ARDMS SPI STUDY GUIDE QUESTIONS
AND ANSWERS ALREADY GRADED A+
When the sonographer changes the imaging depth what parameters are changed? answer -
PRP, PRF, Duty Factor
What is duty factor? 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 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 ability of an object to resist compression and relates to the hardness of a medium? answer
- Stiffness.
, Think:
↑ Stiffness ↑ Speed
↓ Density ↑ Speed
An increase in pulse repetition frequency would lead to: answer - Increasing pulse repetition
frequency, increases duty factor.
↑ PRF ↑ Duty Factor
Which of the following would have the highest propagation speed? answer - Bone has the
highest propagation speed, at 2000-4000 m/s.
What has the lowest propagation speed? answer - air technically has the lowest propagation
speed at 300 m/s
Which has the Slowest Propagation Speed?
Water
Soft Tissue
Bone
Lung tissue answer - Lung Tissue
As imaging depth increases, the pulse repetition frequency (PRF) must: answer - Decrease
As imaging depth increase, pulse repeition freqency (PRF) decreases.
↑ Imaging Depth ↓ PRF
AND ANSWERS ALREADY GRADED A+
When the sonographer changes the imaging depth what parameters are changed? answer -
PRP, PRF, Duty Factor
What is duty factor? 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 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 ability of an object to resist compression and relates to the hardness of a medium? answer
- Stiffness.
, Think:
↑ Stiffness ↑ Speed
↓ Density ↑ Speed
An increase in pulse repetition frequency would lead to: answer - Increasing pulse repetition
frequency, increases duty factor.
↑ PRF ↑ Duty Factor
Which of the following would have the highest propagation speed? answer - Bone has the
highest propagation speed, at 2000-4000 m/s.
What has the lowest propagation speed? answer - air technically has the lowest propagation
speed at 300 m/s
Which has the Slowest Propagation Speed?
Water
Soft Tissue
Bone
Lung tissue answer - Lung Tissue
As imaging depth increases, the pulse repetition frequency (PRF) must: answer - Decrease
As imaging depth increase, pulse repeition freqency (PRF) decreases.
↑ Imaging Depth ↓ PRF
