Unit 6 Equipment/Monitors: Ultrasound

Question 1

What does a piezoelectic crystal do?

Answer 1

Converts mechanical energy to electric energy and vice versa.

Question 2

What determines the brightness of each dot on an ultrasound screen?

Answer 2

amplitude of the returning signal.

Question 3

how do hyperechoic structures appear?

Answer 3

bright

Question 4

how do nerves appear under ultrasound?

Answer 4

nerves near the neuraxis tend to appear anechoic (black) and peripheral nerves are hyperechoic (white) with the characteristic honeycomb appearance.

Question 5

Define resolution

Answer 5

ability to see two separate things as two separate things

Question 6

name the three ultrasound axes?

Answer 6

axial
lateral
elevational

Question 7

describe the focal zone

Answer 7

where the bean is the narrowest

Question 8

describe the Fresnel zone

Answer 8

region between the transducer and the focal zone. aka near zone

Question 9

describe the Frauhofer zone

Answer 9

region beyond the focal zone aka far zone

Question 10

Describe attenuation

Answer 10

what happens as sound waves travel through the body their strength naturally decreases, and some sound waves never make it back to the ultrasound probe.

Question 11

Name some examples of attenuation

Answer 11

absorption
reflection
scatter
refraction

Question 12

What are the pros and cons of lower frequencies?

Answer 12

an see deeper inside the body but this depth comes at the sacrifice of image resolution.

Question 13

What are the pros and cons of higher freqencies?

Answer 13

Better image resolution but comes at the expense of not being able to see as deep.

Question 14

Describe gain

Answer 14

ability to adjust the strength of the returning echoes displayed on the screen

Question 15

What is B-mode?

Answer 15

B stands for brighness. B mode imagine produces real time image of the sonoanatomy. This is the mode most often used for bedside ultrasound procedures.

Question 16

What is M-mode?

Answer 16

M mode is an alternative ultrasound modality. This is like a time-lapse photo that illustrates the relative movement of structures over time.

Question 17

Describe the Doppler effect.

Answer 17

When there is relative motion between a sound’s source and an observer. Ie. ultrasound probe.

Question 18

Describe positive and negative doppler shifts.

Answer 18

Positive is a shift towards the ultrasound probe, and negative is a shift away. Positive appear red under ultrasound and negative are blue.

Question 19

Describe the angle of insonation

Answer 19

if ultrasound probe is perpendicular to blow flow it will not appear red or blue.

if angle of insonation is > 90 degrees the color dopler result will the the opposite of actual blood flow direction

If angle of insonation is < 90 degrees the color flow will match actual blood flow direction

Question 20

which angle of incidence is best to optimize image quality?

Answer 20

90 degrees between probe and structure being imaged, unless using doppler flow when the opposite is true.

Question 21

name the methods of transducer manipulation

Answer 21

tilt
rock
slide
compression
rotation

Question 22

name common ultrasound artifacts

Answer 22

air
shadow
acoustic enhancement
mirror image
reverberation
bayoneting

Question 23

name the three standard imaging windows of a basic cardiac exam

Answer 23

parasternal
apical
subcostal

Question 24

name the five views of a basic cardiac exam

Answer 24

parasternal long axis
parasternal short axis
apical 4 chamber
subcostal 4 chamber
subcostal IVC

Question 25

how is lung sliding imagine useful?

Answer 25

It can help diagnose pneumothorax or endobronchial intubation

Question 26

how do you estimate gastric volume with ultrasound?

Answer 26

By measuring the cross-sectional area of the antrum at the level of the aorta when the pt is in the right lateral decubitus position

Question 27

What are a lines?

Answer 27

horizontal lines that result form reverberation artifact when the pleura acts as a strong reflector

Question 28

what are b lines?

Answer 28

vertical lines seen when imagine the lung and sometimes called tail lines. They can be a normal finding, but can also suggest pathology such as pulmonary edema.

Question 29

how do clear liquids appear on gastric ultrasound?

Answer 29

anechoic

Question 30

Gastric volume equation

Answer 30

27+14.6 x CSA - (1.28 x age in years)