wk 2. Sonographic Artifacts in MSK

Question 1

appears when highly reflective structures such as tendons appear hypoechoic rather than hyperechoic because the incidence sound beam is > or < 90 degrees.

Answer 1

anisotrophy

Question 2

anisotrophy occurs when the incident angle is NOT __ degrees

Answer 2

90

Question 3

___ artifact occurs when the beam is reflected, absorbed or refracted

Answer 3

posterior acoustic shadowing

Question 4

__ shadow occurs on small radius curvature or rough surface

Answer 4

clean

Question 5

__ shadow occurs on large radius of curvature or smooth surfaces

Answer 5

dirty

Question 6

also called “critical angle shadowing” or “edge shadowing”

Answer 6

refractile shadowing

Question 7

refractile shadowing occurs at ___

Answer 7

edge of highly curved surfaces

Question 8

change in direction of sound beam results in hypoechoic band posterior to structure

Answer 8

refractile shadowing

Question 9

Occurs deep to fluid filled structures

Answer 9

posterior acoustic enhancement

Question 10

“ring down artifact” or “comet tail artifact” is also called

Answer 10

posterior reverberation

Question 11

Series of reflect echoes is more continuous deep to structure

Answer 11

ring down

Question 12

short segment of posterior bright echoes, narrows further from the source of artifact

Answer 12

comet tail artifact

Question 13

seen with soft tissue gas

Answer 13

comet tail artifact

Question 14

seen with metal surfaces

Answer 14

ring down

Question 15

occurs when returning sound wave has been passed between two tissues with different speeds

Answer 15

time of flight (speed of sound) artifact

Question 16

time of flight artifact results from assumption that speed of sound is ___

Answer 16

constant (1540m/s)

Question 17

if the speed of sound is less than average in tissue, the artifact appears ___in relation to transducer

Answer 17

farther away

Question 18

faster speeds in tissue result in artifact being ___ in relation to transducer

Answer 18

closer to

Question 19

creation of this type of image false info occurs most commonly when imaging obese pts at muscle-fat interface

Answer 19

time of flight

Question 20

a strong reflector located outside the main US beam may generate echoes that are detectable by the transducer

Answer 20

beam-width artifact

Question 21

how to fix beam width artifact

Answer 21

adjust focal zone to level of the object of interest

Question 22

how to fix anisotrophy artifact

Answer 22

heel-toe rocking probe to create perpendicular angle of incidence on muscle

Question 23

how to fix reverberation artifact

Answer 23

use stand off pad or change angle of incidence

Question 24

how to fix refractile artifact

Answer 24

compound imaging or harmonics

Question 25

how to fix the time of flight artifact

Answer 25

change angle of incidence

Question 26

beams produced at different angles and combined to form a single US image

Answer 26

spatial compound imaging

Question 27

Disadvantage of spatial compound imaging

Answer 27

smoothing effect may reduce the artifact produced by a foreign body

Question 28

Evaluation of deep structures and improved joint/ tendon surface visibility. Delineates the edge of a soft tissue mass, fluid filled tendon tear

Answer 28

harmonic imaging

Question 29

combining image info obtained during real-time scanning to form one “composite” image

Answer 29

extended FOV

Question 30

allows imaging an entire structure no matter the length

Answer 30

extended FOV (panoramic)

Question 31

examples of uses for US guidance (4)

Answer 31

1. steroid injection
2. barbottage
3. lavage and aspiration
4. biopsy

Question 32

treatment for calcific tendonitis that breaks up the calcium deposits so they can be absorbed by the body

Answer 32

barbottage