Flow phenomenon, gating, and artifacts

Question 1

_______________the FOV will help reduce aliasing

Answer 1

increasing

Question 2

Patient motion usually affects the image in the ___________ axis.

Answer 2

phase

Question 3

A(n) ________________in NEX can also help reduce motion artifacts.

Answer 3

increase

Question 4

Cardiac gating is triggered on:

Answer 4

R wave

Question 5

If ghosting/phase mismapping occurs in the phase axis the direction of phase encoding can be changed/swapped.

Answer 5

true

Question 6

A respiratory compensatory bellow should be placed:

Answer 6

at the level of the diaphragm

Question 7

Time of flight phenomenon is affected by:

1. TE
2. TR
3. Slice thickness

Answer 7

1 & 3 only

Question 8

Flow in the same direction is called:

Answer 8

co-current

Question 9

If the coil is too large for the area being imaged, which type of artifact may occur?

Answer 9

shading

Question 10

In gradient moment nulling:

1. High signal is produced from flowing nuclei
2. The slice number available is reduced
3. The minimum TE is increased

Answer 10

1, 2, & 3

Question 11

To reduce mismapping:

1. Swap to the phase axis
2. Increase the FOV
3. Use a pre-sat pulse

Answer 11

1 & 3 only

Question 12

The trigger window for cardic gating should be _________% of the R-wave to R-wave interval.

Answer 12

15

Question 13

This method helps visualize cardiac wall motion, blood flow, and CSF flow:

Answer 13

cine

Question 14

The cables from the ECG leads should:

1. Have a layer of either a sheet, blanket, or gown between them and the patient’s bare skin
2. Be free of frays and tears in insulation
3. Be run down the middle of the patient’s body if possible

Answer 14

1, 2, & 3

Question 15

_________________phenomenon can show the difference between the venous and arterial blood flow.

Answer 15

entry slice

Question 16

The corrugated portions of the bellows, is placed on the ____________ portion of the patient.

Answer 16

anterior

Question 17

Which artifact is helpful to see a hemorrhage in the brain?

Answer 17

magnetic susceptibility

Question 18

If TE is increased, what happens in TOF

Answer 18

increase in signal loss

Question 19

if a flowing nucleus has a faster flow, what happens in TOF

Answer 19

signal loss increases

Question 20

definition of in-flow (aka entry slice)

Answer 20

nuclei that have received multiple RF signals are saturated

Question 21

Entry slice is dependent on what

Answer 21

TR
slice thickness
velocity of flow
direction of flow