Study guide Ch 21,22,23:test 4

Question 1

What describes portions of an image that are brighter than surrounding tissues or tissues that appear brighter than normal?

Answer 1

hyperechoic

Question 2

What describes images that are not as bright as surrounding tissues or appear less bright than normal?

Answer 2

hypoechoic

Question 3

What describes a structure without echoes?

Answer 3

anechoic

Question 4

What describes a tissue or structure that has a similar echo throughout?

Answer 4

isoechoic

Question 5

What describes a tissue displaying a variety of different echogenic characteristics?

Answer 5

heterogeneous

Question 6

What are considered errors in imaging?

Answer 6

reverbation, comet tail, shadow & edge shadow, enhancement & focal enhancement, mirror image & cross talk, curved & oblique reflectors, temporal resolution, spatial resolution, speed error, lobes: side & grating lobes, refraction, slice thickness, lateral resolution, axial resolution, multipath, range ambiguity, noise: speckle & clutter

Question 7

Equipment malfunction and design, the physics of ultrasound, and operator error: what are these called?

Answer 7

causes of artifacts

Question 8

Multiple, equally spaced, parallel lines: what does this describe?

Answer 8

characteristics of reverberation

Question 9

Which artifact is unrelated to the dimensions of an ultrasound pulse?

Answer 9

refraction

Question 10

Which artifact produces an image with an incorrect number of reflectors side by side?

Answer 10

side lobes

Question 11

What does not result in the placement of too many echoes on the image?

Answer 11

shadowing

Question 12

What does not result from multiple reflections?

Answer 12

enhancement

Question 13

Two distinct reflections are observed on an image, but they actually arise from a single anatomic structure. The artifact is positioned deeper than the correct reflection. What is the most likely cause of this artifact?

Answer 13

mirror image

Question 14

Two reflections, side by side, only one is real. What is most likely the cause of this artifact?

Answer 14

refraction

Question 15

Which artifacts create one reflection on an image from two closely spaced reflectors?

Answer 15

axial resolution

Question 16

When the beam dimention is greater than the reflector size, what type of artifact can occur?

Question 17

What are lobes created by array transducers called?

Answer 17

grating lobes

Question 18

What methods can be used to eliminate lobe artifacts?

Answer 18

subdicing and apodization

Question 19

A single, solid, hyperechoic line parallel to the sound beam with no spaces in the echogenic line is what artifact?

Answer 19

comet tail

Question 20

What artifact occurs when the beam is unable to pass through a structure?

Answer 20

shadowing

Question 21

Refraction at the end of a circular structure can cause what artifact?

Answer 21

edge shadow (shadowing by refraction)

Question 22

What artifact occurs when there is too much gain in the focal zone?

Answer 22

focal enhancement

Question 23

What artifact occurs when the medium to which the sound travels has a lower attenuation rate than soft tissue?

Answer 23

speed error

Question 24

Which artifact occurs when you see reflectors at incorrect depths?

Answer 24

speed error

Question 25

When propagation speed is greater than 1,540 m/s, the reflector will be placed to what on the display?

Answer 25

reflectors are too shallow on the image

Question 26

Grading lobes are caused by which type of transducer?

Answer 26

array transducers

Question 27

What artifact can be cured by lowering the PRF?

Answer 27

range ambiguity

Question 28

Which artifact is only found with doppler?

Answer 28

cross talk

Question 29

A grainy appearance not directly from tissues created by interference is called what?

Answer 29

speckle

Question 30

If the media in which the ultrasound travels doesn't propagate at 1,540 m/s, then the assumed relationship between time and distance is invalid. What artifact occurs?

Answer 30

speed error (range error artifact)

Question 31

Propagation speed errors appear as a what?

Answer 31

a step off

Question 32

What are errors in imaging?

Answer 32

not real not seen on the image incorrect shape or size incorrect position incorrect brightness

Question 33

What are causes of artifacts?

Answer 33

violation of assumptions equipment malfunction or poor design the physics of ultrasound operator error

Question 34

What are the two causes for crosstalk?

Answer 34

Doppler gain is set too high incident angle is near 90° between the sound beam and the flow direction, when flow is at the beam's focus

Question 35

What is color flash also referred to as?

Question 36

What are wall filters used to reject?

Question 37

If the path to a reflector is of a different length than the returning path, the reflector will be in an incorrect position, it results in general image degradation. What artifact is it?

Answer 37

speed error

Question 38

What produces shadowing?

Answer 38

attenuation is higher in the tissues above the shadow

Question 39

Where does enhancement appear on an image?

Answer 39

beneath tissues with abnormally low attenuation

Question 40

Which transducer may have poor elevational resolution?

Question 41

What term is defined by avoidance of unnecessary risk, harm or needless injury?

Answer 41

nonmaleficence

Question 42

What provides the basis for an informed consent?

Answer 42

autonomy

Question 43

When can a patient revoke consent?

Answer 43

at any time

Question 44

What is the first action when a sonographer enters a patient's room?

Answer 44

intorduce themselves to the patient

Question 45

What is the study between a worker and their environment called?

Answer 45

ergonomics

Question 46

What standard is best used in a quality assurance program?

Answer 46

objective

Question 47

All of the following are characteristics of a tissue equilavent phantom except:

Answer 47

density similar to that of soft tissue

Question 48

What form of resolution is evaluated by measuring the width of reflections arising from small, point targets?

Answer 48

lateral resolution

Question 49

What form of resolution is evaluated by visualizing closely spaced pins that are parallel to the sound beam's main axis?

Answer 49

axial resolution

Question 50

At what interval should quality assurance evaluations be performed?

Answer 50

routinely