Brainscape's Knowledge GenomeTM

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


See full index

MRI Quiz.com > Physics > Flashcards

Physics Flashcards

1
Q

What is letter A?

A

Magnetic field strength

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

What is letter B?

A

Gyromagnetic ratio

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

10,000 Gauss= ❓Tesla

A

1

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

Iron & Iron-like substances that can generate a relatively strong magnetic field are?

A

Ferromagnetic

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

Substances with a very weak magnetic field are?

A

Paramagnetic

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

Substances that have no magnetic field are?

A

Diamagnetic

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

Hydrogen protons in the anti-parallel state are referred to as….?

A

Spin down and/or high energy spins

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

T1 relaxation is also known as…?

A

Spin lattice relaxtion

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

⬆️ NEX/NSA DOES WHAT TO SNR?

A

⬆️ SNR

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

⬆️ FOV does what to SNR?

A

⬆️ SNR

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

⬆️ TR does what to SNR?

A

⬆️ SNR

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

⬆️ Slice thickness does what to SNR?

A

⬆️ SNR

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

⬇️ Phase matrix does what to SNR?

A

⬆️ SNR

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

⬇️ BW does what to SNR?

A

⬆️ SNR

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

⬇️ ETL does what to SNR?

A

⬆️ SNR

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

Pixel Area x Slice Thickness= ?

A

Voxel volume 3

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

Phase pix size X Freq. pixel size= ?

A

Pixel Area2

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

FOV/Matrix=?

A

Pixel Size

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

TR x Phase Matrix x NEX x #Slices= ?

A

3D gradient echo scan time

Divide by 1,000 to convert to seconds

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

TR x Phase Matrix x NEX / ETL = ?

A

FSE scan time

Divide by 1,000 to convert to seconds

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

TR x Phase Matrix x NEX= ?

A

Spin Echo scan time

Divide by 1,000 to convert to ms to seconds

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

FOV/Phase Matrix= ?

A

Pixe size dimensions
(Phase encoding direction)

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

FOV/Freq. Matrix= ?

A

Pixe size dimensions
(Freq. encoding direction)

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

T2 weighting & contrast are controlled by ____

A

TE (Echo Time)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Spatially locating (encoding) signal along the short axis of the slice is known as_____

A

Phase Encoding

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

Spatially locating (encoding) signal along the long axis of the slice is know as____

A

Freq. Encoding

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

M

How do T2 contrast agents work?

A

By shortening T2 decay time

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

How do T1 contrast agents work?

A

By shortening T1 recovery time

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

Proton density is____

A

the # of mobile hydrogen protons per unit volume of a tissue

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

Parameters that can be change/under our control are called___

A

Extrinsic contrast parameters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

List the extrinisic contrast parameters

A
  • TR
  • TE
  • TI
  • ETL
  • Flip Angle
  • b-value
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Parameters that cannot be chaged; are inherent to body tissue are called_

A

Intrinisic contrast parameters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

List the intrinsic contrast parameters

A
  • T1 recovery time
  • T2 decay time
  • Proton density
  • Flow
  • Apparent diffusion coefficient (ADC)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

T1 weighting/contrast are controlled by___

A

TR

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

A range of frequencies is known as__

A

Bandwidth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

A range of freq. transmitted in an RF excitation pluse are known as___

A

Transmit Bandwidth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

A range of freq. that are sampled during readout are known as___

A

Receive Bandwidth

38
Q

The center of the bore of the magnet in all planes is known as___

A

Magnetic Isocenter

39
Q

Magnetic homogeneity is___

A

Eveness of the magnetic field

40
Q

Nuclei that possess an odd mass # are considered___

A

MR Active nuclei

41
Q

an event in a superconducting MR system causing a loss of
superconductivity, a rapid loss of the magnet cryogens, potentially creating a hazard for patients / operators in the magnet room

A

Quench

41
Q

A Flair sequenc is used to…..

A

Suppress CSF/Fluid

42
Q

A STIR sequence is used to…

A

Suppress fat

43
Q

Based on this info what will your image be?
Slice selection- Z Gradient
Phase encoding- Y Gradient
Freq. encoding- X Gradient

A

Axial (body)

44
Q

Based on this info what will your image be?
Slice selection- Z Gradient
Phase encoding- X Gradient
Freq. encoding- Y Gradient

A

Axial (head)

45
Q

Based on this info what will your image be?
Slice selection- X Gradient
Phase encoding- Y Gradient
Freq. encoding- Z Gradient

A

Sagittal

46
Q

Based on this info what will your image be?
Slice selection- Y Gradient
Phase encoding- X Gradient
Freq. encoding- Z Gradient

A

Coronal

47
Q

TR (repetition time) is…

A

the time from one RF excitation pulse to the next

48
Q

What is the Gyromagnetic ratio of hydrogen is…

A

42.5774

49
Q

TE (echo time) is….

A

Time from RF excitation pulse to the peak signal induced in the receiver coil.

50
Q

What gradient runs from head-toe of the patient?

A

Z-Gradient

51
Q

What gradient runs from RT-LT of the patient?

A

X-Gradient

52
Q

What gradient runs from anterior-posterior of the patient?

A

Y-Gradient

53
Q

What are the trade offs of decreasing TR?

A
  • Lower SNR
  • Decrease scan time
  • Enhance T1 weighting
  • Decrease # of available slices
54
Q

What are the trade offs of increasing TR?

A
  • Improve SNR
  • Increase scan time
  • Reduce T1 weighting
  • Increase # of available slices
55
Q

On T2 weighted images how do fat and water appear?

A

Fat=Dark
Water=Bright

56
Q

On T1 weighted images how do fat and water appear?

A

Fat=Bright
Water=Dark

57
Q
A
58
Q

What is this formula?

A

Larmor equation

59
Q

What is letter C?

A

Precessional Freq.

60
Q

The outter lines of K-space are filled with…?

A

High Resolution Date

61
Q

The central lines of K-space are filled with…?

A

Signal & Contrast Data

62
Q

K-space is…?

A

Storage location of MR signal data

63
Q

T1 relaxtion time is the time it takes for…?

A

63% of the longitudinal magnetisation to recover.

64
Q

T2 relaxtion time is the time it takes for…?

A

63% of the transverse mag. to decay
or
37% of spins to de-phase

65
Q

T1 relaxation is also knows as…

A

Spin-Lattice relaxtion

66
Q

T2 relaxtion is also known as…

A

Spin-Spin relaxation

67
Q

A scan with a short TR and short TE will have what weighting?

A

T1 weighted

68
Q

TR range for a T1 weighted image is…

A

300-750ms

68
Q

TE range for a T1 weighted image is…

A

10-30ms

69
Q

A scan with a long TR and short TE will have what weighting?

A

Proton Density (PD)

70
Q

TR range for a PD weighted image is…

A

1600-4000ms

71
Q

TE range for a PD weighted image is…

A

10-30ms

72
Q

A scan with a long TR and long TE will have what weighting?

A

T2

73
Q

TR range for a T2 weighted image is…

A

2000-6000ms

74
Q

TE range for a T2 weighted image is…

A

80-120ms

75
Q

What are the 3 factors that control contrast for an inversion recovery squence?

A
  • TR
  • TE
  • TI
76
Q

A spin echo pulse sequence preceded by a 180 RF pulse is…..

A

An inversion recovery pulse sequence

77
Q

An inversion recovery sequence with a short TI is…

A

A STIR

78
Q

An inversion recovery sequence with a long TI is…

A

A FLAIR

79
Q

The time between 180° preparation pulse and the 90° excitation pulse during an inversion recovery sequence is known as…

A

TI (inversion time)

80
Q

A 90° RF followed by 180° RF produces what type of pulse sequence?

A

Spin Echo

81
Q

A 90° RF followed by train of 180° RF pulses produces what type of pulse sequence?

A

Fast Spin Echo (FSE)

82
Q

A 180° RF followed by 90°RF produces what type of pulse sequence?

A

Inversion Recovery

83
Q

A variable° RF followed by gradient to produce echo produces what type of pulse sequence?

A

Gradient Echo

84
Q

____ corresponds to the amount of radiofrequency energy deposited in the patient, which may result in heating.

A

SAR

85
Q

What is B0 in the following equation?

A

B0 = static magnetic field amplitude

86
Q

What is B1 in the following equation?

A

B1 = RF pulse amplitude

87
Q

What is a in the following equation?

A

α = flip angle

88
Q

What is **D **in the following equation?

A

D = cyclic ratio (fraction of the duration of the sequence during which the RF waves are transmitted)

89
Q

What is p in the following equation?

A

ρ = density

MRI Quiz.com (5 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions