CVT 151 Chapter 19/20 Doppler

This image is an example of an ultrasound system

process called _____ Doppler.

• pulsed wave

• continuous wave

• color

• power

Which Doppler modality processes the strength of the reflected signal without regard to the

blood's direction and speed.

• pulsed wave

• continuous wave

• color

• power

What is the direction of flow in this image?

• left to right

• right to left

Which Doppler processing system is a digital computer system based on technology that is less accurate but

processes enormous amounts of infomation.

• fast fourier transform

• autocorrelation

What is the extremely accurate analysis system used to break the complex velocity signals

into individual velocities that make up the reflected Doppler signal?

• fast fouier transform

• autocorrelation

Which of the Doppler systems creates mean velocity signals on the ultrasound image?

• pulsed wave

• continuous wave

• color Doppler

True or false: Selecting a new ultrasound view with a deeper sample volume will decrease aliasing.

• true

• false

The arow is pointing to a place on the image where the color flow changes colors. Why does the color

change from red to black to blue in this image?

• flow changes direction in the center of the image

• This is a "sector"

  image - black is perpendicular to blood

  flow. With sector the angle of insonation cannot be

  changed.

• the color box direction is set in the wrong direction

• In this view the vessels are side by side. One is an artery and the other is a vein. You cannot predict flow

  when they are viewed side by side like this.

High pass wall filters removes color from _____ but does not effect ____ velocities.

• low velocities (tissue), high velocities

• high velocities (tissue) , low velocities

Look at the image of the same vessel with different color box

angles. Why is there no color in the top image?

• this vessel has no blood

• wall filters are too high

• angle between the direction of flow and the direction of the sound beam is 90 degrees