Week 4 Ultrasound Flashcards Preview

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Flashcards in Week 4 Ultrasound Deck (20):
1

what frequency waves are audible by human ear?

20Hz to 20kHz

2

what frequency sound waves to ultrasound use?

20kHz to 20MHz

3

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

piezoelectric effect: allows ultrasond to work

4

what are the four type of US probes? Uses?

Linear (6-13 MHz): superficial

Curvilinear (2-5 MHz): abdomen

Phased array (1-5 MHz): cardiac

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

5

High frequency =

better resolution

 

6

low frequency =

better penetration

7

describe the process of US

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

8

sound waves can be (4)

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

9

what is attenuation?

the gradual loss of intensity

10

water has an attentuation of 0 what does this mean?

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

11

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

the signal is lost when passing through air

12

what are the modes of ultrasound

A mode

B mode

M mode

Pulse Wave Doppler

Color Doppler

Power Doppler

 

13

Q image thumb

A mode (used in opto)

14

Q image thumb

B-mode 

15

Anechoic, hyperchoic, hypochoic?

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 image thumb

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

17

Q image thumb

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

18

Q image thumb

pulse wave doppler

19

Q image thumb

M-mode "motion" can show breathing or heart tones

20

Q image thumb

A image thumb

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