MRI practice/questions

Question 1

How to reduce Scan time

Answer 1

Reduce TR
Reduce NEX/NSA
Increase Parallel Imaging factor
Utilize half fourier
Use coarsest matrix possible

Question 2

What happens when TR is increased

Answer 2

Increased SNR
Increased Scan time
Decreased T1 weighting
Increased number of Avail. Slices

Question 3

What happens to TE when increased

Answer 3

Decreased SNR
Increased scan time
Increased T2 weighting
Decreased number of avail. slices

Question 4

What is another name for incoherent gradient echo sequence?

Answer 4

Spoiled gradient echo sequence

Question 5

Incoherent gradient echo (spoiled echo gradient) yield what type of contrast due to removal of residual transverse magnetization before next excitation

Answer 5

T1 contrast

Question 6

To reduce steady state (T2*) effect, a technique known as what can be employed to allow for fast scans with T1 contrast

Answer 6

Spoiling

Question 7

In a spine echo sequence the time between the 90 degree RF pulse and the 180 degree RF pulse is known as the

Answer 7

1/2 TE time (Tau)

Question 8

How does Echo Train Length affect other parameters

Answer 8

Reduces scan time
Reduces SNR
Increases SAR absorption
Increases blurring

Question 9

In a fast spin echo pulse sequence, if the TSE factor is increased by a factor of 3, the scan time will be how many times faster

Answer 9

Three

Question 10

In an inversion recover sequence, the time interval between the 180 degree RF pulse and the 90 degree RF pulse is the

Answer 10

TI (inversion time)

Question 11

What directly results as the frequency matrix increases?

Answer 11

SNR decreases

Question 12

At what distasnce should an attached IV bag be hung above the IV site?

Answer 12

18-24 inches

Question 13

What plane best demonstrates the Cruciate ligaments of the knee

Answer 13

Sagittal

Question 14

An image with hyperintense signal from fluid/water and hypointense fluid signal from fat would be what type of image contrast?

Answer 14

T2 contrast

Question 15

What type of image data acquisition imaging option in which all data is acquired as a volume with no gap space?

Answer 15

3D imaging

Question 16

What imaging option applies an extra 90 degree RF pulse prior to the alpha pulse to null signal from user specified areas of unwanted anatomy?

Answer 16

Spatial saturation pulse

Question 17

What term represents the difference in SNR between 2 adjacent pixels?

Answer 17

Contrast to noise ratio

Question 18

What ratio of compressions to breaths should be applied for CPR?

Answer 18

30 compressions/ 2 breaths

Question 19

After the injection of GAD, scar tissue within the spines disc spaces enhance how quickly?

Answer 19

Immediately

Question 20

What cranial nerves run through the IAC’s?

Answer 20

VII and VIII

Question 21

Normal GFR is

Answer 21

90ml/min/1.73m or higher

Question 22

Gradient moment nulling is applied during the acquisition of coronal or sagittal images, which gradient is used for flow compensation?

Answer 22

Frequency encoding gradient

Question 23

Which of the following directly results as ETL increases?

Answer 23

T2 weighting increases

Question 24

What is The FDA SAR limit for torso exams

Answer 24

8 W/kg over 5 mis

Question 25

At 1.5T Flair pulse sequences use an inversion time in the approx. range of _______ in order to null the signal from fluid

Answer 25

1700-2200ms

Question 26

Coherent Gradient echo sequences are typically used to obtain what weighted images?

Answer 26

T2*

Question 27

Which factor has the greatest effect on entry slice phenomenon?

Answer 27

Direction of flow

Question 28

What term best describes an infection or illness originating from a medical exam or treatment?

Answer 28

Iatrogenic infection

Question 29

Trunctation artifact can be compensated for by

Answer 29

increasing the NSA/NEX and increasing the phase encoding matrix

Question 30

The T2 decay time of fat is approx

Answer 30

100ms

Question 31

What plane best demonstrates the pituitary gland

Answer 31

Coronal and sagittal

Question 32

The fastest form of data acquisition is achieved by which pulse sequence

Answer 32

Echo planar pulse sequences

Question 33

During a steady state pulse sequence, if two excitation pulses with a variable flip angle are applied, which echo is created?

Answer 33

Conventional echo

Question 34

Which of the following directly results as the phase matrix increases?

Answer 34

Spatial resoltion increases

Question 35

During TOF imaging, what TR is used to saturate stationary non-flowing spins?

Answer 35

20-50ms