Ch. 10-11 Physics

Question 1

Ability to create accurate images

Answer 1

resolution

Question 2

Measures the ability of the system to display two structures that are very close together with the structures parallel to the sound beams main axis

Answer 2

axial resolution

Question 3

Axial resolution is related to

Answer 3

pulse duration, spatial pulse length

Question 4

What pulses (in length and time) improve axial resolution

Answer 4

shorter

Question 5

What frequencies have better axial resolution

Answer 5

higher

Question 6

A short pulse is created in what 2 ways

Answer 6

less ringing (damping), higher frequency

Question 7

A pulse is short if there are few cycles in a pulse is referred to as

Answer 7

less ringing (damping)

Question 8

A pulse is short if each cycle in the pulse has a short wavelength is related to

Answer 8

higher frequency

Question 9

LARRD axial resolution

Answer 9

longitudinal, axial, range, radial, depth

Question 10

Image quality is better when axial resolution has a ____ numerical value

Answer 10

lower

Question 11

Better axial resolution is associated with what 5 things

Answer 11

shorter SPL, shorter PD, higher frequencies, fever cycles per pulse, lower numerical values

Question 12

Measures the ability of the system to display two structures that are very close together when they are ______ to the sound beams main axis is called ____

Answer 12

side-by-side/perpendicular, lateral resolution

Question 13

Lateral resolution LATA

Answer 13

lateral, angular, transverse, azimuthal

Question 14

Lateral resolution is determined by the beam

Answer 14

width

Question 15

Beam width caries with

Answer 15

depth

Question 16

Lateral resolution=

Answer 16

beam diameter

Question 17

When two side-by-side reflectors are ____ together then the ____ of the beam, only one reflector is observed on the image

Answer 17

closer, width

Question 18

____ frequencies improve axial and lateral resolution

Answer 18

higher

Question 19

Is improved in the entire image because shorter pulses are associated with high frequency sound

Answer 19

axial resolution

Question 20

Is improved at the focus AND in the far field because higher frequency pulses diverge less in the far field than low frequency pulses

Answer 20

Lateral resolution

Question 21

Concentrates the sound energy into a narrower beam and thus improves lateral resolution

Answer 21

focusing

Question 22

Three methods of focusing are

Answer 22

external, internal, phased array

Question 23

With a FIXED lens (in a fixed focus transducer)

Answer 23

external focusing

Question 24

In external focusing, the lens is placed

Answer 24

in front of the crystal

Question 25

With a curved active element ( in a fixed focus transducer)

Answer 25

internal focusing

Question 26

Use of a curved crystal

Answer 26

internal focusing

Question 27

With the ELECTRONICS of the ultrasound system

Answer 27

phased array focusing

Question 28

Phased array focusing is used only on ______ element transducers and never on a single element transducer

Answer 28

multiple active

Question 29

A sound beam undergoes four distinct modifications when focused:

Answer 29

near field beam diameter and focal zone are reduced, focal depth is shallower, beam diameter in far zone increases, size of focal zone smaller

Question 30

When focused, a sound beam diameter in the near field and focal zone is

Answer 30

narrowed/reduced

Question 31

When focused, a sound beam focal depth is

Answer 31

shallower

Question 32

When focused, a sound beam diameter in the far zone

Answer 32

increases

Question 33

When focusing, a sound beam the size of the focal zone is

Answer 33

smaller

Question 34

What are the determinants of sound beams

Answer 34

frequency in cw transducers, frequency in pw transducers, focal length, beam divergence, lateral resolution

Question 35

Frequency in continuous wave transducers=

Answer 35

frequency of electoral signal from US system

Question 36

Frequency in pulsed wave transducers are determined by

Answer 36

thickness of crystal and speed of sound in the crystal

Question 37

Focal length is determined by

Answer 37

diameter of crystal and frequency of sound

Question 38

Beam divergence is determined by

Answer 38

diameter of crystal and frequency of sound

Question 39

Lateral resolution is determined by

Answer 39

beam width

Question 40

Basic modes of display

Answer 40

a mode, b mode, m mode

Question 41

A mode is called

Answer 41

amplitude mode

Question 42

B mode is called

Answer 42

brightness mode

Question 43

M mode is called

Answer 43

motion mode

Question 44

Appears as a series of spikes

Answer 44

A mode

Question 45

The height of the upward deflection is proportional to the

Answer 45

amplitude of the returning echo is A mode

Question 46

A mode is accurate in determining the

Answer 46

depth of reflectors

Question 47

In A mode, x-axis displays

Answer 47

depth of reflector (which is derived from time-of-flight)

Question 48

In A mode, the y-axis represents

Answer 48

reflection amplitude

Question 49

Appears as a line of dots of varying brightness

Answer 49

B mode

Question 50

The brightness of the dot indicates

Answer 50

strength of reflection in B mode

Question 51

Weaker reflections appear as

Answer 51

dark gray dots

Question 52

Strong reflectors appear as

Answer 52

bright white dots

Question 53

Is the basis of all other types of gray scale imaging, including real time imaging

Answer 53

B mode

Question 54

In B mode, x-axis represents

Answer 54

reflector depth (derived from time-of-flight)

Question 55

In B mode, y-axis represents

Answer 55

nothing

Question 56

In B mode, z-axis is

Answer 56

brightness or amplitude

Question 57

Appears as a group of horizontal wavy lines

Answer 57

M mode

Question 58

M mode is the ONLY display mode that provides information about

Answer 58

reflectors changing location and depth with respect to time

Question 59

In M mode, x-axis represents

Answer 59

time

Question 60

In M mode, y axis represents (derived from time-of-flight)

Answer 60

depth