MRI FINAL not mine


Terms in this set (...)

For a given number of slices, which pulse sequence uses the most 180• RF pulses during each TR period?
Dual contrast spin echo
_________ is the fastest imaging technique
Single shot EPI
What type of PS consists of a 180• RF pulse followed by a 90• RF pulse within each TR period?
Inversion recovery
In an inversion recovery PS, the time from the investing pulse to the 90• pulse is called the:
The scan time of a fast spin echo PS with a TR of 3000 ms, 1 signal average, a 256 matrix, and 4 echoes collected for each slice during TR period is ___________ minutes
In a dual contrast spin echo sequence with echo times of 25 msec and 90 msec, the second echo image has:
More T2 contrast and lower S-N ratio (1&2)
CSF suppression is performed with which type of technique?
Which is the following sequences is best for visualizing hemorrhage?
Gradient echo
Compared to a spin echo pulse sequence, a gradient echo PS:
May use shorter repetition, flip angle is <90• (1&2)
Gradient echo imaging is commonly used for all of the following except:
Ruling out tumours
In the figure shown, which letter corresponds to the echo time for the second echo?
MR angiography uses which kind of PS?
Gradient echo
"An EPI sequence in which all of the echoes necessary to reconstruct the image are collected following a single RF excitation:"
Single shot EPI
STIR is used for ________ suppression
Which of the following sequences is best for cardiac?
Echo planar
A voxel is identical to a single:
3D volume element...
Which PS would you expect to find the shortest TR?
Gradient echo
The pixel size of the images which result from a 3D acquisition using a 280mm FOV, 256x256 matrix, 32 slices, and 64mm ST is:
1.09 x 1.09
A fast spin echo is faster than a conventional spin echo because:
Several echoes...
Which is an advantage of using 3D rather than 2D?
Slices have a greater S-N ratio, no crosstalk (1&2)
MPR are usually reserved for images with a 3D pulse sequence because:
2D slices are too thick, often gaps between 2D slices (2&3)
Which is a characteristic of an isotopic data set?
Voxels are perfect cubes, ST = in plane resolution (1&3)
Which of the following sequences is best for performing diffusion-weighting imaging?
Echo planar imaging
Which of the following is not a benefit of contrast enhanced MRA?
Timing of scan relative...
The scan time of a 3D pulse sequence with 200 phase steps in the image matrix, a TR of 40 ms, 15 slices, and 2 signal averages is ___________ minutes
An image acquired with a 3D pulse sequence:
May be used as the base data
The MIP algorithm:
Projects high-intensity pixels...
_______________ MR angiography assists bright pixels to protons that have more phase
Phase contrast
Which MR technique is used to evaluate stroke?
MRA based images are post-processed with algorithms such as MIPS and volume rendering to:
Show the entire course...
The ___________ of the blood is responsible for the bright blood signal in TOF MRA exams
The degree of stenosis _______________________ with TOF MRA
May be overestimated
When using phase contrast MR angiography compared to TOF MR angiography:
An MRA study:
Is at most, minimally invasive
Which is not a metabolic found on 1H spectrum of a normal brain tissue?
Olefin sulfate
Which of the MRA techniques had a scan time short enough to complete an abdominal study in a single breath hold?
Contrast enhanced (3 only)
Which MRA technique demonstrates the actual size of vessel lumen?
Contrast enhanced (2 only)
The final result of a perfusion study is:
Calculated maps which indicate...
The height of a peak on a MR spectrum corresponds to the ___________ of a substance that was detected