MRI 2

Question 1

What is longitudinal relaxation?

Answer 1

when the radiofrequency pulse is turned off and the spins of the hydrogen nuclei relax back into their lower energy state

Question 2

What is spin lattice relaxation?

Answer 2

the recovery of the longitudinal overall magnetization of the patient in the direction of the magnetic field strength, this is caused by the exchange of energy from spins to their surroundings. This occurs slowly.

Question 3

How is longitudinal relaxation the basis of T1 weighted imaging

Answer 3

fat relaxes faster than water so during longitudinal relaxation fat appears brighter and water dark.

Question 4

What is T1 weighted imaging useful for

Answer 4

viewing anatomy

Question 5

What is transverse relaxation?

Answer 5

the decay of the transverse overall net magnetization of the patient due to the dephasing spins caused by the neighboring interactions of magnetic fields. This happens quickly

Question 6

How is transverse relaxation the basis of T2 weighted imaging?

Answer 6

during transverse relaxation the fast relaxes fast and the water slow so in a T2 weighted image the fat appears grey and the water bright.

Question 7

What is T2 weighted image useful for

Answer 7

viewing pathologies because they are fluid filled

Question 8

What do both longitudinal and transverse relaxation contribute to

Answer 8

image contrast and proton density

Question 9

What do both longitudinal and transverse relaxation contribute to

Answer 9

image contrast and proton density