Pulsed Ultrasound and Imaging

Question 1

What is pulse?

Answer 1

ultrasound energy that starts and stops again shortly after

Question 2

As pulse duration decreases, what happens to the frequency?

Answer 2

It increases

Question 3

What is pulse repetition frequency?

Answer 3

Number of transmit pulses per second

Question 4

What is the pulse echo prinicple?

Answer 4

Measure the time between transmission of transmit pulse and the reception of each echo, machine then calculates distance between probe and structure that causes the echo

Question 5

A large depth of penetration forces the US machine to use what?

Answer 5

low pulse repetition frequency (decreased rate of imaging)

Question 6

Is frame rate directly proportional to the PRF?

Answer 6

Yes

Question 7

Is frame rate directly proportional to the number of pulses required to produce each image?

Answer 7

No, inversely proportional

Question 8

What is temporal resolution?

Answer 8

The machines ability to satisfactorily image moving structures

Question 9

What is a linear probe useful for?

Answer 9

Flat surfaces

Question 10

Which probe has a wider field of view? Linear or curvy?

Answer 10

Curvy

Question 11

Explain the field of view for a phased array probe

Answer 11

Good field of view at depth but not superfically

Question 12

What is the footprint?

Answer 12

Contact area of the probe

Question 13

What is B mode?

Answer 13

Brightness
2D

Question 13

What is M mode?

Answer 13

Motion mode
1D

Question 13

What is A mode?

Answer 13

Amplitude mode
1D

Question 14

What is the piezoelectrial transducer?

Answer 14

Transmits electrical signal into acoustic energy and back again

Question 15

What is the pulse repetition period?

Answer 15

Time from beginning of one pulse to the beginning of the next pulse

Question 16

What does lens do?

Answer 16

Helps focus the beam and protect the transducer

Question 17

What does the housing of the probe do?

Answer 17

Acts as electrical insulator (protection)

Question 18

What does the backing on the transducer do?

Answer 18

Shortens pulse by removing vibrational energy

Question 19

What does the matching layers on the transducer do?

Answer 19

help transfer the ultrasound energy from the elements to the medium

Question 20

What does the acoustic absorber do?

Answer 20

prevent sound waves from reflecting off hard surfaces, which reduces the amount of airborne noise within a space

Question 21

What does the PZT do on the transducer?

Answer 21

Transmits electrical energy to acoustic energy and vice versa

Question 22

What is beam sweeping?

Answer 22

Process of moving the ultrasound beam across the field of view (linear/curvy use electronic sweeping by selecting new aperature)

Question 23

What is beam steering?

Answer 23

altering the angle of the ultrasound beam with respect to the transducer without moving the probe.

Question 24

How many elements are used to steer the beam in a phased array probe?

Answer 24

All elements

Question 25

How many elements are used to steer the beam in a linear probe?

Answer 25

A set of elements to produce a single beam

Question 26

How many KHz is ultrasound?

Answer 26

20KHz

Question 27

If we increase the ultrasound frequency, what happens to axial resolution?

Answer 27

Shortens pulse duration and improves axial resolution