Chapter 12 quiz Flashcards

(31 cards)

1
Q

The minimum number of active elements in a mechanical transducer is:

A

1

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2
Q

T or F. Many active elements fire at almost the same time in a phased array scanner.

A

True

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3
Q

Which of the following transducers is best describes as mechanically steered and fixed, single focused?

A

Mechanical

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4
Q

Which of the following is best described as mechanically steered and multi-focus?

A

Annular phased array transducer

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5
Q

Which of the following transducers creates a rectangular shaped image?

A

Linear sequential array

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6
Q

A linear phased array transducer has 128 crystals. How many of these crystals are fired to create a single sound beam?

A

128 (All of them)

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7
Q

A linear sequential array transducer has 128 crystals. How many of these crystals are fired to create a single sound beam?

A

A small group

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8
Q

In a linear phased array, what is the firing pattern that steers a beam up or down?

A

Slope

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9
Q

In a linear phased array, what is the firing pattern that focuses a sound beam?

A

Curve

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10
Q

T or F. There are large time delays in the firing pattern that focuses a sound beam.

A

False

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11
Q

T or F. A machine that displays A-mode and two-dimensional images is called a duplex scanner.

A

False

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12
Q
When looking at image produce by these transducer systems, which one can be distinguished from all the others?
Linear phased array
Linear switched array
Annular phased array
Mechanical transducer
A

Linear switched array

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13
Q

T or F. All phased array transducer systems direct ultrasound pulses in many directions to create a two-dimensional image.

A

True

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14
Q

What is true of the electrical pulses that excite the active elements of an annular phased array transducer?

A

They arrive at each PZT crystal at different times microseconds apart

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15
Q

The pattern of electrical signals exciting the PZT crystals of a linear phased array transducer ________.

A

Typically changes from one acoustic pulse to the next

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16
Q

How are PZT crystals excited when using an ultrasound system with sequential linear array transducer?

A

In a specific order

17
Q

How are the PZT crystal of a linear phased array transducer fired?

A

At almost exactly the same time

18
Q

T or F. The “curvature pattern” of delays in the electrical spikes used in linear phase array transducer focuses the beam during transmission.

19
Q
Which of the following forms of focusing is different that the others?
Lens
Mirror
Phased
Dynamic recieve
20
Q

T or F. The “curved pattern” of delays in the electrical spikes used in linear phase array transducer focuses the beam during reception.

21
Q

Which two of the following terms are associated with phased array transducer?

A

Adjustable

Multi-focus

22
Q

What helps to determine the frequency of the sound produced by the transducer of a continuous wave ultrasound system?

A

Ultrasound system electronics

23
Q

What is the shape of the elements in an annular phased array transducer?

24
Q
Which best describes the element in a linear phased array transducer?
Rectangular, 1/4 wavelength thick
Rectangular, 1/2 to 1/4 wavelength wide
Circular
Squares, 1/2 wavelength thick
A

Rectangular, 1/2 to 1/4 wavelength wide

25
``` Which best describes the element in a linear sequential array transducer? Rectangular, 1/4 wavelength thick Rectangular, 1/2 to 1/4 wavelength wide Circular Squares, 1/2 wavelength thick ```
Circular
26
What image is created with a two-dimensional array transducer?
3D real time image
27
All of the following describe dynamic receive focusing except: Delay pattern change continuously throughout reception May be used by single crystal transducers Focusing occurs at many depths Automatically performed by system
May be used by single crystal transducer
28
Which transducer possesses the best slice thickness resolution?
1 1/2 dimensional arrays
29
While using a linear sequential array transducer during a color doppler exam, the shape of the grayscale image is most often _________, whereas the shape of the color doppler portion of the image is __________.
Rectangular | Parallelogram
30
Numerical value is higher in _______ and lower in _______.
Axial resolution | Lateral resolution
31
Lateral resolution has to do with _______.
Width