ARDMS SPI Exam Review Questions with
100% Correct Answers
In soft tissue, if the frequency of a wave is increased the Propagation Speed (PS) will...
Remain the Same because stiffness and density affect Propagation Speed.
What is the audible range?
20-20,000Hz
>20,000Hz=Ultrasound
Frequency is measured in
Hertz (Hz)
is
Cycles per Second
Not affected by sonographer
Increase Frequency; Decrease Depth
A period is the length of time it takes for
one complete wavelength to pass a fixed point
PRP is determined by
Transmit time and receive time.
Period is measured in
Time (μs)
,When the sonographer changes the imaging depth what parameters are changed?
PRP, PRF, Duty Factor
What is duty factor?
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
1.54 mm/μs
(1540 m/sec)
Unit of measurement for Pulse Duration, Duty Factor, PRP, and Period
Time, (μs)
Pulse duration is determined by
Sound Source Only
Pulse Duration is controlled by
the ultrasound system and transducer
Pulse Duration Formula
pulse duration (μs) = # cycles in pulse/frequency(MHz)
PD= Number of cycles in Pulse/ Frequency(Hz)
Spatial Pulse Length (SPL) (measurement)
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.
0.1 to 1.0 mm
Spatial pulse length is determined by
sound source and medium
Spatial Pulse Length is directly proportional to
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
Frequency (MHz)
(Inversely Proportional means that increased SPL will lower frequency. This is because axial
resolution is better with lower frequency)
Pulse Duration (PD)
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
100% Correct Answers
In soft tissue, if the frequency of a wave is increased the Propagation Speed (PS) will...
Remain the Same because stiffness and density affect Propagation Speed.
What is the audible range?
20-20,000Hz
>20,000Hz=Ultrasound
Frequency is measured in
Hertz (Hz)
is
Cycles per Second
Not affected by sonographer
Increase Frequency; Decrease Depth
A period is the length of time it takes for
one complete wavelength to pass a fixed point
PRP is determined by
Transmit time and receive time.
Period is measured in
Time (μs)
,When the sonographer changes the imaging depth what parameters are changed?
PRP, PRF, Duty Factor
What is duty factor?
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
1.54 mm/μs
(1540 m/sec)
Unit of measurement for Pulse Duration, Duty Factor, PRP, and Period
Time, (μs)
Pulse duration is determined by
Sound Source Only
Pulse Duration is controlled by
the ultrasound system and transducer
Pulse Duration Formula
pulse duration (μs) = # cycles in pulse/frequency(MHz)
PD= Number of cycles in Pulse/ Frequency(Hz)
Spatial Pulse Length (SPL) (measurement)
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.
0.1 to 1.0 mm
Spatial pulse length is determined by
sound source and medium
Spatial Pulse Length is directly proportional to
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
Frequency (MHz)
(Inversely Proportional means that increased SPL will lower frequency. This is because axial
resolution is better with lower frequency)
Pulse Duration (PD)
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
