Artifacts, Quality Assurance & Bioeffects

Question 1

You are most likely to encounter the range ambiguity artifact in Doppler under which of the following conditions

Answer 1

Pulsed wave Doppler, PRF 22 kHz, 3 MHz Doppler frequency

Question 2

From a SAFETY standpoint, which one of the following methods is the best

Answer 2

Low transmit output and high receiver gain

Question 3

Sometimes this can be interpreted as an additional vessel which has a spectrum similar to that of the real vessel.

Answer 3

Doppler Mirror Image

Question 4

When you increase the PRF in an attempt to solve the problem of aliasing, you can encounter

Answer 4

Range Ambiguity

Question 5

An artifact that gives rise to a double or duplicated image is called

Answer 5

Split Image / Refraction

Question 6

The most likely cause for a beam thickness artifact is

Answer 6

Volume Averaging

Question 7

With this artifact, the correct number of echoes appear on the image; there is less than average attenuation of a structure; and the artifact is parallel to the sound beam

Answer 7

Enhancement

Question 8

This artifact causes a sound beam to bounce off a reflector and be redirected. It places the artifact deeper than the true reflector

Answer 8

Mirror Image

Question 9

This artifact places structures much closer to the surface than they should be.

Answer 9

Propagation Speed Error

Question 10

With this artifact, there is high attenuation, absence of true anatomy on the scan, and structures that lie deeper than the original structure are not imaged

Answer 10

Shadow

Question 11

The most common type of artifact encountered in patients with a shotgun wound is

Answer 11

Commet Tail Artifact

Question 12

At this point, aliasing begins

Answer 12

The Nyquist Limit

Question 13

With this color representation, low velocity red is separated from low velocity blue by a black line

Answer 13

Flow Reversal

Question 14

With this color representation, high velocity red and high velocity blue are shown directly next to one another with no black line in between

Answer 14

Aliasing

Question 15

If the wires in an AIUM test object do not appear in the same place as on the display, what is the issue

Answer 15

Registration Accuracy

Question 16

A shadow artifact occurs behind a gallstone as a result of

Answer 16

Higher than usual attenuation

Question 17

True or False: If sound is traveling faster than the machine expects, it places the structure shallower than it should be

Answer 17

True

Question 18

A quality assurance program is:

Answer 18

Needed by all labs

Question 19

The force exerted by a sound beam on an absorber or a reflector is called

Answer 19

Radiation Force

Question 20

• Explain the ALARA principle.
• What does ALARA stand for?
• How can we observe the principle for which ALARA stands (give at least 3 examples)

Answer 20

-Power is set AS LOW AS REASONABLY ACHIEVABLE (while still getting diagnostic information).
-As Low As Reasonably Achievable.
-See below:
Minimize exposure time (but perform a complete diagnostic exam).
Use minimum output power & highest receiver gain required to produce optimal images.
Do not prolong studies without reason.
Do not perform studies without reason.

Question 21

Which of the following best describes an ideal epidemiologic bioeffects study

Answer 21

Randomized and prospective

Question 22

All of the following statements regarding in-vitro bioeffects are true EXCEPT:

Answer 22

In vitro bioeffects conclusions are clinically relevant

Question 23

Two things that can help reduce grating lobes are

Answer 23

The two things are subdicing and apodization

Question 24

True or False: A mirror image artifact can appear along side of the true anatomy

Answer 24

False. This artifact is always deep to the true anatomy.

Question 25

True or False: No known bioeffects are proven to occur at the levels used in diagnostic ultrasound

Answer 25

True

Question 26

What is the highest SPTA intensity of an unfocused ultrasound wave where there have been no observed bioeffects

Answer 26

100 mW/cm2

Question 27

If the output of an US machine is calibrated in dB and the output is increased by 20 dB, the beam intensity is increased by

Answer 27

100 times

Question 28

Which type of artifact appears most commonly with highly reflective objects

Answer 28

Shadowing

Question 29

Of the following choices, which is considered most important for the sonographer with regard to bioeffects

Answer 29

Duration of study

Question 30

Which one of the following sets of properties of a test phantom is most relevant when assessing depth calibration accuracy

Answer 30

Reflector spacing & Propagation speed

Question 31

The temperature increase depends on what factors

Answer 31

- Applied intensity or power - Frequency (absorption is directly proportional to frequency) - Beam focusing - Tissue perfusion

Question 32

With this artifact, the correct number of echoes appear on the image; there is less than average attenuation of a structure; and the artifact is parallel to the sound beam

Answer 32

Enhancement

Question 33

An artifact that is produced from interaction of the incident beam with a curved surface and results in an acoustic shadow is

Answer 33

a refractive edge shadow artifact

Question 34

You are performing a QA test on an US system using a tissue equivalent phantom. You make an adjustment using a knob on the system console that changes the appearance of reflector brightness from fully bright to barely visible. You are evaluating what?

Answer 34

Sensitivity

Question 35

Which artifact has a grainy appearance and is caused by the interference effects of scattered sound

Answer 35

Speckle

Question 36

True or False: Generally, linear array transducers have excellent elevational resolution

Answer 36

False. The elements in a linear array transducers tend to be wide. This artifact can be rectified by using a one and a half dimensional array transducer, which makes thinner slices.

Question 37

Under which circumstances is cavitation most likely to occur

Answer 37

High pressure; low frequency

Question 38

The propagation speed of US in the AIUM test object is

Answer 38

1.54 mm/microsec

Question 39

At what location in a sound beam is the SPTA intensity the highest

Answer 39

The focal point

Question 40

True or False: Mirror image artifact is often seen around the pancreas

Answer 40

False

Question 41

How is range ambiguity artifact eliminated

Answer 41

Lower the PRF

Question 42

Side lobes are caused by the use of

Answer 42

single crystal transducers

Question 43

Grating lobes are caused by the use of:

Answer 43

Arrays

Question 44

A mirror image artifact is a result of the machine's assumption that

Answer 44

Sound travels directly to the reflector and then back to the transducer

Question 45

True or False: With transient cavitation, the bubble bursts.

Answer 45

True

Question 46

When producing an ultrasound image, all of the following assumptions are made except

Answer 46

all structures create reflections of equal magnitude