ARDMS SPI Review Exam Questions With Correct Answers
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Course
ARDMS SPI
Institution
ARDMS SPI
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? -...
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
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