MRI physics

Question 1

Gibbs artifact

Answer 1

Series of white lines from abrupt changes in signal intensity (brain-CSF interface)

Question 2

TR and TE of different sequences

Answer 2

1. T1 Short TR (< 500 ms), short TE (< 20 ms)
2. T2 Long TR (> 2000 ms), long TE (> 70 ms)
3. PD Long TR (2000-3000 ms), short TE (25-30 ms)

Question 3

MRI zones

Answer 3

Zone 1: Reception area
Zone 2: Screening area
Zone 3: Scanner control area
Zone 4: MRI scanner room

Unscreened ppl only allowed in 1 and 2

Question 5

Standing wave/dielectric artifact

Answer 5

Signal at center of image is less

Question 6

Artifact in frequency encoding direction

Answer 6

Chemical shift ONLY - India ink around fat/water interface

Question 7

Which sequences allow for motion correction by collecting redundant data in k-space

Answer 7

Propeller or Blade

Question 8

What are the different TR and TE for T1, T2, and PD weighting?

Answer 8

T1: Short TR, short TE. TR = 500 ms, TE = 10 ms
T2: Long TR, long TE. TR = 3000 ms, TE = 100 ms
PD: Long TR, short TE. TR = 3000 ms, TE = 10 ms