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MRI QUIZ > MRI Hardware, History and Magnetism > Flashcards

MRI Hardware, History and Magnetism Flashcards

1
Q

Gadolinium contrast gets first approval by FDA in what year?

A

1988!!

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2
Q

How does Gad function as a contrast agent?

A

it SHORTENS the t1 time of tissue

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3
Q

The substances that bind to gadolinium ions are defined as

A

Chelates

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4
Q

Gadolinium chelates used in MR imaging are :

diamagnetic or paramagnetic?

A

paramagnetic

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5
Q

Gadolinium has ___ unpaired electrons?

A

7

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6
Q

Gadolinium makes bowel appear T1 and T2 Hypointense

True or False

A

True

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7
Q

an anti-peristalsis agent in MR Enterography procedures.

A

Glucagon

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8
Q

How come when we use contrast, a metastatic lesion will enhance?

A

has to do with the breakdown in the blood brain barrier

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9
Q

What is the standard dose of gadolinium?

A

0.1 mmol/KG (pay attention, must be in KG)

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10
Q

Following the administration of IV gadolinium contrast, it is recommended to:

A

Follow the injection with a flush of 5 mL saline

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11
Q

VoLumen is a contrast agent used for

A

bowel enhancement

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12
Q

The location of the coils installed in the MRI scanner, from the inner point closest
to the patient to the outer most edge are :

shim coils, main magnet, RF coils and gradient coils..what order?

A

RF radiofrequency coils, gradient coils,

shim coils, main magnet

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13
Q

the time it takes for the gradient to reach its full amplitude is called

A

gradient rise time

think about the time it takes for you to fully stand up/rise up??

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14
Q

What rise time measured in?

A

microseconds “mT/m (millitestla / meter)

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15
Q

s the speed rate of ascent or descent of a gradient from

zero to its maximum amplitude, either positive or negative

A

the gradient slew rate

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16
Q

How do we calculate the gradient slew rate

A

it is the amplitude divided by the rise time in msec.

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17
Q

the time the gradients are on during a TR period, the

“gradient working time.”

A

duty cycle

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18
Q

What is the primary cause of the noise in the MRI room?

A

the rapid successive switching of gradient coils

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19
Q

If a sagittal slice plane has been selected, the ___ gradient is enabled to alter the
magnetic field around the patient’s body.

x y or z

A

x

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20
Q

If a coronal slice plane has been selected, the __ gradient is enabled to alter the
magnetic field around the patient’s body.

x y or z

A

Y

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21
Q

If a axial slice plane has been selected, the ___ gradient is enabled to alter the
magnetic field around the patient’s body.

A

z

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22
Q

Applying two gradients simultaneously during slice selection would produce an
____ slice

A

oblique

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23
Q

what is an example of when we do a “oblique” slice?

A

YX gradient combination in a coronal

oblique of the shoulder, parallel to the supraspinatus tendon

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24
Q

In a cross sectional view of MRI system coils, the RF coils are closest to the patient.

True or False?

A

true

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25
Q

Why is a fast spin echo the most concerning in regards to RF heating?

A

it has multiple echo train lengths leading to potential increase in tissue heating.

26
Q

What is the SAR measured in?

A

watts / kg

27
Q

Larger patient = increased or decrease SAR??

A

large patient = increased SAR

28
Q

When going from a linear coil to a quadrature coil, SNR is increased by ___ %?

40 , 60 , 80

A

40

29
Q

Radiofrequency (RF) shielding can be achieved by lining the scanner room walls
with copper.
True or False

A

True

30
Q

doubling the magnetic field strength will double the SNR

A

True

31
Q

What is the ideal consistent room temp that the MRI scanning room should be?

A

65-75 with humidity of 50-70%

32
Q

what is a positive to using the body coil?

A

the large FOV capability, but it lacks the high SNR.

33
Q

The MRI system component that produces the magnetization of proton spins
(alignment) is known as the

main magnet or the gradient system?

A

main magnet

34
Q

The MRI system component that provides the ability to perform spatial
encoding is the

main magnet or gradient system?

A

gradient system

35
Q

The liquid cryogens are cooled in a superconducting magnet at a temperature of _________

A

4 Kelvin

36
Q

The purpose of shimming the magnet is to make the B0 field as homogenous as possible

True or False?

A

True

37
Q

The array processor is responsible for reconstructing the collected MR images/data using the Fourier transform, and is located in the MR equipment room.

A

True

38
Q

Field strength at magnet isocenter is measured in units of:

tesla or gauss?

A

Tesla

39
Q

The unit of measurement of the magnetic field surrounding the periphery of the MR scanner is expressed as:

Gauss or Tesla?

A

gauss

40
Q

The liquid cryogens most often used to maintain field strength in a super conducting MR system are

A

Helium

41
Q

Doubling the magnetic field strength will ___ the SNR.

double or decrease?

A

double

42
Q

who coined the word electricity?

A

William Gilbert

43
Q

What is Joseph Fourier famous for?

A

he developed the mathematical equation to analyze the heat transfer between solid bodies

44
Q

Who first realized that the earth was one big giant?

A

William Gilbert, same person that coined the world electricity

45
Q

Who discovered that an electric current could produce a magnetic field?

A

Oersted

46
Q

Who is Michael Faraday?

A

He discovered electromagnetic induction. When a magnet was moved inside a coil of copper, a tiny electric current flows through the wire (aka Faradays Law)

47
Q

Whos equations describe how electric and magnetic fields are generated and altered by each other and by charges and currents?

A

Maxwell

48
Q

Who is Nikola Tesla?

A

He discovered the first rotating magnetic field. aka Tesla :)

49
Q

who developed the equation showing precession of nuclear spins being proportional to magnetic field strength?

A

Larmor

50
Q

In 1946 _____ proposed a Nobel Prize winning paper stating that the nucleus behaves like a magnet. He realized that a charged particle (proton) spinning on its own axis has a _____ momentum.

A

Feliz Bloch, and magnetic momentum

51
Q

Who created the fourier transform?

A

Richard Ernst in 1975

52
Q

Who obtained the first MRI picture?

A

Lauterbur

53
Q

The type of rock upon which magnetism was discovered is called?

A

magnetite

54
Q

______ discovered that tumors and normal tissue can be distinguished by NMR because of their relaxation times

A

Damadian

55
Q

What is the principle nucleus utilized in MR and why is it it used so much in MR?

A

hydrogen, bc our body has an abundance of it and its a primary element in both water and fat

56
Q

Magnetic field inhomogeneity is expressed in ____ per million

A

parts per million (ppm)

57
Q

10,000 gauss= __ tesla?

A

10,000 gauss= 1 tesla

58
Q

The main magnetic field is parallel to the long axis of B___

b0 or b1?
.

A

b0

59
Q

one of the three magnetic states of matter :

weak magnetic moment

A

paramagnetic

60
Q

one of the three magnetic states of matter :

relatively strong magnetic field..are iron or iron-like substances

A

ferromagnetic

61
Q

one of the three magnetic states of matter :

no magnetic field

A

Diamagnetic

62
Q

Gadolinium is considered what type of magnetic state?

Ferromagnetic, paramagnetic, or diamagnetic

A

Paramagnetic because it creates a weak magnetic field

MRI QUIZ (10 decks)

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