MRI CAMRT Exam with all Correct & 100% Verified
Answers |Actual Complete Exam| Already Graded A+
(Just Released)
Is SNR proportional or inversely proportional to voxel volume ✔Correct Answer-Proportional
3 fields used in MRI ✔Correct Answer--static magnetic field
-TVMF (gradient field)
-RF field
3 main types of magnets used ✔Correct Answer--Superconducting (most common_
-Resistive
-Permanent
FDA limits for the 3 fields in MRI ✔Correct Answer-Static field: 2T
TVMF: 3T/s
RF field:
- does not cause an increase in temperature of more than .5 deg C or any body part of 1 deg C
-SAR does not exceed 1W/kg avg over 25% of whole body for longer than 15mins
-SAR does not exceed 2W/kg avg over 25% of whole body for durations of 15mins or less
Eddy currents are caused by ✔Correct Answer-TVMF (gradients)
What are Eddy Currents ✔Correct Answer-Small currents induced in the body via the TVMF
Biological effects of the TVMF ✔Correct Answer--Fibrillation
-Electroshock
-Visual phosphenes
-Peripheral nerve stimulation
SAR meaning and units ✔Correct Answer-Specific Absorption Rate
W/kg- Watts/kilogram
Which field is responsible for tissue heating and temperature increase ✔Correct Answer-The RF
field
How are cardiac pacemakers affected in MRI ✔Correct Answer-Affected by all 3 fields
-Static field affects the operation and also exerts torque
-TVMF and RF field can interfere with circuitry
3 types of ferromagnetic materials? ✔Correct Answer-iron, cobalt, nickel
Level 1 MR Personnel ✔Correct Answer-Passed MR safety education requirements
Level 2 MR Personnel ✔Correct Answer-Those more extensively trained and educated in MRI
safety
, How many times should a non emergent patient be screened ✔Correct Answer-Twice, once
verbally with a level 2 MR Tech
How should emergent patients and their non MR personnel be screened ✔Correct Answer-Once
How should unconscious/ unresponsive patients be screened ✔Correct Answer-- A family member
should fill out the screening form
-If no reliable history can be obtained and MR exam cannot wait they must undergo plain film
radiography of head/neck, chest, abdomen/pelvis, upper arms and thighs
How should children and teens be screened ✔Correct Answer-Twice, once in front of parents and
once without
MRI and pregnant patients ✔Correct Answer-No known harmful effects but risk vs benefit
assessment should be made
MRI contrast and pregnant patients ✔Correct Answer-Should not be routinely given to pregnant
patients but risk vs benefit assessment needed
What is the spatial field gradient ✔Correct Answer-The variance in the fixed static field surrounding
the scanner, the manufacturerer supplies a SFG map
Lenz forces ✔Correct Answer-Faradays law states that a changing magnetic field will induce a
current in a conductor, Lenzs law states that the induced current will generate a secondary field that
opposes the original field
TVMF (gradient) effects ✔Correct Answer--Induced voltages
-Auditory considerations
Normal temperature ranges ✔Correct Answer-Adult: 36.7-37.4 C
Child (4-13): 36.7-37 C
Infant (3mo-3yrs): 37.2-37.7 C
Normal pulse ranges ✔Correct Answer-Adult: 60-90 bpm
Child (4-10): 90-100 bpm
Infant: 120 bpm
Normal respiratory ranges ✔Correct Answer-Adult: 15-20 breaths per minute
Infant: 30-60 breaths per minute
Normal pulse oximetry ✔Correct Answer-95%-100%
Tachycardia ✔Correct Answer-Fast heart rate over 100 bpm
Bradycardia ✔Correct Answer-Slow heart rate less than 60 bpm
Spots to get a pulse reading ✔Correct Answer--Radial (wrist)
-Carotid (neck)
-Popliteal (knee)
-Temporal (head)
Answers |Actual Complete Exam| Already Graded A+
(Just Released)
Is SNR proportional or inversely proportional to voxel volume ✔Correct Answer-Proportional
3 fields used in MRI ✔Correct Answer--static magnetic field
-TVMF (gradient field)
-RF field
3 main types of magnets used ✔Correct Answer--Superconducting (most common_
-Resistive
-Permanent
FDA limits for the 3 fields in MRI ✔Correct Answer-Static field: 2T
TVMF: 3T/s
RF field:
- does not cause an increase in temperature of more than .5 deg C or any body part of 1 deg C
-SAR does not exceed 1W/kg avg over 25% of whole body for longer than 15mins
-SAR does not exceed 2W/kg avg over 25% of whole body for durations of 15mins or less
Eddy currents are caused by ✔Correct Answer-TVMF (gradients)
What are Eddy Currents ✔Correct Answer-Small currents induced in the body via the TVMF
Biological effects of the TVMF ✔Correct Answer--Fibrillation
-Electroshock
-Visual phosphenes
-Peripheral nerve stimulation
SAR meaning and units ✔Correct Answer-Specific Absorption Rate
W/kg- Watts/kilogram
Which field is responsible for tissue heating and temperature increase ✔Correct Answer-The RF
field
How are cardiac pacemakers affected in MRI ✔Correct Answer-Affected by all 3 fields
-Static field affects the operation and also exerts torque
-TVMF and RF field can interfere with circuitry
3 types of ferromagnetic materials? ✔Correct Answer-iron, cobalt, nickel
Level 1 MR Personnel ✔Correct Answer-Passed MR safety education requirements
Level 2 MR Personnel ✔Correct Answer-Those more extensively trained and educated in MRI
safety
, How many times should a non emergent patient be screened ✔Correct Answer-Twice, once
verbally with a level 2 MR Tech
How should emergent patients and their non MR personnel be screened ✔Correct Answer-Once
How should unconscious/ unresponsive patients be screened ✔Correct Answer-- A family member
should fill out the screening form
-If no reliable history can be obtained and MR exam cannot wait they must undergo plain film
radiography of head/neck, chest, abdomen/pelvis, upper arms and thighs
How should children and teens be screened ✔Correct Answer-Twice, once in front of parents and
once without
MRI and pregnant patients ✔Correct Answer-No known harmful effects but risk vs benefit
assessment should be made
MRI contrast and pregnant patients ✔Correct Answer-Should not be routinely given to pregnant
patients but risk vs benefit assessment needed
What is the spatial field gradient ✔Correct Answer-The variance in the fixed static field surrounding
the scanner, the manufacturerer supplies a SFG map
Lenz forces ✔Correct Answer-Faradays law states that a changing magnetic field will induce a
current in a conductor, Lenzs law states that the induced current will generate a secondary field that
opposes the original field
TVMF (gradient) effects ✔Correct Answer--Induced voltages
-Auditory considerations
Normal temperature ranges ✔Correct Answer-Adult: 36.7-37.4 C
Child (4-13): 36.7-37 C
Infant (3mo-3yrs): 37.2-37.7 C
Normal pulse ranges ✔Correct Answer-Adult: 60-90 bpm
Child (4-10): 90-100 bpm
Infant: 120 bpm
Normal respiratory ranges ✔Correct Answer-Adult: 15-20 breaths per minute
Infant: 30-60 breaths per minute
Normal pulse oximetry ✔Correct Answer-95%-100%
Tachycardia ✔Correct Answer-Fast heart rate over 100 bpm
Bradycardia ✔Correct Answer-Slow heart rate less than 60 bpm
Spots to get a pulse reading ✔Correct Answer--Radial (wrist)
-Carotid (neck)
-Popliteal (knee)
-Temporal (head)
