2 Ch 14: Pulsed Echo Instrumentation

Question 1

What are the two major functions of the u/s system?

Answer 1

1. preparation and transmission

2. reception

Question 2

This u/s component transforms electrical energy into acoustic energy. During reception it converts the returning acoustic energy into electrical energy.

Answer 2

transducer

Question 3

The u/s component creates and controls the electrical signals sent to the transducer that generates sound pulses.

Answer 3

pulser and beam former

Question 4

The u/s component determines the amplitude, pulse repetition period, and pulse repetition frequency.

Answer 4

pulser

Question 5

This u/s component determines the firing delay patterns for phased array systems.

Answer 5

beam former

Question 6

This u/s component transforms the electrical signals from the transducer into a form suitable for display.

Answer 6

receiver

Question 7

This u/s component presents processed data.

Answer 7

display

Question 8

This u/s component archives the u/s studies.

Answer 8

storage

Question 9

This u/s component maintains and organizes the proper timing and interaction of the system’s components.

Answer 9

master synchronizer

Question 10

T/F? The pulser functions during reception.

Answer 10

FALSE, during transmission

Question 11

Synonyms for pulser voltage?

Answer 11

1. output gain
2. acoustic power
3. pulser power
4. energy output
5. transmitter output
6. power
7. gain

Question 12

Is the pulser voltage adjustable by the sonographer?

Answer 12

yes

Question 13

Can output power alone make an image of uniform brightness from top to bottom?

Answer 13

nope

Question 14

This is loosely defined as a random and persistent disturbance that obscures or reduces a signal’s clarity.

Answer 14

noise

Question 15

This is a comparison of the meaningful information in an image compared to the amount of contamination.

Answer 15

signal-to-noise ratio

Question 16

When the signal-to-noise ratio is high, the signal is much ___ than the noise and the image is of ___ quality.

Answer 16

stronger, high

Question 17

When the signal-to-noise ratio is low, the signal is much ___ and the image is of ___ quality.

Answer 17

lower, low

Question 18

How does transducer output affect noise?

Answer 18

Increasing power output also increases signal-to-noise ratio.

Question 19

The ___ determines the time between one voltage spike and the next (PRP).

Answer 19

pulser

Question 20

The beam former adjusts electrical spike voltages to reduce lobe artifacts in a process called…

Answer 20

apodization

Question 21

Modern beam formers use advanced microprocessor technology called a…

Answer 21

digital beam former.

Question 22

What are the advantages of a digital beam former?

Answer 22

1. softward programming
2. extremely stable
3. versatile

Question 23

The ___ protects the receiver components from the signals that are created for pulse transmission and directs the electrical signals from the transducer to the appropriate electronic and processing components.

Answer 23

switch

Question 24

The ___ prepares the information contained in minuscule signals for eventual display on the system’s monitor.

Answer 24

receiver

Question 25

What is the order of receiver operations?

Answer 25

1. amplification 2. compensation 3. compression 4. demodulation 5. reject

Question 26

During ___, each electronic signal returning from the transducer is made larger.

Answer 26

amplification

Question 27

T/F? Each signal undergoes an equal amount of amplification.

Answer 27

true

Question 28

T/F? Amplication alone can make an image of uniform brightness from top to bottom.

Answer 28

FALSE, cannot

Question 29

Is amplification adjustable by the sonographer?

Answer 29

yes

Question 30

Amplification is measured in units of...

Answer 30

decibels (dB)

Question 31

What's a typical value for amplification?

Answer 31

60-100 dB

Question 32

This is the process of improving the quality of a signal before it is amplified.

Answer 32

preamplification

Question 33

Preamplification occurs where?

Answer 33

in the transducer itself

Question 34

The receiver corrects for attenuation with a process called...

Answer 34

compensation

Question 35

T/F? Compensation creates an image that is uniformly bright from top to bottom.

Answer 35

true

Question 36

Is compensation adjustable by the sonographer?

Answer 36

yes

Question 37

Synonyms for compensation?

Answer 37

1. time-gain compensation (TGC) 2. depth gain compensation (DGC) 3. swept gain

Question 38

The depth at which variable compensation begins is known as the....

Answer 38

delay.

Question 39

Compensation corrects for the effects of increasing attenuation that result from increasing path length in the region of the...

Answer 39

slope.

Question 40

Reflections are maximally compensated by the u/s at the region of the...

Answer 40

knee.

Question 41

This region indicates the maximum amount of compensation that the receiver can provide.

Answer 41

far gain

Question 42

T/F? Compression is performed twice.

Answer 42

true

Question 43

This keeps the electrical signal levels within the accuracy range of the system.

Answer 43

compression

Question 44

This keeps an image's gray scale content within the range of detection by the human eye.

Answer 44

compression

Question 45

Is compression adjustable by the sonographer?

Answer 45

yes

Question 46

Synonyms of compression?

Answer 46

log compression, dynamic range

Question 47

Compression is reported in units of...

Answer 47

decibels (dB)

Question 48

This is a two-part process that changes the electrical signals within the receiver into a form more sutiable for display ona monitor.

Answer 48

demodulation

Question 49

This converts all negative voltages into positive voltages.

Answer 49

rectification

Question 50

This places a smooth line around the 'bumps' and evens them out.

Answer 50

smoothing or enveloping

Question 51

Is demodulation adjustable by the sonographer?

Answer 51

nope

Question 52

How does demodulation effect the image?

Answer 52

Trick question! It doesn't.

Question 53

This allows the sonographer to control whether low-level gray scale information within the data will appear on the displayed image.

Answer 53

reject

Question 54

Synonyms for reject?

Answer 54

threshold or suppression

Question 55

Is reject adjustable by the sonographer?

Answer 55

yes

Question 56

How does reject effect the image?

Answer 56

It effects only low-levels echoes, not bright echoes.

Question 57

Systems with ___ use only the high frequency part of the reflected pulse's bandwidth to create the superficial portion of the image.

Answer 57

dynamic frequency tuning

Question 58

This affects image brightness by altering the strength of the sound pulse that the transducer sends to the body.

Answer 58

output power

Question 59

Increasing output power improves the ___ because the meaningful diagnostic echoes become stronger while the noise level remains unchanged.

Answer 59

signal-to-noise ratio

Question 60

This alters the strength of the voltages in the receiver that the transducer created during reception.

Answer 60

receiver gain (amplification)

Question 61

T/F? Increasing amplification does not alter the signal-to-noise ratio.

Answer 61

true, both signals and noise are treated identically

Question 62

Patient exposure to sound energy is affected by alteration in ___ but not by changes in ___.

Answer 62

output power, amplification

Question 63

ALARA stands for...

Answer 63

As Low As Reasonably Achievable

Question 64

If the image is too dark, first increase the ___ which does no increase patient exposure.

Answer 64

receiver gain

Question 65

If the image is too bright, first decrease the ___ which decreases patient exposure.

Answer 65

output power