ARDMS SPI STUDY GUIDE Exam 2026
Questions and Answers
In soft tissue, if the frequency of a wave is increased the Propagation Speed (PS)
will... - Correct answer-Remain the Same because stiffness and density affect
Propagation Speed.
What is the audible range? - Correct answer-20-20,000Hz
>20,000Hz=Ultrasound
Frequency is measured in - Correct answer-Hertz (Hz)
is
Cycles per Second
Not affected by sonographer
Increase Frequency; Decrease Depth
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,A period is the length of time it takes for - Correct answer-one complete
wavelength to pass a fixed point
PRP is determined by - Correct answer-Transmit time and receive time.
Period is measured in - Correct answer-Time (μs)
When the sonographer changes the imaging depth what parameters are changed? -
Correct answer-PRP, PRF, Duty Factor
What is duty factor? - Correct answer-The percentage or fraction of time that the
system is transmitting a pulse (Time Sound is ON or ON-Time).
Propagation Speed in SOFT TISSUE - Correct answer-1.54 mm/μs
(1540 m/sec)
Unit of measurement for Pulse Duration, Duty Factor, PRP, and Period - Correct
answer-Time, (μs)
Pulse duration is determined by - Correct answer-Sound Source Only
Pulse Duration is controlled by - Correct answer-the ultrasound system and
transducer
Pulse Duration Formula - Correct answer-pulse duration (μs) = # cycles in
pulse/frequency(MHz)
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,PD= Number of cycles in Pulse/ Frequency(Hz)
Spatial Pulse Length (SPL) (measurement) - Correct answer-The distance that a
pulse occupies in space from the start to the end of a pulse.
(mm)
Typical values for spatial pulse length in soft tissue. - Correct answer-0.1 to 1.0
mm
Spatial pulse length is determined by - Correct answer-sound source and medium
Spatial Pulse Length is directly proportional to - Correct answer-the Number of
Cycles in the Pulse
and
the Wavelength
(Directly Proportional means that increased SPL will increase both the number of
cycles in the pulse and the wavelength if increased).
Spatial pulse length is inversely proportional to - Correct answer-Frequency (MHz)
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, (Inversely Proportional means that increased SPL will lower frequency. This is
because axial resolution is better with lower frequency)
Pulse Duration (PD) - Correct answer-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).
Pulse Length - Correct answer-The distance of the pulse start to end or the
duration or length of a single pulse
Pulse Length is typically measured in (mm).
the ability of an object to resist compression and relates to the hardness of a
medium? - Correct answer-Stiffness.
Think:
↑ Stiffness ↑ Speed
↓ Density ↑ Speed
An increase in pulse repetition frequency would lead to: - Correct answer-
Increasing pulse repetition frequency, increases duty factor.
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Questions and Answers
In soft tissue, if the frequency of a wave is increased the Propagation Speed (PS)
will... - Correct answer-Remain the Same because stiffness and density affect
Propagation Speed.
What is the audible range? - Correct answer-20-20,000Hz
>20,000Hz=Ultrasound
Frequency is measured in - Correct answer-Hertz (Hz)
is
Cycles per Second
Not affected by sonographer
Increase Frequency; Decrease Depth
©COPYRIGHT 2025 ALL RIGHTS RESERVED 1
,A period is the length of time it takes for - Correct answer-one complete
wavelength to pass a fixed point
PRP is determined by - Correct answer-Transmit time and receive time.
Period is measured in - Correct answer-Time (μs)
When the sonographer changes the imaging depth what parameters are changed? -
Correct answer-PRP, PRF, Duty Factor
What is duty factor? - Correct answer-The percentage or fraction of time that the
system is transmitting a pulse (Time Sound is ON or ON-Time).
Propagation Speed in SOFT TISSUE - Correct answer-1.54 mm/μs
(1540 m/sec)
Unit of measurement for Pulse Duration, Duty Factor, PRP, and Period - Correct
answer-Time, (μs)
Pulse duration is determined by - Correct answer-Sound Source Only
Pulse Duration is controlled by - Correct answer-the ultrasound system and
transducer
Pulse Duration Formula - Correct answer-pulse duration (μs) = # cycles in
pulse/frequency(MHz)
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,PD= Number of cycles in Pulse/ Frequency(Hz)
Spatial Pulse Length (SPL) (measurement) - Correct answer-The distance that a
pulse occupies in space from the start to the end of a pulse.
(mm)
Typical values for spatial pulse length in soft tissue. - Correct answer-0.1 to 1.0
mm
Spatial pulse length is determined by - Correct answer-sound source and medium
Spatial Pulse Length is directly proportional to - Correct answer-the Number of
Cycles in the Pulse
and
the Wavelength
(Directly Proportional means that increased SPL will increase both the number of
cycles in the pulse and the wavelength if increased).
Spatial pulse length is inversely proportional to - Correct answer-Frequency (MHz)
©COPYRIGHT 2025 ALL RIGHTS RESERVED 3
, (Inversely Proportional means that increased SPL will lower frequency. This is
because axial resolution is better with lower frequency)
Pulse Duration (PD) - Correct answer-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).
Pulse Length - Correct answer-The distance of the pulse start to end or the
duration or length of a single pulse
Pulse Length is typically measured in (mm).
the ability of an object to resist compression and relates to the hardness of a
medium? - Correct answer-Stiffness.
Think:
↑ Stiffness ↑ Speed
↓ Density ↑ Speed
An increase in pulse repetition frequency would lead to: - Correct answer-
Increasing pulse repetition frequency, increases duty factor.
©COPYRIGHT 2025 ALL RIGHTS RESERVED 4
