Chapter 10 Flashcards
MRI safety
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
b. 5
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
c. Should be screened as if they are going through the procedure themselves
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
c. Patient who is having a study with gadolinium
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
c. 4
Hemodynamic effect of the main magnetic field (B0) results in elevation of ______ wave
a. T
b. R
c. Q
d. P
a. T
RF energy can affect the patient by:
a. Decreasing body temperature
b. Increasing body temperature
c. Hearing loss
d. Loss of hair
b. Increasing body temperature
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
c. Specific absorption rate
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)
d. Echo planar (EPI)
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
b. Testis/eye
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
d. Ask the patient and family about the possibility of having metal fragments in the body
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
b. Pregnant patient in the first trimester
Release of cryogens, explicitly helium, can:
a. Make patients warm
b. Cause localized tissue warming
c. Cause frostbite/asphyxiation
d. Cause hallucinations
c. Cause frostbite/asphyxiation
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. True
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
b. Cochlear implants/penile implants
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
c. Dentures
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
b. Induce currents in conductors
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
b. False
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.
d. Both b. & c.
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
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
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
b. 1 degree C
An item that is known to pose hazards in all MRI environments is termed, “MR ______?”
a. Safe
b. Conditional
c. Unsafe
d. Unconditional
c. Unsafe
There have been several burns and fires associated with exposure to RF in MRI
a. True
b. False
a. True
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
d. Missile affect
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
b. II
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
b. 2
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
c. MRI technologist on duty
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. Quench
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
b. Torque
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
d. Translational attraction
Prior to entering the MRI environment all patients must go through a screening process:
a. Verbally
b. Written
c. Verbally and written
d. Physician
c. Verbally and written
A ferromagnetic object in the shape of a sphere will NOT experience:
a. Heating
b. Torque
c. Translational attraction
d. Conductivity
b. Torque
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
c. Acoustic noise, peripheral nerve stimulation and magnetophosphenes
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
b. Any strength
Unless specifically designated, neurostimulators and bone growth stimulators are NOT considered safe for scanning
a. True
b. False
a. True
Acoustic noise is experienced during an MRI study and is caused by:
a. RF
b. GMF
c. B0
d. Shim coils
b. GMF
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. Hemodynamic effect, fatigue and headaches
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
c. The patient’s weight in kilograms
Guidelines which exclude pregnant individuals from exposure to MRI are mainly to protect them from:
a. B0
b. Cryogens
c. RF
d. GMF
c. RF
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
d. w/kg
Magnetophosphenes are described as:
a. An increase of phosphorous levels in the body
b. Palpitations
c. Seeing flashes of light
d. 2nd degree burns
c. Seeing flashes of light
Painful peripheral nerve stimulation can be caused by:
a. GMF
b. B0
c. Torque
d. RF
a. GMF
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
d. Patients with titanium screws in a bone
What government agency sets the SAR for MRI systems?
a. FAA
b. FDA
c. FCC
d. FBI
b. FDA
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. No more than 4 w/kg
SAR stands for Specific Acquisition Rate
a. True
b. False
b. False
