Aquisition

Question 1

In a 2D conventional spin echo multislice pulse sequence, scan time is given by
A) Time X number of phase encodings (# PEs) X TR (time to
repetition)
B) TR (time to repetition) x FOV (field of view) X number of
signals
C. TR (time to repetition) X number of slices (#SI) X number
of signals
D) TR (time to repetition) X number of signals averaged
(NSA) X number of phase encodings (#PES)

Answer 1

D) TR (time to repetition) X number of signals averaged (NSA) X number
of phase encodings (#PEs)

Question 2

In an inversion recovery pulse sequence, image contrast is controlled by:
a TR and TE only
b TI only
c TI and TE only
d TR, TE, and TI

Answer 2

d TR, TE, and TI

Question 3

In an inversion recovery pulse sequence, the time between the initializing 180° pulse and the 90° pulse is known as:

Answer 3

TI

Question 4

Another name for TI is:

Answer 4

Tau

Question 5

A short TI inversion recovery (STIR) sequence can suppress the signal from:

Answer 5

Fat and gadolinium-enhancing lesion

Question 6

Decreasing the receiver bandwidth (narrow BW):

Answer 6

Increases the SNR

Question 7

Decreasing the receiver bandwidth (narrow BW):

Answer 7

Reduces chemical shift artifact

Question 8

Decreasing the receiver bandwidth (narrow BW):

Answer 8

Increases readout time

Question 9

Decreasing the receiver bandwidth (narrow BW):

Answer 9

Increases susceptibility artifact

Question 10

Decreasing the receiver bandwidth (narrow BW):

Answer 10

Decreases the number of slices

Question 11

Increasing the receiver bandwidth (wide BW):

Answer 11

Increases the available ETL

Question 12

The time during which the frequency encoding gradient is on:

Answer 12

Decreases with a reduction in receiver bandwidth

Question 13

In a conventional spin echo multi-echo sequence, it is possible to create multiple images, each with different amounts of:

Answer 13

T2 weighting

Question 14

The SNR will increase in a 3D sequence with an increase in:

Answer 14

FOV and Number of slices

Question 15

Between slices 2D acquisitions generally require:

Answer 15

Gaps

Question 16

Doubling the number of signals averaged (NSA) will:

Answer 16

Increase the SNR by the square root of 2

Question 17

Increasing the number of phase encodings will produce an image with:

Answer 17

Decreased voxel volume

Question 18

Reducing NSA will reduce the scan time and:

Answer 18

Decrease the SNR

Question 19

Doubling the NSA will increase the SNR by a factor of:

Answer 19

4

Question 20

Reducing the FOV by a factor of 2 will reduce the voxel volume by a factor of:

Answer 20

4

Question 21

If a STIR sequence using a TR of 3000, a TE of 20, and a TI of 140 produces an image with dark fat and bright water. The contrast in such an image is primarily based on:

Answer 21

T1

Question 22

In choosing the direction of phase encoding, the technologist usually considers the direction in which the:

Answer 22

Motion artifacts traverse the least tissue or areas of interest

Question 23

A chemical or spectral fat suppression sequence will suppress the signal from fat based on the:

Answer 23

Precessional frequency of fat and T2 relaxation time of fat

Question 24

Increasing slice thickness from 5 to 10mm (by a factor of 2, i.e. 2 X thicker), the SNR:

Answer 24

Increases by a factor of 4

Question 25

Increasing the number of phase encodings (matrix) from 128 to 256 (by a factor of 2), the SNR:

Answer 25

Is not affected

Question 26

Gradient moment nulling is most effective when correcting for motion-induced signal loss from:

Answer 26

Pulsatile flow

Question 27

To rephase the signal from moving spins, gradient moment nulling techniques:

Answer 27

Series of short rapid pulses that are strategically timed