Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Ultrasonography > ATTENUATION > Flashcards

ATTENUATION Flashcards

1
Q

Other term for acoustic boundaries

A

tissue interface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Difference between acoustic impedance from one to another

A

acoustic boundaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

 Position within the tissue where the values of acoustic impedance change.

A

acoustic boundaries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

 Weakening of the sound as it propagates through a medium

A

attenuation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

factors affecting attenuation

A

medium and frequency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

unit of attenuation

A

decibel

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

↑ densely packed = _ attenuation

A

high

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

low frequency = _ penetration = _attenuation

A

high, low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

unit of attenuation coefficien

A

dB/cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

For soft tissues, the typical value for attenuation coefficient is

A

0.5 db/cm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Process by which energy in the ultrasound beam is transferred to the propagating medium

A

absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

converted to heat

A

absorption

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

concepts that affect attenuation

A

absorption, reflection, refraction, scattering, divergence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

 The major interaction of interest for diagnostic ultrasound

A

reflection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

 Occurs when two large structures of significantly different acoustic impedance form an interface

A

reflection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

sound that hits an acoustic interface

A

incdent energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

reflected beam is called

A

echoes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

factor of strength of reflection

A

size of reflector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

small difference on the acoustic impedance makes _ echoes

A

small

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

two types of reflectors

A

speculative and diffuse

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

occurs when the boundary is smooth and larger than the beam.

A

specular reflector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

in specular reflector, the angle of incidence is equal to

A

the angle of reflection

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Terms to describe when the beam is perpendicular to the interface

A

normal incidence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Denotes a direction of travel of the incident ultrasound that is
not perpendicular to the boundary between two media

A

oblque incidence

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q
  • Incident beam is reflected in many different directions.
A

diffuse reflector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

reflecting interface is irregular in shape and its dimensions are smaller than the diameter of the ultrasound beam.

A

diffuse reflector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

 Is responsible for providing the internal texture of organs in the image

A

scattering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

 Occurs when an ultrasound wave strikes a boundary or interface between 2 small structures and the wave is scattered in different directions

A

scattering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

scatter in equal direction

A

rayleigh scattering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

redirection of beam

A

refraction

31
Q

what happens to refraction when angle of incidence is 90 °

A

none

32
Q

gives the relationship between the angle of incidence and the angle of refraction when a beam of sound passes through an interface between two tissues where the speed of sound is different

A

snell’s law

33
Q

what happens when p2>p1?

A

angle of transmission is higher than the angle of incidence

34
Q

two requirements for refraction

A
  1. Oblique incidence
  2. Different propagation speed on either side of the boundary
35
Q

 Power spread over a large area

A

divergence

36
Q

↑area = _ divergence = _ intensity

A

high, low

37
Q

transducers convert _ energy to _ energy

A

electrical to ultrasound

38
Q

general compositions of transducer

A

physical housing, electrode, piezoelectric element, backing material, matching layer

39
Q

 Contains all the individual components including the crystals, electrodes, matching later, and backing material.

A

physical housing

40
Q

 Provides structural support and acts as an electrical and acoustic insulator.

A

physical housing

41
Q

o Protects patients from electric shock.

A

outside electrodes

42
Q

other term for outside electrons

A

grounded electrode

43
Q

inside electrodeis also

A

live electrode

44
Q

o Abuts against a thick backing block

A

inside electrode

45
Q

are connected to the UTZ machine which generates the short burst of electrical pulses to excite the crystals

A

electrodes

46
Q

size of piezoelectric element

A

6-19mm diameter, 0.22mm thickness

47
Q

most commont type of pizeoelectric element

A

lead zirconate titanate PZT

48
Q

piezo means

A

to press

49
Q

 Eliminate the vibrations from the back face and to control the length of vibrations from the face of the crystals.

A

backing material

50
Q

 Sandwiched between the piezoelectric crystal and the patient

A

matching layer

51
Q

Region nearest the transducer face, characterized by a highly collimated beam with more uniform intensity

A

near field

52
Q

aka nearfield

A

fresnel zone

53
Q

aka far field

A

fraunhofer zone

54
Q

 Region farthest from the transducer and characterized by the divergence of the beam with great variation in intensity.

A

far field

55
Q

The location where the beam reaches its minimum diameter

A

focus points

56
Q

Energy from the transducer that radiates at various angles from the transducer face

A

Side lobes

57
Q

The arrangement of crystals within the transducer

A

array

58
Q

types of electronic array

A

linear, curvilinear, phased

59
Q

PROBE REFERS TO THE PHYSICAL SIZE OF THE PART OF THE ULTRASOUND THAT CONTACTS THE PATIENTS.

A

foot print

60
Q

THE WIDTH OF THE IMAGE THAT IS SEEN ON THE SCREEN.

A

field of view

61
Q

 Produces parallel scan lines and has
a rectangular field of view

A

linear

62
Q

linear array is Used to image superficial structures and vessels and therefore operate at frequencies above

A

4MHz

63
Q

Extensively used for vascular, small parts and musculoskeletal applications.

A

linear

64
Q

other term for curvilinear

A

sector

65
Q

Similar to the linear array but the transducer face is formed into a curve (convex in shape) which provides a wide field of view which diverges with depth

A

curvilinear

66
Q

 Operate at lower frequencies, typically around 3.5 MHz and are best suited to image deep lying structures

A

curvilinear

67
Q

 Main application are in
abdominal and obstetric scanning

A

curvilinear

68
Q

commonly used in echocardiography

A

phased

69
Q

similar to curvilinear transducers, they are used to image deep-lying structures and perform trans-cranial investigation

A

phased

70
Q

smaller and flatter footprint, which allows the users to maneuver more easily between the ribs and small spaces

A

phased

71
Q

 Transducers designed to enter the body via the vagina, rectum, esophagus or a blood vessel (catheter-mounted type)

A

invasive

72
Q

use __ for cleaning

A

transeptics

73
Q

 Improves sound transmission into and out of the patient by eliminating air reflection.

A

coupling medium

74
Q

coupling medium is also referred to as

A

aqueous gel

Ultrasonography (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions