Week 14 Real Time Imaging

Question 1

What is Frame rate?

Answer 1

The system’s ability to create numerous frames each second.
Number of frames per second.

Question 2

What is Frame Rate determined by?

Answer 2

1. Sounds speed in a medium
2. Depth

Question 3

What are the units of Frame rate?

Answer 3

Hz

Question 4

What is temporal resolution?

Answer 4

Pertains to accuracy in time. The ability to precisely position moving structures from instant to instant.

Question 5

What is Temporal Resolution determined by?

Answer 5

Frame Rate

Question 6

What is the unit for Temporal resolution?

Answer 6

Hertz or “per second”

Question 7

How many lines of sound are needed to create 1 frame?

Answer 7

100

Question 8

How are frame rate and time for one frame related (T frame)?

Answer 8

Inverse and reciprocal

Question 9

What is the formula for T frame?

Answer 9

Tframe x Frame rate = 1

Question 10

When an ultrasound system creates an image in 1/10 of a second, what is the frame rate?

Answer 10

10 Hz or 10 frames per second.

Question 11

When an ultrasound creates an image in 1/50th of a second, what is the frame rate?

Answer 11

50 Hz or 50 frames per second.

Question 12

What 2 system settings affect frame rate?

Answer 12

1. imaging depth
2. number of pulses per frame

Question 13

What determines a high frame rate?

Answer 13

Displaying a high number of images per second.

Question 14

What determines a low frame rate?

Answer 14

Displaying a low number of images per second.

Question 15

How are temporal resolution and frame rate related?

Answer 15

Directly

Question 16

What improves temporal resolution, High or Low frame rate?

Answer 16

High frame rate improves temporal resolution.

Question 17

How are imaging depth and frame rate related?

Answer 17

Inversely

Question 18

Does shallow imaging improve or degrade temporal resolution?

Answer 18

improves temporal resolution

Question 19

Does deeper imaging improve or degrade temporal resolution?

Answer 19

Degrades temporal resolution

Question 20

What is the formula for T frame?

Answer 20

T frame = # of pulses x PRP

Question 21

An ultrasound system creases each image with 100 distinct sound pulses. Each pulse travels to a maximum depth that requires a round trip time (PRP) of 1/1000 second. What is the time needed to make a single frame?

Answer 21

100 x 1/1000 = 1/10 second

The frame rate is 10 Hz

Question 22

Now, the sonographer decreases the depth of view by half. The PRP will be .5/1000. Since the image still requires 100 pulses, what is the T frame now?

Answer 22

100 x .0005 second
.05 or 1/20 second

Frame rate = 20 Hz.

Question 23

Shallow imaging

Answer 23

1. Short go-return time
2. Shorter T frame
3. Higher frame rate
4. superior temporal resolution

Question 24

Deeper imaging

Answer 24

1. Long go-return time
2. Longer T frame
3. Lower frame rate
4. Inferior temporal resolution

Question 25

What 3 factors determine number of pulses per frame?

Answer 25

1. number of focal points 2. Sector size 3. line density

Question 26

A Multi focus transducer has what?

Answer 26

1. Many pulses per scan line 2. Longer T Frame 3. Lower frame rate 4. diminished temporal resolution 5. improved lateral resolution

Question 27

A Single Focus transducer has what?

Answer 27

1. One pulse per scan line 2. Shorter T frame 3. higher frame rate 4. Better Temporal resolution 5. Poorer lateral resolution

Question 28

Narrow sector size has:

Answer 28

1. few pulses per frame 2. shorter T frame 3. Higher Frame Rate 4. Superior Temporal resolution

Question 29

Wide sector size has:

Answer 29

1. more pulses per frame 2. longer T frame 3. lower frame rate 4. inferior temporal resolution

Question 30

Wide Line density has:

Answer 30

1. widely spaced lines 2. fewer pulses per frame 3. Shorter T frame 4. higher frame rate 5. Higher temporal resolution 6. Poor spatial resolution

Question 31

Hight Line Density has:

Answer 31

1. tightly packed lines 2. More pulses per frame 3. Longer T frame 4. Lower frame rate 5. Low temporal resolution 6. excellent spatial resolution

Question 32

What is the advantage of high line density?

Answer 32

The gaps between the lines are smaller therefore improving the accuracy of each individual image.

Question 33

What is line density?

Answer 33

The spacing between sound beams.

Question 34

Sector size requires what?

Answer 34

more pulses to create an image.

Question 35

Temporal resolution is better when:

Answer 35

1. shallow imaging 2. single focus 3. narrow sector 4. low line density

Question 36

Temporal resolution degrades with:

Answer 36

1. deeper imaging 2. multiple focal points 3. wide sector 4. high line density

Question 37

Lateral resolution improves with....?

Answer 37

Multi-focusing

Question 38

Spatial resolution improves with...?

Answer 38

Higher line density