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MRI > Memorize > Flashcards

Memorize Flashcards

1
Q

T1 CSE Parameters (TR/TE)

A

Short TR: 300 to 700ms
Short TE: 10 to 30ms

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2
Q

T2 CSE Parameters

A

Long TR: 2000ms+
Long TE: 80ms+

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3
Q

PD CSE Parameters

A

Long TR: 2000ms+
Short TE: 20ms

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4
Q

T1 FSE Parameters

A

Short TR: 300 to 700ms
Short Effective TE: minimum

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5
Q

T2 FSE Parameters

A

Long TR: 3000 to 10000ms
Long Effective TE: 80 to 140ms

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6
Q

PD FSE Parameters

A

Long TR: 3000 to 10000ms
Short Effective TE: minimum

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7
Q

Fat Inversion Time

A

100 to 175ms

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8
Q

CSF Inversion Time

A

1700 to 2200ms

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9
Q

T1 CGE Parameters

A

Short TR: less than 50ms
Short TE: 1 to 5ms
Large Flip angle: 70 to 110 deg

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10
Q

T2 CGE Parameters

A

Long TR: 200ms+
Long TE: 15 to 25ms+
Small Flip Angle: 5 to 20 degrees

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11
Q

PD CGE Parameters

A

Long TR: 200ms+
Short TE: 5 to 10ms
Small Flip Angle: 5 to 20 degrees

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12
Q

T1 Incoherent GRE Parameters

A

TR: 20 to 50ms
TE: 5 to 10ms
Flip Angle: 30 to 45 degrees

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13
Q

T2* Coherent GRE Parameters

A

TR: 20 to 50ms
Long TE: 15 to 25ms
Flip Angle: 30 to 45 degrees

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14
Q

T2 Steady State Free Precession Parameters

A

TR: 20 to 50ms
TE: minimum
Flip Angle: 30 to 45 degrees

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15
Q

TOF Parameters

A

Short TR: 2500ms
TE: minimum
Flip Angle: 45 to 60 degrees

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16
Q

Ideal Temperature for Scanner Room

A

65 to 75 degrees F

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17
Q

Ideal Humidity for Scanner Room

A

50 to 70%

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18
Q

FDA Whole Body SAR Limits

A

4 W/kg /15min

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19
Q

FDA Head SAR Limit

A

3 W/kg /10min

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20
Q

FDA Torso SAR Limit

A

8 W/kg /5min

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21
Q

FDA Extremities SAR Limit

A

12W/ kg / 5min

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22
Q

FDA Static Field Strength Limit Under 1 Month

A

4T

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23
Q

FDA Static Field Strength Limit Over 1 Month

A

8T

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24
Q

Precessional Frequency Equation

A

Wo=Bo x ∆
Precessional Frequency (MHz)= Mag Field Strength (T) x Gyromagnetic ratio of Hydrogen (42.6)

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25
Q

T1 Relaxation Time of Fat

A

200ms

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26
Q

T1 Relaxation Time of Water

A

2500ms

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27
Q

T2 Decay Time for Fat

A

100ms

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28
Q

T2 Decay Time for Water

A

2500ms

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29
Q

Precessional Frequency Difference Between Fat and Water at 1T

A

147Hz

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30
Q

Precessional Frequency Difference Between Fat and Water at 1.5T

A

220Hz

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31
Q

Precessional Frequency Difference Between Fat and Water at 2T

A

440Hz

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32
Q

Voxel Volume Equation

A

Pixel Phase Dim x Pixel Freq. Dim x Slice Thickness

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33
Q

Beneficence means

A

Do no harm

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34
Q

Asepsis types

A

Medical and Surgical

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35
Q

Medical asepsis

A

Reduction in the number of pathogens to restrict spread and create a clean environment

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36
Q

Surgical asepsis

A

The complete elimination of all microorganisms to create a sterile environment

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37
Q

Nosocomial infection

A

An infection or illness originating from within a hospital

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38
Q

Iatrogenic infection

A

Infection or illness originating from medical exam or treatment

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39
Q

Adult heart rate

A

70 to 80 bpm

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40
Q

Child HR

A

90 to 100 bpm

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41
Q

Blood pressure

A

110 to 140
60 to 80

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42
Q

Resp rate

A

12 to 20 bpm

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43
Q

Temperatures per region

A

Oral: 98.6
Axillary: 97.6
Tymp: 97.6
Rectal: 99.6

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44
Q

Percent of claustrophobic patients

A

5%

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45
Q

Cpr sequence

A

CAB

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46
Q

Rate of compressions

A

80 to 100 per min

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47
Q

CPR Depth for Adults

A

1.5 to 2 in

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48
Q

Ratio of compressions to breath for 1 and 2 rescuers

A

1: 30 and 2
2. 30 and 2

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49
Q

Location for compressions

A

Lower 1/3 of sternum

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50
Q

Gd Contrast agents _____ T1 Relaxation Time

A

Reduce- brightening them

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51
Q

Gd Contrast agents slightly _____ T2 relaxation times resulting in _____ images

A

Reduce. Darker

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52
Q

80 percent of Gad is excreted in ____ hrs and 98 percent is excreted in ____ hours

A

3, 12

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53
Q

Structures that Gd enhances in the brain

A

Tumors, infection, acute infarct, inflammation and lesions

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54
Q

Super paramagnetic agents are stronger than paramagnetic agents. They ____ T2 Decay times in tissues

A

Shorten

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55
Q

Most common super paramagnetic agent is

A

Iron oxide

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56
Q

Iron oxide is the primary contrast agent for imaging the

A

Liver

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57
Q

Manganese is also used in liver imaging. It causes normal liver cells to

A

Enhance

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58
Q

Hyperpolarized helium agents are for studies of the

A

Lungs

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59
Q

Normal GFR

A

90 or higher

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60
Q

Gd dosing mmol/kg and ml/kg

A

0.1mmol or 0.2 ml

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61
Q

Level one personnel can be responsible for

A

Safety of themselves only

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62
Q

Level two personal can be responsible for

A

Safety of themselves and all others. They are allowed to also screen patients

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63
Q

Temperature of the MR scan room

A

65 to 75° Fahrenheit

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64
Q

Humidity percentage of the scan room

A

50 to 70%

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65
Q

Zone 1 are areas that are

A

Freely accessible to everybody

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66
Q

Zone 2 is accessible to everybody only there is an

A

MRI gatekeeper between zone 2 and zone 3

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67
Q

Zone 3 contains

A

The scanner consule

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68
Q

Zone ___ is only suitable for screened patients

A

4

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69
Q

This type of shielding is accomplished through the use of electromagnetics located at the end of the gantry

A

Active

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70
Q

This type of shielding is accomplished with steel plates, located within the gantry or the rooms walls, that help to contain the fringe field

A

Passive

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71
Q

What is the rooms Faraday cage made out of

A

Copper

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72
Q

Rf pulses can cause reactions in tissue. Name three

A

Tissue heating, antenna effects and thermal injuries

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73
Q

Which pulse sequence is associated with the highest risk of time varying magnetic field effects

A

EPI- rapidly switching gradients

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74
Q

Peripheral nerve stimulation includes

A

Involuntary muscle contractions and cutaneous sensations

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75
Q

The process of seeing stars when sensory receptors in the retina are stimulated by changing magnetic fields

A

Magnetophosphenes

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76
Q

Decibels exceeding ____ can cause immediate acoustic trauma

A

130 to 140

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77
Q

This effect increases the amplitude of the T-Wave on the EKG

A

Magneto hemodynamic effects

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78
Q

Faraday’s law states that for electromagnetic induction to take place, what must be present

A

a conductor, magnetic field, and motion (between the two) must be present.

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79
Q

Lenz’s Law - The second law of electromagnetism. Lenz’s law states that an electromagnetically induced current within a conductor creates a magnetic field opposing the magnetic field that produced the electromagnetically induced current. These opposing magnetic fields are also
referred to as

A

Eddy currents

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80
Q

Superconductive magnets are made of what

A

Niobium and titanium

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81
Q

These magnets have the best magnetic field homogeniety

A

Superconductive

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82
Q

copper, oxygen, silver, mercury, lead, water, and
graphite have no magnetic moment and are considered

A

Diamagnetic

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83
Q

tungsten, cesium, lithium, aluminum, magnesium, sodium, platinum, and
gadolinium contrast agents have a small magnetic moment and are considered

A

Paramagnetic

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84
Q

_________ substances only display a
magnetic moment when grouped. Individualmolecules
have no magnetic moment by themselves. Examples include iron oxide particles and iron oxide contrast agents

A

Superparamagnetic

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85
Q

__________substances retain their magnetization even
after the removal of the external magnetic field. Examples include; steel, iron, nickel, and cobalt

A

Ferromagnetic

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86
Q

The ________ coil is the first layer of instrumentation within the gantry of an MRI
machine.

A

RF

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87
Q

A cylindrical transceiver coil within the circumference of the magnet bore
that acts as the primary RF transmitter in closed-bore MRI systems. This coil provides
a large coverage area, and poor SNR

A

Body coil

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88
Q

The dephasing of spins due to magnetic field inhomogeneities is

A

T2 Prime

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89
Q

Pressional frequency is measured in

A

mHz

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90
Q

What term describes the ratio of a magnetic moment to it’s angular momentum

A

Gyromagnetic ratio

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91
Q

What constant of proportionality represents the frequency of at element at one Tesla

A

Gyromagnetic ratio

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92
Q

In the presence of a strong magnetic field, hydrogen nuclei within the body tend to precess _______ during thermal equilibrium

A

Out of phase

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93
Q

After the application of an RF pulse oscillating at the processional frequency of hydrogen, there are more spins in a high energy state than a low energy state. T or f

A

True

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94
Q

True or false. Phase coherence occurs when an RF pulse is transmitted at the precessional frequency of hydrogen

A

True

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95
Q

T or f. Phase coherence occurs at the same time as resonance

A

True

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96
Q

Phased array coils are also called

A

Multichannel coils

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97
Q

Transmit bandwidth is indirectly controlled by adjusting

A

Slice Thickness

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98
Q

Receive bandwidth is directly controlled T or F

A

T

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99
Q

Decreasing the receiver bandwidth _____ SNR

A

Increases- Narrower window for noise

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100
Q

Decreasing the receiver bandwidth _____ chemical shift

A

Increases

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101
Q

Increasing the receiver bandwidth _____ SNR

A

Decreases

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102
Q

Increasing the receiver bandwidth _____ chemical shift

A

Decreases

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103
Q

A gap space of _____% the slice Thickness should be selected to prevent sampling of the RF waveforms outer edge

A

30

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104
Q

The time it takes for a gradient to achieve max gradient amplitude

A

Gradient Slew Rate

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105
Q

Gradient Slew Rate describes speed and strength and speed and is mesured in

A

mT/m/s

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106
Q

Typical Slew Rates are between

A

70 to 200 mT/m/s

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107
Q

Maximum gradient amplitude is the max strength and is measured in

A

mT/m or G/cm

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108
Q

Gradient rise time is the time it takes for the gradient to turn on, achieve the required strength and turn off. It is measured in

A

Microseconds

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109
Q

A duty cycle is the time that a gradient is capable of working at max amplitude and is measured in

A

%

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110
Q

What 2 things occur with resonance

A
  1. Spins flip into transverse plane
  2. Spins precess in phase
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111
Q

FID is the loss off ____ in the transverse plane (T2 Decay) and along the longitudinal axis (T1 Recovery)

A

Magnetization

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112
Q

The controlling factor of T1 relaxation is ___ in SE sequences and in GE sequences the controlling factor is ____ and _____. Inversion recovery ____ and ______.

A

SE: TR
GE: TR and Flip Angle
IR: TR and TI

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113
Q

The controlling factor for T2 decay during all pulse sequences is

A

TE

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114
Q

T2* is a tissue characteristic similar to T2 decay, except that transverse decay occurs ______ due to T2 decay and magnetic field inhomogeneities (T2’)

A

Faster

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115
Q

T2* Decay is also called

A

Susceptibility decay

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116
Q

T2’

A

The dephasing of precessing spins due to magnetic field inhomogeneities

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117
Q

T or F the slice Selection gradient is turned on with the RF pulse

A

T

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118
Q

The phase Encoding gradient encodes the signal samples along the _____ axis of they anatomy (typically)

A

Short

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119
Q

The phase Encoding gradient energizes after the application of the ________ and before the ______

A

Alpha pulse, rephasing pulse

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120
Q

The greater the steepness of the phase Encoding gradient, the _____ the phase shift

A

Larger

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121
Q

The phase Encoding gradient acts as a rewinder gradient during _______and _______ pulse sequences

A

Coherent Gradient Echo and Steady State

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122
Q

The frequency Encoding gradient is applied during the collection of the

A

Echo

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123
Q

The applied ____ and _____ of the phase Encoding gradient determines which line of k space will be filled in

A

Slope and polarity

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124
Q

The _____ of the phase Encoding gradient determines the degree of _____ between the spins along the slope

A

Steepness, phase shift

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125
Q

The number of frequencies sampled during the collection of the echo is determined by the

A

Frequency matrix

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126
Q

The slope of the frequency Encoding gradient is determined by the

A

Frequency fov

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127
Q

The frequency Encoding gradient is also used for rephasing during ______ pulse sequences

A

Gradient Echo

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128
Q

K space is rectangular. T or F

A

T

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129
Q

K space has an X axis for frequency and a Y Axis for

A

Phase

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130
Q

The ___ half of k space mirrors the ___half of k space

A

R, L

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131
Q

The ____ half of k space mirrors the ____

A

Top, bottom

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132
Q

A steep phase Encoding gradient stores

A

Spatial resolution

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133
Q

Low signal amplitude is stored on the ____ of k space

A

Outer edge

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134
Q

Low signal amplitude results from a ____ phase Encoding gradient

A

Steep

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135
Q

A shallow phase Encoding gradient results on ____ signal amplitude

A

High

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136
Q

High signal amplitude resulting from a shallow phase Encoding gradient is stored in the _____ of k space

A

Center

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137
Q

K space is located in the

A

Array processor

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138
Q

A mathematical process that converts data obtained during image acquisition to be stored in kspace

A

Fast Fourier transform

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139
Q

T or F during a pulse sequence, phase Encoding occurs after frequency Encoding

A

False

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140
Q

Which of the following parameters would provide the best T1 weighting for CSE pulse

150ms TR, 5ms TE
450ms TR, 20ms TE
900ms TR, 60ms TE
400ms TR, 80m TE

A

450ms TR, 20ms TE

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141
Q

T or F Increasing the ETL during FSE sequences will cause acquisition time to increase

A

False

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142
Q

As ETL increases, more T2 weighting occurs T or F

A

true

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143
Q

What 2 advantages do FSE pulses provide

A
  1. Magnetic susceptibility artifact decreases
  2. Data is acquired faster than with CSE
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144
Q

3 disadvantages of FSE

A
  1. Motion artifact decreases
  2. SNR Decreases
  3. True image weighting is not possible
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145
Q

Is CSE or FSE better for detection of small hemhorrhages

A

CSE

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146
Q

What FSE pulse sequence uses a partial Fourier transform to fill all lines of kspace during a single TR period

A

SSFSE

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147
Q

T or F SSFSE sequence causes increased tissue heated compared to FSE or CSE

A

T

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148
Q

What FSE pulse sequence uses a reverse flip angle excitation pulse after the applied echo train in order to push the transverse magnetization into the longitudinal plane so that the T1 relaxation can occur quicker?

A

Dirven equilibrium Fourier transform

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149
Q

What does this pulse sequence represent 90-180-180-90

A

DRIVE sequence

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150
Q

Which sequence most accurately represents an IR sequence

180-90-180-180
180-90-90

A

180-90-180-180

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151
Q

The time between the 180° inversion pulse and then 90° alpha pulse is known as the

A

Inversion Time

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152
Q

Gradient Echo sequences use flip angles less than

A

90 degrees

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153
Q

Gradient Echo pulse sequences use the _____ to rephase FID

A

Frequency Encoding gradient

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154
Q

T or F All gradient Echo pulse sequences have some extent of T2*

A

T

155
Q

GE pulse sequences are sensitive to ___

A

Flow

156
Q

GE sequences are best when demonstrating _____

A

Brain hemorrhage

157
Q

What type of gradient echo pulse sequence uses an alpha pulse with a variable flip angle as well as a single application of the frequency encoding gradient for rephasing purposes

A

Conventional Gradient Echo pulse sequences

158
Q

How many lines of k space are filled during a single CGE sequence

A

1

159
Q

T1 CGE pulse sequences generally require the use of a ___ flip angle

A

Large

160
Q

What type of EPI sequence uses a 90° excitation pulse followed by a 180° rephasing pulse and a pulsing phase Encoding ingredient?

A

Spin Echo EPI pulse sequence

161
Q

EPA sequences can be performed as either a spin echo EPI or a gradient echo EPA true or false

A

T

162
Q

True or false. Distortions and chemical shift artifacts are common problems associated with EPI sequences

A

T

163
Q

EPI sequences can be used to prevent

A

Physiological motion artifacts

164
Q

True or false. EPI sequences are commonly used to perform physiological studies such as for fusion, diffusion and spectroscopy

A

T

165
Q

What type of gradient echo pulse uses constant oscillation of the phase encoding gradient in order to fill all lines of k space during a single TR period

A

EPI

166
Q

Balanced gradient echo pulse sequences are useful in providing good SNR and CNR between

A

Fat, water and surrounding tissue

167
Q

What type of gradient Echo post sequence uses a significantly shorter TE by only transmitting part of an RF pulse and only sampling a portion of the echo

A

Fast gradient echo

168
Q

The flip angles applied during steady state free precession full sequences fall within the range of

A

30 to 45°

169
Q

The flip angles applied during coherent gradient echo pulse sequences will fall within the range of

A

30 to 45 degrees

170
Q

The flip angles applied during incoherent gradient echo pulse sequences fall within the range of

A

30 to 45 degrees

171
Q

For T1 weighted images the ETL needs to be in the range of

A

2-4

172
Q

For PD weighted images the ETL needs to be in the range of

A

6 to 12

173
Q

For T2 weighted images the ETL needs to be in the range of

A

12 to 32

174
Q

Spoilers are gradients that

A

Dephase

175
Q

Rewinders are gradients that

A

Rephase

176
Q

Coherent (rewound) GRE Creates ___ weighted images and ____ effect

A

T2*, angiographic

177
Q

Incoherent (spoiled) GRE Creates ____ and _____ weighted images because residual transverse magnetization is removed prior to the next excitation pulse.

A

T1, PD

178
Q

Due to they very short scan times and high ETL, SSFSE are used in ____sequences

A

MRCP

179
Q

DRIVE uses a reverse flip angle of

A

270 degrees

180
Q

Steep gradients produce a ____ amplitude signal

A

Low

181
Q

Sampling time= frequency matrix ÷

A

rBW

182
Q

Spin echo time formula

A

TR X phase matrix X NEX

183
Q

FSE scan time formula

A

TR X Phase Matrix X NEX
__________________________
ETL

184
Q

GRE (2D) Scan Time Formula

A

TR X Phase Matrix X NEX

185
Q

GRE (3D) Scan Time Formula

A

TR X Phase Matrix X NEX X #Slices

186
Q

Narrow rBW increase _____ artifact

A

Susceptibility

187
Q

A Narrow rBW produces a ____ SNR because noise is sampled less

A

High

188
Q

A Narrow rBW ____ chemical shift

A

Increases

189
Q

A wide rBW reduces susceptibility artifact and chemical _____

A

Shift

190
Q

Increasing Phase and frequency matrix _____ SNR due to smaller pixel size

A

Decreases

191
Q

To reduce chemical shift _____ the rBW

A

Increase

192
Q

To prevent aliasing or wrap _____ the FOV

A

Increase

193
Q

Out of phase signal cancellation produces a ring of dark signal where fat and water interface. Select the ____ that matches the periodicity of fat and water to compensate.

A

TE

194
Q

Magnetic susceptibility artifact can be reduced by running a _____ sequence and avoiding ______ sequences

A

FSE, GRE

195
Q

Truncation or Gibbs artifact can be reduced by increasing the number of ______ Encoding steps

A

Phase

196
Q

Cross talk can be reduced by increasing _____ spacing

A

Slice

197
Q

Zipper artifact is cause by ____ leakage

A

RF

198
Q

Moire artifacts cause black and white banding on the edges of the FOV on _____ sequences. Use a ____sequence instead.

A

GRE, FSE

199
Q

Time of flight phenomena are nuclei that are excited and are not rephased produce a signal ____

A

Void

200
Q

Doubling the field strength ____ the SAR potential

A

Quadruples

201
Q

A spoiled gradient echo sequence removes any residual ____ magnetization

A

Transverse

202
Q

Incoherent gradient Echo sequences are also known as ____ gradient Echo

A

Spoiled

203
Q

Gradient Echo sequences are influenced by susceptibility, chemical shift and inhomogenities because it does not contain a

A

180° RF pulse

204
Q

Steady state occurs when the _____ in a gradient echo is less than the T2 or T2* causing residual transverse magnetization

A

TR

205
Q

Incoherent gradient echo sequences have _____contrast due to the removal of residual transverse magnetization before the next excitation

A

T1

206
Q

______ sequences are variation of high T2 signal, balance steady state sequences

A

Fiesta

207
Q

Fiesta sequences are equipped with sliced, phase and frequency rewinder pulses. These images have mixed _____ contrast

A

T2/T1

208
Q

Fiesta sequences are great for the evaluation of______

A

Cranial nerves

209
Q

A _____ gradient echo sequence removes any residual transverse magnetization

A

Spoiled

210
Q

Steady state refers to residual ______

A

Transverse magnetization

211
Q

Spoiled gradient echo sequences spoil away residual transverse magnetization. This creates _____ contrast

A

T1

212
Q

Spoiling reduces T2*(transverse magnetization) effect and is achieved by using ____ pulses

A

RF

213
Q

A dual contrast spin Echo sequence uses echo times of ____ms and. ____ ms

A

25, 90

214
Q

In a dual echo spin Echo sequence, What two types of images are produced

A

PD (short TE) and T2 (Long TE)

215
Q

Increasing the echo train lengths can lead to increased______

A

Blurring

216
Q

In the fast spin echo pull sequence the number of shots is calculated by the number of _____÷______

A

Phases, ETL

217
Q

To calculate the number of shots in an FSE sequence you need to divide the number of _____ by _____

A

Phase Encoding, ETL

For example: 128 matrix ÷ 128 ETL
=1 Shot

218
Q

___ sequences are typically used for the evaluation of periventricilar white matter

A

FLAIR

219
Q

During a spin Echo pole sequence the application of the slice slut gradient occurs at the same time as the____ and ____ pulses

A

RF excitation pulse, Rephasing

220
Q

During a pulse sequence ______ encoding occurs during readout

A

Frequency

221
Q

At 1.5T what TI range best suppresses signal from fluid

100-175
2000-3500
400-550
1700-2200

A

1700-2200

222
Q

Gradient Echo sequences use flip angles:

Greater than 90 deg
Equal to 90 deg
Less than 90 deg
Equal to 90 deg

A

Less than 90 deg

223
Q

Which of the following parameters would produce the best T2 weighting when a GE pulse sequence is applied?

<50ms TR, 15-25ms TE, 90-110 FA
80-100ms TR, 20-50ms TE, 5-20 FA
200+ms TR, 15-25ms TE, 5-20 FA
200+ms TR, 1-5ms TE, 90-110 FA

A

200+ms TR, 15-25ms TE, 5-20 FA

224
Q

What sub group of GE pulse sequences use 2 excitation pulses to create a stimulated echo?

Fast gradient echo
Steady state pulse sequences
Balanced gradient echo pulse seq
Echo planar Pulse Sequences

A

Steady state pulse sequences

225
Q

What type of pulse sequence maintains partial longitudinal and transverse magnetization at all times

A

Steady State pulse sequences

226
Q

During a steady state pulse sequence, if 2 excitation pulses with variable flip angles are applied, a _____ is created

A

Stimulated echo

227
Q

If a Steady state pulse sequence uses 2 90 degree excitation pulses, the echo is called a

A

Hann echo

228
Q

Steady state pulse sequences typically use flip angles in the range of

A

30 to 45 degrees

229
Q

What type of steady state pulse sequence only samples the gradient echo (FID)?

Fast GRE
SSFP
Incoherent GRE
Coherent GRE

A

Incoherent GRE

230
Q

Incoherent GE pulse sequences prevent the stimulated echo from contributing to image contrast by using:

RF spoiling
Gradient spoiling
Rewinder gradients
RF spoiling and Gradient Spoiling

A

RF spoiling and Gradient Spoiling

231
Q

T or F
RF spoiling can be accomplished through the use of digitized RF pulses

A

T

232
Q

T or F
Gradient Spoiling can be accomplished through the application of all 3 gradients

A

T

233
Q

Incoherent GE pulse sequences are typically used to obtain _____ and ____ weighted images

A

T1 and PD

234
Q

Which of the following parameters would most likely produce T1 weighted images when an incoherent GE pulse sequence is applied

100ms TR, 10ms TE, 45 deg FA
30ms TR, 5ms TE, 35 deg FA
30ms TR, 30ms TE, 90 deg FA
200ms TR, 5ms TE, 90 deg FA

A

30ms TR, 5ms TE, 35 deg FA

235
Q

The flip angles applied during incoherent gradient echo pulse sequences fall within a range of

5 to 20
30 to 45
45 to 60
70 to 110

A

30 to 45

236
Q

What type of steady state pulse sequence samples both the gradient echo (FID) and the stimulated echo (RTM)?

Fast GRE
SSFP
Incoherent GRE
Coherent GRE

A

Coherent GRE

237
Q

Coherent GRE pulse sequences apply _____ to allow both the FID and stimulated echo to contribute to image contrast

A

Rewinder gradients

238
Q

Coherent GE pulse sequences are achieved through the application of a rewinder _______ gradient

A

Phase encoding

239
Q

Coherent GRE sequence are used to obtain ___ weighted images

A

T2*

240
Q

Which set of parameters would provide the best T2* images when a coherent gradient echo pulse sequence is applied

30ms TR, 20ms TE, 35 deg FA
100ms TR, 10ms TE, 45 deg FA
30ms TR, 20ms TE, 65 deg FA
5ms TR, 15ms TE, 35 deg FA

A

30ms TR, 20ms TE, 35 deg FA

241
Q

What type of steady state pulse sequence only samples the stimulated echo?

Fast GRE
SSFP
Incoherent GRE
Coherent GRE

A

SSFP

242
Q

SSFP pulse sequences apply _____ in order to rephase the stimulated echo (RTM) so it may contribute to image contrast

A

Rewinder gradients

243
Q

T or F

Magnetic field inhomogeneities greatly effect image quality when applying a SSFP pulse sequence

A

F

244
Q

SSFP typically provide ____ T2 Contrast

A

Truer

245
Q

SSFP pulse sequences are achieved through the application of a rewinder _____ gradient

A

Phase encoding

246
Q

T or F
SSFP sequences compensate for dephasing caused by magnetic field inhomogeneities

A

T

247
Q

Which of the following sets a parameters would likely provide the best T2 image weighting when a SSFP pulse sequence is applied

40ms TR, minimum TE, 40° flip angle

100 MS TR, 10 MS TE, 40° flip angle
40 MS TR, minimum TE, 65° flip angle

5 MS TR, 15 MS TE, 65° flip angle

A

40ms TR, minimum TE, 40° flip angle

248
Q

The flip angles applied during SSFP pulse sequences fall within a range of

A

30 to 45°

249
Q

What type of gradient Echo pole sequence uses a significantly shorter TE by only transmitting part of a RF pulse and only sampling and portion of the echo

A

Fast gradient Echo pulse sequence

250
Q

What term describes the method used when only a portion of the echo is sampled

A

Partial ecotechnique

251
Q

What type of gradient Echo pulse sequence uses a balanced gradient system and larger flip angles in order to correct phase errors from flowing blood

A

Balance gradient Echo pull sequence

252
Q

Phase mismapping is also referred to as

A

Phase ghosting or motion artifact

253
Q

Aliasing is also referred to as

A

Phase wrap

254
Q

Aliasing is occurred when ______ occurs along the Phase axis

A

Undersampling

255
Q

Truncation or Gibbs artifact appears as ______ occurring at the interface of high and low signal intensities

A

Black bands

256
Q

Tunication or Gibbs artifact can be reduced by increasing the _____ to prevent undersampling

A

NEX

257
Q

List the precessional frequency differences between fat and water at 1T, 1.5T and 2T

A

147, 220, 440Hz

258
Q

Chemical shift occurs at what axis

A

Frequency encoding

259
Q

Chemical shift artifacts are caused by the difference between precessional frequencies of ____and____

A

Fat, water

260
Q

Chemical shift artifacts appear as ________ at the interface between fat and water along the frequency encoding axis

A

Dark edges

261
Q

The larger the pixel size the more chemical shift artifact occurs. T or F

A

T

262
Q

Chemical misregistration is also known as _____ artifact

A

Type 2

263
Q

Chemical misregistration or type 2 artifact appear as _______ around certain organs were fat and water interface within the same voxel

A

Rings of dark signal

264
Q

What body part does chemical misregistration usually occur around

A

Kidneys

265
Q

Using an _______ sequence can compensate for chemical misregistration artifact because of their 180° rephasing pulse

A

SE

266
Q

What TE interval are fat and n water in phase with each other

A

4.2ms

267
Q

Dixon technique is known as _____ of phase imaging

A

Out

268
Q

For out of phase or Dixon technique TE of ______is desirable to allow chemical misregistration artifact to occur so a dark outline will appear around structures or fat and water interface

A

2.1ms

269
Q

Partial volume averaging is present in all images to some degree. T or F

A

T

270
Q

Partial volume averaging is caused by the use of ______ voxels

A

Large

271
Q

Cross talk appears as areas of_____ signal

A

Dark

272
Q

Cross excitation appears as a reduction in image_____

A

Contrast - image is darker

273
Q

To compensate for cross excitation a slice gap of____ is recommended

A

30%

274
Q

Interleaving excites every other slice into acquisitions so no gap spaces needed. T or F

A

T

275
Q

Moire artifact is only present in_____ pulse sequences

A

GE

276
Q

Moire artifact presents as black and white _____ along the edges of the field of view

A

Banding

277
Q

Moire artifact is caused by a combination of wrap around artifacts and magnetic field inhomogeneities. T or F

A

T

278
Q

To compensate for Moire artifact, switch to a ____ pulse sequence, keep anatomy away from the ____ and Make sure all anatomy is in the ___

A

SE, bore, FOV

279
Q

Parallel imaging artifact is only seen when performing parallel imaging and using multichannel _______ coils

A

Phased array

280
Q

Parallel imaging artifacts appear as anatomy from the outside of the____ folded onto the end anatomy inside along the_____ encoding axis

A

FOV, phase

281
Q

Two compensate for a parallel imaging artifact you may reduce the_____ factor or use a calibration scan

A

Acceleration

282
Q

Magic angle artifact can occur around areas where _____are present in the imaging volume

A

Tendons

283
Q

Magic angle artifacts appear as an area of _______signal intensity in your areas where collagen is present

A

High

284
Q

Magic angle artifacts are caused when collagen-containing structures light at an angle of _____ to the main magnetic field

A

550 degrees

285
Q

To compensate for magic angle artifact, alter the angle of the anatomical structure or lengthen the ____

A

TE

286
Q

What is the pixel phase dimension when given a FOV of 240 mm and a 256x128 Matrix?

A

240/256

287
Q

____ directly controls T1 weighting

A

TR

288
Q

The TE is the time between the alpha pulse and the

A

Peak of the Echo

289
Q

____ directly controls T2 image weighting

A

TE

290
Q

Doubling the NSA, the scan time is ___

A

Doubled

291
Q

If the NSA is quadrupled the scantime is

A

Quadrupled

292
Q

Doubling the field of view _____the signal

A

Quadruples

293
Q

Slice thickness is determined by the _____of the slicelet gradient and the transmitted bandwidth

A

Slope

294
Q

A steep slice select gradient and a narrow transmit bandwidth are needed to achieve____ slices

A

Thin

295
Q

A shallow slice select gradient slope and a broad transmit bandwidth are needed to achieve _____slices

A

Thick

296
Q

Gap is determined by the ____ of the slices as well as the corresponding slice select gradient slope

A

Thickness

297
Q

The ETL corresponds to the number of _____ applied

A

180 degree rephasing pulses

298
Q

Echoes that represent image contrast get placed in the _____ of k space

A

Center

299
Q

Spatial resolution data are put where in case space

A

Periphery

300
Q

The transmit bandwidth is influenced by the slice ____

A

Thickness

301
Q

If you double the receive bandwidth then ______percent of the signal is lost

A

40

302
Q

T2 shine through artifact occurs when areas with a very long ____ decay time remain bright on DWI trace images

A

T2

303
Q

Areas with pathology or restricted diffusion appear bright on______ images

A

DWI Trace

304
Q

Pathology or areas with restricted diffusion appear _____ on ADC post-processing maps

A

Dark

305
Q

Normal tissue or free diffusion has a dark appearance on

A

DWI Trace images

306
Q

Normal tissue or free diffusion areas have a bright appearance on

A

ADC post-processing maps

307
Q

Lemonar flow is considered_____ order motion

A

First

308
Q

Laminar flow has a ____ velocity

A

Constant

309
Q

Turbulent flow is considered ____ order motion

A

3rd

310
Q

Turbulent flow is the _____ fluctuation of blood through an occlusion

A

Random

311
Q

Time of flight phenomenon is only observed using ____ sequences

A

SE

312
Q

TOF phenomenon is not observed during GE sequences because the rephasing ingredient is not

A

Slice selective

313
Q

TOF effects increase as flow velocity

A

Inceases

314
Q

As the ____ increases, more flowing nuclei exit the slice between the excitation pulse and the rephasing pulse

A

TE

315
Q

Increasing the ____ thickness decreases TOF effects

A

Slice

316
Q

Entry slice phenomenon is also known as the

A

Inflow effect

317
Q

The inflow effect explains how spins flowing _____ to a stack of slices enter the stack unsaturated and produce more signal than stationary nuclei that receive repeated excitation

A

Perpendicular

318
Q

The further the flow of nuclei enter the stack, they become more saturated which _____ entry slice phenomenon

A

Decreases

319
Q

Time of flight imaging uses an _____ GE pulse with gradient moment nulling

A

Incoherent

320
Q

Increasing the field of view from 120 mm to 240 mm we’ll have what effect on SNR

A

Snr increases by a factor of 4

321
Q

When steep gradient slopes are applied, data gets mapped into the_____ of k space

A

Periphery

322
Q

True or false. Imaging coils perform best when positioned perpendicular to the XY plane

A

T

323
Q

Which of the following parameters influences SNR the greatest?

Field of view, TR, receive bandwidth, NSA

A

Field of view

324
Q

The slope of the ______, along with the transmit bandwidth determines the slice thickness

A

Slice select gradient

325
Q

During gradient echo pulse sequences, the controlling factors for T1 relaxation are ____ and _____

A

TR and Flip Angle

326
Q

DTI sequences are commonly used to view what in the brain

A

White matter tracks

327
Q

The ETL is directly related to the number of_______ during a fast spin echo pulse sequence

A

Echo sampled and 180° rephasing pulses applied

328
Q

When scanning a female pelvis what plane best demonstrates the uterus

A

Sagittal

329
Q

Both magneto hemodynamic and magneto hydrodynamic effects increase the amplitude of the

A

T wave

330
Q

The field of view is the parameter that directly impacts______ the greatest

A

SNR

331
Q

What type of flow is gradient moment nulling most efficient at rephasing

A

Laminar flow

332
Q

Typically, when GMN is applied during the acquisition of axial images, the _____ gradient is used for flow compensation

A

Slice select

333
Q

What term describes the accidental administration of contrast agents into surrounding tissue instead of directly into the vein

A

Infiltration

334
Q

A special saturation pulses capable of saturating all tissues within a specified area through the use of an extra 90° RF pulse and a

A

Broad transmission bandwidth

335
Q

Areas containing pathology appear _____ on DW Trace images

A

Bright

336
Q

Which of the following full sequences most accurately represents an IR pulse sequence

180,90,180,180
180,90,90
90,180,180
180,90,90,180

A

180, 90, 180,180

337
Q

Incoherent GE pull sequences are typically used to obtain what weighted images

A

T1 and PD

338
Q

In order to increase the SNR by 100% ( double the SNR) The NSA/NEX must be increased by a factor of

A

4

339
Q

A _______ is a bipolar gradient used during phase contrast imaging

A

Velocity gradient

340
Q

If the number of signal averages is increased by a factor of 2, what happens to the signal to noise ratio

A

The SNR increases by the root of 2 or by a factor of 1.41 or 41%

341
Q

Has slice thickness increases, spatial resolution

A

Decreases

342
Q

If attempting to obtain T2 images of a patient with a 60 BPM, what is the minimum number of R to R intervals that should be selected

A

2

343
Q

In order to more accurately diagnose a syrinx,______ can be used to reduce pulsatile flow artifacts within the spinal canal

A

Peripheral gating / triggering

344
Q

Which of the following is an imaging option that applies an extra 90° RF pulse prior to the alpha pulse in order to know the signal from a specified type of tissue throughout the entire imaging volume

Chemical band, spatial saturation, saturation band, chemical suppression

A

Chemical suppression

345
Q

Why is cardiac gating useful when imaging patients prone to seizures

A

It helps reduce pulsatile flow related artifacts within the temporal lobe

346
Q

A trigger window of ______is commonly used to compensate for heart rate fluctuation

A

10 to 20%

347
Q

The T1 relaxation time of fat is

A

200ms

348
Q

What is achieved when there are more protons aligned in a low energy state than in the high energy state

A

Equilibrium magnetization

349
Q

If the receive bandwidth is doubled approximately what percentage of the SNR is lost

A

40

350
Q

Scan time can be reduced using a ____ ETL

A

Longer

351
Q

Blurring can be reduced using a ____ etl

A

Shorter

352
Q

When a GRE sequence is used during fast breath hold dynamic contrast injections, gradient ____ is used

A

Spoiling

353
Q

If the desire is to null specific tissue using an IR sequence, the TI selected should be ___% of then T1 Relaxation Time of that tissue

A

69

354
Q

The flip angle is doubled, RF deposition increases by a factor of

A

4

355
Q

Reducing the field of view by a factor of two will reduce the voxel Volume by a factor of ____

A

4

356
Q

T or F decreasing ETL improves SNR

A

T

357
Q

T or F, decreasing RBW improves SNR

A

T

358
Q

Decreasing phase matrix____ SNR

A

Increases

359
Q

Parallel imaging can be used to _____ magnetic susceptibility artifacts

A

Decrease

360
Q

A dual Echo spin sequence generates a proton density image in a T2 weighted image. The t2 weighted image has ____ SNR

A

Lower

361
Q

Each train of echoes in a fast-spin echo sequences reduces scan time but also ____ SNR and ____ SAR

A

Decreases, increases

362
Q

In a FSE sequence, if the ETL factor is increased by a factor of three, the scan time will be 3 times _____

A

Faster

363
Q

In a FSE Sequence, the number of shots is calculated by

A

phase encodings/ETL

364
Q

A 3D IR sequence is ____ weighted

A

T1

365
Q

In a STIR sequence, the null point of fat in a 1.5 t magnet is approximately ______milliseconds

A

140 to 160

366
Q

As the TE is increased, the available number of slices is

A

Decreased

367
Q

As the TR is increased, the available number of slices is

A

Increased

368
Q

As the TR is increased, SNR is

A

Increased

369
Q

Reducing the flip angle yields images with _____ T1 information

A

Less

370
Q

Reducing the phase Matrix____ the SNR

A

Increases

371
Q

Reducing the receive____SNR

A

Increases

372
Q

Reducing the ETL ____ SNR

A

Increases

373
Q

A decrease in TR and a reduction in pixel size both____ the SNR

A

Decrease

374
Q

Increasing the ETL____ SNR

A

Decreases

375
Q

Increasing the NEX increases the SNR by

A

√Nex increase

376
Q

Decreasing the bandwidth by a factor of two increases the SNR by

A

√2

377
Q

Reducing the field of view decreases the SNR by the

A

FOV^2

378
Q

Calculate effective TR in cardiac imaging

A

60,000 / HR

379
Q

Calculate available imaging time in a cardiac MR. HR is 80bpm, trigger window 10%, trigger delay 50ms

A
  1. Find TR
    60,000/80bpm = 750ms
  2. Subtract trigger window
    750ms-( 10% of 750)
    750ms- 75 = 675
  3. Subtract delay
    675-50

Final answer is 625ms

380
Q

Signal and contrast are store in the ____ of k space

A

Center

381
Q

Data containing ____ resolution information is located in the periphery of k space

A

High

382
Q

Low frequency means ____ amplitude signal

A

High

383
Q

2D aquisitions require an ____ gap

A

Interslice

384
Q

A narrow receiver bandwidth ____ susceptibility artifact

A

Increases

MRI (1 decks)

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