Img Prod.

Question 1

If a Dual Spin Echo has a short T1 and a long T2, can it have both T1 and T2 in a sequence?

Answer 1

False, there can only be one weighting

Question 2

What parameters control T1 and T2 weighting on images?

Answer 2

TR controls T1
TE controls T2

Question 3

Do T1 recovery and T2 dephasing occur at the same time? If not, which one is faster?

Answer 3

T1 recovery and T2 dephasing occur at the same time, but at different rates. T2 dephasing occurs faster than T1 recovery

Question 4

What is T2 relaxation/decay time?

Answer 4

T2 relaxation/decay time refers to the time it takes for 63% of transverse net magnetization to be lost (or recovered in the longitudinal plane)

Question 5

What is the Larmor Equation? What does each parameter represent?

Answer 5

w = yB0
w = angular precessional frequency of the proton
y = gyromagnetic ratio
B0 = strength of external magnetic field

Question 6

What does NMV stand for?

Answer 6

Net Magnetization Vector

Question 7

What is it called when Rf is transmitted at the same Larmor Frequency as hydrogen?

Answer 7

Resonance

Question 8

True or False: the three gradient echoes have no function during spin echo sequences, they are only used in gradient echoes

Answer 8

False

Question 9

If you minimize T1 and T2 effects, what type of weighting are you going to get?

Answer 9

PD
PD = short TE and long TR

Question 10

TR

Answer 10

repetition time (time from initial excitation pulse to the next one)

Question 11

TE

Answer 11

echo time (time from initial excitation pulse to the signal readout)

Question 12

Flip Angle

Answer 12

degree at which the NMV is deflected from the longitudinal axis

Question 13

TI

Answer 13

inversion time (time between an inversion pulse and a 90 pulse)

Question 14

Echo Train Length/Turbo Factor

Answer 14

number of echoes acquired after the initial excitation

Question 15

T1 SE

Answer 15

short TE (10 ms)
short TR (500 ms)

Question 16

T2 SE

Answer 16

long TE (100 ms)
long TR (5000 ms)

Question 17

PD SE

Answer 17

short TE (10 ms)
long TR (5000 ms)

Question 18

T1 GE

Answer 18

large flip angle (70)
short TE (5-10 ms)
short TR (<50 ms)

Question 19

T2 GE

Answer 19

small flip angle (20)
long TE (15-25 ms)
long TR (>200 ms)

Question 20

PD GE

Answer 20

small flip angle (20)
short TE (5-10 ms)
long TR (<200 ms)

Question 21

What is the name of the signal produced by the excitation pulse?

Answer 21

FID = free induction decay, rephased by the gradients

Question 22

Scan time Calculation

Answer 22

(TRxNEXxphase)/ETL

Question 23

Looking at a FSE pulse sequence, count how many RF pulses occur during each TR period

Answer 23

Count all pulses on diagram, including the 90 and 180

Question 24

What determines the depth dimension of a voxel?

Answer 24

Slice thickness
voxel size = (FOV/matrix)* slice thickness
Pixel size = (FOV/matrix)

Question 25

Pulses that employ multiple RF pulses (such as IR) should be used sparingly because they have the same tissue effects such as heating

Answer 25

False

Question 26

What do Inversion Recovery pulse sequences start with?

Answer 26

180 pulse

Question 27

What are the units of the Larmor Equation?

Answer 27

MHz

Question 28

When the matrix is finer

Answer 28

the resolution is higher but the signal is lower

Question 29

STIR

Answer 29

short tau inversion recovery

Question 30

If you increase NEX

Answer 30

n = sqr(n)

Question 31

What does a FLAIR sequence null?

Answer 31

CSF