Ch 13 Flashcards Preview

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Flashcards in Ch 13 Deck (31):
1

Static Imaging

images displayed one frame at a time

"picture"

2

Real Time Imaging

each frame is created and displayed very quickly, providing the impression of constant motion

"movie"

3

Duplex Imaging

real time imaging and Doppler at same time

4

Frame rate

system’s ability to create numerous frames each second

5

Two things that determine frame rate

speed of sound in medium
depth

6

Units of frame rate

Hz

7

Temporal Resolution

ability to precisely position moving structures from instant to instant

8

Speed is a fundamental limition of what?

temporal resolution

9

4 factors that affect temporal resolution

1. depth
2. focus
3. Sector Size
4. Line Density

10

If shallower or fewer pulses

go return time
t frame
frame rate
temporal resolution

short go-return time
shorter t frame
higher frame rate
superior temporal resolution

11

If deeper or more pulses

go return time
t frame
frame rate
temporal resolution

long go-return time
longer t frame
lower frame rate
inferior temporal resolution

12

t frame

time for one frame to be created

13

t frame and frame rate relationship

inversely related

14

# pulses x PRP =

t frame

Example:

100 x 1/1000 second = 1/10 second or 10 Hz

15

Factors Determining number of pulses per frame

number of focal points
sector size
line density

16

Imaging depth and frame rate are what related?

Inversely

17

Pulse per frame and frame rate are what related?

inversely

18

Single Focus

pulses per frame
t frame
frame rate
temporal resolution
lateral resolution

one pulse per scan line
shorter t frame
higher frame rate
better temporal resolution
poorer lateral resolution

19

Multi-focus

pulses per frame
t frame
frame rate
temporal resolution
lateral resolution

many pulses per scan line
longer t frame
lower frame rate
dimished temporal resolution
improved lateral resolution

20

Frame rate and time are what related?

inversely related

21

t frame x frame rate =

1

Example:

1/10 of a second, frame rate = 10 frames/second or 10 Hz

22

Narrow Sector

pulses per frame
t frame
frame rate
temporal resolution

fewer pulses per frame
shorter t frame
higher frame rate
superior temporal resolution

23

Wide Sector

pulses per frame
t frame
frame rate
temporal resolution

more pulses per frame
longer t frame
lower frame rate
inferior temporal resolution

24

how to change sector size?

field of view

25

Triplex Imaging

Pulse Waves, Color Doppler and real time imaging

26

Low Line Density

spaced line
pulses per frame
t frame
frame rate
temporal resolution
spatial resolution

widely spaced line
fewer pulses per frame
shorter t frame (faster)
higher frame rate
high temporal resolution
poor spatial resolution

27

High Line Density

spaced line
pulses per frame
t frame
frame rate
temporal resolution
spatial resolution

tightly packed line
more pulses per frame
longer t frame
lower rate rate
lower temporal resolution
excellent spatial resolution

28

What is line density?

alter the spacing between sound beams

29

Better Temporal

Resolution
depth
focus
sector
density
frame rate

shallow imaging
single focus
narrow sector
low line density
higher frame rate

30

Worse Temporal

Resolution
depth
focus
sector
density
frame rate

deep imaging
multiple focal points (improves lateral resolution)
wide sector
high line density (improves spatial resolution)
lower frame rate

31

Image vs movie quality

Some system settings produces an excellent photograph are inconsistent with producing an excellent movie. A low frame rate and poor temporal resolution create a great image but a poor movie