ARDMS SPI STUDY GUIDE QUESTIONS AND
100% CORRECT ANSWERS
Tissue: If the frequency of a wave is increased the PS will. - ANSWER Remain the Same
because stiffness and density effect PS.
What is the audible range? - ANSWER 20-20,000Hz
>20,000Hz=Ultrasound
Frequency is measured in - ANSWER Hertz (Hz)is
Cycles per Second
Not effected by sonographer
Increase Frequency; Decrease Depth
A period is the length of time it takes for - ANSWER one complete wavelength to pass a
fixed point
PRP is determined by - ANSWER Transmit time and receive time.
Period is measured in - ANSWER Time (μs)
If the sonographer changes the imaging depth what parameters are changed? -
ANSWER PRP, PRF, Duty Factor
,What is duty factor? - ANSWER The % or fraction of time that the system is transmitting a
pulse. (Time Sound is ON or ON-Time).
Propagation Speed in SOFT TISSUE - ANSWER 1.54 mm/μs
(1540 m/sec)
Unit of measurement for Pulse Duration, Duty Factor, PRP, and Period - ANSWER Time,
(μs)
Pulse duration is determined by - ANSWER Sound Source Only
Pulse Duration is controlled by - ANSWER the ultrasound system and transducer
Pulse Duration Formula - ANSWER pulse duration (μs) = # cycles in
pulse/frequency(MHz)
PD= Number of cycles in Pulse/ Frequency(Hz)
Spatial Pulse Length (SPL) (measurement) - 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. - ANSWER 0.1 to 1.0 mm
Spatial pulse length is determined by - ANSWER sound source and medium
Spatial Pulse Length is directly proportional to - 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 - 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) - 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 - 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 property of a medium that characterizes, qualitatively, the resistance of the medium
to compression and is proportional to the hardness of the medium? - ANSWER Stiffness.
Concept:
↑ Stiffness ↑ Speed
↓ Density ↑ Speed
If pulse repetition frequency were increased, what would occur? - ANSWER Increasing
pulse repetition frequency, increases duty factor.
100% CORRECT ANSWERS
Tissue: If the frequency of a wave is increased the PS will. - ANSWER Remain the Same
because stiffness and density effect PS.
What is the audible range? - ANSWER 20-20,000Hz
>20,000Hz=Ultrasound
Frequency is measured in - ANSWER Hertz (Hz)is
Cycles per Second
Not effected by sonographer
Increase Frequency; Decrease Depth
A period is the length of time it takes for - ANSWER one complete wavelength to pass a
fixed point
PRP is determined by - ANSWER Transmit time and receive time.
Period is measured in - ANSWER Time (μs)
If the sonographer changes the imaging depth what parameters are changed? -
ANSWER PRP, PRF, Duty Factor
,What is duty factor? - ANSWER The % or fraction of time that the system is transmitting a
pulse. (Time Sound is ON or ON-Time).
Propagation Speed in SOFT TISSUE - ANSWER 1.54 mm/μs
(1540 m/sec)
Unit of measurement for Pulse Duration, Duty Factor, PRP, and Period - ANSWER Time,
(μs)
Pulse duration is determined by - ANSWER Sound Source Only
Pulse Duration is controlled by - ANSWER the ultrasound system and transducer
Pulse Duration Formula - ANSWER pulse duration (μs) = # cycles in
pulse/frequency(MHz)
PD= Number of cycles in Pulse/ Frequency(Hz)
Spatial Pulse Length (SPL) (measurement) - 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. - ANSWER 0.1 to 1.0 mm
Spatial pulse length is determined by - ANSWER sound source and medium
Spatial Pulse Length is directly proportional to - 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 - 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) - 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 - 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 property of a medium that characterizes, qualitatively, the resistance of the medium
to compression and is proportional to the hardness of the medium? - ANSWER Stiffness.
Concept:
↑ Stiffness ↑ Speed
↓ Density ↑ Speed
If pulse repetition frequency were increased, what would occur? - ANSWER Increasing
pulse repetition frequency, increases duty factor.
