Physics Test Ch. 12 and 13

Question 1

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

Answer 1

Single crystal transducer. Mechanical transducer Pg 167

Question 2

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

Answer 2

annular phased array

Question 3

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

Answer 3

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

Question 4

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

Answer 4

Slice thickness and Elevational resolution Pg 188

Question 5

What is the image shape of a vector array transducer?

Answer 5

Trapezoidal Pg 187

Question 6

Which transducer has active elements arranged in a straight line?

Answer 6

Linear Pg 168

Question 7

Which transducer has active elements arranged in circular rings?

Answer 7

Annular Pg 168

Question 8

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

Answer 8

Convex Pg168

Question 9

Phased array always means what?

Answer 9

Adjustable or multi-focused Pg 170

Question 10

Linear switch transducer has what type of steering technique?

Answer 10

Also called linear sequential. Has electronic steering. Pg 187

Question 11

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

Answer 11

Linear and convex Pg 187

Question 12

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

Answer 12

Annular phased array. Pg187

Question 13

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

Answer 13

Mechanical Pg187

Question 14

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

Answer 14

Dynamic aperture? *found on a quizlet

Question 15

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

Answer 15

Duplex pg 313

Question 16

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

Answer 16

Temporal resolution Pg 198

Question 17

What will decrease temporal resolution?

Answer 17

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

Question 18

Real-time imaging could be referred to as…?

Answer 18

Ultrasound “movie” Pg 197

Question 19

What determines temporal resolution?

Answer 19

Frame rate Pg 198

Question 20

What are the factors that limit frame rate?

Answer 20

• speed of sound in the medium

- Imaging depth Pg 198

Question 21

What will affect the pulses in a single image?

Answer 21

• Number of focal points
• Sector size
• Line density Pg 201

Question 22

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

Answer 22

Frame rate is halved Pg 210

Question 23

Imaging to greater depth of view requires what?

Answer 23

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

Question 24

What will degrade temporal resolution?

Answer 24

(Lower frame rate)

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

Question 25

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

Answer 25

The narrowest sector size p. 204

Question 26

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

Answer 26

Temporal resolution decreases p. 211

Question 27

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

Answer 27

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

Question 28

Lateral resolution improves with what?

Answer 28

Multi-focusing p 209

Question 29

Low line density creates what?

Answer 29

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

Question 30

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

Answer 30

- Poor temporal resolution | - Low frame rate Pg 208

Question 31

Increasing the line density degrades _____ and improves _____.

Answer 31

Degrades temporal resolution and improves spatial resolution p. 207

Question 32

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

Answer 32

Time pg 213

Question 33

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

Answer 33

100 frames per second p. 213

Question 34

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

Answer 34

Temporal resolution increases pg 211

Question 35

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

Answer 35

High line density p. 207

Question 36

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

Answer 36

a lot

Question 37

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

Answer 37

100 per second or 100 Hz p. 213

Question 38

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

Answer 38

``` Mechanical - sector Linear sequential - rectangle Phased array - sector Annular phased - sector Convex - blunted sector Vector - trapezoidal ```

Question 39

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

Answer 39

Electronic slope

Question 40

What is apodization?

Answer 40

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

Question 41

Focused and unfocused

Answer 41

~

Question 42

What are side lobes?

Answer 42

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

Question 43

What are grating lobes?

Answer 43

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

Question 44

What is dynamic aperture?

Answer 44

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

Question 45

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

Answer 45

Electronic curvature

Question 46

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

Answer 46

4-10 nanoseconds-what seniors had | 10 nanoseconds-in book p 172