PS 1

Question 1

In a pulse sequence diagram, gradient indications are for physical or logical gradients?

Answer 1

Logical

Question 2

In a spin echo sequence, the 90° RF Pulse places the LMV into the________

Answer 2

transverse plane

Question 3

In a spin echo pulse sequence, immediately after the 90° RF pulse the spins are in the ________ plane & are ________ coherent.

Answer 3

in the TRANSVERSE plane & are PHASE coherent.

Question 4

Completing all of the selected number of phase encoding steps in a spin echo sequence is equivalent to _______ NEX/NSA

Answer 4

1

Question 5

Doubling the NEX / NSA yields approximately a ____________.

Answer 5

40% increase in SNR.

Question 6

Another term for “frequency encoding” is

Answer 6

readout

Question 7

In a spin echo pulse sequence, ______ phase encoding steps are collected every TR period.

Answer 7

1

Question 8

The domain where phase encoding data is stored is called

Answer 8

K-Space

Question 9

In a spin echo pulse sequence, how many TR periods occur if the user selected 200 phase encoding steps?

Answer 9

200

Question 10

In a spin echo sequence, FID stands for what?

Answer 10

Free Induction Decay

Question 11

True or False:

The Set-up Pulse is an essential step shown in a pulse sequence diagram.

Answer 11

False

Question 12

In a pulse sequence diagram, “GX” indicates what?

Answer 12

Gradient used for Frequency encoding

Question 13

In a pulse sequence diagram, “GZ” indicates what?

Answer 13

gradient used for slice encoding

Question 14

in a spin echo pulse sequence, the time from one 90° RF Pulse to the next 90° RF pulse is:

Answer 14

TR

Question 15

In a spin echo pulse sequence, the phase encoding gradient is turned on when?

Answer 15

immediately following the 90° RF pulse

Question 16

The purpose of gradients is to change the _______ of spins.

Answer 16

the precessional frequency of the spins.

Question 17

What are the 4 categories of magnetic susceptibility?

Answer 17

Diamagnetic
Paramagnetic
Super-Paramagnetic
Ferromagnetic

Question 18

What is defined as the tendency of a substance to attract or repel magnetic lines of force dependent on the magnetic properties of its electrons?

Answer 18

Magnetic Susceptibility

Question 19

In K-space, the outer lines contain the majority of the _______ information.

Answer 19

Spatial Resolution

Question 20

The purpse of phase & frequency encoding gradients is to _______.

Answer 20

Spatially locate where the signals are coming from.

Question 21

What are the 4 main parts of every pulse sequence?

Answer 21

Slice Excitation
Phase encoding
Frequency encoding (readout)
Echo Generation

Question 22

In a spin echo pulse sequence, if TR is increased, what happens to your scan time?

Answer 22

Scan time is increased.

(Also increases T1w)

Question 23

In a spin echo pulse sequence, if the time from the 90° RF Pulse to the 180° RF Pulse is INCREASED, then _______ is also increased.

Answer 23

TE

Question 24

In a spin echo pulse sequence, the REFOCUSING PULSE is accomplished by using a ______ RF pulse.

Answer 24

A 180° RF Pulse.

Question 25

In K-space, the central or middle lines contain the majority of the ________.

Answer 25

SNR / Contrast

Question 26

Substances with ________ susceptibility weakly attract or repel magnetic lines of force. Magnetic susceptibility of most human body tissues are described as _______.

Answer 26

Diamagnetic

Question 27

What is the function of the "SET-UP" pulse?

Answer 27

to create the desired amount of T1 relaxation.

Question 28

In a spin echo pulse sequence, the only thing that changes from one TR period to the next is the:

Answer 28

Phase encoding gradient (Gy)

Question 29

In a spin echo pulse sequence, FID immediately:

Answer 29

Dephased & Phase encoded.

Question 30

In a spin echo pulse sequence, if the TE is increased, what happens to T2W?

Answer 30

t2w is increased.

Question 31

In a spin echo sequence, the first RF Pulse is the________

Answer 31

slice excitation 90° RF Pulse

Question 32

In a spin echo pulse sequence, what is the first gradient that is used?

Answer 32

Slice Encoding Gradient (Gz)

Question 33

In a spin echo pulse sequence, for the best proton density weighting, use a long TR and ______ TE.

Answer 33

short.

Question 34

In a spin echo pulse sequence, for the best T1 weighting, use a ________.

Answer 34

moderate TR.