Chapter 19 Flashcards
Which of the following is true about color map 1?
Red indicated flow towards the transducer
Which one of the following is true about map 1?
Blue indicated flow away from the transducer
Which of the following is true about color map 2?
Blue indicates flow away from the transducer
Which of the following is true about color map 2?
Green indicates higher velocity flow toward the transducer
Which statement is true about color map 1?
Red and yellow indicate flow toward the transducer
Which statement is true about color map 1?
Green indicates turbulent flow away from the transducer
Which statement is the best reason why color map 1 is a variance mode map?
Blue and green indicate flow away from the transducer
Which statement is true about color map 2?
Dark blue indicates laminar flow away from the transducer
Which statement is true about color map 2?
Light blue indicates turbulent flow
In which direction does blood flow through the top vessel?
Left to right
What does the black area (yellow area) in the center of both vessels represent?
Zero doppler shift
In which direction is blood flowing through the vessel?
Right to left
The doppler effect is presented as a _______ when the source and receiver are _______.
Frequency shift
In motion relative to each other
Starting from the same point, the sound source is moving toward the east at 12 miles/hour and the receiver is moving toward the west at 10 miles/hour. The doppler shift is _________.
Negative
Starting from the same point, the receiver is moving toward the west at 12 miles/hour and the source is moving toward the west at 10 miles/hour. The doppler shift is _________.
Negative
Doppler shift produces information about ________
Velocity
At what angle between the sound beam and the direction of the motion will the doppler shift be the highest?
0 degrees to 180 degrees
At what angle between the sound beam and the direction of the motion will the doppler shift be the closest to 0?
90 degrees
What is the difference between speed and velocity?
Speed has only a magnitude. Velocity has magnitude and direction.
What is the current method of processing doppler signals?
The fast Fourier transform (FFT) OR Spectral analysis
What is the typical range of doppler shift found in diagnostic imaging examinations?
Between 20 Hz and 20 kHz
The phenomenon where high velocities appear in the opposite direction is called ______
Aliasing
The frequency at which aliasing occurs is called _______
Nyquist limit
The area of interrogation in a pulsed doppler exam is called _____
Sample volume
