ARDMS SPI Review Exam Questions
With Correct Answers
Example of nonspecular reflector - ANSWER- red blood cells
What happens to spatial pulse length when frequency increases? - ANSWER-
decreases
Axial resolution is dependent on? - ANSWER- wavelength
Lateral resolution is dependent on? - ANSWER- beam diameter
Where does the beam of an unfocused transducer diverge? - ANSWER- Fraunhofer
zone
Reverberation artifacts are a result of - ANSWER- two or more strong reflecting
surfaces
True/False: Grating lobes are essential for the proper operation of a linear phased
array. - ANSWER- False
True/False: Electronically steered scanners always produce higher resolution images
than do mechanically steered scanners. - ANSWER- False
True/False: An annular array scanner uses mechanical beam steering. - ANSWER-
True
True/False: A linear sequenced array cannot be dynamically focused. - ANSWER-
False
registration or B-mode alignment - ANSWER- Which AIUM test object function utilizes
all the groups of wires in the AIUM 100 mm test object?
axial resolution - ANSWER- Which AIUM test object function utilizes the A group of
wires in the AIUM 100 mm test object?
lateral resolution - ANSWER- Which AIUM test object function utilizes the B group of
wires in the AIUM 100 mm test object?
dead zone - ANSWER- Which AIUM test object function utilizes the D group of wires in
the AIUM 100 mm test object?
depth calibration - ANSWER- Which AIUM test object function utilizes the C or E groups
of wires in the AIUM 100 mm test object?
,What happens to axial resolution when spatial pulse length is decreased? - ANSWER-
improves
How much will a 3.5 MHz pulse be attenuated after passing through 2 cm of soft tissue?
- ANSWER- 3.5 dB
Propagation speed errors result in - ANSWER- improper axial position
Enhancement is caused by - ANSWER- weakly attenuating structures
The Doppler shift frequency is - ANSWER- directly proportional to the velocity of the
reflector
The number of frames per second necessary for a real-time image to be flicker free is -
ANSWER- more than 15
True/False: The SPTA intensity will always be larger than the SATA intensity. -
ANSWER- True
The intensity of the ultrasound beam is usually greater at the focal zone because of -
ANSWER- the smaller beam diameter
If the amplitude is doubled, the intensity is - ANSWER- quadrupled
The attenuation for soft tissue is - ANSWER- increased with tissue thickness
The acoustic impedance of the matching layer - ANSWER- can be chosen to improve
transmission into the body
True/False: In a pulse-echo system, the quality factor should be made as large as
possible. - ANSWER- False
True/False: The beam diameter is constant in the near zone. - ANSWER- False
The operating frequency is dependent on - ANSWER- thickness of the crystal
The period of an ultrasound wave is - ANSWER- the time of one wavelength
The dynamic range of a system is - ANSWER- the ratio of smallest to largest power
level that the system can handle
True/False: The intensity of an ultrasonic beam can be measured with radiation force
balance. - ANSWER- True
,Increasing the pulse repetition period - ANSWER- increases the maximum depth that
can be imaged
Ultrasound bioeffects - ANSWER- are not confirmed below 100 mW/cm² SPTA
True/False: No refraction can occur at an interface if the media impedances are equal. -
ANSWER- False
True/False: Smaller transducers always produce smaller beam diameters. - ANSWER-
False
True/False: The ultrasound beam profile can be measured with a hydrophone. -
ANSWER- True
True/False: The pulsed-Doppler system yields better depth resolution than the
continuous wave (CW) system. - ANSWER- True
True/False: The gray-scale display was made possible when digital scan converters
replaced analog scan converters. - ANSWER- False
True/False: Videotape recorders operating at 30 frames per second cannot be used
with mechanical real-time units because the fram rate is too slow. - ANSWER- False
True/False: Linear phased array scanners need no form of mechanical focusing
because focusing is performed electronically. - ANSWER- False
True/False: The fram rate of real-time scanners depends on the number of lines used to
form the image. - ANSWER- True
True/False: It is not possible to steer an annular phased array electronically. -
ANSWER- True
True/False: The near zone length should be kept as short as possible. - ANSWER-
False
What percentage of intensity of an ultrasound pulse incident on an interface of 0.25 and
0.75 rayls is reflected? - ANSWER- 25%
Axial resolution can be improved by using - ANSWER- higher frequency transducers
When particle motion of a medium is parallel to the direction of a wave propagation, the
wave being transmitted is called a - ANSWER- longitudinal wave
The wavelength in a material having a wave velocity of 1500 m/s emplying a transducer
frequency of 5 MHz is - ANSWER- 0.3 mm
, The factor that determines the amount of reflection at the interface of two dissimilar
materials is - ANSWER- difference in acoustic impedances
The equation that describes the relationship among propagation, wavelength, and
frequency is - ANSWER- λ = c/ƒ
What three things can occur when an ultrasonic beam reaches the interface of two
dissimilar materials? - ANSWER- reflection, refraction, mode conversion
The acoustic impedance of a material is - ANSWER- equal to the product of density and
velocity
The average velocity of ultrasonic waves in soft tissue is - ANSWER- 1540 m/s
True/False: Receiver-angle values in CW Doppler analysis do not influence the final
Doppler shift. - ANSWER- False
Refraction occurs because of difference in ______ across an interface between two
materials - ANSWER- wave velocity
Reflection factor at an interface between two materials depends primarily on the change
in ______ across the interface. - ANSWER- acoustic impedance
The velocity of sound waves is primarily dependent on - ANSWER- medium and mode
of vibration
Increasing the frequency of an ultrasonic longitudinal wave will result in ______ in the
velocity of that wave. - ANSWER- no change
The change in direction of an ultrasonic beam, when it passes from one medium to
another, in which elasticity and density differ from those of the first medium is called -
ANSWER- refraction
A long near zone can be obtained by - ANSWER- using a higher frequency transducer
If a 2 MHz frequency is used in human soft tissue, the wavelength is approximately -
ANSWER- 0.75 mm
The ratio of particle pressure to particle velocity at a given point within the ultrasonic
field is - ANSWER- impedance
What is the following formula used to determine?
(2 × velocity of reflector × original frequency) / velocity of sound - ANSWER- Doppler
shift frequency
With Correct Answers
Example of nonspecular reflector - ANSWER- red blood cells
What happens to spatial pulse length when frequency increases? - ANSWER-
decreases
Axial resolution is dependent on? - ANSWER- wavelength
Lateral resolution is dependent on? - ANSWER- beam diameter
Where does the beam of an unfocused transducer diverge? - ANSWER- Fraunhofer
zone
Reverberation artifacts are a result of - ANSWER- two or more strong reflecting
surfaces
True/False: Grating lobes are essential for the proper operation of a linear phased
array. - ANSWER- False
True/False: Electronically steered scanners always produce higher resolution images
than do mechanically steered scanners. - ANSWER- False
True/False: An annular array scanner uses mechanical beam steering. - ANSWER-
True
True/False: A linear sequenced array cannot be dynamically focused. - ANSWER-
False
registration or B-mode alignment - ANSWER- Which AIUM test object function utilizes
all the groups of wires in the AIUM 100 mm test object?
axial resolution - ANSWER- Which AIUM test object function utilizes the A group of
wires in the AIUM 100 mm test object?
lateral resolution - ANSWER- Which AIUM test object function utilizes the B group of
wires in the AIUM 100 mm test object?
dead zone - ANSWER- Which AIUM test object function utilizes the D group of wires in
the AIUM 100 mm test object?
depth calibration - ANSWER- Which AIUM test object function utilizes the C or E groups
of wires in the AIUM 100 mm test object?
,What happens to axial resolution when spatial pulse length is decreased? - ANSWER-
improves
How much will a 3.5 MHz pulse be attenuated after passing through 2 cm of soft tissue?
- ANSWER- 3.5 dB
Propagation speed errors result in - ANSWER- improper axial position
Enhancement is caused by - ANSWER- weakly attenuating structures
The Doppler shift frequency is - ANSWER- directly proportional to the velocity of the
reflector
The number of frames per second necessary for a real-time image to be flicker free is -
ANSWER- more than 15
True/False: The SPTA intensity will always be larger than the SATA intensity. -
ANSWER- True
The intensity of the ultrasound beam is usually greater at the focal zone because of -
ANSWER- the smaller beam diameter
If the amplitude is doubled, the intensity is - ANSWER- quadrupled
The attenuation for soft tissue is - ANSWER- increased with tissue thickness
The acoustic impedance of the matching layer - ANSWER- can be chosen to improve
transmission into the body
True/False: In a pulse-echo system, the quality factor should be made as large as
possible. - ANSWER- False
True/False: The beam diameter is constant in the near zone. - ANSWER- False
The operating frequency is dependent on - ANSWER- thickness of the crystal
The period of an ultrasound wave is - ANSWER- the time of one wavelength
The dynamic range of a system is - ANSWER- the ratio of smallest to largest power
level that the system can handle
True/False: The intensity of an ultrasonic beam can be measured with radiation force
balance. - ANSWER- True
,Increasing the pulse repetition period - ANSWER- increases the maximum depth that
can be imaged
Ultrasound bioeffects - ANSWER- are not confirmed below 100 mW/cm² SPTA
True/False: No refraction can occur at an interface if the media impedances are equal. -
ANSWER- False
True/False: Smaller transducers always produce smaller beam diameters. - ANSWER-
False
True/False: The ultrasound beam profile can be measured with a hydrophone. -
ANSWER- True
True/False: The pulsed-Doppler system yields better depth resolution than the
continuous wave (CW) system. - ANSWER- True
True/False: The gray-scale display was made possible when digital scan converters
replaced analog scan converters. - ANSWER- False
True/False: Videotape recorders operating at 30 frames per second cannot be used
with mechanical real-time units because the fram rate is too slow. - ANSWER- False
True/False: Linear phased array scanners need no form of mechanical focusing
because focusing is performed electronically. - ANSWER- False
True/False: The fram rate of real-time scanners depends on the number of lines used to
form the image. - ANSWER- True
True/False: It is not possible to steer an annular phased array electronically. -
ANSWER- True
True/False: The near zone length should be kept as short as possible. - ANSWER-
False
What percentage of intensity of an ultrasound pulse incident on an interface of 0.25 and
0.75 rayls is reflected? - ANSWER- 25%
Axial resolution can be improved by using - ANSWER- higher frequency transducers
When particle motion of a medium is parallel to the direction of a wave propagation, the
wave being transmitted is called a - ANSWER- longitudinal wave
The wavelength in a material having a wave velocity of 1500 m/s emplying a transducer
frequency of 5 MHz is - ANSWER- 0.3 mm
, The factor that determines the amount of reflection at the interface of two dissimilar
materials is - ANSWER- difference in acoustic impedances
The equation that describes the relationship among propagation, wavelength, and
frequency is - ANSWER- λ = c/ƒ
What three things can occur when an ultrasonic beam reaches the interface of two
dissimilar materials? - ANSWER- reflection, refraction, mode conversion
The acoustic impedance of a material is - ANSWER- equal to the product of density and
velocity
The average velocity of ultrasonic waves in soft tissue is - ANSWER- 1540 m/s
True/False: Receiver-angle values in CW Doppler analysis do not influence the final
Doppler shift. - ANSWER- False
Refraction occurs because of difference in ______ across an interface between two
materials - ANSWER- wave velocity
Reflection factor at an interface between two materials depends primarily on the change
in ______ across the interface. - ANSWER- acoustic impedance
The velocity of sound waves is primarily dependent on - ANSWER- medium and mode
of vibration
Increasing the frequency of an ultrasonic longitudinal wave will result in ______ in the
velocity of that wave. - ANSWER- no change
The change in direction of an ultrasonic beam, when it passes from one medium to
another, in which elasticity and density differ from those of the first medium is called -
ANSWER- refraction
A long near zone can be obtained by - ANSWER- using a higher frequency transducer
If a 2 MHz frequency is used in human soft tissue, the wavelength is approximately -
ANSWER- 0.75 mm
The ratio of particle pressure to particle velocity at a given point within the ultrasonic
field is - ANSWER- impedance
What is the following formula used to determine?
(2 × velocity of reflector × original frequency) / velocity of sound - ANSWER- Doppler
shift frequency
