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MRI exam > MRI screening and safety > Flashcards

MRI screening and safety Flashcards

1
Q

family members and ancillary personnel accompanying the patient into the scan room
A) do not need to be screened as they are not scanned
B) can enter the room to check on the patient but can’t stay during the scan
C) should be screened as if they are undergoing the procedure
D) must wear a lead apron during the procedure

A

c

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2
Q

in preparation for the MRI scan patients should be encouraged to
A) wear their own clothing
B) wear a wrist watch so that they can be aware of the time
C) keep their hearing aids in so they can hear us
D) change into a hospital gown that is MR safe

A

d

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3
Q

MRS jones has just been sent to the MRI department from the emergency department following an MVA. She has suffered a C3 fracture and her drs are worried about cord compression at that level. the best method for proceeding is
A) rush her quickly on her own stretcher into the scan room so not to aggravate her fracture
B) ask her and her family about the possibility of metal fragments in her body
C) on finding out she has a THR cancel the exam
D) allow her to wear her favourite gold necklace during the procedure

A

b

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4
Q

people who should be educated about the effects of the static MF include
1. nursing staff and the code team
2. house keeping staff and members of the fire department
3. anaesthesiologists and the respiratory team
4. technologist and radiologists
A) 4
B) 1, 4
C) 1, 3, 4
D) 1, 2, 3, 4

A

d

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5
Q

according tot he white paper of MR safety persons are identified into levels, what includes a level 2 personnel
A) no MRI safety training
B) limited MRI safety training
C) extensive MRI safety training
D) there is no level 2

A

c

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6
Q

imaging centres should be separated into zones including all of the following except
A) Zone 0- the parking lot
B) zone 1- freely accessible to any level of MR personnel
C) zone 2- interface between zone 1 and 3
D) zone 3- console room and last stop before entering the scan room
E) zone 4- the hot zone or scan room itself

A

a

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7
Q

a screening questionnaire for patients about to undergo MRI should include information about
A) prior injuries
B) prior surgery or implants
C) pregnancy
D) all of the above

A

d

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8
Q

terminology for devices and implants changed a few years ago, whereby the term MR compatible has been replaced with the following except
A) MR reliable
B) MR safe
C) MR unsafe
D) MR conditional

A

a

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9
Q

absolute contraindication for MRI include
1. intracranial vascular clips, unless they are known to be safe
2. cardiac pacemakers, unless they are known to be safe
3. pregnancy
4. intraoccular ferrous foreign bodies
A) 1
B) 1, 2
C) 1, 2, 3
D) 1, 2, 4

A

d

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10
Q

the accepted standard of care for detection of intraocular foreign bodies is
A) CT
B) MRI
C) Plain film
D) visual examination

A

c

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11
Q

a method that is most accurate for detection of small intraocular ferous foreign bodies is
A) CT
B) MRI
C) plain film
D) visual examination

A

a

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12
Q

before the patient enters the MRI environment they should be screened for
A) prior injuries
B) prior surgical implants
C) pregnancy
D) all of the above

A

d

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13
Q

of the following implants which is considered safe to be scanned by MRI
A) ferrous aneurysm clips
B) neurostimulators
C) cardiac pacemakers
D) heart valves

A

d

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14
Q

if monitoring is to be achieved by electrical and or mechanical devices it is important that compatibility with the MRI system is to be demonstrated by
A) clearance by the FDA
B) prior testing
C) manufacturers declaration
D) all of the above

A

d

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15
Q

the following items are usually allowed to enter the scan room in high magnetic field systems
A) surgical stainless steel hemostats
B) surgical stainless steel scissors
C) copper tools
D) laryngoscopes

A

c

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16
Q

when used for MRI, cables from RF coils and ECG leads should be
A) braided and places straight through the imager
B) laid along the patients right arm, along the bore
C) formed into loops within the imager
D) neatly coiled ready for use

A

a

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17
Q

surface coil cables can potentially cause damage to a patient when
A) they are not frayed and rest alongside the arm of the patient
B) they are slightly touching the patient and are frayed
C) they are looped and not touching the patient
D) all of the above
E) none of the above

A

d

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18
Q

a quench can be used to
A) improve image quality in MRI
B) rapidly remove superconductivity and the magnetic field
C) satisfy the thirst of the technologist
D) lubricate the magnet coils

A

b

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19
Q

during a quench, patients and operators should be evacuated from the room to avoid
A) asphyxiation and frostbite
B) subarachnoid hemorrhage
C) ruptures tympanic membranes
D) a and c
E) a, b, c

A

d

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20
Q

what is regulated by the FDA
A) length of the bore
B) diameter of the bore
C) acoustic noise
D) scan time

A

c

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21
Q

for optimum operation of the MRI systems, the ambient temperature and relative humidity should remain between
A) 30-50˚F and 30-50%
B) 65-75˚F and 30-70%
C) 70-90˚F and 70-100%
D) none specifically

A

b

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22
Q

the acceptable safe level of exposure to magnetic fringe fields for patients with cardiac pacemakers is
A) 5-15g
B) 5-15T
C) 15-10g
D) below 5g

A

d

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23
Q

the magnetic field shielding can be achieved either actively or passively. passive shielding is achieved by lining the mri room with
A) copper
B) steel
C) lead
D) none of the above

A

b

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24
Q

RF shielding can be achieved by lining the room with
A) copper
B) steel
C) lead
D) none of the above

A

a

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25
Q

it is acceptable for the general population to be exposed to a field strength of
A) 2T
B) 4T
C) 8T
D) 5g

A

d

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26
Q

unit of measurement for RF absorption is
A) watts per pound
B) volts per pound
C) watts per kg
D) volts per kg

A

c

27
Q

MR imagers are magnetic field shielded such that
A) any metallic objects can enter the scan room
B) fringe field is confined to the bore
C) the fringe field is confined tot he scan room
D) there is no fringe field

A

c

28
Q

fringe fields are less of a concern for
A) mid field superconducting imagers
B) low field resistive imagers
C) high field superconductive imagers that are shielded
D) low field, vertical field permanent magnet imagers

A

d

29
Q

FDA limit for RF absorption for the head is
A) 2W/kg
B) 3W/kg
C) 4W/kg
D) 12W/kg

A

c

30
Q

FDA limits allowable RF absorption to
A) 0.2W/kg
B) 0.4W/kg
C) 2W/kg
D) 4W/kg

A

d

31
Q

term used to describe RF absorption is
A) sensitive acquisition range
B) specific absorption rate
C) susceptibility attack rate
D) none of the above

A

b

32
Q

predominant biological effect of the RF fields is
A) induced voltages
B) tissue heating
C) hypothermia
D) magnetic hemodynamic effect

A

b

33
Q

RF antenna effects can cause
A) better reception for your car radio
B) RF interference artefacts
C) thermal injury and flames
D) b and c

A

d

34
Q

the FDA limits RF to increase core body temperature of
A) 0.1˚C
B) 1˚C
C) 10˚F
D) there is no limit

A

b

35
Q

the increase in body temperature as a result of the RF absorption is
A) barely detectable
B) greatest on the outside, becoming less at the centre
C) greatest at the centre, becoming less on the surface
D) evenly distributed throughout the body

A

b

36
Q

RF energy used in MRI is classified as
A) high energy, ionising radiation
B) high energy, non-ionising radiation
C) low energy, non-ionising radiation
D) low energy, ionising radiation

A

c

37
Q

as the flip angle is doubles, RF deposition increases by a factor of
A) 1
B) 2
C) 3
D) 4

A

d. as the flip angle increases by double the RF absorption increases by a factor of 4

38
Q

RF heating is more of a concern in sequences such as
A) GE
B) epi
C) SE
D) FSE

A

d. due to a train of RF pulses

39
Q

areas of the body that are most sensitive to heat from SAR are
A) brain and spinal cord
B) vertebral bodies
C) globes of eyes and testicles
D) pancreas and liver

A

c

40
Q

for adult imaging in MRI, the FDA guidelines limit the field strength of clinical imagers to
A) 1.5T and above
B) 2T and below
C) 4T
D) 8T

A

d

41
Q

a magnetic field of 1T is equal to
A) 1000 G
B) 10 000 G
C) 100 000 G
D) 10 G

A

b

42
Q

all of the following are regulated by the FDA except
A) field strength of the main magnet
B) RF (SAR)
C) gradient length
D) acoustic noise

A

c

43
Q

no biological effects have been reported in humans as a result of the exposure to
A) static MF above 2T
B) time varying MF
C) RF fields
D) static MF below 2T

A

d

44
Q

the field strength at the isocentre is measured in units of
A) G
B) T
C) Watts
D) SAR

A

b

45
Q

Magnetic field strength outside the imager is usually measured in
A) G
B) T
C) Watts
D) SAR

A

a

46
Q

the attractive force that an object will experience at a distance of 6 feet from the iso centre will depend on
A) ferromagnetic properties of the object
B) mass of the object
C) field strength of the system
D) all of the above

A

d

47
Q

as a conductive medium moves across a MF, an effect known as the magnetic hemodynamic effect occurs, resulting in
A) increased blood pressure
B) elevated temperature
C) elevated T wave
D) nothing

A

c

48
Q

it is ____ for all patients t be provided with hearing protection in the form of _____
A) required, headphones or earplugs
B) recommended, headphones or ear plugs
C) required, head coil
D) recommended, helmet

A

b

49
Q

the gradient MF
A) produce head in the gradient coil during the scan
B) can produce noise to cause temporary hearing loss
C) change rapidly during the scanning process
D) all of the above

A

d

50
Q

when placed within the bore of the MRI, an effect can be noted on an ECG whereby there is an elevated T wave. this effect is known as all of the following except
A) magnetohydrodynamic effect
B) magnet- hydrodynamic effect
C) magnet-hemonynamic effect
D) magnetophosphenes

A

d

51
Q

the effect where a patient experiences a visual impression of seeing stars is known as
A) magnetohydrodynamic effect
B) magnet- hydrodynamic effect
C) magnet-hemonynamic effect
D) magnetophosphenes

A

d

52
Q

the FDA limit on time-varying magnetic fields is
A) 10G/cm
B) 6T/s
C) 1G/cm
D) until the patient experiences peripheral nerve stimulation

A

d

53
Q

time-varying magnetic field effects include all of the following except
A) heat and increased body temperature
B) acoustic damage and hearing loss
C) peripheral nerve stimulation
D) magnetophosphenes and stars in the eyes

A

a

54
Q

TVMF effects are of greater concern for which of the following sequences
A) FSE
B) EPI
C) GE
D) SE

A

b

55
Q

strength of a gradient MF are measured in
A) mT/m
B) W/kg of body weight
C) W/time
D) G/cm
E) a and d

A

e. (10mT/m=1g/cm)

56
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

57
Q

time varying magnetic fields are reported to have caused
A) mild cutaneous sensations and images of flashing lights for patients
B) involuntary muscle contractions and cardiac arrhythmias
C) neither of the above
D) a and b

A

d

58
Q

FDA limit for static MF for clinic imaging of patients over 1 month of age is
A) 1T
B) 1.5 T
C) 4T
D) 8T

A

c

59
Q

FDA limit for clinical imaging in all a patients is
A) 1 T
B) 1.5T
C) 4T
D) 8T

A

c

60
Q

imaging sequence that is of most concern for TVMF effects is
A) SE
B) GE
C) FSE
D) EPI

A

d. this is because all of k-space is filling in one TR

61
Q

gradient rise time is
A) time it takes for gradient to get to full amplitude
B) time it takes for cake to rise
C) time it takes for 1 TR period to occur
D) time it takes for one acquisition to be complete

A

a

62
Q

the duty cycle is
A) time it takes for the gradient to get to full amplitude
B) time it takes for one TR to occur
C) the time gradient is on during one TR
D) how much the gradient changes the MF over a specific distance

A

c

63
Q
A

MRI exam (14 decks)

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