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LMC Ultrasound > Physics Test Ch. 12 and 13 > Flashcards

Physics Test Ch. 12 and 13 Flashcards

1
Q

When the crystals are defective, the entire image is destroyed with this type of transducer

A

Single crystal transducer. Mechanical transducer Pg 167

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2
Q

Which transducer creates a beam that is focused in all planes and at all depths?

A

annular phased array

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3
Q

What is the advantage of using a 1 1/2 dimensional array transducer?

A

Creates thinner beams with improved slice thickness ( or elevational resolution) over a greater range of depths p 190

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4
Q

What type of resolution is improved with a 1 1/2 dimensional array transducer?

A

Slice thickness and Elevational resolution Pg 188

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5
Q

What is the image shape of a vector array transducer?

A

Trapezoidal Pg 187

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6
Q

Which transducer has active elements arranged in a straight line?

A

Linear Pg 168

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7
Q

Which transducer has active elements arranged in circular rings?

A

Annular Pg 168

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8
Q

Which transducer has active elements arranged in an arched or bowed matter?

A

Convex Pg168

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9
Q

Phased array always means what?

A

Adjustable or multi-focused Pg 170

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10
Q

Linear switch transducer has what type of steering technique?

A

Also called linear sequential. Has electronic steering. Pg 187

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11
Q

What type of probe has dropout lines of image information from top to bottom?

A

Linear and convex Pg 187

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12
Q

Horizontal or side to side dropout occurs in which transducer type when crystals are bad?

A

Annular phased array. Pg187

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13
Q

Which transducer is designed to be mechanically steered and fixed with single focus?

A

Mechanical Pg187

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14
Q

The use of more active elements to receive reflections with a greater time of flight is called

A

Dynamic aperture? *found on a quizlet

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15
Q

What is the ultrasound machine that can display real time images and Doppler?

A

Duplex pg 313

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16
Q

The ability to accurately locate moving structures at any time is what kind of resolution?

A

Temporal resolution Pg 198

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17
Q

What will decrease temporal resolution?

A

Deeper imaging, which decrease frame rate and degrades temporal resolution Pg 200

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18
Q

Real-time imaging could be referred to as…?

A

Ultrasound “movie” Pg 197

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19
Q

What determines temporal resolution?

A

Frame rate Pg 198

20
Q

What are the factors that limit frame rate?

A
  • speed of sound in the medium

- Imaging depth Pg 198

21
Q

What will affect the pulses in a single image?

A
  • Number of focal points
  • Sector size
  • Line density Pg 201
22
Q

If we double imaging depth, what happens to frame rate?

A

Frame rate is halved Pg 210

23
Q

Imaging to greater depth of view requires what?

A
  • Long go-return time
  • Longer Tframe
  • Lower frame rate
  • Inferior temporal resolution Pg 200
24
Q

What will degrade temporal resolution?

A

(Lower frame rate)

  • Deeper imaging
  • Multiple focal points
  • Wide sector
  • High line density Pg 209
25
Q

What is the sector size that will use the fewest pulses?

A

The narrowest sector size p. 204

26
Q

The sonographer increases line density from 1 line to 3 lines, what will be the consequence of this action?

A

Temporal resolution decreases p. 211

27
Q

If the frame rate is 50 Hz, how long does it take to create a frame?

A

1/50 sec p. 214 (#23 is an example of this)

28
Q

Lateral resolution improves with what?

A

Multi-focusing p 209

29
Q

Low line density creates what?

A
  • widely spaced lines
  • fewer pulses per frame
  • shorter T frame
  • higher frame rate
  • high temporal resolution
  • poor spatial resolution p. 207 (yellow box)
30
Q

What creates an image with poor movie quality but high image quality?

A
  • Poor temporal resolution

- Low frame rate Pg 208

31
Q

Increasing the line density degrades _____ and improves _____.

A

Degrades temporal resolution and improves spatial resolution p. 207

32
Q

A critical factor in determining frame rate, line density and imaging depth is?

A

Time pg 213

33
Q

If imaging depth is 15 cm and there’s 100 lines… When frame is made quickly…how many Frames created per second?

A

100 frames per second p. 213

34
Q

Using a phased array ultrasound system, if you turn off the multi-focus feature what will most likely be a consequence of this action?

A

Temporal resolution increases pg 211

35
Q

Which of the following is consistent with increased or improved spatial resolution?

A

High line density p. 207

36
Q

When a frame is made quickly, how many frames are created per second?

A

a lot

37
Q

When you have 1 frame created in 1/100 second, what is the frame rate?

A

100 per second or 100 Hz p. 213

38
Q

What are the different shapes of images for all different probes?

A 
Mechanical - sector 
Linear sequential - rectangle 
Phased array - sector 
Annular phased - sector 
Convex - blunted sector 
Vector - trapezoidal
39
Q

In a linear phased array, what is the firing pattern that steers a beam to the left or right?

A

Electronic slope

40
Q

What is apodization?

A

Stronger electrical signals are used to excite inner crystals, and progressively weaker spikes excite the outer crystals then lobes are diminished p. 193

41
Q

Focused and unfocused

A

~

42
Q

What are side lobes?

A

sound beams created by single element transducers and are additional areas of sound energy extend outside of the main beam in the far zone

43
Q

What are grating lobes?

A

created by array transducers, the extra off-axis sound beams are undesirable because they degrade lateral resolution, reduce image quality, and create artifacts p. 192

44
Q

What is dynamic aperture?

A

“transmit hole” or “listening hole” makes sound beam narrow over a greater range of depths improves lateral resolution Pg194

45
Q

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

A

Electronic curvature

46
Q

What’s the typical value for the electrical signal delay in a phased array transducer?

A

4-10 nanoseconds-what seniors had

10 nanoseconds-in book p 172

LMC Ultrasound (32 decks)

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