APEX Ultrasound

Question 1

How fast does US propogate into tissues? What about sound into bone?

Answer 1

1540 m/sec
3000-5000 m/sec

Question 2

Frequency of sound wave

Answer 2

tells us the pitch
US frequency is range of 1-20 million far above the range we can hear
we can hear 20-20,000Hz

Question 3

Wavelength of sound waves

Answer 3

peak to peak
higher frequency decreases wavelength
lower frequency produces longer sound wave

Question 4

Amplitude

Answer 4

Sounds loudness in decibels

Question 5

Modern US employ a piezoelectric material called ___

Answer 5

lead zirconate titanate
can transduce electrical energy to mechanical energy and vice versa

Question 6

Vertical vs horizontal dot on the us screen

Answer 6

vertical- time delay
horizontal- the crystal it receives

Question 7

Hyperechoic

Answer 7

white
high amplitude echos
bones

Question 8

hypoechoic

Answer 8

grey
low amplitude
liver, skin, adipose, cartilage

Question 9

anechoic

Answer 9

black
no echo
cysts, ascites, vascular ascites

Question 10

absorption us

Answer 10

waves are lost to heat

Question 11

reflection us

Answer 11

sound wave bounces off a tissue boundary

Question 12

scatter ultrasound

Answer 12

sound wave encounters object smaller than the wave

Question 13

refraction us

Answer 13

bending of us that encounters a tissue boundary at an oblique angle

Question 14

Axial resolution

Answer 14

beam depth
improved by using a higher frequency
5/6 good
7/8 bad

Question 15

Lateral resolution

Answer 15

Beam width
1 and 2 good
3 and 4 bad

Question 16

Evaluation resolution

Answer 16

beam thickness

Question 17

3 zones in us beam

Answer 17

near
focal- best resolution z axis
far

Question 18

attenuation us

Answer 18

sound waves lose strength as it goes further into the body
this will decrease image quality
bone>soft>fluid
most to least attenuation
the result of 4 processes: absorption, reflection, scatter, refraction

Question 19

Short axis

Answer 19

looks in cross section
what you see in us iv machine

Question 20

long axis us

Answer 20

looks along the length

Question 21

When to use high vs low freq us

Answer 21

high- shallow organ with high res
low- deep organ w low res

Question 22

Different types of transducers

Answer 22

linear-flat- for organs with same width as transducer, accurate representation on screen
phased array-short- for deep organs
curvilinear- curved- signal is narrow on top but widens as it gets deeper

Question 23

Which setting controls strength of returning echoes

Answer 23

gain

Question 24

Depth US

Answer 24

how deep u can see into body

Question 25

US modes

Answer 25

M- motion
B- brightness

Question 26

What happens when the sound moves closer to the person listening?

Answer 26

wavelength gets shorter
Frequency (pitch) increases