Artifacts

Question 1

Reflection

Answer 1

Sounds ave strikes specular interface, rebounds off

Angle of incidence = angle of reflection

Question 2

Refraction / ghost image artifact cause

Answer 2

Sound wave bents as it passes through tissue with different sound velocity
Machine assumes straight line
Requires oblique incidence

Question 3

Refraction / ghost image artifact appearance

Answer 3

Structures misplaced laterally

Side by side double image

Question 4

Fixing refraction/ghost image

Answer 4

Angulation change

Question 5

Scatter

Answer 5

Waves scatter in many directions off small or rough objects

Higher frequency = increased scatter

Question 6

Reverberation artifact / multi path reflection artifact

Answer 6

Multiple, equal spaced echoes caused by wave bouncing between 2 strong reflects parallel to main beam
May look like rungs of a latter
Parallel to sound beam

Question 7

Fixing reverberation artifact

Answer 7

Angulation change

Contrast and color go through

Question 8

Comet tail artifact / ring down artifact

Answer 8

Closely spaced reverberations merge, causes single hyper echoic line
Parallel to main sound beam

Question 9

Near field reflection artifact cause

Answer 9

Strong acoustic signals close to transducer
Return signal reflected back off transducer, creates additional images
i.e. artifact at apex

Question 10

Near field reflection artifact fix

Answer 10

Contrast

Question 11

Shadow artifact cause

Answer 11

Hypoechoic / anechoic region below a structure causes strong attenuation
Reduction in strength of returning echo caused by intervening structure
Prevents display of true anatomic structures

Question 12

Shadow artifact fix

Answer 12

Change angle

Question 13

Enhancement artifact

Answer 13

Hyperechoic region below tissue with low attenuation

Opposite of shadowing

Question 14

Multipath duplication / mirror image artifact cause

Answer 14

Sound hits reflector and returns to transducer

Some of reflection bounces back at an angle and takes longer to come back, creating a separate deeper structure

Question 15

Multipath duplication / mirror image appearance

Answer 15

Appears as replica of true reflector (artifact always deeper)
Color is fooled

Question 16

Resolution artifact

Answer 16

2 reflectors that are closely spaced together appear as one

Question 17

Axial / longitudinal resolution

Answer 17

Differentiating objects parallel to or along long axis

Better with higher frequency

Question 18

Lateral resolution

Answer 18

Differentiating structures perpendicular to beam

Beam width is key

Question 19

Stitch artifact

Answer 19

3D image made by stitching together multiple cardiac cycles

Question 20

Velocity error artifact

Answer 20

Sound propagates through some structures at velocity other than 1540 m/s

Question 21

Lobe artifact cause

Answer 21

Strong reflector outside main beam may generate echoes detected by transducer

Question 22

Lobe artifact appearance

Answer 22

Misplaced echoes displayed as having originated within main beam
May overlap with normal structure

Question 23

Range ambiguity artifact appearance

Answer 23

Distal structure appears to float over cardiac structures, doesn’t move with them

Question 24

Range ambiguity cause

Answer 24

Structure distal to image with echoes returning from a different pulse

Question 25

Fixing range ambiguity

Answer 25

Increase depth or alter transducer position

Question 26

Linear artifact in ascending aorta

Answer 26

Reverberation More common when aortic diameter > LA diameter Moves with posterior aortic wall

Question 27

Beam width artifact / slice thickness artifact

Answer 27

Occur distal to focal zone where lateral resolution is worst | Lateral resolution degraded, may have alteration in size or shape of a structure

Question 28

Improving beam width artifact

Answer 28

Focusing

Question 29

PRF as imaging depth increases

Answer 29

PRF decreases

Question 30

Avoiding range ambiguity artifact

Answer 30

PRF is reduced when scanning deeper structrues

Question 31

Spectral doppler mirror-image artifact

Answer 31

Symmetric spectral images on opposite side of baseline from true signal created

Question 32

Reducing spectral doppler mirror-image artifact

Answer 32

Decrease power output or gain | Optimize angle between beam and doppler flow

Question 33

Distinguish LV thrombus from artifact

Answer 33

Increase frequency Decrease depth Using multiple views Use contrast

Question 34

Mirror image structure locations

Answer 34

Structure located in front of highly reflective surface

Question 35

Near field clutter artifact

Answer 35

High amplitude oscillations of piezoelectric elements | Affects near field of US beam

Question 36

Eliminating near field clutter artifact

Answer 36

``` Higher frequency Decreasing depth Changing views Contrast Harmonic imaging ```

Question 37

Figure of 8 artifact

Answer 37

From atrial septal occluder device | Looks like 8 in LA

Question 38

Shielding artifact

Answer 38

White echoes | Bright beam of ultrasound artifact that obscures visualization beyond that point

Question 39

Ghosting

Answer 39

Color doppler distorted beyond anatomic borders due to multiple reflections