Basic Instrumentation

Question 1

The machine will process stored voltages to do what

Answer 1

it will convert them and this will reconstruct the image from the reflectors in the body

Question 2

Pulser

Answer 2

Sends the voltage pulse to the probe which will determine the: PRF,intensity and operating frequency

Question 3

Range ambiguity is controlled by the?

Answer 3

Pulser

Question 4

Pulse delays

Answer 4

Applies the delays ness art to accomplish focusing, beam steering and aperture size

Question 5

Aperture size

Answer 5

How many crystals in a group that will be fired

Question 6

Transmit/receive switch

Answer 6

Directs the pulse in the correct direction to protect the sensitive components from large voltage pulses

Question 7

Transducer

Answer 7

What sends the pulse into the pulse when it receives it from the transmit receive switch

Question 8

Amplifiers

Answer 8

Amplifies the weak pulses that return from the patient so that the pulses can make it through the entire circuit

Question 9

ADC

Answer 9

Analog to digital converter

Pulses pass through this and are converted from analog to digital so they can be stored in the memory

Question 10

Why is storing the voltages useful

Answer 10

Allows for manipulation of the image later on

Question 11

Is the information lost in the process of analog to digital significant

Answer 11

No

Question 12

Echo delays

Answer 12

Holds the first echo so all the other echos can catch up, so they are all in phase

Question 13

Sum

Answer 13

Adds together the pulses from each element in the segment to form the resulting scan line

Question 14

Why is digitation of the voltage crucial

Answer 14

Maintains the integrity of the data throughout the system

Question 15

This process involves converting the voltage into a binary number

Answer 15

Digitization

Question 16

Is a voltage or a binary number more stable

Answer 16

Binary number

Question 17

When can digitization occur

Answer 17

Before or after the echo delay in the beam former

Question 18

When is digitization preferred

Answer 18

Before the echo delay so the signal is stabilized early on

Question 19

What are the two processes in signal processing

Answer 19

ADC

Receiver

Question 20

What is the function of the receiver

Answer 20

Process the returned echoes as analog voltages in preparation for display

Question 21

What are the five steps to the receiver

Answer 21

Amplification 
Compensation
Compression
Rejection 
Demodulation

Question 22

Amplification

Answer 22

Is the gain control
Amplifies weak return echos so they can complete the entire circuit
Can control the amount to brighten or darken the image

Question 23

What is gain expressed in and what is the typical range

Answer 23

Decibels and it ranges from 60-100 dB

Question 24

What does compensation do

Answer 24

It helps compensate for the attention of sound as it travels

Question 25

Why is there a need for compensation

Answer 25

Similar signals from reflectors should have the same echogenisty regardless of the depth the reflector is imaged from

Question 26

What control is related to compensation and how is it expressed as well as what is the range

Answer 26

TGC | Expressed in decibels and has a range of approx. 60dB

Question 27

What’s another name for TGC

Answer 27

DGC-depth gain compensator

Question 28

How does TGC operate and what does it correct for

Answer 28

Usually in one cm increments | Corrects for the main bang artifact and attention in the far field

Question 29

Main bang artifact

Answer 29

As soon as the sound leaves the transducer it hits the skin of patient and sound energy is lost

Question 30

What does compression do and how is it accomplished

Answer 30

Decreases the difference between the smallest and largest amplitudes Accomplished by using a logarithmic amplification

Question 31

Compression is also known as what

Answer 31

Dynamic range

Question 32

How is compression expressed

Answer 32

In decibels

Question 33

What is the reject level

Answer 33

Smallest amplitudes

Question 34

What is the saturation level

Answer 34

Largest amplifications

Question 35

What is logarithmic amplification

Answer 35

The gain applied exponentially as a function of the input signal level and it results in the compression of the dynamic range

Question 36

Dynamic range

Answer 36

Reduces the number of shades of grey into range of shades that are more distinct from one another

Question 37

What does rejection do

Answer 37

Eliminates or suppresses low level echoes that may represent noise, improves the signal to noise ratio

Question 38

What does rejection help with and is it operator controlled

Answer 38

Reducing the dynamic range | May or may not be operator controlled

Question 39

What else is rejection known as

Answer 39

Threshold of suppression

Question 40

What is the demodulation process

Answer 40

Converts radio frequency signal into a video signal for monitor display

Question 41

What are the two stages of demodulation

Answer 41

Rectification and smoothing

Question 42

Rectification

Answer 42

Turns all negative portions of a single into positive portions

Question 43

Smoothing

Answer 43

Also called enveloping | Filters the signal to smooth out the bumps

Question 44

Scan conversion

Answer 44

Writes vertically acquires ultrasound data horizontally to the memory

Question 45

How does the analog scan converter differ from the CRT

Answer 45

Replaces the phosphor face with a dielectric matrix

Question 46

Dielectric matrix

Answer 46

A wafer of silicon

Question 47

What is the scan converter also known as

Answer 47

The memory

Question 48

electron beam moves across the dielectric matrix in what kind of format

Answer 48

raster

Question 49

what is pre-processing

Answer 49

any processing of the wave signal before it is transferred and stroed in the memory

Question 50

do different ultrasound machines use different processing

Answer 50

yes

Question 51

what are some pre-processing functions

Answer 51

``` receiever functions maps interpolation edge enhancement write zoom persistance ```

Question 52

what are maps

Answer 52

curves applied to the shades to accentuate different levels

Question 53

what is the purpose of maps

Answer 53

to enhance the visualization of certain aspects of the image

Question 54

what does interpolation do

Answer 54

averages pixel grey scal values and fills in the noexistant information

Question 55

what does interpolation improve and is there a trade off

Answer 55

improves the apperance but it creates the "what is real" question

Question 56

what can too much interpolation do

Answer 56

misrepresent the image

Question 57

what is edge enhancement

Answer 57

sharpens the boundaries of an image to make them more distinguishable making measurments more precise improves the overall look of an image

Question 58

what is applied to an image to adchieve edge enhancement

Answer 58

a kernal

Question 59

what is write zoom

Answer 59

expands the image before storage in the memory

Question 60

what is another term for write zoom

Answer 60

regional expansion

Question 61

is the region of interst controlled by the sonographer

Answer 61

yes

Question 62

what is the advantage of the ROI

Answer 62

its rescanned and additional scan lines are added

Question 63

when additional scan lines are added what increases

Answer 63

spatial resoultion detail pixel ratio

Question 64

what is persistance

Answer 64

takes data from several frames and avearges them before displaying the image

Question 65

what does persistance improve

Answer 65

signal to noise ratio

Question 66

what will sampling over time do

Answer 66

will decreaser temporal resolution

Question 67

what must the be small so blurring does not occur

Answer 67

rate of movement

Question 68

when is persistance not used

Answer 68

obsetrical ad echocardiography

Question 69

what is post-processing

Answer 69

any processing that occurs after the information has been stored into the memory

Question 70

when is post processing applied

Answer 70

to a frozen image

Question 71

some post processing functions are

Answer 71

``` measuring annotations post processing curves read zoom colour doppler mapping angle correct b-colour ```

Question 72

curves can be applied to a frozen image in the assignment of what

Answer 72

display intensity to a digital scale

Question 73

is curves operator controlled and where is it accomplished in the machine

Answer 73

yes and in the DAC

Question 74

what is the most common curve used

Answer 74

linear

Question 75

what is the approx number of curves that eachmanufactor develops in accordance to their own hardware

Answer 75

~5-10

Question 76

what is read zoom

Answer 76

maginfies a frozen image by reassigning the pixel size

Question 77

what happens when read zoom is applied

Answer 77

a decrease in resolution

Question 78

what is the B-colour funtion

Answer 78

uses various colour schemes from oranges to purples to blues to be applied to each digital value instead of shades of grey

Question 79

Is the B-colour function operator controlled

Answer 79

yes

Question 80

what does the B-colour potentially improve

Answer 80

contrast resolution of the image

Question 81

what is the final step of image processing

Answer 81

the DAC reconverts the digital information into a voltage signal

Question 82

why is the information converted back into a voltage signal

Answer 82

because display systems will only accept a voltage

Question 83

what are the different voltages that a display system will accept

Answer 83

video | analog