Physics 111 Chapter 4

Question 1

The rule that states that it takes 13 ms for sound to travel 1 cm in soft tissue

Answer 1

13 ms rule

Question 2

Amplitude mode; the height of the spike on the image is related to the strength (amplitude) of the echo generated by the reflector

Answer 2

A-Mode

Question 3

As low as reasonably achievable; the principle that states one should always use the lowest power and shortest scanning time possible to reduce potential exposure to the patient

Answer 3

ALARA

Question 4

The part of the receiver that increases or decreases the received echoes equally, regardless of depth.

Answer 4

Amplification

Question 5

The maximum or minimum deviation of an acoustic variable from the average value of that variable; the strength of the reflector.

Answer 5

Amplitude

Question 6

The part of the digital scan converter that converts the analog signals from the receiver to binary for processing by the computer

Answer 6

Analog-to-digital (A-to-D) converter

Question 7

Without echoes or black

Answer 7

Anechoic

Question 8

The technique that varies the voltage to the individual elements to reduce grating lobes

Answer 8

Apodization

Question 9

Echoes on the screen that are not representative of actual anatomy, or reflectors in the body that are not displayed on the screen

Answer 9

Artifacts

Question 10

Brightness mode; the brightness of the dots is proportional to the strength of the echo generated by the reflector

Answer 10

B-Mode

Question 11

The instrument that shapes and steers the beam on the transmit end

Answer 11

Beam Former

Question 12

The digital language of zeroes and ones

Answer 12

Binary

Question 13

Black and white image

Answer 13

Bistable

Question 14

The smallest unit of memory in a digital device

Answer 14

Bit

Question 15

Eight bits of memory

Answer 15

Byte

Question 16

Display that uses an electron gun to produce a stream of electrons toward a phosphor-coated screen

Answer 16

Cathode ray tube (CRT)

Question 17

A way of processing the pulse to improve contrast resolution and reduce speckle

Answer 17

Coded excitation

Question 18

A type of reverberation artifact caused by small reflectors

Answer 18

Comet tail

Question 19

The function of the receiver that changes the brightness of the echo amplitudes to compensate for attenuation with depth

Answer 19

Compensation

Question 20

The function of the receiver that decreases the range of signal amplitudes present with the machines receiver; opposite of dynamic range

Answer 20

Compression

Question 21

The ability to differentiate one shade of gray from another

Answer 21

Contrast resolution

Question 22

The function of the receiver that makes the signal easier to process by performing rectification and smoothing

Answer 22

Demodulation

Question 23

Part of the digital scan converter that converts the binary signals from computer memory to analog for display and storage

Answer 23

Digital-to-analog (D to A) converter

Question 24

The series of echo amplitudes present within the signal

Answer 24

Dynamic range

Question 25

Refraction artifact caused by the curved surface of the reflector

Answer 25

Edge shadowing

Question 26

Arc-like bands that occur when the machine is too close to an unshielded electrical device

Answer 26

Electrical interference

Question 27

An artifact caused by sound passing through an area of lower attenuation

Answer 27

Enhancement

Question 28

One half of a frame on the display

Answer 28

Field

Question 29

Places pixels where there is no signal information based on adjacent scan lines

Answer 29

Fill-in interpolation

Question 30

One complete ultrasound image

Answer 30

Frame

Question 31

Averages the frequencies across the image to improve contrast resolution and reduce speckel

Answer 31

Frequency compounding

Question 32

The operating or resonating frequency emitted by the transducer

Answer 32

Fundamental frequency

Question 33

An artifact caused by extraneous sound not along primary beam path; occurs with arrays; reduced or eliminated by apodization, subdicing and tissue harmonics

Answer 33

Grating lobes

Question 34

Displayed echoes that are relatively brighter than the surrounding tissue; may also be referred to as echogenic

Answer 34

Hyperechoic

Question 35

Displayed echoes that are relatively darker than the surrounding tissue

Answer 35

Hypoechoic

Question 36

Display that uses the twisting and untwisting of liquid crystals in front of a light source

Answer 36

Liquid crystal display (LCD)

Question 37

Motion mode; used to display motion of the reflectors

Answer 37

M-Mode

Question 38

The timing component of the ultrasound machine that notes how long it takes for signals to return from reflectors

Answer 38

Master synchronizer

Question 39

An artifact caused by sound bouncing off of a strong reflector and causing a structure to appear on both sides of the reflector

Answer 39

Mirror image

Question 40

An artifact caused by the beam bouncing off of several reflectors before returning to the transducer

Answer 40

Multipath

Question 41

Principle that pressure waves change in shape as they travel deeper, through in a disproportionate way

Answer 41

Nonlinear propagation

Question 42

Waves that are not pure sine waves

Answer 42

Nonsinusoidal

Question 43

Output power; strength of sound entering the patient

Answer 43

Output

Question 44

Receiver function that increases or decreases all the echo amplitudes equally

Answer 44

Overall gain

Question 45

Picture archiving and communication system; a type of display and storage device commonly used in ultrasound and other imaging modalities

Answer 45

PACS

Question 46

The smallest component of a 2D digital iamge

Answer 46

Pixel (picture element)

Question 47

Occurs in the A to D converter; The image must be live

Answer 47

Preprocessing

Question 48

Occurs in the D-to -A converter; the image must be frozen

Answer 48

Postprocessing

Question 49

Part of the beam former that controls the amount of energy in the pulse

Answer 49

Pulser

Question 50

Equation used to calculate the distance to the reflector; in soft tissue, d=0.77t where "d" is the depth of the reflector and "t" represents the round trip time of the pulse

Answer 50

Range equation

Question 51

The type of magnification performed in the D to A converter (postprocessing) that magnifies the image by enlarging the pixels

Answer 51

Read zone

Question 52

The component of the machine that processes the signals coming back from the patient

Answer 52

Receiver

Question 53

The part of the receiver that inverts the negative voltages to positives

Answer 53

Rectification

Question 54

Function of the receiver that is used to reduce image noise; sets a threshold below which the signal will not be displayed

Answer 54

Rejection

Question 55

An artifact caused by the beam bouncing between two strong reflectors

Answer 55

Reverberation

Question 56

A type of reverberation artifact caused by air

Answer 56

Ring down

Question 57

The part of the ultrasound machine that processes the signals from the receiver; consist of the A - to - D converter, computer memory, and D - to - A converter

Answer 57

Scan converter

Question 58

Created when one or more pulses of sound return from the tissue containing information related to the depth and amplitude of the reflectors

Answer 58

Scan line

Question 59

An artifact caused by the failure of sound to pass through a strong attenuator

Answer 59

Shadowing

Question 60

An artifact caused by extraneous sound that is not found along the primary beam path; occurs with single-element transducers

Answer 60

Side lobes

Question 61

Part of the demodulation component of the receiver; an "envelope" is wrapped around the signal to eliminate the "humps"

Answer 61

Smoothing

Question 62

Algorithm used in signal processing to reduce the amount of acoustic speckle

Answer 62

Speckle reduction

Question 63

Dividing the piezoelectric elements into very small pieces to reduce grating lobes

Answer 63

Subdicing

Question 64

Harmonic signal produced by the patient and is a multiple of the fundamental frequency; also referred to as native tissue harmonic imaging

Answer 64

Tissue harmonics

Question 65

Time gain compensation; Compensation

Answer 65

TGC

Question 66

The smallest component of a 3D image

Answer 66

Voxel (volume element)

Question 67

The type of magnification performed in the A -to- D converter (postprocessing) that magnifies the image by redrawing it before it is stored in memory

Answer 67

Write zoom

Question 68

the plane that is perpendicular to the beam path

Answer 68

X-Axis

Question 69

The plane that is parallel to the beam path

Answer 69

Y-Axis

Question 70

The brightness, or amplitude, of the dots on the display

Answer 70

Z-Axis

Question 71

Having two possible states

Answer 71

Bistable

Question 72

Sequential display of all the frames stored in memory at a controllable frame rate

Answer 72

Cine loop

Question 73

A sophisticated form of transmission in which the driving voltage pulses have intrapulse variations in amplitude, frequency, and/or phase

Answer 73

Coded excitation

Question 74

A single one or two way path for transmitting electric signals, in distribution from other parallel paths; an independent transmission delay line and transducer element path; an independent reception transducer element , amplifier, analog - to - digital converter, and delay line path

Answer 74

Channel

Question 75

Conversion of voltage pulses from radio frequency to video form. Also called demodulation , amplitude detection and envelope detection.

Answer 75

Detection

Question 76

Imaging tissue stiffness by tracking movement under mechanical stress

Answer 76

Elastography

Question 77

A backlighted rectangular matrix of thousands of liquid crystal elements

Answer 77

Flat panel display

Question 78

Constant display of one of the frames in memory

Answer 78

Freeze