MRSO UPDATED COMPLETE QUESTIONS AND ANSWERS PREMIUM LEARNING COMPANION

MRSO UPDATED COMPLETE QUESTIONS
AND ANSWERS PREMIUM LEARNING
COMPANION

●● parameters to reduce noise in MRI
Answer: -thicker slices
-larger FOV
-smaller matrix
-parallel imaging
-reducing bandwidth (increasing TE)
-active noise reduction
-Low SAR RF mode (increase in echo spacing)-thicker slices


●● MRI sequence that produces the most and least noise in MRI
Answer: Most noise EPI/DWI


least noise spin echo sequence


●● an increase in slew rate and gradient amplitude causes an increase in
Answer: Peripheral nerve stimulation

,●● stimulation of the eyes in a patient causing an appearance of flashing
lights
Answer: magnetophosphenes


●● stimulation of the vestibular system causing a vestibular ocular
reflex where the eyes rapidly move side to side
Answer: nystagmus


●● what force causes the noise heard in MRI
Answer: lorentz forces


●● B1+rms
Answer: the amplitude of the B1 frequency over 10 seconds--the
intensity of the changing magnetic field in our patient will determine the
amount of energy transferred to our patient


●● SAR
Answer: energy per patient mass measured in J/Kg


SAR is measured per sequence


●● SAR limits: whole body--receive only coil & integrated Body coil
Answer: whole body measured over 6 minutes

, first level operating mode 4 w/kg


normal operating mode 2 w/kg


SAR limit for head is 3.2 w/kg in both first level and normal operating
mode


●● SAR limits local transmit/receive coil
Answer: local coil measured over 6 minutes


head--
normal operating mode 10 W/kg
first level operating mode 20 W/kg


trunk--
normal operating mode 10 w/kg
first level operating mode 20 w/kg


extremities--
normal operating mode 20 w/kg
first level operating mode 40 w/kg