SPI PRACTICE EXAM Questions and Answers
(100% Correct Answers) Already Graded A+
The typical frame rate of an Ultrasound system is? [ Ans: ]
Between 30 Hz and 100 Hz
Temporal resolution is synonymous with frame rate.
Typical frame rates in imaging systems are 30-100 Hz. [
Ans: ] The temporal resolution or frame rate = 1/(time to
scan 1 frame). Frame rate can drop down to 5 Hz.
Pulse duration is related to bandwidth how? [ Ans: ] Pulse
Duration = 1 / Bandwidth
Specular reflectors have physical dimensions that are
what size in relation to the wavelength? [ Ans: ] Greater
Two identical systems produce a pulse. One pulse is 0.8
usec in duration while the other is 1.4 usec. The best
radial resolution will be created by which system? [ Ans: ]
0.8 Pulse duration (length of pulse) With a short pulse
duration we have a small pulse length. The shorter the SPL
the better the longitudinal resolution.
To achieve better depth (axial) resolution. You must have
what? [ Ans: ] FEWER CYCLES PER PULSE -Axial resolution =
SPL / 2 or # cycles in the pulse x wavelength / 2
Ultrasound wave attenuation is denoted by which units? [
Ans: ] dB (DECIBELS)
, If it takes 1/20 of a second to construct a single frame,
what is the current frame rate? [ Ans: ] 20 hz--Hz = cycles
per second. The rate is 1/20th of a second. So 20 cycles
per second = 20 Hz
With a focused ultrasound beam, bioeffects...? [ Ans: ] Are
less likely to occur
The smaller the beam the less likelihood of cavitation.
Exam duration has the greatest effect on patient exposure.
[ Ans: ] Bioeffects intensity limit: SPTA >100 mW/cm2
Unfocused >1 W/cm2 or 1000 mW/cm2 Focused
HIGHEST output intensities used with pulsed doppler. [
Ans: ] Lowest output intensities are with gray-scale
imaging.
With which type of array are grating lobes most common?
[ Ans: ] Linear array
Which equation is used to find the doppler shift? [ Ans: ]
Fd = 2 Fi v / c
In standard diagnostic imaging instrumentation, which
has the higher numerical value? [ Ans: ] Lateral
Resolution-LATA= higher numerical value LARD = smaller
value
Reflectors that are closer together than the width of the
beam create what artifact? [ Ans: ] Pulse Width artifact-
Also known as lateral resolution artifact and beam width
artifact.
(100% Correct Answers) Already Graded A+
The typical frame rate of an Ultrasound system is? [ Ans: ]
Between 30 Hz and 100 Hz
Temporal resolution is synonymous with frame rate.
Typical frame rates in imaging systems are 30-100 Hz. [
Ans: ] The temporal resolution or frame rate = 1/(time to
scan 1 frame). Frame rate can drop down to 5 Hz.
Pulse duration is related to bandwidth how? [ Ans: ] Pulse
Duration = 1 / Bandwidth
Specular reflectors have physical dimensions that are
what size in relation to the wavelength? [ Ans: ] Greater
Two identical systems produce a pulse. One pulse is 0.8
usec in duration while the other is 1.4 usec. The best
radial resolution will be created by which system? [ Ans: ]
0.8 Pulse duration (length of pulse) With a short pulse
duration we have a small pulse length. The shorter the SPL
the better the longitudinal resolution.
To achieve better depth (axial) resolution. You must have
what? [ Ans: ] FEWER CYCLES PER PULSE -Axial resolution =
SPL / 2 or # cycles in the pulse x wavelength / 2
Ultrasound wave attenuation is denoted by which units? [
Ans: ] dB (DECIBELS)
, If it takes 1/20 of a second to construct a single frame,
what is the current frame rate? [ Ans: ] 20 hz--Hz = cycles
per second. The rate is 1/20th of a second. So 20 cycles
per second = 20 Hz
With a focused ultrasound beam, bioeffects...? [ Ans: ] Are
less likely to occur
The smaller the beam the less likelihood of cavitation.
Exam duration has the greatest effect on patient exposure.
[ Ans: ] Bioeffects intensity limit: SPTA >100 mW/cm2
Unfocused >1 W/cm2 or 1000 mW/cm2 Focused
HIGHEST output intensities used with pulsed doppler. [
Ans: ] Lowest output intensities are with gray-scale
imaging.
With which type of array are grating lobes most common?
[ Ans: ] Linear array
Which equation is used to find the doppler shift? [ Ans: ]
Fd = 2 Fi v / c
In standard diagnostic imaging instrumentation, which
has the higher numerical value? [ Ans: ] Lateral
Resolution-LATA= higher numerical value LARD = smaller
value
Reflectors that are closer together than the width of the
beam create what artifact? [ Ans: ] Pulse Width artifact-
Also known as lateral resolution artifact and beam width
artifact.
