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MRI in practice 5th ed. > Chapter 10 > Flashcards

Chapter 10 Flashcards

MRI safety

1
Q

The safe Gauss line determined by the FDA for a person with an electromechanical device is ____.

a. 0.5
b. 5
c. 10
d. 0.1

A

b. 5

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2
Q

Family members and ancillary personnel accompanying the patient into the scan room:

a. Don’t need to be screened because they are not having the MRI
b. Can enter the scan room to check on the patient, but cannot stay during scanning
c. Should be screened as if they are going through the procedure themselves
d. Must wear a lead apron during the scan

A

c. Should be screened as if they are going through the procedure themselves

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3
Q

Which of the following would NOT be considered a high risk patient:

a. Patients likely to develop seizures or claustrophobic reactions
b. Patients with a greater than normal potential for cardiac arrest
c. Patient who is having a study with gadolinium
d. Unconscious, heavily sedated, or confused patients with whom reliable communication cannot be maintained

A

c. Patient who is having a study with gadolinium

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4
Q

Doubling the flip angle (ex: from 90 degrees to 180 degrees) results in ______ times as much RF absorption

a. 2
b. 3
c. 4
d. .32

A

c. 4

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5
Q

Hemodynamic effect of the main magnetic field (B0) results in elevation of ______ wave

a. T
b. R
c. Q
d. P

A

a. T

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6
Q

RF energy can affect the patient by:

a. Decreasing body temperature
b. Increasing body temperature
c. Hearing loss
d. Loss of hair

A

b. Increasing body temperature

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7
Q

The name given to the unit of RF absorption is ____________.

a. Sensitization rate
b. Specialized absorption rate
c. Specific absorption rate
d. None of the above

A

c. Specific absorption rate

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8
Q

The imaging sequence that is of most concern for time varying/gradient magnetic field effects is:

a. Spin echo
b. Gradient echo
c. Fast spin echo
d. Echo planar (EPI)

A

d. Echo planar (EPI)

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9
Q

Which of the following organs have proven to be the most sensitive to elevated temperatures during MRI scanning, because of reduced capabilities of heat dissipation?

a. Pituitary/adrenal
b. Testis/eye
c. Testis/prostate
d. Eye/cuticles

A

b. Testis/eye

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10
Q

Following a motor vehicle accident, you are asked a patient with a C3 fracture to evaluate for cord compression, what would be the bast way to proceed?

a. Quickly rush the patient into the scanner on the stretcher they came on so that you don’t aggravate the fracture
b. Allow the patient to wear their favorite gold necklace during the procedure
c. Upon finding out the patient had a total hip replacement, cancel the exam
d. Ask the patient and family about the possibility of having metal fragments in the body

A

d. Ask the patient and family about the possibility of having metal fragments in the body

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11
Q

Which of the following patients should probably NOT be scanned?

a. Patient with a stent
b. Pregnant patient in the first trimester
c. Nursing mother
d. Patient with elevated BUN and low creatine levels

A

b. Pregnant patient in the first trimester

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12
Q

Release of cryogens, explicitly helium, can:

a. Make patients warm
b. Cause localized tissue warming
c. Cause frostbite/asphyxiation
d. Cause hallucinations

A

c. Cause frostbite/asphyxiation

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13
Q

If large loops are formed creating a “biological circuit” patients can be burned where there is a small surface area of skin in contact

a. True
b. False

A

a. True

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14
Q

Which of the following have been contraindicated for MRI scans?

a. Prosthetic hip replacements
b. Cochlear implants/penile implants
c. Silastic heart valves
d. Intravascular coils, filters and stents

A

b. Cochlear implants/penile implants

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15
Q

Which of the following is NOT a hazard to the patient for MRI scanning?

a. Neurostimulator
b. Cochlear implant
c. Dentures
d. All of the above

A

c. Dentures

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16
Q

Gradient magnetic fields are a safety concern because they:

a. Produce large amounts of RF energy
b. Induce currents in conductors
c. Cause short-term memory loss
d. All of the above

A

b. Induce currents in conductors

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17
Q

An object that has been tested and found to be MR Safe at 3.0T will be MR Safe at 1.5T as well.

a. True
b. False

A

b. False

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18
Q

Which of the following cases would be safe to scan?

a. Patient with an intracranial ferromagnetic aneurysm clip
b. Patient with an abdominal aortic stent
c. Patient with a known nonferrous intracranial aneurysm clip
d. Both b. & c.

A

d. Both b. & c.

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19
Q

If a patient to be scanned needs an IV drip, O2 tank and is unable to walk what is the proper procedure?

a. Reschedule exam until the patient no longer has these limitations
b. Bring the patient into the scan room with the equipment
c. Remove all equipment to do the scan
d. Place the IV on an MR Safe pole, use MR Safe O2 tank and transfer the patient to an MR Safe gurney for transport into the scan room

A

d. Place the IV on an MR Safe pole, use MR Safe O2 tank and transfer the patient to an MR Safe gurney for transport into the scan room

20
Q

The FDA limits the effects of RF absorption to an increase in core body temperature of:

a. 0.1 degree C
b. 1 degree C
c. 1 degree F
d. There is no limit

A

b. 1 degree C

21
Q

An item that is known to pose hazards in all MRI environments is termed, “MR ______?”

a. Safe
b. Conditional
c. Unsafe
d. Unconditional

A

c. Unsafe

22
Q

There have been several burns and fires associated with exposure to RF in MRI

a. True
b. False

A

a. True

23
Q

Ferromagnetic metal objects can become airborne projectiles in the presence of a strong magnetic field. This is known as the __________ ?

a. Dart phenomena
b. Target affect
c. Airborne phenomenon
d. Missile affect

A

d. Missile affect

24
Q

Regarding MRI facility zones, the ACR white paper would term an area that generally pertains to the patient waiting room as Zone _____?

a. I
b. II
c. III
d. IV

A

b. II

25
Q

Regarding levels of personnel, the ACR white paper deems individuals who have very extensive training in MRI safety issues as Level _______?

a. 1
b. 2
c. 3
d. 4

A

b. 2

26
Q

The MRI environment, especially the scan room, is ultimately the responsibility of the:

a. Physician reading the MRI film
b. MRI office manager
c. MRI technologist on duty
d. Radiographer

A

c. MRI technologist on duty

27
Q

An explosive boiling off of liquid helium and a sudden loss of superconductivity is known as a:

a. Quench
b. Ramp up
c. Ramp down
d. Service

A

a. Quench

28
Q

Passed through a strong magnetic field, some implanted and ferromagnetic devices such as neuro-aneurysm clips, suture material and surgical clips may experience the force of:

a. Inertia
b. Torque
c. Acceleration
d. Deceleration

A

b. Torque

29
Q

The force that can cause a ferromagnetic object such as an O2 tank to become a projectile in the fringe field is called:

a. GMF
b. Torque
c. RF
d. Translational attraction

A

d. Translational attraction

30
Q

Prior to entering the MRI environment all patients must go through a screening process:

a. Verbally
b. Written
c. Verbally and written
d. Physician

A

c. Verbally and written

31
Q

A ferromagnetic object in the shape of a sphere will NOT experience:

a. Heating
b. Torque
c. Translational attraction
d. Conductivity

A

b. Torque

32
Q

Side effects associated with gradient magnetic field (GMF) are:

a. Tissue heating and cataract formation
b. Infertility
c. Acoustic noise, peripheral nerve stimulation and magnetophosphenes
d. Testicular degeneration in mice

A

c. Acoustic noise, peripheral nerve stimulation and magnetophosphenes

33
Q

Patients with cardiac pacemakers are contraindicated for an MRI scan in magnets with a field strength of:

a. O.5T or higher
b. Any strength
c. 1.5T or higher
d. 1T or higher

A

b. Any strength

34
Q

Unless specifically designated, neurostimulators and bone growth stimulators are NOT considered safe for scanning

a. True
b. False

A

a. True

35
Q

Acoustic noise is experienced during an MRI study and is caused by:

a. RF
b. GMF
c. B0
d. Shim coils

A

b. GMF

36
Q

Side effects associated with the main magnetic field (B0) are:

a. Hemodynamic effect, fatigue and headaches
b. Infertility
c. Bones healing faster, cardiac fibrillation, magnetophosphenes
d. Testicular degeneration in mice

A

a. Hemodynamic effect, fatigue and headaches

37
Q

The factor which determines the calculated SAR averages is:

a. Heat dissipated over time
b. Field strength
c. The patient’s weight in kilograms
d. An average calculation of heat per milliseconds

A

c. The patient’s weight in kilograms

38
Q

Guidelines which exclude pregnant individuals from exposure to MRI are mainly to protect them from:

a. B0
b. Cryogens
c. RF
d. GMF

A

c. RF

39
Q

SAR is the rate that electromagnetic energy is introduced to body tissue and is measured in:

a. g/cm
b. mt/m
c. MHZ/T
d. w/kg

A

d. w/kg

40
Q

Magnetophosphenes are described as:

a. An increase of phosphorous levels in the body
b. Palpitations
c. Seeing flashes of light
d. 2nd degree burns

A

c. Seeing flashes of light

41
Q

Painful peripheral nerve stimulation can be caused by:

a. GMF
b. B0
c. Torque
d. RF

A

a. GMF

42
Q

Of the following groups of patients, which one would NOT present any special safety considerations?

a. Patients with a cardiac pacemaker
b. Patients on life support
c. Patients with a history as a metal worker
d. Patients with titanium screws in a bone

A

d. Patients with titanium screws in a bone

43
Q

What government agency sets the SAR for MRI systems?

a. FAA
b. FDA
c. FCC
d. FBI

A

b. FDA

44
Q

Maximum exposure to RF averaged over the whole body is:

a. No more than 4 w/kg
b. No more than 3.2 w/kg
c. No more than 8 w/kg
d. A maximum spatial peak of 8 w/kg

A

a. No more than 4 w/kg

45
Q

SAR stands for Specific Acquisition Rate

a. True
b. False

A

b. False

MRI in practice 5th ed. (10 decks)

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