Midterm 1

0.0(0)
studied byStudied by 1 person
learnLearn
examPractice Test
spaced repetitionSpaced Repetition
heart puzzleMatch
flashcardsFlashcards
Get a hint
Hint

How many types of principal flow are there?

Get a hint
Hint

four

Get a hint
Hint

The image above represents which kind of flow?

Get a hint
Hint

Spiral

Card Sorting

1/90

Anonymous user
Anonymous user
encourage image

There's no tags or description

Looks like no tags are added yet.

Study Analytics
Name
Mastery
Learn
Test
Matching
Spaced

No study sessions yet.

91 Terms

1
New cards

How many types of principal flow are there?

four

2
New cards

The image above represents which kind of flow?

Spiral

3
New cards

The Image above represents which kind of flow?

Laminar

4
New cards

The image above represents which kind of flow?

Vortex

5
New cards

Pre-sat bands can’t be brought into the FOV itself

false

6
New cards

The frequency difference between fat and water is called chemical shift

true

7
New cards

The frequency difference between fat and water at 1.5 T is:

220 Hz

8
New cards

Which type of saturation does the above image have?

Fat

9
New cards

Ghosting or _ produces replications of moving anatomy

Phase mismapping

10
New cards

Ghosting only occurs along the ___ gradient

Phase encoding

11
New cards

Phase mipmapping occurs because of

Anatomy moving along the phase encoding gradient

12
New cards

According to the Nyquist theorem, frequencies must be sampled at least _____ per cycle to map them correctly

twice

13
New cards

Chemical shift artifact occurs along the frequency encoding axis

true

14
New cards

Truncation artifact produces a banding artefact at the interfaces of high and low signal

true

15
New cards

Magnetic susceptibility artifact is more prominent in

Gradient echo sequences

16
New cards

To reduce magnetic susceptibility artifact:

Use SE instead of GE, decrease TE, and reduce the FOV

17
New cards

Zipper artifact is caused by extraneous RF entering the room

True

18
New cards

The image above demonstrates which artifact?

phase mismapping

19
New cards

The image above demonstrates which artifact?

Magnetic susceptibility artifact

20
New cards

The image above demonstrates which artifact?

Aliasing

21
New cards

The image above demonstrates which artifact?

Zipper artifact

22
New cards

The image above demonstrates which artifact?

Chemical misregistration

23
New cards
<p>The image above demonstrates which artifact?</p>

The image above demonstrates which artifact?

Magic angle artifact

24
New cards

MRI and MRA techniques rely on the anatomy of the vessel itself (rather than the motion of blood within the vessel).

False

25
New cards

MRCP stand for:

Magnetic Resonance Cholangiopancreatography

26
New cards

Aluminum and gadolinium are examples of materials with what type of magnetism?

Paramagnetism

27
New cards

Once a ferromagnetic material is exposed to an external magnetic field it retains magnetization and therefore becomes magnetized.

True

28
New cards

Which type of materials display the greatest positive magnetic susceptibility?

Ferromagnetic

29
New cards

The magnetic field strength in superconducting magnets is maintained with cryogens at a temperature of:

4 K (450 F)

30
New cards

Passive magnetic shielding can be accomplished by lining the scan room walls with:

Steel

31
New cards

The type of MRI magnet that allows the highest field strength is a _______.

Superconductive magnet

32
New cards

In a typical superconducting (cylindrical bore) magnet, the direction of the magnetic field is:

horizontal

33
New cards

The direction of the magnetic field in a typical permanent magnet is:

vertical

34
New cards

What is the maximum field strength of commercially available MRI scanners traditionally used for clinical imaging of humans?

3T

35
New cards

Shielding reduces the magnetic fringe field

True

36
New cards

Since water has a high signal intensity in T2 weighted images, pathology is commonly evaluated using this type of weighting

True

37
New cards

The most commonly used contrast agents are __________ based.

Gadolinium

38
New cards

Gadolinium is an example of a T1 agent.

True

39
New cards

Gadolinium is highly toxic, but it can be made safe for use by binding or chelating the gadolinium to other molecules.

True

40
New cards

Gadolinium can cross the breakdowns in the blood–brain barrier (BBB)

True

41
New cards

Nephrogenic Systemic Fibrosis is a fatal condition with virtually no cure

True

42
New cards

If bony lesions are to be evaluated with gadolinium on T1 weighted images, fat suppression techniques should be used.

True

43
New cards

The net displacement of molecules diffusing across an area of tissue per second is called

Diffusion

44
New cards

In areas of restricted diffusion, the ADC is low, whereas in areas of free diffusion it is high

True

45
New cards

The most common use of DWI is in the brain after infarction.

true

46
New cards

The directional term “Superior” denotes:

towards the head

47
New cards

The directional term “Lateral” denotes:

Away from the midsagittal plane

48
New cards

The directional term “Medial” denotes

towards the midsagittal plane

49
New cards

The directional term "Plantar" denotes

The sole of the foot

50
New cards

The directional term “Superficial” denotes

Near the body surface

51
New cards

The directional term “Proximal” denotes:

Toward a reference point or source within the body

52
New cards

The directional term “Anterior” denotes:

toward the front of the body

53
New cards

The regional term “Cephalic” denotes:

head

54
New cards

The regional term “Antecubital” denotes

anterior surface of the elbow area of the arm

55
New cards

The sella turcica houses the:

pituitary gland

56
New cards

Located in the ________ bone is the foramen magnum, which allows the brainstem to continue inferiorly as the spinal cord.

occipital

57
New cards

There are _______ vertebrae in the Cervical Spine.

7

58
New cards

Compared with conventional spin echo

sequences, the fast pulse sequences,

such as fast spin echo (FSE) or rapid

acquisition relaxation enhanced (RARE)

have ________RF deposition.

the same?

59
New cards

__ is technique in which a complete image is obtained from one selective excitation pulse

EPI

60
New cards

A 90° excitation pulse followed by one or more 180° rephasing pulses is called a

Spin echo

61
New cards

The pulse sequence interval from the 90° RF pulse to the collection of the MR signal is termed what?

TE (echo time)

62
New cards

The IR the sequence interval from the initial 180° RF pulse, used to flip the net magnetization into the negative “z” plane, to the 90° RF pulse is termed________.

TI

63
New cards

In a T1  weighted Image; a short TR is used to______.

maximize t1 effects

64
New cards

The vertical axis of K space represents which axis of the image?

phase encoding

65
New cards

In a T2  weighted Image; a long TE is used to______

maximize t2 effects

66
New cards

TOF effects depend on which of the following?

slice thickness, echo time, and velocity of flow

67
New cards

In a Spin Echo Sequence, TR is the time between each 90° excitation pulse for each slice and TE is the time between the 90° excitation pulse and the peak of the spin echo.

true

68
New cards

The superimposition of signal that occurs when a LARGE FOV is acquired is known as:

partial volume averaging

69
New cards

motion is seen as a smearing in the

phase encoding direction

70
New cards

The superimposition of signal that occurs when a SMALL FOV is acquired is known as:

wrap around/fold over/aliasing

71
New cards

Aliasing occurs because tissue outside the selected FOV is:

undersampled

72
New cards

Gibbs, or truncation artifact is seen as:

high and low signal intensity bands

73
New cards

Chemical shift occurs because the:

fat and water precesses at different frequencies

74
New cards

In order to compensate for aliasing

oversample & FOV can be enlarged

75
New cards

To correct for Gibbs artifact, the

number of phase encoding is increased

76
New cards

Chemical shift becomes more obvious as the

reciver bandwidth is decreased

77
New cards

Magnetic susceptibility effects are more prominent with

gradient echo sequences

78
New cards

A leak in the RF shielding can appear as a:

“zipper” artifact in the frequency direction

79
New cards

Susceptibility effects can be reduced by:

reducing the FOV and reducing the TE

80
New cards

Flow artifacts can be reduced by:

GMN, spatial pre-sat pulses, & shortening the TE

81
New cards

A decrease in voxel volume leads to a decrease in:

chemical shihft & partial volume averaging

82
New cards

As slice thickness increases, partial volume averaging

increases

83
New cards

As FOV increases, partial volume averaging:

increases

84
New cards

As TR increases, partial volume averaging:

stays the same (not affected, TR does not mess with voxel size)

85
New cards

Respiratory artifacts can be reduced by:

respiratory gating/triggering and Increasing the number of signals averaged

86
New cards

Motion artifact occurs due to period and/or aperiodic motion, whereby following motions are examples of what?

A. periodic motion

B. aperiodic motion

C. pulsatile motion

D. daily motion

  • Patient movement= B

  • Peristaltic motion= B & D

  • Respiratory motion = A

  • Cardiac motion= A & C

87
New cards
<p>Which artifact?</p>

Which artifact?

phase mismapping

88
New cards
<p>Which artifact?</p>

Which artifact?

Magic angle artifact

89
New cards
<p>which artifact?</p>

which artifact?

Aliasing

90
New cards

Chemical shift artifacts occur in which direction?

frequency encoding

91
New cards

Motion artifacts for conventional MR imaging occur in which direction?

phase encoding