Diagnostic Imaging - Image Formation

Question 1

Ultrasound frequencies are above…

Answer 1

human hearing range

Question 2

Velocity is

Answer 2

frequency x wavelength

Question 3

There is an inverse relationship between

Answer 3

frequency and wavelength

Question 4

ultrasound transducers are assembled in an

Answer 4

array

Question 5

What is an array?

Answer 5

group of piezoelectric effects within transducer housing which causes currents to regenerate and produce images

Question 6

Electric current causes crystal to resonate at a certain frequency emitting…

Answer 6

an ultrasound wave of that frequency where the amount of returning echo produces an image

Question 7

Types of array determine…

Answer 7

the type of transducer

Question 8

Linear array transducers have a …. and are great for…

Answer 8

straight surface
great for tendons or rectal scans

Question 9

Curvilinear array transducers have a … surface, which increases…

Answer 9

curved, wider surface
increases surface area

Question 10

Phased array transducers are… and have a smaller… making it great for viewing …

Answer 10

blockier
footprint
between the ribs

Question 11

Why do we use gel when doing an ultrasound?

Answer 11

Sound cannot pass through air so gel is used as a coupling agent

Question 12

What types of frequencies can be found in a transducer/probe?

Answer 12

• single frequency
• range of frequencies
• multiple frequencies simultaneously

Question 13

What happens to the ultrasound beam inside the patient?

Answer 13

Reflection
Refraction
Absorption

Question 14

What is axial resolution?

Answer 14

the higher the frequency, the greater the resolution, the poorer the depth penetration

low frequency, lower resolution, better penetration

Question 15

what is the most ideal for axial resolution?

Answer 15

use the highest MHz with the best resolution of the image created

Question 16

Higher frequency means

Answer 16

a thinner beam which means better lateral resolution

Question 17

The focal point is …

Answer 17

the narrowest area of beam making for better lateral resolution

Question 18

After the focal point, the beam gets

Answer 18

wider, leading to worse resolution

Question 19

What are the various modes of scanning?

Answer 19

A- mode (aptitude)
B-Mode (brightness)
M-mode (Motion)

Question 20

In B-mode, the brightness is proportional to…

Answer 20

the strength of the echo

Question 21

B-mode is used to evaluate…

Answer 21

tissue echotexture

Question 22

Define: Anechoic

Answer 22

Without echoes
appears black

Question 23

Define: hypoechoic

Answer 23

some echoes present
appears dark grey

Question 24

Define: hyperechoic

Answer 24

large number of returning echoes
appears bright grey

Question 25

What is M-mode?

Answer 25

time against motion

Question 26

When is M-mode commonly used?

Answer 26

to assess the contractility of the heart

Question 27

What are some of the common controls found on an ultrasound machine?

Answer 27

depth frequency power gain TGC (time gain compensation) focus

Question 28

Depth on ultrasound allows you to

Answer 28

scan with the least depth of tissue between it and the transducer

Question 29

When should frequency be changed on ultrasound?

Answer 29

based on the depth of the tissue

Question 30

What does power control on ultrasound?

Answer 30

general brightness of an image

Question 31

higher power means

Answer 31

a stronger beam

Question 32

too high of power means there are

Answer 32

more artefacts w/ meaningless echoes displayed in the image

Question 33

too low of power means

Answer 33

the returning echoes are not strong enough to create an adequate image so the image is too dark

Question 34

Power does not..., it just...

Answer 34

change the beam itself amplifies the signal of returning echoes.

Question 35

What does TGC do?

Answer 35

each slider controls signal amplification within the corresponding band in the image

Question 36

TGC can be adjusted to achieve

Answer 36

even brightness

Question 37

Altering the focus on ultrasound allows you to

Answer 37

focus an area of interest and improve resolution

Question 38

The focus is the ...

Answer 38

narrowest point of the beam

Question 39

Narrower beam means

Answer 39

higher resolution

Question 40

What types of artefacts can be found on ultrasound?

Answer 40

reverberations comet tails acoustic shadowing acoustic enhancement edge shadowing mirror image side lobe artifact other...

Question 41

What type of artefact is demonstrated here?

Answer 41

Reverberations

Question 42

What artefact is present here?

Answer 42

Comet tails

Question 43

What artefact is present here?

Answer 43

Acoustic Shadowing

Question 44

What artefact is present here?

Answer 44

Acoustic enhancement

Question 45

What artefact is present here?

Answer 45

Edge shadowing

Question 46

What artefact is present here?

Answer 46

Mirror image

Question 47

What artefact is present here?

Answer 47

Side lobe artefact

Question 48

What is doppler used for?

Answer 48

to measure movement, usually blood flow

Question 49

What are the different types of doppler?

Answer 49

- color flow doppler - continuous wave - pulsed wave - power doppler

Question 50

What does color flow doppler show?

Answer 50

color-codes the direction of flow

Question 51

What type of doppler uses this? What does it mean?

Answer 51

Color-flow doppler Blue away, red towards blue takes longer to move away from you, red means it is coming towards you/the probe Tells you the direction of the flow of blood

Question 52

When using color flow doppler, what can it measure?

Answer 52

how long it is expected for blood to move vs how long it actually takes.

Question 53

when using color flow doppler, what is important to remember?

Answer 53

you must have the probe pointed parallel to the blood flow you are looking at.

Question 54

Continuous wave doppler shows the

Answer 54

direction and velocity of flow

Question 55

pulsed wave doppler shows

Answer 55

the direction and velocity of lower velocity flow in a limited 'gate' area

Question 56

What type of doppler is demonstrated here?

Answer 56

Pulsed wave doppler

Question 57

What should you remember when using PW and CW dopplers?

Answer 57

blood flow velocity cannot be overestimated, only underestimated

Question 58

Power doppler shows

Answer 58

flow and movement

Question 59

power doppler is good for viewing

Answer 59

vascularity in tumors

Question 60

What is an exception to a power doppler?

Answer 60

it does not give velocity or direction, but rather that there is flow

Question 61

Which doppler has an audible sound?

Answer 61

Power doppler