MRI Review Questions Pg 248-284

In which of the following EPI sequences would one expect there to be the least susceptibility (distortion) artifacts?

Multi-shot (4 shot) SE, EPI, 256 phase x 256 frequency

In an image acquired with a balanced GRE sequence (Figure C.2), all of the following have high (bright) signal EXCEPT

Normal myocardium

Parallel imaging techniques are also known as all of the following EXCEPT

SAT

Gradient echo sequences can yield either T1 or T2* characteristics True or False

True

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

calibration scan

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

To evaluate the circle of Willis (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

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

incoherent gradient echoes

Gradient echo sequences acquired for high signal from fluid are known as all the following EXCEPT

incoherent gradient echoes

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

incoherent/spoiled

In a fast spin echo (FSE) sequence, acquired with long effective TE (T2-weighted images), scan time can be reduced by the selection of

longer ETL

When doing an MRV of the superior sagittal sinus, a saturation band should be placed _____ to the axial slices.

inferior

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:

interleaved acquisition

The number of shots is calculated by

#PEs/ETL

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

bottom

Phase encoding is performed

prior to frequency encoding

A single shot FSE sequence is acquired when

#PEs = 256 and ETL = 256

A multi-shot FSE sequence is acquired (with four shots) when:

#PEs = 256 and ETL = 64

Which of the following field strengths would require the shortest (lowest) TI time to suppress/null the signal from fat when acquiring a STIR sequence in an MR exam of the knee?

0.35 T

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

12

An inversion recovery (IR) spin echo sequence begins with a

180 degree RF pulse

A typical inversion recovery (IR) spin echo sequence spin echo sequence uses pulses

180 degree, 90 degree, 180 degree

If the pulse sequence shown in Figure C.1 were a fast spin echo sequence, the number of lines of k space filled during each TR period would be

2

In the multi-echo spin echo sequence shown in Figure C.1, the number of images PER SLICE LOCATION created will be

2

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

2 minutes

In the multi-echo spin echo sequence shown in Figure C.1, the number of LONG TE images created with a 20-slice will be

20

In the multi-echo spin echo sequence shown in Figure C.1, the number of SHORT TE images created with a 20-slice sequence will be

20

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

256 times

In the multi echo spin echo sequence shown in Figure C.1, the total number of images created with a 20-slice sequence will be

40

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 (SE) sequence uses pulses

90 degree, 180 degree

A FLAIR sequence is utilized to suppress the signal from

CSF

In which of the following sequences would MS plaques appear hyper intense relative to both CSF and normal white matter?

T2 FLAIR

In the multi-echo spin echo sequence shown in Figure C.1, images will be acquired with varying amounts of

T2 information

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

TR period

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

TR x #PEs NSA/ETL

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

TR x #PEs x NSA

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

TR x #PEs x NSA

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

TR x #PEs x NSA

Scan time for a "volume" acquisition can be calculated by

TR x #PEs x NSA x #slices

Scan time for EPI pulse sequences can be calculated by

TR x #shots x NSA

In a volume acquisition, the scan time is

TR x NSA x number of phase encodings x number of slices

The scan time for a 3D (or volume) acquisition is given by

TR x NSA x number of phase encodings x number of slices

Which of the following best describes an EPI sequence ?

a "train" of gradient echoes

Which of the following best describes an FSE sequence?

a "train" of spin echoes

Which of the following best describes an IR sequence?

a 180 degree pulse followed by a 90 degree/180 degree combination

Which of the following best describes a SE sequence?

a 90 degree pulse followed by a 180 degree pulse

In a 3D acquisition, the slices are produced by

a phase-encoding gradient applied in the slice selection direction

In order to produce high-quality reformatted image, the

acquisition voxel should be isotropic

Gradient echo sequences can yield either T1 or T2 characteristics, with influences caused by all of the following EXCEPT

aliasing

A typical gradient echo sequence begins with a

alpha pulse that varies with desired image contrast

STIR sequences can suppress the signal from all of the following EXCEPT:

fluid CSF

Short tau inversion recovery (STIR) sequences are typically used for the evaluation of all of the following EXCEPT:

fluid CSF

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

four times as fast

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

frequency

The "readout" gradient is also known as the

frequency

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

frequency

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

frequency encoding gradient/readout 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?

gradient echo EPI

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

high amplitude phase-encoding gradients

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

low amplitude phase-encoding gradients

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

maximum intensity pixel

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

multiplayer reformatting

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

periventricular white matter disease

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

segmenting

In a fast spin echo (FSE) sequence, acquired with short effective TE (T1-or PD-weighted images), 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

The 180 degree pulse that follows the initial 90 degree 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

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

spoiling

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

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 saturation band should be placed _____ to the axial slices.

superior

When doing an MRA of the circle of Willis, a saturation band should be placed _____ to the axial slices.

superior

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

susceptibility

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

switching device

In a balanced GRE acquisition, the contrast weighting is

weighted for the ratio of T2/T1