Chap 20 Physics

Front 1

an error in imaging?

Back 1

artifact

Front 2

artifact include reflection?

Back 2

1. not real
2. not seen on the image
3. not of correct shape or size
4. not in correct position
5. not of correct brightness

Front 3

violation of assumptions and equipment malfunciton or poor design cause___?

Back 3

artifacts

Front 4

the physics of ultrasound and operator error cause____?

Back 4

artifacts

Front 5

ultrasound image are discribed by_______?

Back 5

1. hyperechoic
2. hypoechoic
3. anechoic
4. isoechoic
5. homogeneous
6. heterogeneous

Front 6

brighter image than sounding tissues?

Back 6

hyperechoic

Front 7

not brighter image than surroundin tissues?

Back 7

hypoechoic

Front 8

equal echo brightness?

Back 8

isoechoic

Front 9

tissue or image that has similar echo characteristics?

Back 9

homogeneous

Front 10

tissue or image that has differing echo characteristics?

Back 10

heterogeneous

Front 11

six assumptions of imaging system?

Back 11

1. sound travel in a straight line
2. sound travels directly to a reflector and back
3. sound travel at 1,540m/s
4. reflection arises from beam's main axis
5. the image plane is very thin
6. the strength of reflection is related to characteristics of the tissue creating the reflection

Front 12

artifact_____and disappear in some views?

Back 12

appear

Front 13

actual anatomy always remains___?

Back 13

visible

Front 14

reverberation appears on the display when _____?

Back 14

multiple, equally spaced echoes

Front 15

bouncing of the sound wave betweeen two strong reflectors positioned parellel to the ultrasound beam cause_____?

Back 15

multiple, equally spaced echoes

Front 16

sound travels directly to a reflector and back, is invalid that causes_____?(assumption 2)

Back 16

reverberation

Front 17

characteristics of reverberation?

Back 17

1. appears in multiples
2. appears as equally spaced
3. located parallel to the sound beam's main axis
4. increasing depths

Front 18

reverberation artifact places____?

Back 18

many reflections on the image

Front 19

the first and second reflection, closest to the transducer, are____?

Back 19

real

Front 20

reverberations resemble a____?

Back 20

ladder or Venetian blind

Front 21

comet tail artifact described as____?

Back 21

reverberation with the spaces squeezed out

Front 22

comet tail artifact appears as___?

Back 22

solid hyperechoic line directed downward

Front 23

comet tail artifact also known as____?

Back 23

ring down artifact

Front 24

closely spaced reverberations emerge causes_____?

Back 24

comet tail artifact

Front 25

if the reflecting surfaces in a medium with a very high propagation speed, then____?

Back 25

comet tail artifact appears

Front 26

comet tail artifact also arises from____?

Back 26

resonance, vibration, of small structure like gas bubbles

Front 27

sound travels directly to a reflector and back, is invalid that causes___? (assumption 2)

Back 27

comet tail artifact

Front 28

characteristics of comet tail artifact?

Back 28

1. appears as a single long hyperechoic echo
2. located parallel to the sound beam's main axis

Front 29

shadowing appear as a_____?

Back 29

hypoechoic or anechoic downward from strong attenuating medium

Front 30

shadow has the same color as____?

Back 30

image background

Front 31

shadowing prevents the display of____?

Back 31

true anatomic structure

Front 32

if the attenuation is higher in the tissue above the shadow than in the surrounding tissue, then____?

Back 32

shadows appear

Front 33

(assumption 6), the intensity of a reflection is related to the tissue creating the reflection, is invalid that cause___?

Back 33

shadow

Front 34

characteristics of shadowing?

Back 34

1. hypo or anechoic (background color)
2. too much attenuation
3. abnormally high attenuation
4. prevents visualization of true anatomy on the scan

Front 35

shadow provides____?

Back 35

diagnostic information

Front 36

shadowing is unrelated to___?

Back 36

the speed of sound in a medium

Front 37

edge shadow artifact appears as____?

Back 37

hypoechoic region extending along the edge of a curved reflector

Front 38

hypoechoic region are the same color as___?

Back 38

image background

Front 39

edge shadow artifact prevents the display of____?

Back 39

true anatomic structures within hypoechoic region

Front 40

the decrease in intensity causes_____?

Back 40

edge shadowing

Front 41

edge shadowing also called___?

Back 41

shadowing by refraction

Front 42

(assumption 6), the intensity of a reflection is related to the characteristics of tissue creating the reflection, is invalid that causes____?

Back 42

edge shadow

Front 43

characteristics of edge shadow?

Back 43

1. hypo-or anechoic background color
2. results when the beam spread after striking a curve reflector
3. extend downward from the curved reflector's edge, parallel to the beam
4. prevents visualization of true anatomy on the scan

Front 44

enhancement artifact appears___as a?

Back 44

hyperechoic with abnormally low attenuation

Front 45

hyperechoic regions are the same color as___?

Back 45

the foreground or echoe of the image