Questions and Answers (Latest Update
2025)
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
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.
,ARDMS SPI STUDY GUIDE Exam
Questions and Answers (Latest Update
2025)
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
,ARDMS SPI STUDY GUIDE Exam
Questions and Answers (Latest Update
2025)
Pulse Duration Formula - Correct Answer ✅pulse duration
(μs) = # cycles in pulse/frequency(MHz)
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).
, ARDMS SPI STUDY GUIDE Exam
Questions and Answers (Latest Update
2025)
Spatial pulse length is inversely proportional to - Correct
Answer ✅Frequency (MHz)
(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