ARDMS SPI STUDY GUIDE
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.
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)
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)
(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.
↑ PRF ↑ Duty Factor
Which of the following would have the highest propagation speed? - CORRECT
ANSWER-Bone has the highest propagation speed, at 2000-4000 m/s.
What has the lowest propagation speed? - CORRECT ANSWER-air technically
has the lowest propagation speed at 300 m/s
Which has the Slowest Propagation Speed?
Water
Soft Tissue
Bone
Lung tissue - CORRECT ANSWER-Lung Tissue
As imaging depth increases, the pulse repetition frequency (PRF) must: -
CORRECT ANSWER-Decrease
As imaging depth increase, pulse repeition freqency (PRF) decreases.
↑ Imaging Depth ↓ PRF
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.
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)
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)
(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.
↑ PRF ↑ Duty Factor
Which of the following would have the highest propagation speed? - CORRECT
ANSWER-Bone has the highest propagation speed, at 2000-4000 m/s.
What has the lowest propagation speed? - CORRECT ANSWER-air technically
has the lowest propagation speed at 300 m/s
Which has the Slowest Propagation Speed?
Water
Soft Tissue
Bone
Lung tissue - CORRECT ANSWER-Lung Tissue
As imaging depth increases, the pulse repetition frequency (PRF) must: -
CORRECT ANSWER-Decrease
As imaging depth increase, pulse repeition freqency (PRF) decreases.
↑ Imaging Depth ↓ PRF
