.improved temporal resolution<\/a><\/p>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    what affects the beam width in the near field?
    A.Pulse repetition frequency
    B.Pulse duration
    C.Frame rate
    D.Transducer aperture<\/a><\/p>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    what is the advantage of using pulsed-wave doppler versus continuous-wave doppler?
    A.allows measurement of higher velocities
    B.increases range ambiguity
    C.reduces the potential for aliasing
    D.provides depth specificity<\/a><\/p>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    which parameter is target group C evaluating based on the image?
    A.dead zone
    B.dynamic range
    C.axial resolution
    D.Horizontal distance accuracy<\/a><\/p>\n\n\n\n

    \"Image:<\/figure>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    In this image, which target group is used to evaluate dead zone?<\/a><\/p>\n\n\n\n

    \"Image:<\/figure>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    which ultrasound parameter directly affects an ultrasound beam’s intensity?
    A.TGC
    B.operating frequency
    C.Output power
    D.Frame rate<\/a><\/p>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    the center frequency of a transducer depends primarily upon which characteristics of the crystal?
    A.width
    B.length
    C.spacing
    D.thickness<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    which factor limits image frame rate?
    A.transducer operating frequency
    B.Sample volume size
    C.Speed of sound in tissue
    D.Spatial pulse length<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    when using a 5MHZ transducer, in which tissue is the ultrasound wavelength shortest?
    A.fat
    B.blood
    C.bone
    D.muscle<\/a><\/p>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    which term describes the averaging together of scan lines from multiple angles to create one image?
    A.harmonic imaging
    B.realtime three dimensional imaging
    C.elastography
    D.spatial compounding<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    which variable can cause an acoustic shadow artifact?
    A.small acoustic impedance mismatch
    B.refraction
    C.perpendicular incidence
    D.low attenuation<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    what does coded excitation improve in addition to penetration?
    A.lateral resolution
    B.signal-to-noise ratio
    C.frame rate
    D.dynamic range<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    how is lateral resolution determined for a pulsed-echo system using a tissue-mimicking test object?
    A.by observing spaces between reflectors perpendicular to the beam
    B.by observing spaces between reflectors along the beam path
    C.by observing position of deepest visible reflector along the beam path
    D.by observing position of deepest visible reflector perpendicular to the beam path<\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    which variable caused the color change from blue to red of the vessel in this image?
    A.change in vessel direction
    B.color scale set to low
    C.turbulent flow
    D.severe stenosis<\/a><\/p>\n\n\n\n

    \"Image:<\/figure>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    which artifact is indicated by the arrows in this image?
    A.shadow produced by the diaphragm
    B.acoustic enhancement
    C.comet tail
    D.mirror image<\/a><\/p>\n\n\n\n

    \"Image:<\/figure>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    which control improves the effects of attenuation?
    A.dynamic range
    B.pulse inversion
    C.multiple focal zones
    D.time gain compensation<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    which doppler angle to flow results in the greatest absolute doppler shift?
    A.0 degrees
    B.15 degrees
    C.45 degrees
    D.60 degrees<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    what term describes blood flow changes in response to respiration?
    A.phasic
    B.parabolic
    C.spontaneous
    D.pulsatile<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    an increase in which parameter will improve the accuracy of velocity measurements with autocorrelation?
    A.color field of view
    B.packet size
    C.wall filtering
    D.transmitted frequency<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    which harmonic imaging, how does echo frequency relate to transmitted frequency?
    A.half the transmitted frequency
    B.equal to the transmitted frequency
    C.twice the transmitted frequency
    D.four times the transmitted frequency<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    Which change would minimize the artifact observed in this image, assuming the pulse repetition frequency is at its maximum limit?
    A.adjust the sweep speed
    B.adjust the baseline
    C.increasing dynamic range
    D.increasing the transmitted frequency<\/a><\/p>\n\n\n\n

    \"Image:<\/figure>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    which parameter is most likely to affect spatial resolution?
    A.dynamic range
    B.beam width
    C.system sensitivity
    D.depth of visualization<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    which imaging modality can provide the most accurate measurement of tumor volume?
    A.color doppler
    B.B-mode
    C.A-mode
    D.M-mode<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    according to ALARA (as low as reasonably achievable) guidelines, which parameter should be minimized?
    A.transmit power
    B.frequency
    C.time gain compensation
    D.overall gain<\/a><\/p>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    what is an advantage of using pulsed-wave doppler versus continuous wave doppler?
    A.allows measurement of higher velocities
    B.increases range ambigutiy
    C.reduces the potential for aliasing
    D.provides depth specificity<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    What is demonstrated in this image produced by a linear array transducer placed on a uniform tissue-mimicking phantom?
    A. Time gain compensation not set properly.
    B. System has low dynamic range.
    C. Transducer crystals are damaged.
    D. Focus control is malfunctioning.<\/a><\/p>\n\n\n\n

    \"Image:<\/figure>\n\n\n\n

    3cm<\/a><\/p>\n\n\n\n

    what is the distance to the interface if the round trip time for a sound wave is 39 microseconds?<\/a><\/p>\n\n\n\n

    low frequency, low amplitude<\/a><\/p>\n\n\n\n

    which signals are eliminated by the wall filter in a spectral Doppler display?<\/a><\/p>\n\n\n\n

    two images demonstrating the same pathology from different scan planes<\/a><\/p>\n\n\n\n

    at minimum, what is required when documenting a pathology discovered during an examination?<\/a><\/p>\n\n\n\n

    Increased by 2 times<\/a><\/p>\n\n\n\n

    If the diameter of the sound beam is halved by focusing, what happens to the intensity<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    Which parameter would change on a phantom test if the spatial pulse length were made longer?
    A. axial resolution
    B. lateral resolution
    C. horizontal distance resignation
    D. sensitivity<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    If the ultrasound machine comes in contact with a patients body fluids, what should be done?
    A. remove the machine from use for the day
    B. use an approved disinfectant solution to clean it
    C. call the manufacturer to see what they would do<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    Which parameter is most related to cavitation tissue?
    A. energy
    B. pressure
    C. duty factor
    D. pulse repetition frequency<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    Which interface will cause the maximum reflection of the incident sound beam?
    A. fat\/muscle
    B. soft tissue\/bone
    C. fat\/soft tissue
    D. soft tissue\/lung<\/a><\/p>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    Acoustic enhancement occurs distal to what?
    A. calcifications
    B. near field interface
    C. highly reflecting structure
    D. weakly attenuating structure<\/a><\/p>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    As the pressure amplitude of ultrasound doubles, what happens to the wavelength?
    A. quadruples
    B. doubles
    C. halves
    D. unchanged<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    What is the period of a 5 MHz ultrasound wave?
    A. 0.02 ms
    B. 0.2 ms
    C. .5mc
    D. 5ms<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    What limits diagnostic application at higher frequencies?
    A. noise
    B. tissue penetration
    C. contrast resolution
    D. temporal resolution<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    What is the function of a lens on a transducer?
    A. focus the beam
    B. increase the bandwidth
    C. shorten the pulse length
    D. provide damping<\/a><\/p>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    What would improve axial resolution?
    A. increase the pulse repetition frequency
    B. reduce the receiver gain
    C. change the gray scale map
    D. increase the transducer frequency<\/a><\/p>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    What is true of the far field?
    A. sound beam converges
    B. intensity is highest
    C. lateral resolution is best
    D. sound beam diverges<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    what improves lateral resolution?
    A. decreasing the beam width
    B. increasing the pulse repetition frequency
    C. decreasing transmitted frequency
    D. decreasing the width of the field of view<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    Which statement is true for a linear phased array transducer?
    A. line density increases with depth
    B. elements are all fired nearly simultaneously
    C. elements are fired in successive groups
    D. all scan lines are perpendicular to the face of the transducer<\/a><\/p>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    Which artifact is commonly seen within cystic masses due to the finite dimensions of the ultrasound beam?
    A. duplication
    B. mirror image
    C. reverberation
    D. slice thickness<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    Which technique utilizes frequency modulation of the transmitted pulse to improve signal to noise ratio?
    A. apodization
    B. panoramic imaging
    C. coded excitation
    D. spatial compounding<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    What is varied to implement apodization?
    A. voltage applied to each element
    B. time delays between elements
    C. pulse length
    D. number of active elements<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    What will produce no doppler shift at a receiver?
    A. source and receiver moving at the same speed and direction
    B. source moving toward receiver
    C. source moving away from receiver
    D. receiver moving toward source<\/a><\/p>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    Which mode requires two elements mounted side by side?
    A. real time imaging
    B. duplex imaging
    C. pulsed wave doppler
    D. continuous wave doppler<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    when employing a tissue mimicking phantom, the depth at which echoes are no longer detected is an indicator of what?
    A. dynamic range
    B. lateral resolution
    C. sensitivity
    D. axial resolution<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    What enhances the transmission of ultrasound energy between the transducer and the skin?
    A. the transducer matching layer
    B. a lower pulse repetition frequency
    C. a lower frequency probe
    D. a narrow active probe aperture<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    which technique increases the sharpness of high contrast boundaries?
    a) Edge enhancement
    b) Interpolation
    c) Smoothing
    d) Frame averaging<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    what is the most appropriate action for the sonographer to take when receiving a verbal order for an exam?
    a) Deny performance of the exam until a written request is received
    b) Seek approval from supervisor
    c) Verbally repeat the request back to the referrer to verify correctness
    d) Document two forms of ID of the patient<\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    which setting of an ultrasound system gives the sonographer the ability to display both strong and week echoes?
    a) Dynamic range
    b) Resolution
    c) Range calibration
    d) Sensitivity<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    what is a benefit of using contrast agents?
    a) Output power can be increased after contrast administration to improve visualization
    b) Increased amplitude of the returning doppler signals
    c) Harmonic signals produced by contrast agents are weaker than those produced by tissue
    d) Frame rate is improved when interrogating contrast with power doppler<\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    a sound wave propagates fastest through which substance?
    a) Bone
    b) Muscle
    c) Fat
    d) Gas<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    when the focal point in a B-mode image is electronically changed, which type of focusing is in use?
    a) Lens
    b) Mechanical
    c) Dynamic
    d) Curved crystal<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    when a fluid is flowing at a slow and constant rate within a long tube having a uniform diameter, what is the nature of the flow?
    a) Disturbed
    b) Turbulent
    c) Laminar
    d) Pulsatile<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    what causes range ambiguity artifacts?
    a) Receiver overload
    b) Pulser overload
    c) PRF too high
    d) PRF too low<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    what is the round trip time in soft tissue for an echo from a reflector at a depth of 1 cm?
    a) 1.54 usec
    b) 6.5 usec
    c)13 usec
    d) 26 usec<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    which variable decreases when the number of acoustic lines per frame is increased without changing its maximum depth?
    a) SPL
    b) Frame rate
    c) PRF
    d) Receiver dynamic range<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    frequency compounding improves image quality by doing what?
    a) Increasing frame rate
    b) Improving dynamic range
    c) Reducing speckle
    d) Reducing grading lobes<\/a><\/p>\n\n\n\n

    A<\/a><\/p>\n\n\n\n

    what is the most common cause of localized vertical nonuniformity in a real-time B-mode image?
    a) Improper TGC
    b) Defective transducer elements
    c) Faulty preamplifier
    d) Malfunctioning scan converter<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    what is the cause of the black region in the center of the vessel seen in this image?
    a) Aliasing
    b) Turbulence
    c) Incident angle
    d) Lack of blood flow at that location<\/a><\/p>\n\n\n\n

    \"Image:<\/figure>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    what is increased if the pulse duration is decreased?
    a) Bandwidth
    b) Line Density
    c) Frame Rate
    d) Duty Factor<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    what is the Nyquist limit if a pulsed wave Doppler instrument has a pulse repetition frequency of 16 kHz?
    a) 32 kHz
    b) 10 kHz
    c) 8 kHz
    d) 5 kHz<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    what caused the color pattern demonstrated in the artery indicated by the arrow in this image?
    a) Superimposed venous flow
    b) Aliasing
    c) Flow reversal
    d) Color side lobe artifact<\/a><\/p>\n\n\n\n

    \"Image:<\/figure>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    which adjustment should be made to avoid the aliasing displayed on this spectral Doppler image seen on spectral analysis?
    a) Reposition sample volume so it is deeper.
    b) Decrease acoustic power
    c) Change the doppler angle from 60 to 45 degrees
    d) Decrease the transducer freq<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    If red blood cells are approaching a 5 Mhz Doppler transducer at a speed of 75 cm\/s, what is the approximate received ultrasound frequency?
    a) 4,500 kHz
    b) 4,995 kHz
    c) 5,005 kHz
    d) 5,500 kHz<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    which condition must be present for refraction to occur?
    a) Presence of a strong specular reflector
    b) Presence of several small reflectors
    c) Difference in tissue prop speeds
    d) A change in the angle of reflection<\/a><\/p>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    the thermal index (TI) is most affected by which type of interaction between sound and tissue?
    a) Reflection
    b) Absorption
    c) Scattering
    d) Refraction<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    In an unfocused transducer, what is the region between the transducer face and the point where the beam diverges?
    a) Side lobe
    b) Focal Zone
    c) Near field
    d) Far field<\/a><\/p>\n\n\n\n

    C<\/a><\/p>\n\n\n\n

    What is this artifact?
    A. Shadowing
    B. Side lobe
    C. Reverberation
    D. Mirror image<\/a><\/p>\n\n\n\n

    \"Image:<\/figure>\n\n\n\n

    D<\/a><\/p>\n\n\n\n

    How do you fix this
    A. Decrease the color scale
    B. Decrease the color packet size
    C. Increase the color packet size
    D. Increase the color scale<\/a><\/p>\n\n\n\n

    \"Image:<\/figure>\n\n\n\n

    B<\/a><\/p>\n\n\n\n

    Which way is the blood flowing?
    A. Right to left
    B. Left to right
    C. Bidirectional
    D. Cannot tell<\/a><\/p>\n\n\n\n

    The horizontal axis, or x-axis
    Runs side to side<\/p>\n\n\n\n

    The vertical axis, or y-axis
    Runs up and down<\/p>\n\n\n\n

    Unrelated
    Two items that are not associated<\/p>\n\n\n\n

    Related or Proportional
    Two items that are associated or affiliated
    However, the relationship between the items does not have to be specified<\/p>\n\n\n\n

    Directly related or Directly proportional
    Two items that are associated such that when one item increases, the other increases<\/p>\n\n\n\n

    Inversely related or inversely proportional
    Two items are associated such that when one item increases, the other decreases<\/p>\n\n\n\n

    Reciprocal Relationship
    When two numbers with a reciprocal relationship are multiplied together, the result is one
    Reciprocal numbers are inverse because when one increases, the other decreases<\/p>\n\n\n\n

    For a numerical answer to a question to be comprehensive, it requires a
    Unit<\/p>\n\n\n\n

    “Increase by a factor” means
    To multiply by that number<\/p>\n\n\n\n

    “Decrease by a factor” means
    To divide by that number<\/p>\n\n\n\n

    Scientific or engineering notation is a shorthand manner to represent what types of numbers?
    Very large or very small numbers<\/p>\n\n\n\n

    A number in scientific notation form with a positive exponent has a value
    Greater than 10<\/p>\n\n\n\n

    A number in scientific notation form with an exponent of zero has a value
    Between 1 and 10<\/p>\n\n\n\n

    A number in scientific notation form with a negative exponent has a value
    Less than 1<\/p>\n\n\n\n

    10\u23039
    Prefix: giga
    Symbol: G
    Meaning: billion<\/p>\n\n\n\n

    10\u23036
    Prefix: mega
    Symbol: M
    Meaning: million<\/p>\n\n\n\n

    10\u23033
    Prefix: kilo
    Symbol: k
    Meaning: thousand<\/p>\n\n\n\n

    10\u23032
    Prefix: hecto
    Symbol: h
    Meaning: hundred<\/p>\n\n\n\n

    10\u23031
    Prefix: deca
    Symbol: da
    Meaning: ten<\/p>\n\n\n\n

    10\u2303-1
    Prefix: deci
    Symbol: d
    Meaning: tenth<\/p>\n\n\n\n

    10\u2303-2
    Prefix: centi
    Symbol: c
    Meaning: hundredth<\/p>\n\n\n\n

    10\u2303-3
    Prefix: milli
    Symbol: m
    Meaning: thousandth<\/p>\n\n\n\n

    10^-6
    Prefix: micro
    Symbol: \u03bc
    Meaning: millionth<\/p>\n\n\n\n

    10^-9
    Prefix: nano
    Symbol: n
    Meaning: billionth<\/p>\n\n\n\n

    List all these metric terms in increasing order:
    A. mega
    B. micro
    C. milli
    D. hecto
    E. deca
    F. deci
    micro, milli, deci, deca, hecto, mega<\/p>\n\n\n\n

    List all these metric terms in decreasing order:
    A. nano
    B. canti
    C. giga
    D. kilo
    E. hecto
    F. micro
    giga, kilo,hecto, centi, micro, nano<\/p>\n\n\n\n

    Sound pulses travel through biologic tissue, or __<\/strong>.
    Media<\/p>\n\n\n\n

    All waves carry _<\/strong> from one location to another.
    Energy<\/p>\n\n\n\n

    Sound is a __<\/em><\/strong> wave in which particles in the medium move.
    Mechanical<\/p>\n\n\n\n

    Sound cannot travel through a ; it must travel through a <\/em><\/strong><\/em><\/strong>.
    Vacuum, medium<\/p>\n\n\n\n

    What does compressed mean?
    Squeezed together<\/p>\n\n\n\n

    What does rarefied mean?
    Stretched apart<\/p>\n\n\n\n

    Sound travels in a __<\/em><\/strong> line.
    Straight<\/p>\n\n\n\n

    Sound waves are __<\/strong><\/em><\/strong> waves.
    Longitudinal<\/p>\n\n\n\n

    What is the propagation speed dependent on?
    The medium<\/p>\n\n\n\n

    Are there any biologic effects on tissue?
    No<\/p>\n\n\n\n

    Sound waves are identified by
    Oscillations in acoustic variables<\/p>\n\n\n\n

    What are the three acoustic variables? (With their units)
    pressure – pascals (Pa), density – kg\/cm^3, distance – cm, mm<\/p>\n\n\n\n

    If something other than pressure, density, or distance (particle motion) rhythmically oscillates in a wave, then the wave\u2026
    Is not a sound wave<\/p>\n\n\n\n

    Sound waves are also known as
    Acoustic waves<\/p>\n\n\n\n

    What are the seven Acoustic Parameters?
    Period, frequency, amplitude, power, intensity, wavelength, propagation speed<\/p>\n\n\n\n

    Particles move in a direction that is perpendicular to the direction that the wave propagates in what wave?
    Transverse wave<\/p>\n\n\n\n

    Particles move in the same direction that the wave propagates in a __<\/strong><\/em><\/strong> wave.
    Longitudinal<\/p>\n\n\n\n

    When are a pair of waves considered in-phase?
    When their peaks and troughs occur at the same time and at the same location
    Considered “in step”<\/p>\n\n\n\n

    What happens when two waves are out-of-phase?
    Their peaks occur at different times, and so do their troughs
    “out of step”<\/p>\n\n\n\n

    What is interference?
    When more than one beam travels in a medium and arrive at the same location at exactly the same time
    These waves lose their individual characteristics and combine to form a single wave<\/p>\n\n\n\n

    The interference of in-phase waves results in a single wave of amplitude. This is called __<\/em><\/strong><\/em><\/strong>.
    Greater, constructive interference
    (Larger Wave)<\/p>\n\n\n\n

    The interference of a pair of out-of-phase waves results in the formation of a single wave of _ amplitude. This combination is called _____________<\/strong><\/em><\/strong>.
    Lesser, destructive interference
    (Smaller Wave)<\/p>\n\n\n\n

    When frequencies of waves differ, what kind of wave occurs?
    Both constructive and destructive interference<\/p>\n\n\n\n

    What do waves transfer from one location to another?
    Energy<\/p>\n\n\n\n

    Two waves are traveling in a medium and arrive at a location at the same time. What event takes place?
    Interference<\/p>\n\n\n\n

    Which types of waves will exhibit both constructive and destructive interference?
    Waves of different frequency<\/p>\n\n\n\n

    What units are used to report the pressure of a sound beam?
    Pascals, Pa<\/p>\n\n\n\n

    What describes features of a sound wave?
    Parameters<\/p>\n\n\n\n

    What is the source of a sound wave?
    The ultrasound system and the transducer<\/p>\n\n\n\n

    Some parameters are determined by the tissue through which the sound is traveling, also called a __<\/em><\/strong>.
    Medium<\/p>\n\n\n\n

    What is period? And what is it determined by?
    The time it takes a wave to vibrate a single cycle, or the time from start of a cycle to the start of the next cycle
    It is determined by the source<\/p>\n\n\n\n

    What is frequency? And what is it determined by?
    The number of cycles that occurs in one second
    Determined by the sound source only<\/p>\n\n\n\n

    1 cycle\/second =
    1 Hertz<\/p>\n\n\n\n

    If the frequency of a sound wave is less than , it is below the threshold of human hearing and cannot be heard. These are defined as _____<\/em><\/strong><\/em><\/strong>.
    20 Hz, infrasonic<\/p>\n\n\n\n

    Audible sound waves that humans can hear are frequencies between ___________<\/em><\/strong><\/em><\/strong>.
    20 Hz and 20,000 Hz<\/p>\n\n\n\n

    What is ultrasound’s frequency?
    Greater than 20,000 Hz or 20 kHz<\/p>\n\n\n\n

    Why is frequency important in diagnostic sonography?
    It affects penetration and image quality<\/p>\n\n\n\n

    Period and frequency are __<\/em><\/strong> related to each other.
    Inversely<\/p>\n\n\n\n

    When two reciprocal parameters are multiplied together, the result is:
    1<\/p>\n\n\n\n

    What three parameters describe the size, or magnitude, or strength of a sound wave?
    Amplitude, power, intensity<\/p>\n\n\n\n

    What is Amplitude?
    The “bigness” of a wave. It is the difference between the maximum value and the average or undisturbed value of an acoustic variable
    Also the difference between the minimum value and the average value of the acoustic variable<\/p>\n\n\n\n

    What is Amplitude determined by? And is it adjustable?
    Initially, amplitude is determined only by the sound source, however amplitude decreases as sound propagates through the body (attenuation)
    Yes, a control on ultrasound systems allows the sonographer to alter initial amplitude<\/p>\n\n\n\n

    What is the difference between amplitude and peak-to-peak amplitude?
    Amplitude is measured from the middle value to the maximum value. Peak-to-peak amplitude is the difference between maximum and minimum values of an acoustic variable
    Peak-to-peak is twice the value of the amplitude<\/p>\n\n\n\n

    What is power?
    The rate of energy transfer or the rate at which work is performed. Power, like amplitude, describes the “bigness” of the wave<\/p>\n\n\n\n

    What is power determined by? And can it be changed?
    Determined by the sound source only
    It CAN be changed<\/p>\n\n\n\n

    How are amplitude and power related?
    Both describe the size, or magnitude of a wave. When power increases, so does amplitude<\/p>\n\n\n\n

    Power is proportional to\u2026
    amplitude^2<\/p>\n\n\n\n

    What is intensity?
    The concentration of energy in a sound beam Intensity = Power\/area<\/p>\n\n\n\n

    What is intensity determined by? And is it adjustable?
    Sound Source
    Yes, it is adjustable<\/p>\n\n\n\n

    How is intensity related to power and amplitude?
    Intensity is proportional to power
    Intensity is proportional to amplitude^2<\/p>\n\n\n\n

    What is the distance or length of one complete cycle called?
    Wavelength<\/p>\n\n\n\n

    What is wavelength determined by? And is it adjustable?
    Both the medium and source
    No, it is not adjustable<\/p>\n\n\n\n

    What is the relationship between wavelength and frequency?
    As long as a wave remains in one medium, wavelength and frequency are inversely related
    As frequency increases, wavelength decreases. The lower the frequency, the longer the wavelength<\/p>\n\n\n\n

    What is the wavelength of 1 MHz sound in soft tissue?
    1.54 mm<\/p>\n\n\n\n

    What is the wavelength of other frequency sound waves in soft tissue?
    Sound with a frequency of 2 MHz has a wavelength of 0.77 mm in soft tissue. 1.54mm\/2 = 0.77 mm<\/p>\n\n\n\n

    What is the wavelength equation?
    wavelength = (1.54mm\/\u03bcsec)\/(frequency)<\/p>\n\n\n\n

    Why is wavelength important in diagnostic ultrasound?
    Wavelength plays an important role in image quality
    Shorter wavelength sound usually produces higher quality images with greater detail (higher frequency)<\/p>\n\n\n\n

    What is the distance that a sound wave travels through a medium in 1 second called?
    Propagation Speed<\/p>\n\n\n\n

    What does the speed of sound range from?
    500m\/s to 4000m\/s<\/p>\n\n\n\n

    What is Propagation Speed determined by? And is it adjustable?
    The Medium
    No, it is not adjustable<\/p>\n\n\n\n

    What is the speed of sound in soft tissue?
    1,540 m\/s
    1.54 mm\/\u03bcsec
    1.54 km\/s
    1 mile per second<\/p>\n\n\n\n

    What has the slowest propagation speed? And the longest?
    Slowest: Lung (Air, Gas)
    Longest: Bone<\/p>\n\n\n\n

    What is the speed of sound in Blood?
    1,560 m\/s<\/p>\n\n\n\n

    What is the order for speed of sound from lowest to highest in Water, Metals, and Air?
    Air, Water, Metals<\/p>\n\n\n\n

    What determines the speed of sound in that medium?
    Stiffness, density<\/p>\n\n\n\n

    What describes the ability of an object to resist compression?
    Stiffness; A stiff material will retain its shape if it is squeezed; whereas a non-stiff material will change its shape<\/p>\n\n\n\n

    How does stiffness affect speed?
    Stiffness and Speed are directly related
    As materials become stiffer, the speed of sound in the material increased<\/p>\n\n\n\n

    Non-stiff media are described as\u2026
    Elastic or compressible<\/p>\n\n\n\n

    What describes the relative weight of a material?
    Density<\/p>\n\n\n\n

    How does density affect speed?
    Density and speed are inversely related. As materials become more dense (heavier), the speed of sound in the material decreases<\/p>\n\n\n\n

    When Stiffness increases, Speed __<\/strong>
    Increases<\/p>\n\n\n\n

    When Density Increases, Speed __<\/em><\/strong>
    Increases<\/p>\n\n\n\n

    What two parameters are reciprocals?
    Period and Frequency<\/p>\n\n\n\n

    What is the only parameter that is determined by the medium?
    Speed<\/p>\n\n\n\n

    What is wavelength decided by?
    Both the Sound Source and the Medium<\/p>\n\n\n\n

    What are the units of:
    wavelength –
    frequency –
    intensity –
    propagation speed –
    period –
    power –
    wavelength – millimeters
    frequency – hertz
    intensity – watts\/cm^2
    propagation speed – meters\/second
    period – second
    power – watts<\/p>\n\n\n\n

    Dos the medium or the sound source determine these parameters?
    wavelength –
    frequency –
    intensity (initial) –
    propagation speed –
    period –
    power (initial) –
    amplitude (initial) –
    wavelength – both
    frequency – source
    intensity – source
    propagation speed – medium
    period – source
    power – source
    amplitude – source<\/p>\n\n\n\n

    Which of the following cannot be changed by the operator?
    wavelength
    frequency
    intensity
    propagation speed
    period
    power
    amplitude (initial)
    Wavelength, frequency, propagation speed, period<\/p>\n\n\n\n

    True or False. A wave with a frequency of 15,000 MHz is ultrasonic.
    True (any wave >20,000 hertz)<\/p>\n\n\n\n

    True or False. If the amplitude of a wave is increased to 3 times its original value, the intensity in increased by 6 times.
    False (if we triple amplitude, we increase intensity by a factor of nine)<\/p>\n\n\n\n

    True or False. If the power of a wave is halved ,the intensity is reduced to one-fourth its original value.
    False (intensity is the power\/area, if we halve the power we will halve the intensity)<\/p>\n\n\n\n

    True or False. Propagation Speed increases as Frequency increases.
    False (frequency is unrelated to speed)<\/p>\n\n\n\n

    Medium 1 has a density of 9 and a stiffness of 6. Medium 2 has a density of 8 and a stiffness of 6. In which medium will sound travel slower?
    Medium 1: Since both media have the same stiffness, the medium with the greater density has the lower propagation speed<\/p>\n\n\n\n

    If the power in a beam is 1 watt and the area is 5cm^2, what is the beams intensity?
    0.2 W\/cm^2<\/p>\n\n\n\n

    If intensity remains the same while the power had doubled, what has happened to the beam area?
    Doubled (if intensity stays the same, whatever happens to power also has to happen to area)<\/p>\n\n\n\n

    A sound beam travels a total of 10 cm in 2 seconds. What is the speed of the sound?
    5 cm\/sec<\/p>\n\n\n\n

    True or False. Propagation speed increases as frequency increases.
    False<\/p>\n\n\n\n

    True or False. Propagation speed increases as frequency decreases.
    False<\/p>\n\n\n\n

    True or False. Propagation speed does not change as frequency increases.
    True (propagation speed and frequency are unrelated)<\/p>\n\n\n\n

    What is the wavelength of a 3 MHz sound in soft tissue?
    0.51 mm (wavelength = 1.54mm\/frequency in MHz)<\/p>\n\n\n\n

    The effects of sound waves on tissue in the body are called __<\/em><\/strong>.
    Bioeffects<\/p>\n\n\n\n

    Which of the following are considered acoustic variables?
    Frequency, density, particle motion, temperature, period, and pressure
    Density, particle motion, and pressure<\/p>\n\n\n\n

    Which of the following are considered acoustic parameters?
    frequency, density, distance, pressure, and period
    Frequency and period<\/p>\n\n\n\n

    The effects of tissue on sound waves are called __<\/strong><\/em><\/strong>.
    Acoustic Propagation Properties<\/p>\n\n\n\n

    The effects of a medium on an ultrasound wave are called ___<\/em><\/strong><\/em><\/strong> _<\/em><\/strong>.
    Acoustic Propagation Properties<\/p>\n\n\n\n

    How are frequency and period related?
    Inversely<\/p>\n\n\n\n

    How are amplitude and power related?
    Directly<\/p>\n\n\n\n

    How are amplitude and intensity related?
    Directly<\/p>\n\n\n\n

    How are power and intensity related?
    Directly<\/p>\n\n\n\n

    How are wavelength and intensity related?
    Unrelated<\/p>\n\n\n\n

    How are wavelength and frequency related?
    Inversely<\/p>\n\n\n\n

    How are acoustic velocity and density related?
    Inversely<\/p>\n\n\n\n

    How are elasticity and speed of sound related?
    Inversely<\/p>\n\n\n\n

    How are acoustic velocity and compressibility related?
    Inversely<\/p>\n\n\n\n

    How are stiffness and sound speed related?
    Directly<\/p>\n\n\n\n

    How are frequency and sound speed related?
    Unrelated<\/p>\n\n\n\n

    How are frequency and intensity related?
    Unrelated<\/p>\n\n\n\n

    How are power and frequency related?
    Unrelated<\/p>\n\n\n\n

    What are the five parameters to describe pulsed sound?
    Pulse duration, pulse repetition period, pulse repetition frequency, duty factor, and spatial pulse length<\/p>\n\n\n\n

    What is pulsed ultrasound?
    A pulse of an ultrasound is a collection of cycles that travel together. The entire pulse moves as a single item<\/p>\n\n\n\n

    What are the two components of pulsed ultrasound?
    Transmit, talking, or “on” time
    Receive, listening, or “off” time<\/p>\n\n\n\n

    What is the actual time from the start of pulse to the end of that pulse called?
    Pulse duration (a single “on” time)<\/p>\n\n\n\n

    What is pulse duration determined by? And can it be adjusted?
    Sound source, NO<\/p>\n\n\n\n

    Pulse duration (\u03bcsec) =<\/p>\n\n\n\n

    cycles x period (\u03bcsec)<\/h1>\n\n\n\n

    or<\/p>\n\n\n\n

    cycles\/frequency (MHz)<\/h1>\n\n\n\n

    Pulse duration is directly proportional to _<\/strong><\/em><\/strong>.<\/p>\n\n\n\n

    cycles in a pulse and to period<\/h1>\n\n\n\n

    Pulse duration is __<\/strong><\/em><\/strong> proportional to frequency.
    Inversely<\/p>\n\n\n\n

    What creates pulses of long duration?
    Many cycles in the pulse, and individual cycles with long periods<\/p>\n\n\n\n

    What creates pulses of short duration?
    Few cycles in the pulse, and individual cycles with short periods<\/p>\n\n\n\n

    Which type of pulse duration is more desirable in diagnostic imaging?
    Shorter duration pulses are desirable for imaging because they create images of greater accuracy<\/p>\n\n\n\n

    What is Spatial Pulse Length?
    The distance that a pulse occupies in space from the start to the end of a pulse.<\/p>\n\n\n\n

    What determines Spatial Pulse Length? And is it adjustable?
    Both the source and the medium. No it is not adjustable.<\/p>\n\n\n\n

    Spatial Pulse Length (mm) =<\/p>\n\n\n\n

    cycles x wavelength (mm)<\/h1>\n\n\n\n

    Spatial Pulse Length is _<\/em><\/strong> proportional to frequency.
    Inversely<\/p>\n\n\n\n

    What is the difference between pulse duration and pulse length?
    Pulse duration is the TIME that a pulse in “on”
    pulse length is the DISTANCE of the pulse end to end<\/p>\n\n\n\n

    Two characteristics that create long pulses are:
    Many cycles in the pulse
    Cycles with longer wavelengths<\/p>\n\n\n\n

    Two characteristics that create short pulses are:
    Fewer cycles in the pulse
    Cycles with shorter wavelengths<\/p>\n\n\n\n

    Which types of pulse length is more desirable in diagnostic imaging?
    Shorter pulses are desirable because they create more accurate images<\/p>\n\n\n\n

    What is the time from start of one pulse to the start of the next pulse called?
    Pulse Repetition Period<\/p>\n\n\n\n

    Pulse Repetition Period is determined by the __<\/em><\/strong><\/em> that the sonographer selects.
    Imaging depth<\/p>\n\n\n\n

    What is PRP determined by? And is it adjustable?
    Sound Source
    Yes, it is adjustable<\/p>\n\n\n\n

    When the system is imaging at shallow depths, the time from one pulse to the next is __<\/em><\/strong>.
    Short<\/p>\n\n\n\n

    What is depth of view?
    The maximum distance into the body that an ultrasound system is imaging<\/p>\n\n\n\n

    How are PRP and depth of view related?
    Directly related<\/p>\n\n\n\n

    What are the two components of pulse repetition period?
    Transmit time (pulse duration) and the receive time<\/p>\n\n\n\n

    Which component of PRP can the sonographer change?
    Receive time or “listening time” (alter the depth of the image)<\/p>\n\n\n\n

    What is pulse repetition frequency?
    The number of pulses that an ultrasound system transmits into the body each second<\/p>\n\n\n\n

    What is the PRF determined by? And is it adjustable?
    Sound Source, Yes<\/p>\n\n\n\n

    When the system is imaging shallow, the pulse repetition frequency is _<\/em><\/strong>.
    Higher<\/p>\n\n\n\n

    PRF is not related to frequency. It is related only to _ _ _<\/em><\/strong>.
    Depth of view<\/p>\n\n\n\n

    How are PRF and depth of view related?
    Inversely related (as depth of view increases, PRF decreases)<\/p>\n\n\n\n

    An ultrasound machine is imaging to a depth of 2 cm. Would the pulse repetition frequency be described as high or low?
    High<\/p>\n\n\n\n

    Relationship between Pulse Repetition Period and Pulse Repetition Frequency
    PRP and PRF are inversely related. (when PRF increases, the repetition period decreases)<\/p>\n\n\n\n

    PRF (Hz) =
    1\/PRP
    77,000 cm\/s\/imaging depth (cm)<\/p>\n\n\n\n

    PRP =
    1\/PRF
    imaging depth (cm) x 13 \u03bcsec\/cm<\/p>\n\n\n\n

    PRF x PRP =
    1<\/p>\n\n\n\n

    True or False. Two waves can have identical pulse repetition frequencies, even if their pulse repetition periods are different.
    False (two waves can never have identical PRF’s if their pulse repetition periods are different)<\/p>\n\n\n\n

    True or False. Two waves can have identical PRF’s, even if their periods are different.
    True (period and pulse repetition frequency are unrelated)<\/p>\n\n\n\n

    True or False. Two waves can have identical PRF’s, even if their frequencies are different.
    True (frequency and pulse repetition frequency are unrelated)<\/p>\n\n\n\n

    True or False. PRF and pulse repetition period are determined only by the imaging depth.
    True<\/p>\n\n\n\n

    What is duty factor?
    The percentage or faction of time that the system is transmitting a pulse<\/p>\n\n\n\n

    What is duty factor determined by? And is it adjustable?
    Sound Source
    Yes, it is adjustable<\/p>\n\n\n\n

    Duty factor (%) =
    (pulse duration\/pulse rep. period) x 100<\/p>\n\n\n\n

    What are the maximum and minimum values for duty factor?
    Maximum = 1 or 100%
    Minimum = 0%<\/p>\n\n\n\n

    Pulse wave ultrasound the duty factor is only _<\/strong>%.
    1 (listening 99% of the time)<\/p>\n\n\n\n

    How does the sonographer change duty factor?
    When imaging depth is altered.<\/p>\n\n\n\n

    If all the other factors remain unchanged, what happens to the duty factor when the pulse repetition frequency increases?
    Increases<\/p>\n\n\n\n

    If all other factors remain unchanged, what happens to the duty factor when the pulse repetition frequency increases?
    Decreases<\/p>\n\n\n\n

    If all other factors remain unchanged, what happens to the duty factor when the pulse repetition period increases?
    Decreases<\/p>\n\n\n\n

    If all other factors remain unchanged, what happens to the duty factor when the sonographer uses a new transducer with a longer pulse duration?
    Increases<\/p>\n\n\n\n

    What is the duty factor if the pulse duration is 1 \u03bcsec and the pulse repetition period is 1 ms?
    0.001<\/p>\n\n\n\n

    By adjusting the imaging depth, the operator changes the ______<\/em><\/strong><\/em><\/strong>, ___<\/em><\/strong><\/em><\/strong>, and __<\/strong><\/em><\/strong>.
    Pulse repetition period, pulse repetition frequency, and duty factor<\/p>\n\n\n\n

    __<\/strong><\/em><\/strong> is the time from the start of a pulse to the end of that pulse.
    Pulse duration<\/p>\n\n\n\n

    __<\/strong><\/em><\/strong> is the time from the start of a pulse to the start of the next pulse.
    Pulse Repetition Period<\/p>\n\n\n\n

    Pulse repetition frequency is the reciprocal of _<\/em><\/strong>.
    Pulse repetition period<\/p>\n\n\n\n

    By changing the image depth, what does the operator also change?
    PRF, Duty Factor, and PRP<\/p>\n\n\n\n

    What is the duty factor if the pulse duration is 1 microsecond, and the pulse repetition period is 1 second?
    The duty factor is 0.001 or 10^-3
    (10^-6 divided by 10^-3 = 10^-3 or 0.001)<\/p>\n\n\n\n

    What is the duty factor if the pulse duration is 1 millisecond, and the pulse repetition period is 1 second?
    The duty factor is 0.001 or 0.1%
    (0.001 divided by 1.0 = 0.001)<\/p>\n\n\n\n

    What is Intensity?
    A beam’s power divided by its area<\/p>\n\n\n\n

    What is temporal intensity?
    Refers to all time, transmit (pulse duration) and receive<\/p>\n\n\n\n

    What is pulsed intensity?
    The average intensity for the pulse duration only<\/p>\n\n\n\n

    What does spatial refer to?
    Location or space.<\/p>\n\n\n\n

    What is the beam’s intensity at the location where it is maximum called?
    Spatial peak intensity<\/p>\n\n\n\n

    The average intensity across the beam’s entire cross-sectional area is called __<\/strong><\/em><\/strong>.
    Spatial average intensity<\/p>\n\n\n\n

    Spatial peak intensity is always _<\/em><\/strong> than the spatial average.
    Higher<\/p>\n\n\n\n

    The term temporal refers to __<\/strong>.
    Time<\/p>\n\n\n\n

    Measuring the intensity of the beam at the instant in time of its maximal value is called the _____<\/em><\/strong><\/em><\/strong>.
    Temporal peak intensity<\/p>\n\n\n\n

    What is SPTP?
    Measured at the location where intensity is maximum (highest value intensity)<\/p>\n\n\n\n

    What is SPPA?
    Measured at the location where intensity is maximum, averaged over the transmit time (pulse duration)<\/p>\n\n\n\n

    What is SPTA?
    Measured at the location where intensity is maximum and averaged over all time, both the transmit and receive times (Used to test for bioeffects)<\/p>\n\n\n\n

    What is SATA?
    Measured over the entire cross-sectional area of the sound beam, and over all time (lowest value intensity)<\/p>\n\n\n\n

    All intensities have units of __<\/em><\/strong>.
    W\/cm^2<\/p>\n\n\n\n

    What is the number that describes the spread of a beam in space called?
    The Beam Uniformity Coefficient (SP\/SA factor)
    Unitless with a value of 1 or greater<\/p>\n\n\n\n

    What describes the relationship of beam intensities with time?
    Duty factor<\/p>\n\n\n\n

    For continuous wave ultrasound, the beam is always “on” and the pulse average and temporal average intensities are __<\/strong><\/em><\/strong>.
    The same
    SPTA = SPPA and SATA = SAPA<\/p>\n\n\n\n

    When pulsed and continuous wave sound beams have the same SPTP intensities, the __<\/em><\/strong> wave beam has the higher SPTA intensity.
    Continuous<\/p>\n\n\n\n

    When pulsed and continuous wave sound beams have the same SATP intensities, the __<\/em><\/strong> wave beam has the higher SATA intensity.
    Continuous<\/p>\n\n\n\n

    __<\/em><\/strong> average intensity is averaged only during the pulse duration (“on” time).
    Pulse<\/p>\n\n\n\n

    __<\/em><\/strong> average intensity is averaged during the PRP (both the “on” and “off” times)
    Temporal<\/p>\n\n\n\n

    The rank of intensities from largest to smallest is:
    SPTP -> SPPA -> SPTA -> SATA<\/p>\n\n\n\n

    As sound travels in the body, it weakens, or __<\/em><\/strong>.
    Attenuates<\/p>\n\n\n\n

    After a sound wave is received by the transducer, converted into electricity and returned to the ultrasound system, it is strengthened or __<\/em><\/strong>.
    Amplifide<\/p>\n\n\n\n

    When a waves intensity doubles, the relative change is\u2026
    +3 dB<\/p>\n\n\n\n

    When the intensity increases 10-fold, the relative change is\u2026
    +10 dB.<\/p>\n\n\n\n

    When the intensity is reduced to 1\/2 its original value, the relative change is\u2026
    -3 dB.<\/p>\n\n\n\n

    When the intensity is reduced to 1\/10 its original value, the relative change is\u2026
    -10 dB.<\/p>\n\n\n\n

    A reduction in the intensity of a sound beam to one-half of its original value is _<\/strong> dB.
    -3 dB<\/p>\n\n\n\n

    A reduction in the intensity of a sound beam to one-quarter of its original value is _<\/strong> dB.
    -6 dB<\/p>\n\n\n\n

    -10 dB means that the intensity is reduced to __<\/strong> of its original value.
    One-tenth<\/p>\n\n\n\n

    dB is a mathematical representation with a and ____<\/em><\/strong><\/em><\/strong> scale.
    Logarithmic and relative<\/p>\n\n\n\n

    True or False. We need one intensity to calculate decibels.
    False<\/p>\n\n\n\n

    A waves intensity is 2 mW\/cm^2. There is a change of +9 dB. What is the final intensity?
    16 Mw\/cm^2<\/p>\n\n\n\n

    Every dB change means that the intensity will __<\/strong>.
    Double<\/p>\n\n\n\n

    Every 10 dB change means that the intensity will _<\/em><\/strong>.
    Increase ten times<\/p>\n\n\n\n

    If the final intensity of a sound beam is more than the initial intensity, then the gain in dB is __<\/em><\/strong> .
    Positive<\/p>\n\n\n\n

    If the initial intensity of a sound beam is less than the final intensity, then the gain in dB is _<\/em><\/strong>.
    Positive<\/p>\n\n\n\n

    What is attenuation determined by?
    Path length, and frequency of sound<\/p>\n\n\n\n

    Distance and Attenuation are _<\/strong><\/em><\/strong> related.
    Directly<\/p>\n\n\n\n

    Frequency and Attenuation are _<\/em><\/strong> related.
    Directly<\/p>\n\n\n\n

    As sound strikes a boundary, a portion of the wave’s energy may be redirected, or _<\/em><\/strong>, back to the sound source.
    Reflected<\/p>\n\n\n\n

    Reflection is likely to occur when\u2026
    The boundary is large<\/p>\n\n\n\n

    What is specular reflection?
    When the boundary is smooth, the sound is reflected in only one direction in an organized manner<\/p>\n\n\n\n

    What is diffuse reflection?
    When a wave reflects off an irregular surface, it radiates in more than one direction (also called backscatter)<\/p>\n\n\n\n

    What are the advantages and disadvantages of diffuse reflection?
    Advantage: interfaces as suboptimal angles to the sound beam can still produce reflections that the transducer will receive
    Disadvantage: the backscattered reflections will have a lower strength than specular reflections<\/p>\n\n\n\n

    What is scattering?
    The random redirection of sound in many directions<\/p>\n\n\n\n

    Why does scattering happen?
    When the tissue interface is small; that is, equal to or less than the wavelength of the incident sound beam<\/p>\n\n\n\n

    Scattering is directly related to frequency. Therefore, higher frequency sound beams scatter much __<\/strong> than lower frequency beams.
    More<\/p>\n\n\n\n

    What is a special form of scattering that occurs when the structure’s dimensions are much smaller than the beam’s wavelength?
    Rayleigh scattering<\/p>\n\n\n\n

    Rayleigh scattering =
    Frequency^4<\/p>\n\n\n\n

    When there is a higher frequency, there is pulses, _<\/em><\/strong> penetration, attenuation, and __<\/em><\/strong><\/em> resolution.
    Shorter pulses, less penetration, more attenuation, and better resolution<\/p>\n\n\n\n

    When does absorption occur?
    When ultrasonic energy is converted into another energy form, such as heat<\/p>\n\n\n\n

    Absorption is __<\/em><\/strong> related to frequency.
    Directly<\/p>\n\n\n\n

    What is attenuation coefficient?
    The number of decibels of attenuation that occurs when sound travels one centimeter<\/p>\n\n\n\n

    total attenuation (dB) =
    Attenuation coefficient (dB\/cm) x distance (cm)<\/p>\n\n\n\n

    The attenuation coefficient is __<\/em><\/strong><\/em><\/strong> of the frequency in soft tissue.
    One-half<\/p>\n\n\n\n

    In soft tissue: attenuation coefficient (dB\/cm) =
    Frequency (MHz)\/2
    atten. coef. = 0.5 dB\/cm\/MHz<\/p>\n\n\n\n

    Air (lung) and Bone have extremely __<\/em><\/strong> attenuation compared to sift tissue.
    High<\/p>\n\n\n\n

    Biologic fluids (blood, urine, amniotic fluid) have _<\/strong> attenuation.
    Low<\/p>\n\n\n\n

    What has the lowest attenuation?
    Water<\/p>\n\n\n\n

    What is the half-value layer thickness?
    The distance that sound travels in a tissue that reduces the intensity of sound to one-half its original value<\/p>\n\n\n\n

    What are synonyms of half-value layer?
    Penetration depth, depth of penetration, half-boundary layer<\/p>\n\n\n\n

    What does the half-value layer thickness depend on?
    The medium and the frequency of sound<\/p>\n\n\n\n

    If there is a thin half-value, there is a _ frequency sound and a media with _<\/em><\/strong> attenuation rate.
    High, high<\/p>\n\n\n\n

    If there is a thick half-value, there is a _ frequency sound and a media with _<\/em><\/strong> attenuation rate.
    Low, low<\/p>\n\n\n\n

    What is impedance?
    The acoustic resistance to sound traveling in a medium<\/p>\n\n\n\n

    impedance (rayls) =
    Density (kg\/m^3) x prop. speed (m\/s)<\/p>\n\n\n\n

    What is impedance determined by?
    The medium<\/p>\n\n\n\n

    What is a synonym to impedance?
    Characteristic impedance<\/p>\n\n\n\n

    Name three components of attenuation.
    Absorption, reflection, and scattering<\/p>\n\n\n\n

    As the path length increases, the attenuation of ultrasound in soft tissue __<\/em><\/strong>.
    Increases<\/p>\n\n\n\n

    Attenuation in lung tissue is __<\/em><\/strong> than attenuation in soft tissue.
    Greater<\/p>\n\n\n\n

    Attenuation in bone is __<\/em><\/strong> than attenuation in soft tissue.
    Greater<\/p>\n\n\n\n

    Attenuation in air is __<\/em><\/strong> than attenuation in soft tissue.
    Greater<\/p>\n\n\n\n

    What are the units of attenuation?
    decibels (dB)<\/p>\n\n\n\n

    T or F. In a given medium, attenuation is unrelated to speed of sound.
    True (attenuation and propagation speed are unrelated)<\/p>\n\n\n\n

    What is the relationship between ultrasound frequency and the attenuation coefficient in soft tissue?
    In soft tissue, the attenuation coefficient in dB per centimeter is approximately one half of ultrasonic frequency in MHz<\/p>\n\n\n\n

    What are the units of the half-value layer thickness?
    Distance; centimeters<\/p>\n\n\n\n

    As frequency decreases, depth of penetration _<\/em><\/strong>.
    Increases<\/p>\n\n\n\n

    As path length increases, the half boundary layer __<\/em><\/strong>.
    Remains the same<\/p>\n\n\n\n

    Impedance is a characteristic of _<\/strong><\/em><\/strong>.
    Only the medium<\/p>\n\n\n\n

    As the path length increases, the attenuation coefficient of ultrasound in soft tissue __<\/em><\/strong>.
    Remains the same<\/p>\n\n\n\n

    Acoustic impedance = x ___<\/em><\/strong>.
    Impedance = density (kg\/m^3) x propagation speed (m\/s)<\/p>\n\n\n\n

    Two media A and B have the same densities. The speed of sound in medium A is 10% higher than in medium B. Which medium has the higher acoustic impedance?
    Medium A<\/p>\n\n\n\n

    Impedance is important in _<\/em><\/strong> at boundaries.
    Reflections<\/p>\n\n\n\n

    Which is better to use while examining a carotid artery., a 7.5 or 3.0 MHz transducer?
    7.5 MHz transducer (superficial)<\/p>\n\n\n\n

    What are the three types of angles?
    Acute – <90 degrees Right – exactly 90 degrees Obtuse – >90 degrees<\/p>\n\n\n\n

    All angles that do not equal 90 degrees are called _<\/em><\/strong> angles.
    Oblique<\/p>\n\n\n\n

    What does normal incidence mean?
    The incident sound beam strikes the boundary at exactly 90 degrees.
    (also called: perpendicular, orthogonal, right angle)<\/p>\n\n\n\n

    What is an oblique incidence?
    When the incident sound beam strikes the boundary at any angle other than 90 degrees<\/p>\n\n\n\n

    What is the sound wave’s intensity immediately before it strikes a boundary called?
    Incident intensity<\/p>\n\n\n\n

    What is reflected intensity?
    The intensity of the portion of the incident sound beam that, after striking a boundary, continues forward in the same general direction it was traveling<\/p>\n\n\n\n

    incident (starting) intensity =
    Reflected intensity + transmitted intensity<\/p>\n\n\n\n

    What is the intensity reflection coefficient (IRC)?
    The percentage of the intensity that bounces back when a sound beam strikes the boundary between two media<\/p>\n\n\n\n

    What is the intensity transmission coefficient (ITC)?
    The percentage of ultrasound intensity that passes in the forward direction when the beam strikes an interface between two media<\/p>\n\n\n\n

    IRC (%) + ITC (%) =
    100%<\/p>\n\n\n\n

    A sound wave with intensity of 50 W\/cm^2 strikes a boundary and is totally reflected. What is the intensity reflection coefficient?
    100%<\/p>\n\n\n\n

    A sound wave with intensity of 50 W\/cm^2 strikes a boundary and is totally reflected. What is the reflected intensity?
    50 W\/cm^2<\/p>\n\n\n\n

    IRC (%) =
    (Z2-Z1\/Z2+Z1)^2 x 100<\/p>\n\n\n\n

    If the two media have identical impedances, there will be\u2026
    No reflection<\/p>\n\n\n\n

    If two media have slightly different impedances, there will be\u2026
    A small reflection<\/p>\n\n\n\n

    If two media have substantially different impedances, there will be\u2026
    A large reflection<\/p>\n\n\n\n

    A pulse of ultrasound is propagating in soft tissue, such as liver. The pulse strikes a boundary with a different soft tissue at normal incidence. What portion of the intensity is reflected back toward the transducer? Why?
    A very small percentage of sound, typically less than 1%, is reflected at a boundary between two soft tissues
    Very little reflection occurs when the impedances have similar, but not identical, values<\/p>\n\n\n\n

    Sound is traveling in a medium and strikes a boundary with normal incidence. If 63% of the wave’s intensity is reflected back toward the transducer what percentage is transmitted?
    37%<\/p>\n\n\n\n

    ITC (%) =
    (transmitted intensity\/ incident intensity) x 100
    or
    1 – intensity reflection coefficient<\/p>\n\n\n\n

    Sound is traveling from bone to soft tissue. The impedances of the media differ significantly, and 90% of the beam’s intensity is reflected. What percentage of the intensity is transmitted?
    100% of the energy must be accounted for
    If 90 % is reflected 10% must be transmitted<\/p>\n\n\n\n

    In _<\/strong><\/em><\/strong> incidence, it is complicated to tell whether the sound ill reflect or transmit after striking a boundary.
    Oblique<\/p>\n\n\n\n

    What two principles always apply to reflection with oblique incidence?
    Conservation or energy
    reflection angle = incident angle<\/p>\n\n\n\n

    incident intensity (W\/cm^2) =
    reflected intensity + transmitted intensity<\/p>\n\n\n\n

    angle of incidence =
    angle of reflection<\/p>\n\n\n\n

    If the sound beam bends or changes direction after is strikes an interface at an oblique angle, this is called\u2026
    refraction<\/p>\n\n\n\n

    What is refraction?
    a change in direction of wave propagation when traveling from one medium to another.<\/p>\n\n\n\n

    Refraction only occurs if two conditions are satisfied:
    oblique incidence (not normal)
    and
    propagation speeds of the two media are different<\/p>\n\n\n\n

    What is snell’s law?
    sin(transmission angle)\/sin (incident angle) = speed of Medium 2\/speed of Medium 1<\/p>\n\n\n\n

    Under what conditions will the transmission angle equal the incident angle?
    if the two media are the same<\/p>\n\n\n\n

    Under what conditions will the transmission angle be greater than the incident angle?
    when medium 2 is greater than medium 1<\/p>\n\n\n\n

    Under what conditions will the transmission angle be less than the incident angle?
    when medium 2 is less than medium 1<\/p>\n\n\n\n

    A pulse of ultrasound propagates in soft tissue, such as liver. The pulse strikes a soft tissue – soft tissue interface with oblique incidence. Some of the sound energy is transmitted. To what extent is the transmitted beam refracted?
    The transmitted beam undergoes little to no refraction. A transmitted beam is refracted when the incidence is oblique and the propagation speeds are different.<\/p>\n\n\n\n

    A sound wave strikes a boundary at normal incidence. The impedances of the two media are identical. What percentage of the sound wave is refracted?
    0%, refraction cannot occur with normal incidence<\/p>\n\n\n\n

    What property has units of rayls? How is it determined?
    Impedance
    Impedance = density x speed<\/p>\n\n\n\n

    What is the elapsed time from pulse creation to pulse reception called?
    go-return time or time-of-flight<\/p>\n\n\n\n

    The time-of-flight is __<\/em><\/strong> related to the depth that a sound pulse travels.
    directly<\/p>\n\n\n\n

    depth (mm) =
    1.54 mm\/\u03bcsec x go-return time (\u03bcsec)\/2<\/p>\n\n\n\n

    For every _<\/strong> \u03bcsec of go-return time, the object creating the reflection is 1 centimeter deeper in soft tissue.
    13<\/p>\n\n\n\n

    Since a pulse travels to the reflector and back to the transducer, the total distance that a pulse travels is\u2026
    twice the reflector depth<\/p>\n\n\n\n

    A sound wave is created by a transducer, reflects off an object, and returns to that transducer. The depth of the reflector is 10 cm in soft tissue. What is the go-return time?
    130 \u03bcsec<\/p>\n\n\n\n

    A sound wave is created by a transducer, reflects off an object, and returns to the transducer. The go-return time is 26 \u03bcsec. What is the depth of the reflector?
    2 cm<\/p>\n\n\n\n

    A sound wave is created by a transducer, reflects off an object, and returns to the transducer. The go-return time is 26 \u03bcsec. What is the total distance that the pulse traveled?
    4 cm<\/p>\n\n\n\n

    The maximum imaging depth (depth of view) during an ultrasound exam is 10cm. The sonographer adjusts the imaging depth to 20 cm. What happens to pulse repetition period?
    it is doubled<\/p>\n\n\n\n

    The maximum imaging depth during an ultrasound exam is 10 cm. The sonographer adjusts the imaging depth to 20 cm. What happens to pulse repetition frequency?
    it is halved<\/p>\n\n\n\n

    The imaging depth during an ultrasound exam is 10 cm. The sonographer adjusts the imaging depth to 5 cm. What happens to pulse repetition period?
    it is halved<\/p>\n\n\n\n

    A sound wave is created by a transducer, reflects off an object, and returns to the transducer. The imaging depth is 10 cm in soft tissue. What is the maximum pulse repetition frequency?
    7.7 kHz<\/p>\n\n\n\n

    A sound wave is created by a transducer, reflects off an object, and returns to the transducer. The maximum imaging depth is 7.7 cm. What is the PRF?
    77,000\/7.7 = 10,000 Hz<\/p>\n\n\n\n

    A sound wave is created by a transducer, reflects off an object, and returns to the transducer. The go-return time is 130 \u03bcsec. What is the maximum PRF?
    7,700 Hz.<\/p>\n\n\n\n

    What is axial resolution?
    it measures the ability of a system to display two structures that are very close together when the structures are parallel to the sound beam’s main axis.<\/p>\n\n\n\n

    What is axial resolution determined by? And is it adjustable?
    SPL (shorter pulses improve axial resolution)
    It is not adjustable because the SPL is fixed.<\/p>\n\n\n\n

    What are the synonyms to axial resolution?
    longitudinal, range, radial, or depth resolution
    LARRD<\/p>\n\n\n\n

    What is the relationship between the numerical value of the axial resolution and the image quality?
    Lower numerical values of axial resolution indicate a shorter pulse. Shorter pulses create more accurate images; therefore, the image quality is better with lower numbers.<\/p>\n\n\n\n

    axial resolution (mm) =
    spatial pulse length\/2
    or
    (wavelength (mm) x # cycles in pulse)\/2<\/p>\n\n\n\n

    What allows some transducers to have better axial resolution than others?
    axial resolution is r=determined by the pulse length, with shorter pulses yielding improved axial resolution.<\/p>\n\n\n\n

    How is a shorter pulse created?
    less ringing and higher frequency<\/p>\n\n\n\n

    What is less ringing?
    Dampening the crystal to create fewer cycles in the pulse<\/p>\n\n\n\n

    What is the ability to accurately distinguish two structures lying closely together called?
    resolution<\/p>\n\n\n\n

    The ability to distinguish two structures lying closely together front-to-back or parallel to the sound beam is called __<\/strong><\/em><\/strong>.
    longitudinal, axial, range, radial, depth resolution<\/p>\n\n\n\n

    Axial resolution is measured with units of _<\/em><\/strong>.
    distance, such as mm.<\/p>\n\n\n\n

    The more cycles in a pulse, the _<\/em><\/strong> the numerical value of the range resolution is.
    greater<\/p>\n\n\n\n

    If a new pulsed transducer has many more cycles in its pulse, the image accuracy __<\/em><\/strong>.
    degrades<\/p>\n\n\n\n

    _<\/strong> frequency transducers generally have the best range resolution.
    high<\/p>\n\n\n\n

    In soft tissue, a 3 cycle, 1 MHz pulse has a length of a pulse is 4.5 mm. What is the axial resolution?
    2.25 mm.<\/p>\n\n\n\n

    Two different transducers create sound pulses. One transducer is labeled 5 MHz and the other, 3 MHz. Which transducer is more likely to create a more accurate image with relation to axial resolution? Which transducer probably has a lower numerical measure of axial resolution?
    The 5 MHz transducer. The higher frequency transducer creates a shorter pulse and thus has a lower numerical measure of axial resolution. Lower numbers mean improved image quality.<\/p>\n\n\n\n

    Wha happens during transmission?
    electrical energy from the system is converted into sound<\/p>\n\n\n\n

    What happens during reception?
    the reflected sound pulse is converted into electricity<\/p>\n\n\n\n

    What is the piezoelectric effect?
    the property of certain materials to create a voltage when they are mechanically deformed<\/p>\n\n\n\n

    What is the reverse piezoelectric effect?
    when a voltage is applied to piezoelectric materials, they change shape<\/p>\n\n\n\n

    What are the materials that change sound into electricity (and vice versa)?
    piezoelectric or ferroelectric<\/p>\n\n\n\n

    What materials are commonly used in clinical transducers?
    lead zirconate titanate (PZT)
    also known as ceramic, active element, or crystal<\/p>\n\n\n\n

    What are the 7 components of a basic transducer?
    case, electrical shield, acoustic insulator, PZT or active element, wire, matching layer, and backing material (also called the damping element)<\/p>\n\n\n\n

    What is the case?
    the cylindrical tube, constructed of metal or plastic, that protects the internal components of the transducer from damage.<\/p>\n\n\n\n

    What is the electrical shield?
    Thin metallic barrier lining the inside of the case.<\/p>\n\n\n\n

    What is acoustic insulator?
    A thin barrier of cork or rubber that isolates or “uncouples” the internal components of the transducer from the case. Prevents vibrations in the case from inducing an electrical voltage in the PZT of the transducer.<\/p>\n\n\n\n

    What is the wire?
    Provides an electrical connection between PZT and the ultrasound system.<\/p>\n\n\n\n

    What is the matching layer?
    increases the efficiency of sound energy transfer between the active element and the body, and protects the active element<\/p>\n\n\n\n

    What is the backing material (or damping element)?
    bonded to the back of the active element, it reduces the “ringing” of the pulse.<\/p>\n\n\n\n

    The matching layer and gel _<\/em><\/strong> the efficiency of sound transfer between the transducer’s PZT and the skin.
    increase<\/p>\n\n\n\n

    How thick are the matching layer and the active element of a basic ultrasound transducer?
    The thickness of the matching layer is one quarter of the wavelength of sound in the matching layer.
    The thickness of the active element is one-half of the wavelength of sound in the active element.<\/p>\n\n\n\n

    What are the characteristics of damping material?
    high degree of sound absorption, and acoustic impedance similar to PZT.<\/p>\n\n\n\n

    What are additional consequences related to the use of a backing material?
    decreased sensitivity
    wide bandwidth
    low quality factor<\/p>\n\n\n\n

    What does decreased sensitivity mean?
    the transducers with damping material are less able to convert low-level sound reflections into meaningful electrical signals during reception.<\/p>\n\n\n\n

    What is bandwidth?
    the range, or difference, between the highest and lowest frequencies in the pulse. Thus, imaging probes are identified as short pulse, wide bandwidth.<\/p>\n\n\n\n

    Long duration events are bandwidth, whereas short duration events are<\/em> bandwidth.
    narrow, wide<\/p>\n\n\n\n

    quality factor =
    main frequency\/bandwidth<\/p>\n\n\n\n

    A shorter pulse has a _<\/em><\/strong> Q-factor.
    lower<\/p>\n\n\n\n

    A longer pulse has a __<\/strong> Q-factor.
    higher<\/p>\n\n\n\n

    How is PZT created?
    created by exposing the material to a strong electrical field while being heated to a substantial temperature. (polarization)<\/p>\n\n\n\n

    What is the Curie temperature, and what is its importance?
    the temperature that the PZT is polarized is called the Curie temperature or Curie point.
    If the polarized PZT is heated above the Curie temperature, the crystal’s piezoelectric properties are destroyed. (depolarized)<\/p>\n\n\n\n

    What is the difference between sterilization and disinfection? Which method is used on transducers?
    Sterilization is the destruction of all microorganisms by exposure to extreme heat, chemical agents, or radiation.
    Disinfection is the application of a chemical agent to reduce or eliminate infectious organisms on an object.
    Ultrasound transducers only require disinfection.<\/p>\n\n\n\n

    Pulse length is __<\/strong> related to pulse duration.
    directly<\/p>\n\n\n\n

    Q-factor is _<\/strong><\/em><\/strong> related to bandwidth.
    inversely<\/p>\n\n\n\n

    Pulse duration is __<\/em><\/strong> related to bandwidth.
    inversely<\/p>\n\n\n\n

    T or F. Shorter duration events (such as dampened pulses) are more likely to be wide bandwidth.
    True.<\/p>\n\n\n\n

    What occurs when a PZT crystal’s temperature is elevated above the Curie point?
    the PZT is depolarized<\/p>\n\n\n\n

    In a continuous wave transducer, electrical frequency =
    acoustic frequency<\/p>\n\n\n\n

    The frequency of sound emitted by a continuous wave transducer is determined by what?
    the frequency of the electrical signal created by the ultrasound system<\/p>\n\n\n\n

    What characteristics of the active element determine the frequency of sound created by a pulsed wave transducer?
    speed of sound in the PZT and the thickness of the PZT<\/p>\n\n\n\n

    How does the speed of sound in PZT affect frequency?
    in a pulsed wave transducer, the speed of sound in PZT and the frequency of sound are directly related. When the speed of sound in PZT is faster, the frequency of sound created by a pulsed wave transducer is higher.<\/p>\n\n\n\n

    How does the thickness or the PZT crystal affect frequency?
    For pulsed wave transducers, thinner active elements create higher frequency sound pulses. PZT thickness and frequency are inversely related.<\/p>\n\n\n\n

    The thickness of the PZT crystal in a pulsed wave transducer is equal to _<\/strong><\/em><\/strong> of the wavelength of sound in the PZT.
    one-half<\/p>\n\n\n\n

    frequency (MHz) =
    sounds speed in PZT (mm\/\u03bcsec)\/2 x thickness (mm)<\/p>\n\n\n\n

    True or False. The acoustic impedance of the matching layer is approximately the same as the acoustic impedance of skin.
    False.<\/p>\n\n\n\n

    True or False. Imaging transducers are usually of high rather than low bandwidth.
    True.<\/p>\n\n\n\n

    True or False. A very high Q factor transducer is used more often in diagnostic imaging transducers than a low Q factor.
    False.<\/p>\n\n\n\n

    True or False. A pulse with a long pulse duration is likely to have a narrow bandwidth.
    True.<\/p>\n\n\n\n

    True or False. The damping material in a transducer increases the sensitivity.
    False.<\/p>\n\n\n\n

    True or False. The damping material in a transducer increases pulse length.
    False.<\/p>\n\n\n\n

    True or False. The damping material in a transducer decreases the pulse duration.
    True.<\/p>\n\n\n\n

    True or False. The damping material in a transducer improves the system’s lateral resolution.
    False.<\/p>\n\n\n\n

    True or False. The damping material in a transducer improves the system’s longitudinal resolution.
    True.<\/p>\n\n\n\n

    True or False. The damping material in a transducer decreases the bandwidth.
    False.<\/p>\n\n\n\n

    True or False. The damping material in a transducer decreases the quality factor.
    True.<\/p>\n\n\n\n

    True or False. If the frequency of the electrical excitation voltage of a pulsed wave transducer is 6 MHz, then the operating frequency of the transducer is 6 MHz.
    False. (with pulsed wave transducers, the frequency of sound is not determined by the electrical signal)<\/p>\n\n\n\n

    True or False. If the pulse repetition frequency of a transducer is increased, then the frequency of sound produced by the transducer remains the same.
    True. (frequency and pulse repetition frequency are not related)<\/p>\n\n\n\n

    True or False. The diameter of the active element of a transducer helps to determine the frequency of the sound produced by the transducer.
    False. (the diameter of the active element does not determine the frequency of sound created by the transducer)<\/p>\n\n\n\n

    True or False. If the frequency of the electrical excitation voltage of a continuous wave transducer is 6 MHz, then the operating frequency of the transducer is 6 MHz.
    True. (the frequency of the electrical voltage and the frequency of the sound beam are identical with continuous wave transducers)<\/p>\n\n\n\n

    True or False. Two piezoelectric crystals are made from the same material. The thicker crystal will make a pulsed transducer with a higher frequency.
    False. (thicker active elements create sound with lower frequency, not higher)<\/p>\n\n\n\n

    True or False. Two piezoelectric crystals are made from the same material. The thicker crystal will make a pulsed transducer with a lower frequency.
    False. (with a continuous wave transducer, active element thickness does not determine the sound beam’s frequency)<\/p>\n\n\n\n

    True or False. The normal propagation speed in piezoelectric material is about 3 to 5 times greater than that in soft tissue.
    True. (sound travels much faster in PZT than in soft tissue)<\/p>\n\n\n\n

    Which type of transducer has a greater Q-factor: therapeutic or imaging?
    imaging transducers use more backing material than therapeutic transducers.<\/p>\n\n\n\n

    In an imaging transducer, what is the purpose of attaching the backing material to the PZT?
    improve image quality<\/p>\n\n\n\n

    A pulsed-wave transducer has a resonant frequency of 5 MHz. The lowest frequency in the pulse is 2 MHz and the highest is 8 MHz. What is the bandwidth?
    8 MHz – 2 MHz = 6 MHz<\/p>\n\n\n\n

    The resonant frequency = the _<\/em><\/strong><\/em><\/strong>
    main or center frequency<\/p>\n\n\n\n

    What is the Q-factor?
    resonant frequency\/ bandwidth<\/p>\n\n\n\n

    At the starting point, the beam width is\u2026
    exactly the same as the transducer diameter.<\/p>\n\n\n\n

    What are the five terms that describe the shape and regions of a sound beam?
    focus, near zone, focal length, far zone, focal zone<\/p>\n\n\n\n

    Where is the beam narrowest?
    focal point (one-half the width of the beam as it leaves the transducer)<\/p>\n\n\n\n

    What is the near field? Another name for it?
    the region from the transducer to the focus, fresnel zone<\/p>\n\n\n\n

    What is the focal length or NZL?
    the distance from the transducer to the focus<\/p>\n\n\n\n

    What is the far zone? Another name for it?
    the region starting at the focus and extending deeper, fraunhofer zone<\/p>\n\n\n\n

    At depths more than two bear zone lengths, the beam is _<\/em><\/strong> than the active element.
    wider<\/p>\n\n\n\n

    What is the focal zone?
    a region around the focus where the beam is relatively narrow and image detail is superior (half located in near and other half located in far)<\/p>\n\n\n\n

    The focus marks the end of the _<\/em><\/strong>.
    near zone<\/p>\n\n\n\n

    At the depth of the focus, the sound beam starts to _<\/em><\/strong> or widen, which marks the beginning of the ___<\/em><\/strong><\/em><\/strong> zone.
    diverge, far (Fraunhofer)<\/p>\n\n\n\n

    At depths more than twice the focal length, the beam’s width __<\/em><\/strong> that of the transducer.
    exceeds<\/p>\n\n\n\n

    Adjustable focus systems are called __<\/em><\/strong><\/em><\/strong>.
    Phased array<\/p>\n\n\n\n

    What characteristics of a fixed-focus transducer determine the focal depth?
    transducer diameter and frequency of the sound<\/p>\n\n\n\n

    How does transducer diameter affect the focal depth?
    increasing diameter results in a deeper focus; therefore, transducer diameter and focal depth are directly related.
    (beams from larger diameter active elements will have deeper focus)<\/p>\n\n\n\n

    How does frequency affect focal depth?
    Higher frequency sound results in a deeper focus; therefore, frequency and focal depth are directly related<\/p>\n\n\n\n

    Even with high frequency sound, an extremely small diameter locates the focus _<\/strong><\/em><\/strong>.
    shallower<\/p>\n\n\n\n

    focal depth (cm) =
    diameter (mm)^2 x frequency (MHz)\/61.6
    or
    diameter (mm)^2\/40 x wavelength (mm)<\/p>\n\n\n\n

    A pair of 6 MHz probes are identical except for active element diameter. The active element diameters are 6mm and 10mm, respectively. The sound beam of which probe will have a shallower focus?
    6mm active element. Smaller diameter crystals produce beams with shallower foci.<\/p>\n\n\n\n

    A pair of 9 mm diameter probes are identical except for frequency, which is 3 MHz and 6 MHz, respectively. Which beam will have a shallower focus?
    3 MHz beam. (focal depth increases with increasing frequency)<\/p>\n\n\n\n

    True or False. Transducer frequency and near zone length are inversely related.
    False. (directly related)<\/p>\n\n\n\n

    True or False. Wavelength and near zone length are inversely related.
    True<\/p>\n\n\n\n

    True or False. Active element diameter and near zone length are directly related.
    True<\/p>\n\n\n\n

    Beam divergence describes\u2026
    the gradual spread of the ultrasound beam in the far field.<\/p>\n\n\n\n

    How does transducer diameter affect beam divergence in the far field?
    Smaller diameter crystals produce beams that spread out, or diverge, more in the far zone. (crystal diameter and beam divergence are inversely related) Larger diameter crystals produce beams that diverge less in the far field<\/p>\n\n\n\n

    Larger diameter crystals and higher frequency sound improve __<\/em><\/strong><\/em><\/strong> in the far field.
    lateral resolution<\/p>\n\n\n\n

    How does frequency alter beam divergence in the far field?
    Lower frequency sound beams spread out or diverge more in the deep far zone. (frequency and beam divergence are inversely related)<\/p>\n\n\n\n

    A pair of 6 MHz probes are identical except for active element diameter, which is 6 mm and 10 mm, respectively. Which beam will be more compact in the far field?
    10mm active element has a less divergent beam. (larger diameter crystals produce beams that diverge less in the far field)<\/p>\n\n\n\n

    A pair of 9 mm diameter probes are identical except for frequency, which are 3 MHz and 6 MHz. Which sound beam will spread out more in the far field?
    3 MHz beam is more divergent. (beams are more compact as frequency increases)<\/p>\n\n\n\n

    True or False. Transducer frequency and beam divergence are inversely related.
    True.<\/p>\n\n\n\n

    True or False. Active element diameter and beam divergence are inversely related.
    True.<\/p>\n\n\n\n

    What are sound waves are produced by? What shape do they diverge in?
    tiny pieces of PZT, V-shape<\/p>\n\n\n\n

    When is the V-shaped wave created? And what are they called?
    when the source is about the size of the sound’s wavelength. Called spherical waves, diffraction patterns, or HUYGEN’S wavelets<\/p>\n\n\n\n

    Huygen’s principle states\u2026
    that a large active element may be thought of as millions of tiny, distinct sound sources.<\/p>\n\n\n\n

    Where does destructive interference occur?
    in the areas where the sound beam is absent<\/p>\n\n\n\n

    What does resolution refer to?
    accuracy in imaging<\/p>\n\n\n\n

    Lateral resolution distinctly identifies two structures that are very close together when they are _<\/em><\/strong> to the sound beam.
    perpendicular<\/p>\n\n\n\n

    What is lateral resolution determined by?
    the width of the sound beam (narrower beams have better resolution)<\/p>\n\n\n\n

    Synonyms to lateral resolution are:
    angular, transverse, azimuthal resolution (LATA)<\/p>\n\n\n\n

    Where is lateral resolution best?
    at the focus where the beam is narrowest.<\/p>\n\n\n\n

    lateral resolution (mm) =
    beam diameter (mm)<\/p>\n\n\n\n

    Which type of resolution is superior in clinical imaging systems: lateral resolution or axial resolution?
    Axial resolution because ultrasound pulses are shorter than they are wide.<\/p>\n\n\n\n

    Higher frequencies improve both axial and lateral resolutions because\u2026
    axial: the shorter pulses associated with high frequency sound
    lateral: in the far field, high frequency pulses diverge less than low frequency ones. (high frequency sound beams are narrower than low frequency beams)<\/p>\n\n\n\n

    How does focusing improve lateral resolution?
    by concentrating the sound energy into a narrower beam<\/p>\n\n\n\n

    What are the three methods of focusing?
    external focusing – with a lens
    internal focusing – with a curved active element
    phased array focusing – with the electronics of the ultrasound system<\/p>\n\n\n\n

    Internal and External focusing may be used with\u2026
    single element transducers<\/p>\n\n\n\n

    Both external and internal focusing are considered _<\/strong>.
    fixed (conventional or mechanical)
    focal depth and the extent of focusing cannot be changed<\/p>\n\n\n\n

    What does external focusing use?
    a lens<\/p>\n\n\n\n

    What does internal focusing use?
    a curved piezoelectric crystal that concentrates the sound energy into a narrower beam<\/p>\n\n\n\n

    What type of fixed focusing is the most common?
    Internal Focusing<\/p>\n\n\n\n

    Phased array means\u2026
    adjustable or multiple focusing<\/p>\n\n\n\n

    What happens to a beam when it is focused?
    beam diameter in the near field and focal zone narrows
    focus is moved closer to transducer
    beam diameter beyond focal zone widens (improves lateral resolution in near zone)
    focal zone size is reduced<\/p>\n\n\n\n

    The ability to distinguish two structure lying close together is called __<\/em><\/strong>.
    resolution<\/p>\n\n\n\n

    The ability to distinguish two structures lying close together front-to-back is called _<\/em><\/strong>.
    longitudinal, axial, range, radial, depth resolution<\/p>\n\n\n\n

    The ability to distinguish two structures lying close together side by side is called _<\/em><\/strong>.
    lateral, angular, transverse, azimuthal resolution<\/p>\n\n\n\n

    Axial resolution and lateral resolution are both measured with units of _<\/em><\/strong>.
    distance, such as mm<\/p>\n\n\n\n

    When the number of cycles in a pulse increases while the frequency remains the same, the numerical value of the range resolution _<\/strong><\/em><\/strong>.
    increases (with more cycles in a pulse, the pulse becomes longer)<\/p>\n\n\n\n

    When the number of cycles in a pulse increases (more ringing) while the frequency remains the same, the image quality __<\/em><\/strong>.
    degrades. (when the number of cycles increases, the SPL increases, and the image quality decreases)<\/p>\n\n\n\n

    __<\/strong> frequency transducers have the best range resolution.
    high frequency<\/p>\n\n\n\n

    Name the 4 synonyms for axial resolution.
    longitudinal, range, radial, depth resolution<\/p>\n\n\n\n

    Name the 3 synonyms for lateral resolution.
    angular, azimuthal resolution, and transverse<\/p>\n\n\n\n

    The length of a pulse is 8 mm. What is the minimum distance between two reflectors, positioned one in front of the other, that still produces two echoes on our image?
    4 mm (one half the pulse length!)<\/p>\n\n\n\n

    The frequency of a transducer does not change. If the diameter of the new piezoelectric crystal increases, what happens to the near zone length?
    increases<\/p>\n\n\n\n

    The frequency of a transducer does not change. If the diameter of the new piezoelectric crystal increases, what happens tot he beam diameter in the far zone?
    decreases<\/p>\n\n\n\n

    The frequency of a transducer does not change. If the diameter of the new piezoelectric crystal increases, what happens to the wavelength?
    no change<\/p>\n\n\n\n

    The frequency of a transducer does not change. If the diameter of the new piezoelectric crystal increases, what happens to the beam diameter in the near zone?
    increases<\/p>\n\n\n\n

    Narrow beams improve\u2026
    lateral resolution<\/p>\n\n\n\n

    What is A-mode?
    Amplitude, series of upward spikes. (the higher the returning spike, the higher the amplitude) X-axis of a-mode is depth<\/p>\n\n\n\n

    A-modes are accurate in determining ___<\/em><\/strong><\/em><\/strong>.
    the depth of reflectors<\/p>\n\n\n\n

    What is B-mode?
    Brightness, the brightness of the once invisible dot indicates the strength of the reflection. (weak reflections appear as darker gray dots, strong reflections are white dots) X-axis is depth<\/p>\n\n\n\n

    What was the form form of grayscale imaging?
    B-Mode<\/p>\n\n\n\n

    What is M-mode?
    Motion, horizontal wavy lines represent the changing depth of the reflecting surfaces are produced on the paper. X-axis = time, Y-axis = depth<\/p>\n\n\n\n

    What is M-mode primarily used for?
    assess the motion of cardiac walls and structures<\/p>\n\n\n\n

    What is the only display mode that provides information regarding reflector motion with respect to time?
    M-mode<\/p>\n\n\n\n

    With A-mode, what does the X-axis display?
    depth of the reflector<\/p>\n\n\n\n

    With M-mode, what does the Y-axis display?
    depth of the reflector<\/p>\n\n\n\n

    Which mode provides the foundation for real-time, grayscale anatomic imaging?
    B-mode, or brightness mode<\/p>\n\n\n\n

    With A-mode, what does the Y-axis display?
    amplitude of the reflected signal<\/p>\n\n\n\n

    In M-mode, what does the X-axis display?
    time<\/p>\n\n\n\n

    With B-mode Which axis is related to the strength of the reflection?
    the z-axis<\/p>\n\n\n\n

    How does an ultrasound system create high quality, two-dimensional images?
    Two characteristics of sound that make it difficult to create two-dimensional images are: sound travels only in a straight line, and sound beams must be narrow to optimize lateral resolution.
    The use of multiple pulses to create a two-dimensional image overcomes both of these difficulties.<\/p>\n\n\n\n

    In a mechanical transducer, the PZT crystal is ___<\/em><\/strong><\/em><\/strong> to create the image.
    physically moved<\/p>\n\n\n\n

    Mechanical transducer image shape:
    fan or sector-shaped<\/p>\n\n\n\n

    Mechanical transducers have a _<\/em><\/strong> focal depth.
    fixed<\/p>\n\n\n\n

    When there is any damage done to the crystal in a mechanical transducer,
    the entire image is lost<\/p>\n\n\n\n

    Array transducers are comprised of\u2026
    a single slab of PZT cut into a collection of separate pieces called elements. Each active element is connected by a wire to its own electronic circuitry int he ultrasound system.<\/p>\n\n\n\n

    The linear phased array has _ moving parts. And the beam is steered and focused using an electrical techniques called _<\/em><\/strong>.
    no, phasing<\/p>\n\n\n\n

    What is the image shape created by a phased array?
    fan or sector-shaped<\/p>\n\n\n\n

    Elements of a phased array are what shape?
    rectangular and narrow<\/p>\n\n\n\n

    Sound beams are focused _<\/strong><\/em><\/strong> with linear phased array transducers.
    electronically<\/p>\n\n\n\n

    Advantage of phased array systems is:
    the availability of electronically controlled, adjustable focusing, which allows the sonographer to match the beam’s characteristics to the clinical circumstances.<\/p>\n\n\n\n

    Damage to one of the elements of a phased array transducer results in\u2026
    inconsistent or erratic beam steering and focusing.<\/p>\n\n\n\n

    How many elements in a phased array probe are excited to create a single sound pulse?
    All the active elements in a linear phased array probe are fired to create each sound beam.<\/p>\n\n\n\n

    What is the beam former?
    the electronics within the ultrasound system that create the voltages to the transducer element<\/p>\n\n\n\n

    When the spike line is straight, an __<\/strong><\/em><\/strong> is created.
    unfocused sound beam<\/p>\n\n\n\n

    How does the pattern of electrical spikes from the beam former focus the sound beam during transmission?
    When the outer crystals are excited earlier than the inner crystals, the curved pattern creates a focused sound beam. This means the beam will be directed straight ahead.<\/p>\n\n\n\n

    Brightness of the display is affected by?
    Receiver amplification (gain)<\/p>\n\n\n\n

    Acoustic speckle is an artifact produced by what?
    interference of tiny acoustic wavelets<\/p>\n\n\n\n

    Side lobe artifact is a result of what condition?
    Acoustic energy radiating in a direction different than the main axis of the beam<\/p>\n\n\n\n

    A sound wave is
    mechanical, longitudinal<\/p>\n\n\n\n

    A compression area of a sound wave is
    high pressure, high density<\/p>\n\n\n\n

    A rarefaction area of a sound wave is
    low pressure, low density<\/p>\n\n\n\n

    Which is considered an acoustic variable
    pressure<\/p>\n\n\n\n

    Which is a unit for pressure
    N\/m2<\/p>\n\n\n\n

    Which is a unit for density
    lbs\/cm3<\/p>\n\n\n\n

    Which wave propagates in a medium
    sound<\/p>\n\n\n\n

    The range for ultrasound is
    greater than 20KHz<\/p>\n\n\n\n

    __<\/em> is the number of wave cycles per second
    frequency<\/p>\n\n\n\n

    One kilohertz is equal to
    1,000 cycles per second<\/p>\n\n\n\n

    One megahertz is equal to
    1,000,000 cycles per second<\/p>\n\n\n\n

    The useful frequency range for clinical imaging ultrasound is
    2 MHz to 10 MHz<\/p>\n\n\n\n

    Frequency is determined by the
    source<\/p>\n\n\n\n

    Frequency affects all of the following, except: wavelength, resolution, penetration, impedance
    impedance<\/p>\n\n\n\n

    The times per cycle is
    period<\/p>\n\n\n\n

    The period for a 5 MHz probe is
    0.2usec<\/p>\n\n\n\n

    If frequency increases, period will
    decreases<\/p>\n\n\n\n

    Period is determined by the
    source<\/p>\n\n\n\n

    Period multiplied by the number of cycles in a pulse equals
    pulse duration<\/p>\n\n\n\n

    The distance between cyclical peaks is
    wavelength<\/p>\n\n\n\n

    The symbol for wavelength is
    lambda<\/p>\n\n\n\n

    The wavelength of a 5 MHz probe in soft tissue is
    0.3 mm<\/p>\n\n\n\n

    As frequency increases, wavelength (assume same medium)
    decreases<\/p>\n\n\n\n

    Wavelength is determined by the
    source and medium<\/p>\n\n\n\n

    As wavelength decreases
    resolution improves<\/p>\n\n\n\n

    The rate at which a sound vibration propagates through a medium is called all of the following, except: sound speed, prop speed, speed of sound, velocity
    velocity<\/p>\n\n\n\n

    The units for propagation speed include all the following, except: km\/sec, mph, msec, mm\/sec
    msec<\/p>\n\n\n\n

    The average speed of sound in soft tissue is
    1540 m\/sec<\/p>\n\n\n\n

    Arrange the following in increasing order of sound speed in soft tissue
    air, fat, muscle, soft tissue, muscle, bone<\/p>\n\n\n\n

    The prop speed of sound of the ceramic lead zirconate titanate (PZT) is approx
    4000 m\/sec<\/p>\n\n\n\n

    speed of sound is determined by
    medium<\/p>\n\n\n\n

    The peak variation minus the mean variation is
    amplitude<\/p>\n\n\n\n

    All of the following are possible units for amplitude, except: degrees, decibels, Pascal, watts
    degrees<\/p>\n\n\n\n

    The maximum variation of an acoustic variable is 60. The mean value is 45. The maximum value is 30. The amplitude is
    15<\/p>\n\n\n\n

    Amplitude is determined by
    source<\/p>\n\n\n\n

    Which ultrasound machine control will affect amplitude
    output power<\/p>\n\n\n\n

    As sound propagates through a medium, amplitude
    decreases<\/p>\n\n\n\n

    The total energy transferred is
    power<\/p>\n\n\n\n

    Power is determined by
    source<\/p>\n\n\n\n

    The amplitude of a wave is 4, power is
    8<\/p>\n\n\n\n

    Power may be affected by which gain control
    transmit<\/p>\n\n\n\n

    The rate of energy transferred into a particular area is
    intensity<\/p>\n\n\n\n

    The units for intensity are
    mmHg<\/p>\n\n\n\n

    The highest measured intensity is
    spatial peak, temporal peak<\/p>\n\n\n\n

    The lowest measured intensity is
    spatial average, temporal average<\/p>\n\n\n\n

    According to the AIUM, there have been no proven biological effects for unfocused ultrasound below
    100 mW\/cm2 SPTA<\/p>\n\n\n\n

    According to the AIUM, there have been no proven biological effects for focused ultrasound below
    1 W\/cm2 SATP<\/p>\n\n\n\n

    Intensity is determined by
    source<\/p>\n\n\n\n

    Which gain controls affect intensity
    transmit<\/p>\n\n\n\n

    Assuming the same area, what effect will an increase in power have on intensity
    increase<\/p>\n\n\n\n

    What effect will an increase in area have on intensity if power remains unchanged
    decrease<\/p>\n\n\n\n

    For continuous wave ultrasound, which intensities are equal
    SPTP, SPTA<\/p>\n\n\n\n

    The factor that describes the spatial intensity distribution across a sound beam is the
    SP\/SA factor<\/p>\n\n\n\n

    The minimum value for the beam uniformity ratio is
    1<\/p>\n\n\n\n

    Ultrasound transducer A has an SP\/SA factor of 40. Ultrasound transducer B has a SP\/SA factor of 20. Which transducer has the brightest center
    transducer A<\/p>\n\n\n\n

    An increase in intensity is determined to be 30 decibels. The intensity is increased by
    10 x 10 x 10 or 1,000<\/p>\n\n\n\n

    For soft tissue, a 75% loss in intensity can be expressed in decibels as
    -6dB<\/p>\n\n\n\n

    The number 1540 may be expressed in scientific notation as
    1.540 x 10(-1 power)<\/p>\n\n\n\n

    The number 0.1492 may be written in scientific notation as
    1.492 x 10(-1 power)<\/p>\n\n\n\n

    Arrange the following in the proper increasing order: giga, mega, kilo, hecto, deca
    deca, hecto, kilo, mega, giga<\/p>\n\n\n\n

    Arrange the following in the proper increasing order: milli, centi, deci, micro, nano
    deci, centi, milli, micro, nano<\/p>\n\n\n\n

    Arrange the following units of length in increasing order: kilometer, meter, centimeter, micrometer, nanometer
    micrometer, millimeter, centimeter, meter, kilometer<\/p>\n\n\n\n

    Which unit would be best to use to express aortic valve area
    centimeters squared<\/p>\n\n\n\n

    Express the average prop speed of sound in soft tissue
    1.54 mm\/usec, 1540 m\/sec, 1.54 km\/sec<\/p>\n\n\n\n

    The acoustic characteristic of a medium is
    impedance<\/p>\n\n\n\n

    A reflection will occur at the boundary of two media if the media impedance are
    dissimilar<\/p>\n\n\n\n

    The percentage of sound energy reflected at a fat\/muscle interface is approx
    1%<\/p>\n\n\n\n

    The percentage of sound energy reflected at a soft tissue\/air interface is approx
    50%<\/p>\n\n\n\n

    A reflector that is smooth surfaced and large is called
    specular<\/p>\n\n\n\n

    examples of specular reflectors
    mitral valve, interventricular septum, carotid artery<\/p>\n\n\n\n

    Specular reflectors are highly dependent on
    incident angle<\/p>\n\n\n\n

    Reflectors that are rough surfaced and small are known as
    scatter<\/p>\n\n\n\n

    Scatter reflectors are highly dependent on
    transmit frequecy<\/p>\n\n\n\n

    The strength of backscatter is dependent upon
    density, size, impedance<\/p>\n\n\n\n

    Reflectors that reflect ultrasound energy equally in all directions are called
    Rayleigh<\/p>\n\n\n\n

    The best example of a scatter reflector is (the)
    organ parenchyma<\/p>\n\n\n\n

    The best example of of a Rayleigh scatter is the
    red blood cell<\/p>\n\n\n\n

    The ultrasound beam strikes an interface at 90 degrees. The incidence is considered
    perpendicular<\/p>\n\n\n\n

    The optimal angle to strike specular reflectors are
    direct<\/p>\n\n\n\n

    The reflected intensity coefficient may be calculated by the formula
    [Z2-Z1\/Z2+Z1]2<\/p>\n\n\n\n

    The ultrasound beam strikes an interface at 74 degrees. This incidence is considered
    oblique<\/p>\n\n\n\n

    The incidence angle is 36 degrees. The reflected angle is
    36 degrees<\/p>\n\n\n\n

    The change in sound travel direction as sound crosses a boundary is known as
    refraction<\/p>\n\n\n\n

    The incident angle is 53 degrees. The prop speed in medium 1 is 1540m\/sec. The prop speed in medium 2 is 1580m\/sec. The reflection angle is
    53 degrees<\/p>\n\n\n\n

    The incident angle is 46 degrees. The prop speed in medium 1 is 1540m\/sec. The prop speed in medium 2 is 1540m\/sec. The reflected angle is 46 degrees. The transmitted angle is
    46 degrees<\/p>\n\n\n\n

    The incident angle is 72 degrees. The prop speed in a medium 1 is 1580m\/sec. The prop speed in medium 2 is 1680m\/sec. The reflection angle is 72 degrees. The transmitted angle is
    greater than 72 degrees<\/p>\n\n\n\n

    In soft tissue, if the frequency of a wave is increased the Propagation Speed (PS) will\u2026
    Remain the Same because stiffness and density affect Propagation Speed.<\/p>\n\n\n\n

    What is the audible range?
    20-20,000Hz<\/p>\n\n\n\n

    \n

    20,000Hz=Ultrasound<\/p>\n<\/blockquote>\n\n\n\n

    Frequency is measured in
    Hertz (Hz)
    is
    Cycles per Second<\/p>\n\n\n\n

    Not affected by sonographer<\/p>\n\n\n\n

    Increase Frequency; Decrease Depth<\/p>\n\n\n\n

    A period is the length of time it takes for
    one complete wavelength to pass a fixed point<\/p>\n\n\n\n

    PRP is determined by
    Transmit time and receive time.<\/p>\n\n\n\n

    Period is measured in
    Time (\u03bcs)<\/p>\n\n\n\n

    When the sonographer changes the imaging depth what parameters are changed?
    PRP, PRF, Duty Factor<\/p>\n\n\n\n

    What is duty factor?
    The percentage or fraction of time that the system is transmitting a pulse (Time Sound is ON or ON-Time).<\/p>\n\n\n\n

    Propagation Speed in SOFT TISSUE
    1.54 mm\/\u03bcs
    (1540 m\/sec)<\/p>\n\n\n\n

    Unit of measurement for Pulse Duration, Duty Factor, PRP, and Period
    Time, (\u03bcs)<\/p>\n\n\n\n

    Pulse duration is determined by
    Sound Source Only<\/p>\n\n\n\n

    Pulse Duration is controlled by
    the ultrasound system and transducer<\/p>\n\n\n\n

    Pulse Duration Formula
    pulse duration (\u03bcs) = # cycles in pulse\/frequency(MHz)<\/p>\n\n\n\n

    PD= Number of cycles in Pulse\/ Frequency(Hz)<\/p>\n\n\n\n

    Spatial Pulse Length (SPL) (measurement)
    The distance that a pulse occupies in space from the start to the end of a pulse.
    (mm)<\/p>\n\n\n\n

    Typical values for spatial pulse length in soft tissue.
    0.1 to 1.0 mm<\/p>\n\n\n\n

    Spatial pulse length is determined by
    sound source and medium<\/p>\n\n\n\n

    Spatial Pulse Length is directly proportional to
    the Number of Cycles in the Pulse
    and
    the Wavelength<\/p>\n\n\n\n

    (Directly Proportional means that increased SPL will increase both the number of cycles in the pulse and the wavelength if increased).<\/p>\n\n\n\n

    Spatial pulse length is inversely proportional to
    Frequency (MHz)<\/p>\n\n\n\n

    (Inversely Proportional means that increased SPL will lower frequency. This is because axial resolution is better with lower frequency)<\/p>\n\n\n\n

    Pulse Duration (PD)
    The actual time from the start of a pulse to the end of that pulse; a single transmit, talking, or “on” time.
    Time the pulse is on typically measured in (ms).<\/p>\n\n\n\n

    Pulse Length
    The distance of the pulse start to end or the
    duration or length of a single pulse
    Pulse Length is typically measured in (mm).<\/p>\n\n\n\n

    the ability of an object to resist compression and relates to the hardness of a medium?
    Stiffness.<\/p>\n\n\n\n

    Think:
    \u2191 Stiffness \u2191 Speed
    \u2193 Density \u2191 Speed<\/p>\n\n\n\n

    An increase in pulse repetition frequency would lead to:
    Increasing pulse repetition frequency, increases duty factor.<\/p>\n\n\n\n

    \u2191 PRF \u2191 Duty Factor<\/p>\n\n\n\n

    Which of the following would have the highest propagation speed?
    Bone has the highest propagation speed, at 2000-4000 m\/s.<\/p>\n\n\n\n

    What has the lowest propagation speed?
    air technically has the lowest propagation speed at 300 m\/s<\/p>\n\n\n\n

    Which has the Slowest Propagation Speed?
    Water
    Soft Tissue
    Bone
    Lung tissue
    Lung Tissue<\/p>\n\n\n\n

    As imaging depth increases, the pulse repetition frequency (PRF) must:
    Decrease<\/p>\n\n\n\n

    As imaging depth increase, pulse repeition freqency (PRF) decreases.<\/p>\n\n\n\n

    \u2191 Imaging Depth \u2193 PRF<\/p>\n\n\n\n

    What describes the amount of refraction that occurs at an interface?
    Snell’s law<\/p>\n\n\n\n

    Refraction: the redirection of the transmitted sound beam<\/p>\n\n\n\n

    Snell’s law describes the angle of transmission at an interface based on the angle of incidence and the propagation speeds of the two media.<\/p>\n\n\n\n

    Pressure is typically expressed in:
    Pascals (Pa)<\/p>\n\n\n\n

    The typical range of frequency for diagnostic ultrasound imaging is
    1-20 Mhz is the typical range of frequency for diagnostic ultrasound imaging.<\/p>\n\n\n\n

    The attentuation coefficient in soft tissue is equal to:
    Attentuation Coeffcient = 1\/2 (one half of the frequency in soft tissue)<\/p>\n\n\n\n

    The attentuation coeffcient (in dB\/cm) is the rate at which sound is attentuated per unit depth.<\/p>\n\n\n\n

    Micro is denoted as:
    Micro is denoted as millionth (\u00b5)<\/p>\n\n\n\n

    What is described as the distance over which one cycle occurs?
    Wavelength is distance over which one cycle occurs, or the distance from the beginning of one cycle to the end of the same cycle.<\/p>\n\n\n\n

    Remember, it asks for distance over which one cycle occurs.<\/p>\n\n\n\n

    Stiffness and propagation speed are
    Directly Related
    Also remember:
    \u2191 Stiffness \u2191 Speed
    \u2193 Density \u2191 Speed<\/p>\n\n\n\n

    Areas of high pressure and density are referred to as:
    Compressions<\/p>\n\n\n\n

    What type of wave is sound?
    Mechanical and Longitudinal Wave<\/p>\n\n\n\n

    The frequency ranges for ultrasound are:
    Ultrasound frequency is 20 to 20,000 Hz<\/p>\n\n\n\n

    The speed of sound in soft tissue is
    Speed of sound in soft tissue is 1540 m\/s<\/p>\n\n\n\n

    Which transducer fires the elements in groups?
    Linear sequenced array fires the elements in groups<\/p>\n\n\n\n

    The units for wavelength is
    Wavelength units are (Millimeters)<\/p>\n\n\n\n

    Enhancement is caused by
    Weakly attenuating structures<\/p>\n\n\n\n

    The wavelength in a material having a propagation speed of 1.5 mm\/\u00b5s employing a transudcer frequency of 5.0 MHz is:
    0.3 mm<\/p>\n\n\n\n

    wavelength = c\/f
    1.5 mm\/\u00b5s \/ 5 MHz = 0.3 mm<\/p>\n\n\n\n

    An ultrasound transducer converts
    Electrical energy into Mechanical energy and vice versa<\/p>\n\n\n\n

    Lowest attenuation to highest
    bone, muscle, fat, air<\/p>\n\n\n\n

    If frequency doubles, what happens to the wavelength?
    Wavelength is decreased by 1\/2<\/p>\n\n\n\n

    Frequency and Wavelength are:
    Inversely related<\/p>\n\n\n\n

    What happens to intensity if the amplitude of a signal is halved?
    Amplitude halved will result in intensity quartered<\/p>\n\n\n\n

    amplitude = intensity2<\/p>\n\n\n\n

    Ultrasound pulses contain a range of frequencies called
    bandwidth<\/p>\n\n\n\n

    How is time related to frequency
    inversely<\/p>\n\n\n\n

    What describes the percentage of time that sound is on?
    Duty factor is the percentage of time the sound is being transmitted<\/p>\n\n\n\n

    A 3 dB gain would indicate an increase in intensity by:
    Two Times<\/p>\n\n\n\n

    3 dB results in doubling of intensity (or power)<\/p>\n\n\n\n

    The intensity of the ultraosund beam is usually greater at the focal zone because of
    the smaller beam diameter<\/p>\n\n\n\n

    Attenuation denotes
    Progressive weakening of the sound beam as it travels<\/p>\n\n\n\n

    Which of the following has the lowest intensity
    SATA is the lowest of the intensities<\/p>\n\n\n\n

    What is the definition of the beam uniformity ratio?
    Beam Uniformity Ratio =
    Spatial peak \/ Spatial average<\/p>\n\n\n\n

    Continuous wave Doppler has a duty factor of
    100%<\/p>\n\n\n\n

    CW Doppler is always transmitting sound making it’s duty factor 100%<\/p>\n\n\n\n

    The spatial pulse length is defined as:
    the product of the wavelength and the number of cycles in a pulse?<\/p>\n\n\n\n

    SPL = wavelength x cycles<\/p>\n\n\n\n

    What term and philosophy relates the amount of exposure time for the sonographer and patient during a diagnostic ultrasound examination?
    ALARA – As Low As Reasonably Achievable<\/p>\n\n\n\n

    What term is defined as the body’s pathologic response to illness, trauma or severe physiologic or emotional stress?
    Shock<\/p>\n\n\n\n

    The inertia of the medium describes its:
    Density.<\/p>\n\n\n\n

    Inertia is described by Newton’s principle – an object at rest will stay at rest. An object in motion stays in motion, unless acted on by an outside force.<\/p>\n\n\n\n

    Greatest attenuation would occur at:
    long distance with high frequency<\/p>\n\n\n\n

    A 3MHz sound beam travels through two media. It attenuates 5 dB in medium A and 6 dB in medium B.
    Total attentuation is 11 dB<\/p>\n\n\n\n

    Attenuation simply adds up as sound travels.<\/p>\n\n\n\n

    What would you do to create a wave with the highest possible intensity?
    Highest intensity would occur with a short distance and low frequency.<\/p>\n\n\n\n

    Lowest Attenuation is found at
    lowest frequency, with the shortest path length.<\/p>\n\n\n\n

    What results in the most attenuation?
    most attenuation occurs at the high frequency and long distance.<\/p>\n\n\n\n

    Which media has the greatest attenuation and the slowest speed?
    Air<\/p>\n\n\n\n

    Air > Bone & Lung > Soft Tissue > Water<\/p>\n\n\n\n

    What type of wave is sound?
    Mechanical and Longitudinal wave<\/p>\n\n\n\n

    The speed of sound in soft tissue:
    1540 m\/s<\/p>\n\n\n\n

    The unit for wavelength:
    Distance (mm)<\/p>\n\n\n\n

    Enhancement is caused by:
    weakly attenuating structures<\/p>\n\n\n\n

    Lowest attenuating to highest attenuation
    Fat-Muscle-Bone-Air<\/p>\n\n\n\n

    List propagation speed from lowest to highest
    Air-Fat-Muscle-Bone<\/p>\n\n\n\n

    Which of these media has the lowest attenuation and the greatest speed?<\/p>\n\n\n\n

    bone
    tendon
    lung
    fat
    air
    Bone<\/p>\n\n\n\n

    Air > Bone & Lung > Soft Tissue > Water<\/p>\n\n\n\n

    Bone is more stiff than air<\/p>\n\n\n\n

    (remember \u2191 stiffness, \u2191 speed)<\/p>\n\n\n\n

    What describes the physics of refraction mathematically?
    Snell’s Law<\/p>\n\n\n\n

    What is a reflection arising from a rough boundary?
    Non-specular<\/p>\n\n\n\n

    Specular reflection is from a smooth reflector (like mirrors). They return in one direction.<\/p>\n\n\n\n

    Whereas, non-specular is diffuse or scatter, reflection from a rough boundary.<\/p>\n\n\n\n

    When time-of-flight is measured, we can determine the __<\/em><\/strong>?
    Reflector Depth<\/p>\n\n\n\n

    A sound pulse travels from the transducer to location A, reflects off of it, and returns to the transducer in 130 \u03bcs.
    How deep is location A?
    Location A is 10 cm from the transducer<\/p>\n\n\n\n

    Total travel distance would be 20 cm<\/p>\n\n\n\n

    Which of the following would be considered the narrowest part of a sound beam?
    The focus is the narrowest part of the beam<\/p>\n\n\n\n

    Which of the following is the part of the transducer that stops the ringing of the element?
    The damping material helps stop the ringing of the transducer<\/p>\n\n\n\n

    Along with image depth, which of the following also determines the frame rate?
    Image depth and the number of lines per frame determines the frame rate.<\/p>\n\n\n\n

    Which type of resolution is an accurate representation of moving structures?
    Temporal resolution, also known as frame rate, is the ability to display moving structures in real time.<\/p>\n\n\n\n

    What type of transducer that utilizes elements arranged in a concentric pattern?
    The annular array transducer ultilizes elements arranged in concentric rings<\/p>\n\n\n\n

    What transducer would be considered an advantage of linear array over a phased array transducer?
    The linear array has a wider near field of view compared to a phased array transducer<\/p>\n\n\n\n

    Mechanical Transducers:
    Have moving parts
    Uses a motor to steer the beam
    Most transducers are no longer mechanical May be focused with a lens or phased focuses<\/p>\n\n\n\n

    Along with crystal diameter, the divergence in the far field is also determined by\u2026
    Frequency
    and crystal diameter determines the divergence in the far field<\/p>\n\n\n\n

    What would cause an increase in frame rate?
    Decreasing the imaging depthwould increase the frame rate<\/p>\n\n\n\n

    When you decrease the imaging depth it can work faster (increase frame rate) because it doesn’t have to go as deep.<\/p>\n\n\n\n

    The diameter of the beam in the Fresnel zone\/near zone does what?
    Decreases<\/p>\n\n\n\n

    Which resolution is best in the clinical imaging?
    Axial resolution is best in imaging<\/p>\n\n\n\n

    will increase the near zone length?
    A large crystal diameter with high frequency would increase the near zone length<\/p>\n\n\n\n

    What will decrease beam divergence in the far field?
    A large crystal diameter and high frequency would decrease the beam divergence in the far field<\/p>\n\n\n\n

    Imaging transducers have
    Imaging transducers have low quality factors and wide bandwidiths.<\/p>\n\n\n\n

    What is the speed of a wave with a wavelength of 3 m and a frequency of .1 Hz?
    0.3 m\/s<\/p>\n\n\n\n

    wave speed= frequency x wavelength<\/p>\n\n\n\n

    Wavelength and Frequency are
    inversely proportional to each other<\/p>\n\n\n\n

    How do you calculate the speed of a wave given the wavelength and frequency?
    Frequency (Hz) x wavelength (distance)= Wave Speed<\/p>\n\n\n\n

    What is the speed of a wave with a frequency of 2 Hz and a wavelength of 87 m?
    174 m\/s<\/p>\n\n\n\n

    2Hz x 87m= 174m\/s<\/p>\n\n\n\n

    speed of a wave: frequency x wavelength<\/p>\n\n\n\n

    The __<\/em> of a wave is the number of wavelengths that pass a fixed point in a second.
    frequency<\/p>\n\n\n\n

    Frequency is the number of wavelengths that pass a fixed point in a second<\/p>\n\n\n\n

    A sound wave is traveling in the body and propagates from muscle to air. What percentage of the sound wave is most likely reflected at the muscle-air boundary?
    75%<\/p>\n\n\n\n

    Which of the following lists is in decreasing order?
    Mega, kilo, deca, milli, nano<\/p>\n\n\n\n

    The conversion of sound energy to heat
    Absorption<\/p>\n\n\n\n

    Acoustic Speckle
    the interference pattern caused by scatterers that produces the granular appearance of tissue on a sonographic image<\/p>\n\n\n\n

    Acoustic Variables
    changes that occur within a medium as a result of sound traveling through that medium<\/p>\n\n\n\n

    Amplitude
    The maximum or minimum deviation of an acoustic variable from the average value of that variable; the strength of the reflector<\/p>\n\n\n\n

    Attenuation
    A decrease in the amplitude and intensity of the sound beam as sound travels through tissue.<\/p>\n\n\n\n

    Attenuation Coefficient
    The rate at which sound is attenuated per unit depth<\/p>\n\n\n\n

    Axial Resolution
    The ability to accurately identify reflectors that are arranged parallel to the ultrasound beam<\/p>\n\n\n\n

    Backscatter
    Scattered sound waves that make their way back to the transducer and produce an image on the display<\/p>\n\n\n\n

    Beam Uniformity Ratio
    The ratio of the center intensity to the average spatial intensity; also referred to as the SP\/SA factor or beam uniformity coefficient<\/p>\n\n\n\n

    Capacitive Micromachined Ultrasound Transducers
    Technology used to create comparable transducer technology to piezoelectric materials<\/p>\n\n\n\n

    Compression
    An area in the sound wave of high pressure and density<\/p>\n\n\n\n

    Continuous Wave
    Sound that is continuously transmitted<\/p>\n\n\n\n

    Damping
    The process of reducing the number of cycles of each pulse in order to improve axial resolution<\/p>\n\n\n\n

    Decibels
    A unit that establishes a relationship or comparison between two values of power, intensity, or amplitude<\/p>\n\n\n\n

    Density
    Mass per unit volume<\/p>\n\n\n\n

    Directly Related
    Relationship that implies that if one variable decreases, the other also decreases or if one variable increases, the other also increases;<\/p>\n\n\n\n

    also referred to as Directly Proportional<\/p>\n\n\n\n

    Distance
    How far apart objects are<\/p>\n\n\n\n

    AKA vibration or displacement<\/p>\n\n\n\n

    Duty Factor
    The percentage of time that sound is actually being produced<\/p>\n\n\n\n

    Elasticity
    The ability of a material to bounce back after being disturbed<\/p>\n\n\n\n

    Frequency (Hz)
    The number of cycles per second<\/p>\n\n\n\n

    Half-Intensity Depth
    the depth at which sound has lost half of its intensity<\/p>\n\n\n\n

    Half Intensity Depth is also called
    Half-Value Layer Thickness<\/p>\n\n\n\n

    Hertz (Hz)
    A unit of frequency<\/p>\n\n\n\n

    Hydrophone
    a device used to measure the output intensity of the transducer<\/p>\n\n\n\n

    Impedence
    the resistance to the propagation of sound through a medium.<\/p>\n\n\n\n

    Inertia
    Newton’s principle that states that an object at rest stays at rest and an object in motion stays in motion, unless acted on by an outside force.<\/p>\n\n\n\n

    Intensity
    the power of a wave divided by the area over which it is spread; the energy per unit area<\/p>\n\n\n\n

    Intensity Reflection Coefficient (IRC)
    The percentage of sound reflected at an interface.<\/p>\n\n\n\n

    The percentage of the sounds intensity that is reflected when sound hits a boundary or tissue<\/p>\n\n\n\n

    Interface is the dividing line between 2 different media.<\/p>\n\n\n\n

    Intensity Transmission Coefficient (ITC)
    The percentage of sound transmitted at an interface
    -or-
    The percentage of intensity that continues forward after beam strikes an interface<\/p>\n\n\n\n

    Interface
    The dividing line between two different media<\/p>\n\n\n\n

    Inversely Related
    Relationship that implies that if one variable decreases, the other increases or if one variable increases, the other decreases; also referred to as inversely proportional<\/p>\n\n\n\n

    Longitudinal Wave
    Waves in which the molecules of the medium vibrate back and forth in the same direction that the waves are traveling.<\/p>\n\n\n\n

    Medium
    Any form of matter; Solid, Liquid, or Gas<\/p>\n\n\n\n

    Non-specular Reflectors
    Reflectors that are smaller than the wavelength of the incident beam<\/p>\n\n\n\n

    Which gain will increase the risk of bioeffects?
    Transmit<\/p>\n\n\n\n

    What is considered the memory of an ultrasound instrument?
    Digital Scan Converter<\/p>\n\n\n\n

    Spectral Broadening Suggests
    Turbulent Flow<\/p>\n\n\n\n

    What happens to axial resolution with Pulse Wave Doppler
    Axial Resolution Degrades when using Pulse Wave Doppler<\/p>\n\n\n\n

    What color is usually used in Color Flow Doppler variance map to indicate turbulent flow?
    Green<\/p>\n\n\n\n

    A Doppler (high pass filter) eliminates?
    high amplitude signals, low velocity flow<\/p>\n\n\n\n

    The Doppler wall filter is considered a:
    High Pass Filter<\/p>\n\n\n\n

    The Nyquist Limit is equal to:
    PRF\/2<\/p>\n\n\n\n

    Pulse Repetition Frequency divided by two<\/p>\n\n\n\n

    Multiple echoes, equally spaced originating from a gas bubble is called
    Ring Down<\/p>\n\n\n\n

    An increase in red blood cell velocity will____________Doppler Shift:
    Increase<\/p>\n\n\n\n

    increase in rbc velocity increases Doppler shift<\/p>\n\n\n\n

    The primary advantage of CW Doppler is:
    Absence of Sampling Rate<\/p>\n\n\n\n

    The range for ultrasound begins:
    at 20,000Hz or 20KHz<\/p>\n\n\n\n

    (Useful Frequency Range for Clinical Imaging is 2MHz-10MHz)<\/p>\n\n\n\n

    Which instrument control affects the amplitude (db) of the outgoing signal?
    Transmit Gain;
    Amplitude can be affected by the sonographer<\/p>\n\n\n\n

    What is used to convert Doppler shift information into color?
    Autocorrelation<\/p>\n\n\n\n

    What is used to process conventional Doppler shift information but is too slow of a method for Color Doppler?
    Fast Fourier transform<\/p>\n\n\n\n

    Pulse Repetition Frequency
    The number of pulses that an ultrasound system transmits into the body each second.<\/p>\n\n\n\n

    Unit: Hz. Typically 4-15 KHz.<\/p>\n\n\n\n

    PRF and Depth of View are inversely related.<\/p>\n\n\n\n

    When the system is imaging deeper, the pulse repetition frequency is lower, as well as, the number of pulses created each second.<\/p>\n\n\n\n

    What is the best way to increase the near field length of an ultrasound beam?
    Increase Transducer Diameter<\/p>\n\n\n\n

    What is the range of frequencies produced by a dampened PZT element?
    bandwidth<\/p>\n\n\n\n

    What is bandwidth?
    range of frequencies in a pulse<\/p>\n\n\n\n

    The percentage of time that the ultrasound instrument is emitting ultrasound is called?
    Duty Factor<\/p>\n\n\n\n

    The maximum value is 1, the minimum is 0<\/p>\n\n\n\n

    What is the unit of Duty Factor?
    Duty Factor is Unit-less<\/p>\n\n\n\n

    If the ultrasound is produced as a continuous wave (CW), the duty factor will have a value of 1. With Pulsed Wave the whole value of On-Time is fractioned.<\/p>\n\n\n\n

    What is Q-factor or Quality Factor?
    The “Q factor” describes the bandwidth of the sound emanating from a transducer<\/p>\n\n\n\n

    Transducer Q Factor (Q = Quality) is associated with two characteristics of the crystal<\/p>\n\n\n\n

      \n
    • purity of their sound and<\/li>\n\n\n\n
    • length of time the sound persists<\/li>\n<\/ul>\n\n\n\n

      (Unitless measurement)<\/p>\n\n\n\n

      Fundamental Frequency(Hz)\/Bandwidth(range of frequency in the pulse)<\/p>\n\n\n\n

      The unit of duty factor is:
      Unitless<\/p>\n\n\n\n

      Clinical imaging transducers are:
      Wide bandwidth; Low Q factor<\/p>\n\n\n\n

      Wide range of frequencies in the pulse and short period of time that the sound is emitted (pulsed wave)<\/p>\n\n\n\n

      Power\/Area=
      Intensity<\/p>\n\n\n\n

      Increasing wavelength will_______frequency?
      Decrease<\/p>\n\n\n\n

      Beam Properties
      The ultrasound beam propagates as a longitudinal wave from the transducer surface into the propagation medium, and exhibits two distinct beam patterns: – a slightly converging beam out to a distance specified by the geometry and frequency of the transducer (the near field), and – a diverging beam beyond that point (the far field).<\/p>\n\n\n\n

      Does Beam Width directly affect frame rate?
      No:<\/p>\n\n\n\n

      The following directly affect frame rate:<\/p>\n\n\n\n

      Depth of Penetration
      Field of View
      Number of Focuses
      and Line Density<\/p>\n\n\n\n

      What affects frame rate?
      Depth of Penetration, Field of View, Number of Focuses, and Line Density.<\/p>\n\n\n\n

      Frame Rate= Number of Frames\/Second<\/p>\n\n\n\n

      When will a reflection occur at the boundary of two media?
      If the acoustic impedances of the tow media are different.<\/p>\n\n\n\n

      Snell’s Law
      Describes the relationship between the angles and the velocities of the waves.<\/p>\n\n\n\n

      When an ultrasonic wave passes through an interface between two materials at an oblique angle, and the materials have different indices of refraction, both reflected and refracted waves are produced<\/p>\n\n\n\n

      In ultrasound, Snell’s Law
      is a formula used to describe the relationship between the angles of incidence and refraction, when referring to light or other waves passing through a boundary between two different isotropic media.<\/p>\n\n\n\n

      The ratio of the sine of the angle of incidence to the sine of the angle of refraction is a constant, for a given frequency.<\/p>\n\n\n\n

      The Angle of Incidence
      Refers to the angle of deviation from a perpendicular line to the surface of the tissue<\/p>\n\n\n\n

      Therefore, the desired orthogonal(perpendicular) incident wave in ultrasound should be considered to have an angle of incidence of zero.<\/p>\n\n\n\n

      When the angle of incidence is greater, fewer sound waves are reflected back to the transducer resulting in a more hypoechoic (darker) image with less clarity.<\/p>\n\n\n\n

      The optimal reflection with the most sound waves occurs when the angle of incidence approaches zero and is virtually perpendicular (orthogonal) to the tissue of interest.<\/p>\n\n\n\n

      Law of Reflection
      the angle of incidence is equal to the angle of reflection<\/p>\n\n\n\n

      Mechanical Transducers utilize what kind of focusing?
      Fixed Focusing:<\/p>\n\n\n\n

      Sonographers cannot determine the location of # of foci.<\/p>\n\n\n\n

      Mechanical Transducers use Cross-Sectional imaging, rotating wheel, wobbler, and oscillating mirror.<\/p>\n\n\n\n

      The transducer frequency is primarily determined by the transducer element’s what?
      Thickness<\/p>\n\n\n\n

      For pulsed transducers..the main or center frequency of the transducer is determined by the thickness and the propagation speed of the piezoelectric material.<\/p>\n\n\n\n

      PZT is also called
      Ceramic, Active Element, or Crystal<\/p>\n\n\n\n

      A strongly focused transducer implies a:
      Short focal length and Increased Beam Divergence<\/p>\n\n\n\n

      B-mode displays reflector:
      Amplitude and Distance<\/p>\n\n\n\n

      An increase in the number of pixels on the display will improve:
      Detail Resolution<\/p>\n\n\n\n

      Propagation speed is determined by
      Medium only – density and stiffness of media<\/p>\n\n\n\n

      Bulk Modulus describes the change in the material’s volume under external stress.<\/p>\n\n\n\n

      Increasing transmit gain increases everything except:
      Frequency<\/p>\n\n\n\n

      Gain is a receiving function
      \u2022Does not impact how much energy is transmitted to patient (i.e. power)<\/p>\n\n\n\n

      The correct depth placement of reflectors depends primarily upon:
      Propagation Speed<\/p>\n\n\n\n

      What will increase the color flow jet area displayed?
      Increasing Color Gain<\/p>\n\n\n\n

      Increasing Propagation Speed
      air: 330 m\/sec
      fat: 1450 m\/sec
      water: 1480 m\/sec
      soft tissue: 1540 m\/sec
      liver: 1550 m\/sec
      kidney: 1560 m\/sec
      blood: 1570 m\/sec
      muscle: 1580 m\/sec
      bone: 4080 m\/sec<\/p>\n\n\n\n

      The most common type of transducer used in echo is:
      Sector Phased Array<\/p>\n\n\n\n

      What are the four acoustic variables?<\/p>\n\n\n\n

        \n
      1. Temperature<\/li>\n\n\n\n
      2. Density<\/li>\n\n\n\n
      3. Particle Motion<\/li>\n\n\n\n
      4. Pressure<\/li>\n<\/ol>\n\n\n\n

        The Doppler effect is presented as a _______<\/em><\/strong><\/em><\/strong> when the source and the receiver are in motion relative to each other.
        Frequency Shift<\/p>\n\n\n\n

          \n
        • or – Doppler Shift
          receiver toward the transducer= + shift
          receiver away from transducer = – shift<\/li>\n\n\n\n
        • toward (above baseline)<\/li>\n\n\n\n
        • away (below baseline)<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"

          Which gain will increase the risk of bioeffects?a. transmitb. receivec. gaind. overall gaina. transmit Which of the following is considered the memory of an ultrasound instrument?a. pulserb. transducerc. receiverd. beam formere. digital scan converterf. display monitore. digital scan converter Spectral broadening suggest:a. laminar flowb. turbulent flowc. flow away from the transducerd. flow towards the transducerb. […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[],"tags":[],"class_list":["post-110916","post","type-post","status-publish","format-standard","hentry"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/110916","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=110916"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/110916\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=110916"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=110916"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=110916"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}