Pulse Sequence Design

Question 1

In any given pulse sequence, when there is a transmitted application of 90° or 180° RF pulse, the ________ must be turned on to allow a specific slice to be singled out.

Answer 1

Slice select gradient

Question 2

________ is an imaging technique that suppresses CSF and is used to diagnose periventricular disease and infarct lesions in the cord.

Answer 2

FLAIR

Question 3

What pulse sequences utilize a flip angle between 15° and 60°?

Answer 3

• GRE (gradient recall echo)
• Spoiled Gradient echo
• Steady state cardio echo

Question 4

In an FSE (past spin echo)sequence that has 16 180° refocusing RF pulses after the initial 90° pulse, the echo train length would be:

Answer 4

16

Question 5

________ is a pulse sequence that contains an additional 180° pulse before the 90° pulse.

Answer 5

Inversion recovery (IR)

Question 6

The time from the initial 180° pulse to the 90° pulse is known as _________.

Answer 6

Inversion time (TI)

Question 7

Two types of IR sequences are:

Answer 7

STIR - Short tau inversion recovery

FLAIR - fluid attenuated inversion recovery

Question 8

_______ is an imaging technique widely used as a fat suppression technique.

Answer 8

STIR

Question 9

When studying steady state and spoiled gradient in sequences, steady state aims to ________ transverse magnetization while spoiled aims to _________ transverse magnetization.

Answer 9

Preserve, terminate

Question 10

The readout portion of the pulse sequence reads or _______ the signal data through ________ encoding

Answer 10

Samples, frequency

Question 11

Consisting of alternating read out and phase applications, _________ is the loudest and fastest MRI technique.

Answer 11

EPI (echo planar imaging)

Question 12

The purpose of the initial 180° RF pulse in inversion recovery imaging is to create a _______ environment before the 90° RF pulse.

Answer 12

T1

Question 13

Phase resolution

Answer 13

Sharpness part of matrix

Question 14

True or false: phase resolution is directly related to the TR period.

Answer 14

True. If the phase resolution is 256 then the TR period is 256

Question 15

The principal mechanism of inversion recovery imaging states that an initial RF transmission pulse moves the net magnetization of protons to a ________° position.

Answer 15

180

Question 16

In a fast spin echo sequence, the readout gradient is turned on:

Answer 16

During sampling of the resultant echo
During frequency encoding
Between 90° and 180° pulses

Question 17

Short tau inversion recovery sequences are typically not used for the evaluation of ______.

Answer 17

CSF

Question 18

The time it takes to complete an entire post sequence is called _____.

Answer 18

Echo time (TF)

Question 19

Traditional standard Pulse sequences are:

Answer 19

Spin echo SE
Inversion recovery IR
Gradient echo GE
Echo planar imaging EPI

Question 20

What are the five steps of a timing diagram?

Answer 20

Step one: RF transmit (RF-t)
Step two: RF receive (RF-r)
Step three: slice select gradient
Step four: readout gradient
Step five: phase gradient