Data Acquisition and Processing

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Collecting the low frequency (high amplitude signal) data points in k space at the start of the scan (in a rectilinear fashion) is known as:

Centric

The high frequency (low amplitude) data points in k space provide:

Edge detail (spatial resolution)

The main purpose of producing / calculating an ADC map is to

Eliminate the T2 shine through

Collecting the low frequency (high amplitude signal) data points in k space at the start of the scan (in a spiral fashion) is known as:

Elliptic centric

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

FOV and number of slices

A short T1 inversion recovery (STIR) sequence can suppress the signal from:

Fat and water

STIR sequences can suppress the signal from all of the following except: 1. Fat within bone marrow 2. Gadolinium enhancing lesions 3. retro-orbital fat 4. Fluid (CSF)

Fluid (CSF)

Short tau inversion recovery (STIR) sequences are typically used for the evaluation of all of the following except: 1. Musculoskeletal contusions 2. Fat Suppression 3. Lesions within the retro-orbital fat 4. Fluid (CSF)

Fluid (CSF)

The technique by which signal data is transformed from a plot of signal intensity over time to a plot of signal intensity over frequency is known as:

Fourier Transformation

The technique by which signal data is modified from the "time domain" to the "frequency domain" is known as

Fourier transformation

One direction in k space represents phase, while the other represents:

Frequency

The gradient that is on during the production of the echo is the:

Frequency

The readout gradient is also known as the

Frequency

Gradient echo sequences acquired for high signal from fluid are known as all of the following except: 1. Coherent gradient echo 2. incoherent gradient echo 3. steady state gradient echo 4. T2* gradient echo

Incoherent gradient echo

The technique whereby a portion of the lines of k space are sampled and filled and the remaining lines are interpolated is known as all of the following except: 1. Half fourier 2. Partial fourier 3. Fraction fourier 4. Interleaved acquisition

Interleaved acquisition

Creating additional images in various planes from a 3D dataset is accomplished by a technique known as:

MPR

To create a projection image in MRA, the technique most commonly employed is:

Maximum intensity pixel

Increasing the TE yields images with: 1. More T1 information 2. Less T1 information 3. More T2 information 4. Less T2 information

More T2 information

cardiac analysis performed with a technique using SAT bands to assess wall motion is known as:

Myocardial tagging

A single shot FSE sequence is acquired when PE = _____ and ETL = _____

PE= 256 and ETL = 256

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

Precessional frequency of fat

Parallel imaging techniques are also known as all of the following except: 1. SENSE 2. SMASH 3. GRAPPA 4. SAT

SAT

When using parallel imaging to reduce acquisition times, which of the following is always true?

SNR is reduced and spatial resolution is unaffected

The following is important in MRA sequences to minimize the loss of signal due to dephasing within a voxel:

Small vessels and Short TE

When a gradient echo sequence is acquired for dynamic contrast - enhanced imaging of the liver, __________________________ is performed.

Spoiling

The removal of signal from vessels in an MRA sequence is achieved by:

Spatial presaturation

If the TR of a gradient echo pulse sequence is considerably less than the T2 (and T2*) the condition that will exist is known as:

Steady State

Having acquired a 3D TOF, when producing an MRA projection image set using the MIP technique, which of the following can appear bright and therefore the same as flow within a vessel?

Tissues or substances with extremely short T2 relaxation times.

Gradient echo sequences use flip angles:

To control saturation effects

Fourier Transformation converts signal data from the FID into the spectrum true or false

True

Gradient echo sequences can yield either T1 or T2* characteristics true or false?

True

Normal blood flow is known as:

Turbulent flow

To produce the echo, a gradient echo pulse sequence uses a:

combination of gradient magnetic field and RF pulse

In a time of flight sequence, flowing blood is HYPERintense relative to stationary tissue because of the:

flow related enhancement

The signal intensity on TOF MRA sequences is related to:

flow- related enhancement

The effective TE in a fast spin echo pulse sequence determines the

image contrast

Each "frame" of a cardiac cine sequence displays the heart:

in different phases of the cardiac cycle

A gradient echo sequence in which any residual transverse magnetization is removed prior to the next excitation pulse is known as:

incoherent/ spoiled

Using a conventional spin echo multislice sequence, the number of slices allowed when increasing the TR

increase by a factor of TR/TE

Doubling the NSA will ______________________ the SNR by ________________

increase, square root of 2

Decreasing the receiver bandwidth (narrow BW) _____________________ readout time

increases

Decreasing the receiver bandwidth (narrow BW) _____________________ susceptibility artifact

increases

Increasing the NSA _______________ scan time

increases

Increasing the phase matrix ________________ scan time

increases

Reducing the ETL _______ scan time

increases

Reducing the TE ___________ SNR

increases

The time during which the frequency encoding gradient is on _____________________ with a reduction in receiver bandwidth

increases

increasing the slice thickness ______________ SNR

increases

Increasing the flip angle ____________ SNR

increases SNR up to the Ernst angle

Increasing the TE:

increases the contrast based on the T2 relaxation of the tissues

As the TR increases: SNR _____________________

increases up to a point

Increasing the slice thickness from 5 to 10 mm, the SNR ___________________ by a factor of ____

increases, 2

When doing an MRV of the superior sagittal sinus, a sat band should be placed ____________________ to the axial slices

inferior

Using a 3D acquisition, the number of slices allowed when increasing the TR

is not affected

In order to produce a high quality reformatted image, the voxel should be

isotropic

Increasing the TR _________________ scan time

Increases scan time

The number of shots is calculated by

#PE's / ETL

Which of the following field strengths would require the shortest (lowest) T1 time to suppress/ null the signal from fat when acquiring a STIR sequence in an MR exam of the knee? 1. .35T 2. 1.0T 3. 1.5T 4. 3.0T

.35T

Doubling the NSA will increase the SNR by a factor of

1.41

In a spin echo sequence, the time between the 90 and 180 is

1/2 TE

An inversion recovery spin echo sequence begins with a:

180 RF pulse

A typical inversion recovery spin echo uses pulses:

180, 90, 180

If a given conventional spin echo pulse sequence takes 12 minutes to acquire, a fast spin echo sequence using an ETL of six, with all other factors that affect scan time remaining the same, will take:

2 minutes

If a phase resolution of 256 is desired, then the TR must be repeated (for one NSA)

256 times

The MRA sequence that is least sensitive to slow flow is:

3D TOF

The MRA sequence that is most sensitive to smaller vessels is:

3D TOF

The MRA sequence that is sensitive to flow direction is:

3D phase contrast (PC MRA)

The MRA sequence that can be made sensitive to any flow velocity is:

3D phase contrast MRA (PC MRA)

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

4

In a fast spin echo pulse sequence, if the echo trail length is increased by a factor of four, then the scan will be _____ times as fast

4 times

A FLAIR sequence is utilized to suppress the signal from:

CSF

If one desires to null the signal from a specific tissue using an inversion recovery sequence, one should select an inversion time that is ________ % of the T1 relaxation time of that tissue.

69%

With a fast spin echo sequence utilizing an eight echo train length (ETL), the number of lines of k space filled during each TR will be:

8

A typical spin echo sequence uses pulses:

90 and 180

Cardiac cine acquisitions typically utilize a / an __________________ pulse sequence.

A gradient echo pulse sequence

in a 3D acquisition, the slices are produced by:

A phase encoding gradient applied in the slice selection direction

Single order gradient moment nulling does not compensate for

Accelerated flow and reverse flow

Which technique can be utilized to optimally time the start of a contrast- enhanced MRA

Automated bolus detection, test bolus, and real time / fluoro triggering

The top portion of k space is a mirror image of the:

Bottom

During dynamic enhanced imaging for vasculature or visceral structures, contrast is administered and k space is filled with _____________ to ensure that the contrast enhancement is well visualized.

Centric

The basic MR principle with regard to MR spectroscopy is:

Chemical shift

To evaluate the COW, 3D TOF MRA sequences are acquired and displayed as an axial view of all of the vasculature. This image is known as:

Collapsed Image

Reducing NSA will reduce the scan time and ___________________ the SNR

Decrease the SNR

Decreasing the receiver bandwidth (narrow BW) _______________ number of slices

Decreases

Using a conventional spin echo sequence, the number of slices allowed when increasing the TE from 20 to 40 ms:

Decreases

Reducing the TR down to or below the T1 relaxation time of the tissue

Decreases the signal to noise ratio of the image and increases saturation effects

between slices 2D acquisitions generally require:

Gaps

to rephrase the signal from moving spins, gradient moment nulling techniques use a

Gradient

When acquiring an fMRI series to map out the visual cortex, which of the following pulse sequences would be utilized in order to maximize sensitivity to the BOLD effect? 1. Spin Echo EPI 2. Gradient echo EPI 3. Fast spin echo with driven equilibrium 4. 3D spoiled GRE with MTC

Gradient echo EPI

Acquiring half of the phase views of k space and then interpolating the data for the other half is a technique known as:

Half fourier

In a fast spin echo sequence, spatial resolution is associated with the

High amplitude phase encoding gradients

Dynamic enhanced MRA sequences of the renal arteries are performed with the use of:

Incoherent gradient echos

In a vessel with a plaque producing a high degree of stenosis, the velocity of the blood flow in the center point of the stenosis is:

Increased

Decreasing the receiver bandwidth (narrow BW) ___________________ the SNR

Increases

Decreasing the receiver bandwidth (narrow BW) ______________________ chemical shift artifact

Increases

Normal blood flow (demonstrated by a parabolic blood flow profile) is known as:

Laminar Flow

Increasing the TR yields images with: 1. More T1 information 2. Less T1 information 3. More T2 information 4. Less T2 information

Less T1 information

Reducing the flip angle yields images with: 1. More T1 information 2. Less T1 information 3. More T2 information 4. Less T2 information

Less T1 information

Reducing the TE yields images with 1. more T1 information 2. less T1 information 3. more T2 information 4. less T2 information

Less T2 information

In a fast spin echo (FSE) sequence, acquired with long effective TE, scan time can be reduced by the selection of:

Longer ETL

Complete saturation is a condition where:

Longitudinal magnetization is not allowed to recover between excitations

In a fast spin echo sequence, the effective TE is the echo that is performed with the:

Low amplitude phase encoding gradients

Phase encoding is performed: 1. After frequency encoding 2. Prior to frequency encoding 3. In place of frequency encoding 4. During frequency encoding

Prior to frequency encoding

The presaturation pulses usually occur:

Prior to the excitation pulse

Reducing the TE

Reduces contrast based on T2 relaxation times

In order to reconstruct an image acquired using parallel imaging, which of the following may be required?

Reference or calibration scan

In a gradient echo sequence, reducing the flip angle while holding the TR constant reduces:

Saturation

In a time of flight sequence, the tissue is HYPOintense relative to flowing blood because of the:

Saturation effects

To evaluate the COW, 3D TOF MRA sequences are acquired and background tissue is carved out to provide a better visualization of the intracranial vasculature. This step is known as

Segmenting

The evaluation of cardiac function can be provided by any or all of the following except: 1. Cardiac cine 2. Multiphase imaging 3. Perfusion imaging 4. Short axis single slice, single phase

Short axis single slice, single phase

In a fast spin echo (FSE) sequence, acquired with short effective TE, blurring can be reduced by the selection of:

Shorter ETL

To keep scan time at a minimum, diffusion imaging is typically performed with:

Single shot EPI acquisition

During contrast enhanced imaging of the abdominal organs, images are acquired without and with gad enhancement. To better visualize contrast enhancement, _____________________ can be performed.

Subtraction

When doing an MRA of the IVC, a saturation band should be placed ________________ to the axial slices

Superior

When doing an MRA of the carotid arteries, a sat band should be placed _________________ to the axial slices

Superior

Gradient echo sequences acquired for the evaluation of hemorrhagic lesions rely on:

Susceptibility

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:

T1

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

T2

In which of the following sequences would MS plaque appear hyperintense relative to both CSF and normal white matter? 1. T2 FLAIR 2. T1 FLAIR 3. T2 FSE 4. T2 FSE with RF fat suppression

T2 FLAIR

In a spin echo sequence, flowing blood is normally seen as a signal void because the:

TE is too long to image flow 90 pulse and 180 pulse are both slice selective

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

TI

The time between excitation pulses is known as the:

TR

With conventional spin echo each line of k space is filled in each:

TR period

Scan time for EPI pulse sequences can be calculated by:

TR x #shots x NSA

In a 2D conventional spin echo multislice pulse sequence, scan time is given by the equation:

TR x NSA x PE

The scan time for a 3D acquisition is given by:

TR x NSA x PE x # of slices

In a volume acquisition, the scan time is

TR x NSA x PE x #slices

Scan time for 2D GRE pulse sequences can be calculated by:

TR x PE x NSA

Scan time for 2D IR pulse sequences can be calculated by:

TR x PE x NSA

Scan time for 2D SE pulse sequences can be calculated by

TR x PE x NSA

Scan time for 2D FSE pulse sequences can be calculated by:

TR x PE x NSA/ETL

Scan time for a volume acquisition can be calculated by:

TR x PE's x NSA x #slices

In an inversion recovery pulse sequence, image contrast is controlled by

TR, TE, and TI

Another name for TI is:

Tau

A 3D dataset can be reconstructed to display "what appears to be" a 3D image of the anatomy. This technique is known as

VR- volume rendering

The signal intensity on PC MRA sequences is related to:

Velocity induced phase shift

The swirling blood flow that occurs just past the area of stenosis is known as

Vortex flow

Which of the following best describes an IR sequence? 1. a 90 pulse followed by a 180 pulse 2. a 180 pulse followed by a 90/180 combination 3. a train of gradient echoes 4. a train of spin echoes

a 180 pulse followed by a 90/180 combination

Which of the following best describes a SE sequence? 1. a 90 pulse followed by a 180 pulse 2. a 180 pulse followed by a 90/180 combination 3. a train of gradient echoes 4. a train of spin echoes

a 90 pulse followed by a 180 pulse

Which of the following describes an EPI sequence? 1. a 90 pulse followed by a 180 pulse 2. a 180 pulse followed by a 90/180 combination 3. a train of gradient echoes 4. a train of spin echoes

a train of gradient echoes

Which of the following best describes a FSE sequence? 1 a 90 pulse followed by a 180 pulse 2. a 180 pulse followed by a 90/180 combination 3. a train of gradient echoes 4. a train of spin echoes

a train of spin echoes

When parallel imaging techniques are performed, a low resolution ________________ scan is acquired prior to the acquisition:

calibration

Blood flow at the area of stenosis (vascular narrowing)is known as:

accelerated flow

A typical gradient echo sequence begins with a:

alpha pulse that varies with desired image contrast

The signal intensity on diffusion sequences is related to:

amount of diffusion

Changing the b value alters the

amplitude, timing, and or duration of the diffusion gradients

Fourier Transformation is performed in the

array processor

Blood flow velocities are greatest

at the center of the vessel

Which of the following would result in an image with the greatest amount of diffusion weighting

b value 1100

Increasing the number of phase encodings will produce an image with _______________ voxel volume

decreased

As the TE increases, SNR __________________

decreases

Increasing the matrix ______________ SNR

decreases

Increasing the number of phase encodings from 128 to 256, the SNR

decreases

In a phase contrast technique, it is possible to use the data to determine the:

direction of blood flow

Increasing the FOV ___________ scan time

does not affect

Increasing the number of slices in a 2D acquisition _________________ scan time

does not affect

Increasing the TE _________________ scan time

does not affect scan time

Using a 3D acquisition, increasing the number of slices from 64 to 128 ___________________ scan time

doubles scan time

In a fast spin echo sequence, the central lines of k space are associated with the

effective TE

For a given tissue with a given T1 relaxation time and TR, the flip angle, which will result in the maximum signal for that tissue, is

ernst angle

The gradient that is on during the production of the echo is called the:

frequency encoding gradient

Increasing the receiver bandwidth ______________ the available ETL

has no effect

Increasing the matrix in the frequency direction from 256 to 512 will __________________ scan time

have no effect on the scan time

A major advantage of a 2D TOF sequence over a 3D TOF sequence is the ability to

image a larger area without saturation of the flowing blood

Increasing the flip angle yields images with

more T1 information

Reducing the TR yields images with 1. More T1 information 2. Less T1 information 3. More T2 information 4. Less T2 information

more T1 information

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

motion artifacts traverse the least tissue or areas of interest.

A major advantage of MRA over conventional angiography is that:

multiple views can be produced from a single acquisition

When triggering a scan from the patient's ECG, the TR of the sequence is determined by the

patient's HR

T2 weighted fluid attenuated inversion recovery (FLAIR) sequences are typically used for the evaluation of

periventricular white matter disease

Presaturation pulses are often used to:

reduce flow artifacts

When performing a dynamic perfusion exam of the brain utilizing a gadolinium based MR contrast agent, the result of the T2* shortening is:

reduced MR signal

The 180 pulse that follows the initial 90 pulse in a spin echo sequence will cause the NMR signal to reappear while correcting for:

slight magnetic field inhomogeneities, chemical shift, slight magnetic susceptibility effects

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

slow constant flow

When doing an MRA of the COW, a sat band should be placed __________________ to the axial slices.

superior

The intrinsic contrast mechanism with regard to fMRI is:

the BOLD effect

Phase contrast techniques produce images in which the signal intensity within the vessel is dependent on (among other parameters) the:

velocity of the flowing blood

Cine studies are often performed on various joints. The main purpose of such a study is to:

visualize motion and function

A major advantage of 3D TOF techniques over 2D TOF is the ability to

visualize smaller vessels

In a balanced GRE acquisition, the contrast weighting is: 1. T1 weighted 2. T2 weighted 3. T2* weighted 4. Weighted for the ratio of T2/T1

weighted for the ratio of T2/T1


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