When you adjust pulse repetition frequency, you are changing: Correct Answer: The number of pulses per second
When sound strikes a specular reflector at an oblique angle, the angle of reflection is: Correct Answer: Equal to the angle of incidence
Which of the following describes diffuse ref...
Davies! SPI QUESTIONS AND ANSWERS GRADED A
When you adjust pulse repetition frequency, you are changing: Correct Answer:
The number of pulses per second
When sound strikes a specular reflector at an oblique angle, the angle of reflection
is: Correct Answer: Equal to the angle of incidence
Which of the following describes diffuse reflection? Correct Answer: The
reflected beam is scattered in various directions
Which sound beam frequency would exhibit the greatest intensity loss with
increasing depth? Correct Answer: 10 mhz (the highest frequency)
When you change the transmit frequency, which of the following is altered?
Correct Answer: Number of cycles per second
While performing a Doppler ultrasound exam, you adjust the PRF to 12 kHz. This
can also be expressed as: Correct Answer: 12,000 Hz
An echo from which one of the following sound reflectors is most dependent on
the angle of incidence? Correct Answer: Specular reflector
During production of a sonogram, you image the following structures. (blood, bile,
soft tissue, calcification, muscle) Which is the MOST attenuating? Correct
Answer: Calcification
Which of the following is most likely also to decrease beam intensity? Correct
Answer: Increasing beam area
Relative measurement of intensity based on a logarithmic scale is expressed in:
Correct Answer: Decibels
When you image a structure that is a specular reflector, the strength of the received
signal depends on the following two factors: Correct Answer: Difference in
acoustic impedance and angle of incidence
,You are imaging with a 5MHz linear array transducer. What sound parameter stays
constant as the beam propagates through the tissue? Correct Answer: None of the
above
In order to display a structure on your sonographic image, the sound beam must be
reflected at the interface. What is required for sound reflection at the interface of
two structures? Correct Answer: A difference in the acoustic impedance of the
media
During the performance of a sonogram, you would be most likely to encounter
refraction in this view: Correct Answer: Curved interface
Which of the following frequencies is considered to be ultrasound? Correct
Answer: 2 MHz
Which of the following properties would result in increased propagation speed of
sound through a medium? Correct Answer: Increased stiffness
For pulsed ultrasound, which of the following factors determine the frequency of
the sound wave? Correct Answer: Transmitter frequency
Bulk modulus is closely related to which of the following qualities? Correct
Answer: Stiffness
As you perform a sonogram, you switch from a 3.5 MHz transducer to a 7.0 MHz
transducer to image a superficial structure. Compared to the 3.5 MHz transducer,
what will the 7.0 MHz transducer attenuation rate and wavelength be? Correct
Answer: Double the attenuation rate, one-half the wavelength
Another term for nonspecular reflection is: Correct Answer: Scattering
In sound wave propagation, a region of elevated pressure is termed: Correct
Answer: Compression
The speed of sound is defined as the: Correct Answer: Speed at which the sound
wave propagates through the medium
Acoustic impedance: Correct Answer: Equals density times the propagation speed
Z=pc
,With absorption, acoustic energy is converted to: Correct Answer: Heat
You are scanning a large mass that is composed primarily of fat. Which of the
following are you most likely to encounter? Correct Answer: Axial misregistration
of objects distal to the mass on the screen due to the slower propagation speed
through fat
What sound parameter is determined only by the medium? Correct Answer:
Propagation speed
You are performing a sonographic exam on a large patient. Which transducer
would provide the least amount of signal attenuation? Correct Answer: 2.5 MHz
The transducer you are using transmits wide-bandwidth pulses whose frequency
content is 2-5 MHz. Which of the following most correctly describes the reflected
echo signals after they have transversed the tissue? Correct Answer: The echo
signals will be shifted down in frequency due to the increased attenuation of higher
frequencies
The length of space over which one cycle occurs is known as the: Correct Answer:
Wavelength
In the following illustration, if the propagation speed is unchanged at the interface,
which most correctly describes the sound-tissue interaction that will take place
when the ultrasound wave strikes the depicted interface? Correct Answer:
Scattering
The transfer of acoustic energy into heat is termed: Correct Answer: Absorption
Which of the following best characterizes an ultrasound wave in human tissue?
Correct Answer: Mechanical longitudinal wave
What occurs when you image a structure with oblique incidence? Correct Answer:
The angle of reflection will be oriented away from the transducer resulting in
decreased visualization of the structure.
According to Snell's law, the angle of transmission is related to the incident beam
angle and: Correct Answer: The relative speed of sounds in the two media
, When you perform a Doppler exam, the frequency of the transmitted signal is
determined by: Correct Answer: The frequency of the electrical signal applied to
the transducer
The hyperechoic region (arrow) in this image results from: Correct Answer:
Decreased attenuation through a fluid-filled structure
The propagation speed for sound is lowest in which of the following biological
tissues? Correct Answer: Fat
For soft tissue, one of the factors responsible for determining acoustic impedance
is: Correct Answer: Density
When you image sound reflected from a large, smooth interface, you are observing
results of: Correct Answer: Specular reflection
If the number of cycles in a pulse is increased but the wavelength remains the
same. Which of the following is true? Correct Answer: The pulse duration is
increased
Which most correctly describes sound propagation in a medium? Correct Answer:
Molecules oscillate back and forth to propagate sound waves but do not move from
one end of the medium to another
While performing a sonogram, you encounter the following interfaces. Which will
produce the weakest reflected signal? Correct Answer: Organ parenchyma/organ
parenchyma
Which system control should you adjust to compensate for sound attenuation with
increasing depth? Correct Answer: TGC
You have decreased the acoustic power by -3 dB. Which of the following most
accurately describes this adjustment? Correct Answer: The intensity has been
halved
You may observe sound attenuation by all of the following except: Correct
Answer: Compression
Which of the following increases as frequency increases? Correct Answer: All of
the above
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