Chapter 12/13 Q&A: test 1

Question 1

Mechanical scanning produces pictures that are similar in shape to linear phased array images

Answer 1

True

Question 2

Many active elements fire at almost the same time in a mechanical scanner

Answer 2

False

There is only one active element in a mechanical scanner

Question 3

Many active elements fire at almost the same time in a phased array scanner

Answer 3

True

Question 4

Which transducer is best described as mechanically steered and fixed, single focus?

Answer 4

mechanical

Question 5

Which transducer is best described as mechanically steered and multi-focus?

Answer 5

Annular phased array

Question 6

Which transducer creates a rectangular shaped image?

Answer 6

linear sequential array

Question 7

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

Answer 7

128

With linear phased array transducers, all the active elements are fired

Question 8

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

Answer 8

a small group

With linear sequential array transducers, a small group of active elements are fired

Question 9

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

Answer 9

The firing pattern that steers a beam to the left or right is electronic slope

Question 10

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

Answer 10

The firing pattern that focuses a sound beam is electronic curvature

Question 11

There are large time delays in the firing pattern of a linear phased array transducer

Answer 11

False

there are tiny time delays

Question 12

A machine that displays A-mode and two-dimensional images is called a duplex scanner

Answer 12

False

a machine that displays Doppler and 2D images is a duplex scanner

Question 13

Which transducer improves elevational resolution?

Answer 13

1 1/2 dimensional array

Question 14

Side lobes degrade axial resolution

Answer 14

False

Question 15

Side lobes degrade lateral resolution

Answer 15

True

Question 16

Which form of resolution improves when frame rate increases?

Answer 16

temporal resolution

temporal resolution is directly related to frame rate

higher frame rates improve temporal resolution

Question 17

What is consistent with improved temporal resolution?

Answer 17

higher frame rate

Frame rate determines temporal resolution

Higher frame rates(lower Tframe) result in improved temporal resolution

Question 18

What decreases temporal resolution?

Answer 18

lower frame rate

deeper imaging

multi-focus

Question 19

A sonographer adjusts an ultrasound scan to double the depth of view from 5cm to 10cm.

What happens to the frame rate?

Answer 19

the frame rate is halved

frame rate and imaging depth are inversely related

Question 20

A sonographer adjusts an ultrasound scan to double the depth of view from 5cm to 10cm.

If the frame rate remains the same, what will also occur?

Answer 20

narrower sector

Question 21

A sonographer adjusts an ultrasound machine to change the sector size from 90 to 45 degrees. Nothing else changes. What happens to the frame rate?

Answer 21

the frame rate is doubled

Question 22

A sonographer adjusts an ultrasound system to change the sector size from 90 to 45 degrees. The frame rate was unchanged. What else must have happened?

Answer 22

line density was doubled

Question 23

A sonographer, using a phased array ultrasound system, turns off the multi-focus feature. What is the most likely consequence of this action?

Answer 23

temporal resolution improves

Question 24

A sonographer increases the line density from 1 line per degree of sector to 3 lines per degree of sector. What is the most likely consequence of this action?

Answer 24

temporal resolution decreases

Question 25

A sonographer reduces the sector angle from 90 degrees to 30 degrees. At the same time, the ultrasound system automatically increases the line density from 1 line per degree to 2 lines per degree. No other changes are made. What will happen to the frame rate?

Answer 25

frame rate increases

Question 26

A sonographer reduces the sector angle from 90 degrees to 30 degrees. At the same time, the ultrasound system automatically increases the line density from 1 line per degree to 3 lines per degree. No other changes are made. What will happen to temporal resolution?

Answer 26

temporal resolution is unchanged

Question 27

What is most important in determining the frame rate of a system?

Answer 27

speed of sound in a medium

Question 28

What is most important in determining the frame rate of a system?

Answer 28

depth of view

Question 29

What is the frame rate if each image of the ultrasound system is created in 0.02sec (1/50sec)?

Answer 29

50Hz frame rate and Tframe are reciprocals

Question 30

What is the time needed to make a single image if the frame rate of an ultrasound system is 20Hz?

Answer 30

0.05s (1/20) frame rate and Tframe are reciprocals

Question 31

The critical factor in determining frame rate, line density, and imaging depth is the transducer style

Answer 31

false its time

Question 32

The number of lines per frame and the frame rate determine the frequency.

Answer 32

false it determines PRF

Question 33

The number of lines per frame and the frame rate determine the PRF.

Answer 33

true

Question 34

If the imaging depth of a scan is 15cm and there are 100 lines in the image, then the number of pulses making up the scan is 1500.

Answer 34

false number of pulses would be 100

Question 35

If the imaging depth of a scan is 15cm and there are 100 lines in the image, then the number of pulses making up the scan is 100.

Answer 35

true

Question 36

If 100 scan lines make up an image and the frame rate is 30 per second, then the transducer's frequency is 3,000Hz.

Answer 36

false a transducer's frequency is independent of the characteristics of the image that it creates.

Question 37

If 100 scan lines make up an image and the frame rate is 30 per second, then the system's pulse repetition frequency is 3,000Hz.

Answer 37

true PRF is the number of pulses created per second. It is lines per image multiplied by frame rate.

Question 38

When the frame rate is 30Hz, how long does it take to create a frame?

Answer 38

1/30 sec frame rate and Tframe are reciprocals

Question 39

Under certain conditions, an ultrasound system creates each image in 0.01 seconds. What is the frame rate?

Answer 39

100Hz frame rate and Tframe are reciprocals

Question 40

What is the fundamental limitation of temporal resolution?

Answer 40

speed of sound in the medium