Current Update
What effect does Frequency compounding have on an image? - Answer-
✔✔Frequency compounding improves signal to noise ratio, spatial resolution,
and image quality. It also reduces speckle and clutter artifacts.
Increasing the frequency improves ______, ______, and _____. - Answer- ✔✔Axial
resolution, lateral resolution, and beam width improve with increasing frequency.
Increasing ____ will improve detail resolution the most on the lateral sides of the image.
- Answer- ✔✔Increasing line density will improve detail resolution the most on the
lateral sides of the image. By using more scan lines, the image is created from
more reflected information that allows for improved detail.
Which of the following correctly describes m-mode? - Answer- ✔✔M-mode eval offers
better temporal resolution than 2D imaging. It is used to assess fast moving
structures and eval timing of events in cardiac cycle. Also uses very high
sampling rate
What portion of the TGC curve is the deepest region attenuation compensation can
occur? - Answer- ✔✔The slope of the curve should be straight and with a gradual
increase in amplification until the knee. The knee of a TGC curve is the deepest
region attenuation compensation can occur. The far zone is the area of maximum
amplification.
You are using a 5MHz Xducer to perform a pulsed wave Doppler on the carotid arteries.
You change to a 7.5MHz continuous wave Doppler Xducer to evaluate blood flow. How
will this affect the propagation speed in the soft tissue of the neck? - Answer-
✔✔Remain constant. The media in which the wave is traveling through
determines the propagation speed of the sound wave. Changes in frequency have
no effect on the speed. The same vessels (media) evaluated with the transducers
of different frequency, therefore the speed of the wave will remain constant. The
method of ultrasound wave transmission also has no effect on the propagation
speed.
Decreasing the pulse repetition period leads to: - Answer- ✔✔A decrease in the
imaging depth.. If the PRP decreases, the PRF will increase which means shorter
pulses are emitted more quickly. The shorter pulses will travel a shorter distance
than the pulses emitted from a lower PRF. The imaging depth will decrease with a
decrease in PRP.
, If the output power setting is at 100% and this indicates 0dB, decreasing the power by: -
Answer- ✔✔6dB will decrease the original power by 25%.
A reduction in power of 3dB indicated a decrease of 50% original power. Every
3dB that the power decreases will decrease the power by another 50%.
110%x0.5=50% then 50%x0.5=25%
When you change the PRF, this adjusts: - Answer- ✔✔this adjusts the # of pulses
emitted per second.
In a 4 bit memory, the binary number 1110 indicates which of the following numbers
related to location of the display of the echo on the screen? - Answer- ✔✔Binary
numbers are used to determine echo placement on the image. In a 4 bit system,
They are calculated exponentially as follows: 8 4 2 1
1110
Every time a one is located "under" the binary number, It Is added to the total. If a
zero is present "under" the binary number, it is not added to the total. The
different numbers calculated are used to place the echo on the display
8+4+2+0=14
Which of the following best describes the difference between 3D ultrasound imaging
and 4D imaging? - Answer- ✔✔4D imaging displays 3D images in real time.
If an ellipse is used to document the circumference of a structure, what unit will be used
to report the measurement? - Answer- ✔✔circumference=cm
area=cm^2
volume=cm^3
What is the best way to increase beam penetration? - Answer- ✔✔Decreasing Xducer
frequency will increase beam penetration.
Demodulation is only necessary when: - Answer- ✔✔To prepare the signal for a CRT
or TV monitor.
If the sonographer increases the size of the field of view, the frame rate will _______ -
Answer- ✔✔decrease.
The gray scale map is adjusted to a new map just prior to freezing the image. This is an
example of? - Answer- ✔✔Applying pre-processing.
You are scanning a thyroid gland with a 5cm wide linear array transducer. You are
unable to document the upper and lower poles in the same image to obtain a length
measurement of the gland. Which of the following techniques would assist in
documenting the entire thyroid gland on a single image? - Answer- ✔✔Extend field of
view imaging.