quiz 3 Flashcards
Using a long TE enhances T2 and T2* contrast
True/false
true
A long TE gives spins more time to dephase therefor increasing T2 contrast
true/false
true
What factors determine T1 and T2 relaxation of tissues
Inherent energy of tissues
How well the molecular tumbling rate matches the Larmor frequency
How closely spaced the molecules are.
Select the appropriate weighting of the following parameters.
TR=450 ms TE= 10ms Flip angle of 90 degrees
T1
Select the appropriate weighting.
TR= 2000ms TE=15ms Flip Angle of 90 degrees.
PD
The definition of weighting is the “parameters selected to make one contrast mechanism dominate or the others.”
true/false
true
What is meant by the tumbling rate?
The rate at which a molecule moves. This has a direct effect on T1 and T2 relaxation times of tissues.
Fat has a fast tumbling rate motion due to Lipids tightly packed together.
true/false
false
The T1 time of fat is short
true/false
true
T1 time of water is long
true/false
true
Select all the Extrinsic factors.
TR
TE
Flip angle
Select all that apply to Intrinsic factors
T2 decay
T1 recovery
Proton Density
This parameter determines the—Time between the excitation pulse and the middle of the Spin Echo,Measures in ms and determines amount of Transverse or T2 decay
TE
Time between Excitation Pulses determines the amount of Longitudinal or T1Recovery is…
TR
T2 weighting includes (select all three that apply)
Hypointense”ish” (darker) Fat when compared to a T1
Hyperintense-Bright water
Long TR and TE times
