Sequence Parameters and Options

Question 1

What is the most common data acquisition option in which a single line of K space is filled by data acquired from each slice before the TR period is repeated?

Answer 1

2D Imaging

Question 2

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

Answer 2

3D imaging

Question 3

During 3D imaging, slice encoding occurs when?

Answer 3

Post data acquisiton

Question 4

When data is acquired from each slice consecutively, one after the other is?

Answer 4

Sequential Slice Order

Question 5

How much gap is needed to prevent image artifacts when acquiring slices sequentially?

Answer 5

at least 30% gap

Question 6

When data is acquired from alternate slices through two separate acquisitions.

Answer 6

Interleaving slice order

Question 7

What is typically not need to prevent image artifacts when using slice interleaving option?

Answer 7

Slice Gap
–Because Slice Interleaving DOES NOT acquire sequentially–

Question 8

Spatial Saturation - (?)

Answer 8

Image option where a 90 degree RF pulse prior to the initial pulse in order to null the signal from user-specified AREAS OF UNWANTED ANATOMY.

Question 9

Using an extra 90-degree RF pulse and _____, spatial saturation is able to saturate all other tissues in a specified area.

Answer 9

Broad Transmisson Bandwidth

Question 10

The use of spatial saturation pulses will affect what 3 things?

Answer 10

Tissue Heating
SAR levels
Max # of slices available per acquisition

Question 11

Gradient Moment Nulling (GMN) is..

Answer 11

Imaging option whose primary purpose is to compensate for flow within the image volume.

Question 12

What type of flow is GMN most efficient at rephasing?

Answer 12

Laminar Flow (1st order flow)

Question 13

When GMN is applied to axial images, which gradient is used for flow compensation?

Answer 13

Slice-Select Gradient

Question 14

On Sagittal and Coronal images, which gradient is used when using GMN?

Answer 14

Frequency Encoding

Question 15

What 3 things are true when using GMN?

Answer 15

It’s most effective using slow laminar flow.
It reduces intra-voxel dephasing.
It used the slice-select gradient or frequency encoding gradient to rephase flowing spins.

Question 16

Which imaging option applies a 90 degree RF pulse prior to the initial pulse in order to null the signal from a specified tissue THROUGHOUT THE ENTIRE IMAGE VOLUME?

Answer 16

Chemical Supression.

Question 17

Chemical Sat. pulse is capable of saturating tissues throughout the entire volume using an initial RF pulse of 90 degrees and what?

Answer 17

Narrow Transmission Bandwidth

Question 18

A ___ is used to improve magnetic field homogeneity when using chemical suppression techniques.

Answer 18

Shim

Question 19

When using chemical suppression, magnetic field homogeneity is crucial for ensuring that targeted hydrogen protons are precessing at ____________________

Answer 19

MATCHING the frequency created by the chemical saturation pulse.

Question 20

What determines the time period between the 90 degree saturation pulse and the alpha pulse when applying the chemical sat. technique?

Answer 20

Sat TR

Question 21

What equation is used to calculate the Sat TR needed when using chemical suppression?

Answer 21

TR / # of slices

Question 22

Sat TR is usually represented by?

Answer 22

ms (milliseconds)

Question 23

An imaging option used to track physiological motion so that the data acquisition can be properly timed for minimization of motion.

Answer 23

Physiological Gating/Triggering

Question 24

The P wave of the cardiac cycle represents what?

Answer 24

Atrial Systole

Question 25

The QRS wave of the cardiac cycle represents what?

Answer 25

Ventricular Systole

Question 26

The T wave of the cardiac cycle represents what?

Answer 26

Ventricular Diastole

Question 27

During MRI an increase of the amplitude of the T wave is commonly caused by -

Answer 27

Both magneto-HEMOdynamic and magneto-HYDROdynamic effects.

Question 28

Which component of the QRS phase is of utmost importance?

Answer 28

R phase

Question 29

The R phase represents what?

Answer 29

The PEAK of the QRS complex as well as the PEAK of ventricular contraction.

Question 30

What is the time period between consecutive R phases known as?

Answer 30

R to R interval

Question 31

The R to R interval during MRI is dependent on the patients what?

Answer 31

Heart Rate

Question 32

When applying cardiac gating, what influences the TR?

Answer 32

Pt. Heart Rate R to R interval Desired Image Weighting

Question 33

What is the equation to determine the length of one R to R interval?

Answer 33

60,000ms / BPM

Question 34

The time period between R phases of the R to R interval is represented by what?

Answer 34

TR

Question 35

R to R interval is measured in?

Answer 35

milliseconds (ms)

Question 36

As a patient's heart rate increase, the R to R interval ______

Answer 36

Shortens

Question 37

If a pt. has a considerable high heart rate and only one R to R interval can be selected, a short TR CANNOT be used. (T/F)

Answer 37

False

Question 38

During cardiac imaging, the period when the system stops acquiring data in order to detect the next R phase is called what?

Answer 38

Trigger Window (shown as a %)

Question 39

The Trigger Window is used to help compensate for the fluctuations in pts. what?

Answer 39

Heart Rate

Question 40

A trigger window of what percent is commonly used to compensate for heart rate fluctuations.

Answer 40

10-20%

Question 41

The waiting period following each R phase is

Answer 41

Trigger Delay

Question 42

A trigger delay of what (ms) is common in modern MR systems?

Answer 42

5-10ms

Question 43

Extending the trigger delay is a technique sometimes used to image the heart during

Answer 43

Diastole

Question 44

A form of physiological gating/triggering commonly used to prevent motion artifact from occurring due to blood flow within the extremities and CSF flow within the brain and spine.

Answer 44

Peripheral gating/triggering

Question 45

During peripheral Gaiting/Triggering, motion is tracked using what device?

Answer 45

Pulse Ox

Question 46

A respiratory bellow is a device that converts the ____ from breathing motion into a ___ that the MRI system can detect.

Answer 46

Mechanical Energy - Electrical Signal

Question 47

a respiratory bellow uses a________________ to convert mechanical energy from breathing motion to electrical signal.

Answer 47

Transducer

Question 48

A respiratory navigator echo tracks respiratory motion by monitoring ___ from within its prescribed ROI.

Answer 48

Signal Intensity

Question 49

In phase imaging is achieved by selecting TE values in multiples of -

Answer 49

4.2ms

Question 50

Using a rectangular FOV is an option that uses a -

Answer 50

Phase FOV SMALLER THAN the Frequency FOV.

Question 51

The imaging option that increases the number of phase-encodings performed in the phase direction is?

Answer 51

Anti-Aliasing (over-sampling, no phase wrap, anti-fold over)