Week 4 Ultrasound Flashcards Preview

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Flashcards in Week 4 Ultrasound Deck (20)
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1
Q

what frequency waves are audible by human ear?

A

20Hz to 20kHz

2
Q

what frequency sound waves to ultrasound use?

A

20kHz to 20MHz

3
Q

the ability of certain materials to generate an electric charge in response to applied mechanical stress

A

piezoelectric effect: allows ultrasond to work

4
Q

what are the four type of US probes? Uses?

A

Linear (6-13 MHz): superficial

Curvilinear (2-5 MHz): abdomen

Phased array (1-5 MHz): cardiac

Endoluminal (5-8 MHz): anal, vaginal, oral

5
Q

High frequency =

A

better resolution

6
Q

low frequency =

A

better penetration

7
Q

describe the process of US

A

electrical signal–>crystal–>sound wave–>tissue–>sound wave returns–>crystal–>electrical signal–>picture

8
Q

sound waves can be (4)

A

absorbed (bone), reflected (diaphragm, organs), scattered (air=bad), refracted

9
Q

what is attenuation?

A

the gradual loss of intensity

10
Q

water has an attentuation of 0 what does this mean?

A

the strenght of the singal does not change when passing through water

11
Q

air has an attenuation of 12, what does this mean?

A

the signal is lost when passing through air

12
Q

what are the modes of ultrasound

A

A mode

B mode

M mode

Pulse Wave Doppler

Color Doppler

Power Doppler

13
Q
A

A mode (used in opto)

14
Q
A

B-mode

15
Q

Anechoic, hyperchoic, hypochoic?

A

terms used with B mode US:

Anechoic: no echo produced, appear black, fluid (least dense)

Hypoechoic: some echo produced, appears gray, solid organs

Hyperechoic: alot of echo produced, appears white, dense solid strucutres bone (and air although it is white becuase it scatters)

16
Q
A

power doppler. good for low flow vessels. gives intesnity of flow

17
Q
A

color doppler. gives directionality of flow. red=coming towards, blue=going away

18
Q
A

pulse wave doppler

19
Q
A

M-mode “motion” can show breathing or heart tones

20
Q
A

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