pulse sequence options

Question 1

What does a presaturation pulse do

Answer 1

nullify signal from a volume of tissue

Question 2

Where would you place a Sat Band during a carotids

Answer 2

superiorly

Question 3

Where would you place a Sat Band during a brain venogram

Answer 3

inferiorly

Question 4

How much do the precessional f of fat and water differ

Answer 4

3.5ppm

Question 5

what is the precessional frequency difference in f between fat and water at 1.5T

Answer 5

220Hz

Question 6

What is the process of using a sat band to inhibit the ability of bound protons to interfere with the relaxation of free protons

Answer 6

Magnetisation transfer

Question 7

How does magnetisation transfer help in brain angiography

Answer 7

it suppresses the background brain tissue and increase the contrast between the tissue and the that of the flowing blood

Question 8

how can applying magnetisation transfer help in MRA brains

Answer 8

it allows for the demonstration of smaller vessels

Question 9

what is another term for flow compensation

Answer 9

gradient moment nulling

Question 10

what is flow compensation

Answer 10

compensation for phase shifts acquired by flowing nuclei in the presence of a gradient field

Question 11

how does gradient moment nulling work

Answer 11

with the use of additional gradient pulses that compensate for the motion induced dephasing

Question 12

First order gradient moment nulling

Answer 12

compensates for a flow of a constant velocity

Question 13

second order gradient moment nulling

Answer 13

compensates for a flow of an accelerated velocity