Chapter 19 Flashcards

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1
Q

Which of the following is true about color map 1?

A

Red indicated flow towards the transducer

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2
Q

Which one of the following is true about map 1?

A

Blue indicated flow away from the transducer

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3
Q

Which of the following is true about color map 2?

A

Blue indicates flow away from the transducer

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4
Q

Which of the following is true about color map 2?

A

Green indicates higher velocity flow toward the transducer

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5
Q

Which statement is true about color map 1?

A

Red and yellow indicate flow toward the transducer

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6
Q

Which statement is true about color map 1?

A

Green indicates turbulent flow away from the transducer

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7
Q

Which statement is the best reason why color map 1 is a variance mode map?

A

Blue and green indicate flow away from the transducer

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8
Q

Which statement is true about color map 2?

A

Dark blue indicates laminar flow away from the transducer

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9
Q

Which statement is true about color map 2?

A

Light blue indicates turbulent flow

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10
Q

In which direction does blood flow through the top vessel?

A

Left to right

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11
Q

What does the black area (yellow area) in the center of both vessels represent?

A

Zero doppler shift

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12
Q

In which direction is blood flowing through the vessel?

A

Right to left

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13
Q

The doppler effect is presented as a _______ when the source and receiver are _______.

A

Frequency shift

In motion relative to each other

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14
Q

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 _________.

A

Negative

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15
Q

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 _________.

A

Negative

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16
Q

Doppler shift produces information about ________

A

Velocity

17
Q

At what angle between the sound beam and the direction of the motion will the doppler shift be the highest?

A

0 degrees to 180 degrees

18
Q

At what angle between the sound beam and the direction of the motion will the doppler shift be the closest to 0?

A

90 degrees

19
Q

What is the difference between speed and velocity?

A

Speed has only a magnitude. Velocity has magnitude and direction.

20
Q

What is the current method of processing doppler signals?

A

The fast Fourier transform (FFT) OR Spectral analysis

21
Q

What is the typical range of doppler shift found in diagnostic imaging examinations?

A

Between 20 Hz and 20 kHz

22
Q

The phenomenon where high velocities appear in the opposite direction is called ______

A

Aliasing

23
Q

The frequency at which aliasing occurs is called _______

A

Nyquist limit

24
Q

The area of interrogation in a pulsed doppler exam is called _____

A

Sample volume

25
Q

T or F. The higher the emitted frequency, the more likely a pulsed wave signal is to alias.

A

True

26
Q

T or F. Shallower sample volumes result in more aliasing.

A

False

27
Q

T or F. Only pulsed wave doppler exams have a sample volume.

A

True

28
Q

An 8 MHz transducer with a pulse repetition of 5,000 Hz is imaging to a depth of 7 cm. What is the Nyquist frequency?

A

2.5 kHz or 2,500 Hz

29
Q

An 8 MHz transducer with a pulse repetition of 5,000 Hz measures a doppler shift of 7 kHz. The study is repeated with a 4 MHz transducer. What doppler shift will be measured?

A

3,500 Hz

30
Q

T or F. A successful doppler exam cannot be performed on a severely anemic patient.

A

False

31
Q

Which technique is used to perform spectral analysis on color doppler data?

A

Autocorrelation

32
Q

Which technique is used to perform spectral analysis on pulsed doppler data?

A

Fast Fourier Transform (FFT)

33
Q

Which of the following terms is synonymous with spectral broadening?

A

Turbulent flow

34
Q

Which of the following is an advantage of a large packet size?

A

Increased doppler accuracy

35
Q

Why are dedicated continuous wave doppler transducers so sensitive?

A

Absence of backing material

36
Q

T or F. The lumen of a horizontal vessel evaluated with a color doppler, sector shaped image contains a single color.

A

False