ARDMS SPI STUDY GUIDE
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)
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
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 - ✔️✔️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? -
✔️✔️Stiffness.
Think:
↑ Stiffness ↑ Speed
↓ Density ↑ Speed
An increase in pulse repetition frequency would lead to: - ✔️✔️Increasing pulse
repetition frequency, increases duty factor.
↑ PRF ↑ Duty Factor
, Which of the following would have the highest propagation speed? - ✔️✔️Bone has the
highest propagation speed, at 2000-4000 m/s.
What has the lowest propagation speed? - ✔️✔️air technically has the lowest
propagation speed at 300 m/s
Which has the Slowest Propagation Speed?
Water
Soft Tissue
Bone
Lung tissue - ✔️✔️Lung Tissue
As imaging depth increases, the pulse repetition frequency (PRF) must: -
✔️✔️Decrease
As imaging depth increase, pulse repeition freqency (PRF) decreases.
↑ Imaging Depth ↓ PRF
What describes the amount of refraction that occurs at an interface? - ✔️✔️Snell's law
Refraction: the redirection of the transmitted sound beam
Snell's law describes the angle of transmission at an interface based on the angle of
incidence and the propagation speeds of the two media.
Pressure is typically expressed in: - ✔️✔️Pascals (Pa)
The typical range of frequency for diagnostic ultrasound imaging is - ✔️✔️1-20 Mhz is
the typical range of frequency for diagnostic ultrasound imaging.
The attentuation coefficient in soft tissue is equal to: - ✔️✔️Attentuation Coeffcient =
1/2 (one half of the frequency in soft tissue)
The attentuation coeffcient (in dB/cm) is the rate at which sound is attentuated per unit
depth.
Micro is denoted as: - ✔️✔️Micro is denoted as millionth (µ)
What is described as the distance over which one cycle occurs? - ✔️✔️Wavelength is
distance over which one cycle occurs, or the distance from the beginning of one cycle to
the end of the same cycle.
Remember, it asks for distance over which one cycle occurs.
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)
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
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 - ✔️✔️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? -
✔️✔️Stiffness.
Think:
↑ Stiffness ↑ Speed
↓ Density ↑ Speed
An increase in pulse repetition frequency would lead to: - ✔️✔️Increasing pulse
repetition frequency, increases duty factor.
↑ PRF ↑ Duty Factor
, Which of the following would have the highest propagation speed? - ✔️✔️Bone has the
highest propagation speed, at 2000-4000 m/s.
What has the lowest propagation speed? - ✔️✔️air technically has the lowest
propagation speed at 300 m/s
Which has the Slowest Propagation Speed?
Water
Soft Tissue
Bone
Lung tissue - ✔️✔️Lung Tissue
As imaging depth increases, the pulse repetition frequency (PRF) must: -
✔️✔️Decrease
As imaging depth increase, pulse repeition freqency (PRF) decreases.
↑ Imaging Depth ↓ PRF
What describes the amount of refraction that occurs at an interface? - ✔️✔️Snell's law
Refraction: the redirection of the transmitted sound beam
Snell's law describes the angle of transmission at an interface based on the angle of
incidence and the propagation speeds of the two media.
Pressure is typically expressed in: - ✔️✔️Pascals (Pa)
The typical range of frequency for diagnostic ultrasound imaging is - ✔️✔️1-20 Mhz is
the typical range of frequency for diagnostic ultrasound imaging.
The attentuation coefficient in soft tissue is equal to: - ✔️✔️Attentuation Coeffcient =
1/2 (one half of the frequency in soft tissue)
The attentuation coeffcient (in dB/cm) is the rate at which sound is attentuated per unit
depth.
Micro is denoted as: - ✔️✔️Micro is denoted as millionth (µ)
What is described as the distance over which one cycle occurs? - ✔️✔️Wavelength is
distance over which one cycle occurs, or the distance from the beginning of one cycle to
the end of the same cycle.
Remember, it asks for distance over which one cycle occurs.
