Ch. 13 Physics: Real- Time imaging Flashcards

1
Q

True or false:
two-dimensional images were created through a time-consuming process called static scanning and is still used today.

A

False
Today all modern ultrasound instruments are capable of real-time imaging.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

describes a systems ability to create numerous frames (images) each second.

A

Frame rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Frame rate is determined by …..

A

Sound speed within the medium – most important

Imaging depth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Frame Rate is ___________ to Temporal Resolution

A

Proportional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the typical frame rate per second?

A

30 - 60 frames per second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Maximum imaging depth determines frame rate with speed of sound in soft tissue considered at a constant ________.

A

1.54km/s

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is frame rate measured in?

A

Hz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Accuracy in time – the ability to precisely position moving structures from instant to instant

A

Temporal resolution

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Temporal resolution is determined by what?

A

Frame rate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

_______ frame rate improves temporal resolution

A

High

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

_______ frame rate reduces temporal resolution

A

Low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

If it takes 1/30 of a second to make a frame, then the frame rate is ……

A

30 frames per sec, or 30 Hz

T frame x frame rate = 1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Is the temporal resolution controlled or not controlled by the sonographer?

A

Controlled

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How is temporal resolution controlled?

A

Imaging depth

Number of pulses per frame

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Imaging depth and frame rate are _________ related

A

inversely

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the formula for image depth?

A

Tframe = # pulses x PRP

17
Q

Shallow depths allow for a _______ frame rate

18
Q

Deeper imaging requires more time to create and results in ______ frame rate

19
Q

To maintain better temporal resolution, we would want the most ________ image.

20
Q

_________________ also affects the frame rate since the more pulses needed to create an image would take more time….then the temporal resolution would decrease.

A

Pulses per image

21
Q

What are the three factors that determine the number of pulses needed to create the image?

A

Number of pulses per scan line (multi-focus vs. single focus)

Sector size

Line density

22
Q

What increases lateral resolution, but only at a trade off reducing temporal resolution?

A

Multi-focus

23
Q

Also known as field of view

A

Sector size

24
Q

By expanding the ___________, more pulses are required to create an image so temporal resolution decreases

A

sector size

25
The number of scan lines in the sound beam.
Line density
26
So what do you think happens to the temporal resolution with increased line density?
It would decrease
27
what would happen to our spatial resolution with increased line density?
It would increase
28
More lines = increased detail (spatial resolution), but _____ frame rate (decreased temporal resolution)
slower
29
Few lines = decreased detail (spatial resolution), but _____ frame rate (increased temporal resolution)
faster