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Question 1

Which of the following is not a method for “spoiling” the effects of residual transverse magnetization in gradient echo imaging?

Slice-selective gradients with random intensity at the end of each TR

Long TR

Data acquisition with reversed readout gradient polarity

RF pulse with phase offset

Question 2

Which statement about Fast Spin Echo (FSE) is not correct?

Each echo of FSE fills different phase encoding lines.

The echo filling the k-space edge region determines the image contrast and thus the effective echo time.

FSE can reduce scan time greatly compared to conventional spin echo.

FSE having long echo train causes image blurring.

Question 3

If the image matrix size is 128*128 (

NRO $𝑁_{𝑅𝑂}$ *

NPE $𝑁_{𝑃𝐸}$ ) and the number of segment is 4 for multi-shot EPI, the number of lines per segment is _______.

128

Question 4

Among reconstruction techniques for non-Cartesian imaging, radial K-space sampling is from the method of Computed Tomography (CT) reconstruction.

True

False

Question 5

Short TR is necessary for 3D imaging, because the same volume is excited by every excitation RF pulse.

False

True

Question 6

In multi-slice 2D imaging, the slice loop can be located either inside or outside the phase-encoding loop. When number of slices, field of view, resolution, and total scan time are the same, which option can provide higher signal to noise ratio (SNR)?

When the slice loop is located inside the phase-encoding loop

The answer is different depending on sequence type (gradient echo, spin echo).

When the slice loop is located outside the phase-encoding loop

There is no difference in SNR between the two approaches.

Question 7

Assume a spike noise instantaneously affected an echo in 2D multi-slice imaging and also in 3D imaging. Which images are affected by the noise in a spatially wider area?

3D images

2D multi-slice images

None of the images are not affected by the spike noise because it happened instantaneously.

No difference

Question 8

Which of the following statements is true regarding image contrast using gradient echo sequences?

The optimal condition for acquiring PD-weighted image is using large flip angle, long TE, and short TR.

The optimal condition for acquiring T2*-weighted image is using small flip angle, short TE, and long TR.

The optimal condition for acquiring T1-weighted image is using large flip angle, short TE, and short TR.

The optimal condition for acquiring T2-weighted image is using small flip angle, long TE, and long TR.

Question 9

What flip angle value must be used to obtain the highest signal for gray matter tissue using spoiled GRE sequence with TR = 50 ms at 3T (assume perfect spoiling)?

30.4

∘ $^{\circ}$

15.6

∘ $^{\circ}$

45.5

∘ $^{\circ}$

5.2

∘ $^{\circ}$

Question 10

Which of the follows shows the scan parameters that match the corresponding image contrast?

Question 11

Which statement about spin echo is true?

Spin echo sequence can produce T1- and T2*-weighted images.

The time between the 90

∘ $^{\circ}$ and 180

∘ $^{\circ}$ RF pulses is identical to the time between the 180

∘ $^{\circ}$ RF and the next 90

∘ $^{\circ}$ RF.

It requires two successive RF pulses to form an echo.

After 90

∘ $^{\circ}$ excitation, spins in the transverse plane gain phase coherence by spin-spin interaction.

Question 12

Which statement is true?

Longer echo train length is not desired for reducing total scan time.

FSE is robust to flow and motion artifact.

Multiple 180

∘ $^{\circ}$ RF pulses allow us to get multiple spin echoes.

Applying 180

∘ $^{\circ}$ RF can recover random dephasing.

Question 13

Which of the following statements is not correct regarding echo planar imaging?

Spin echo-EPI utilizes multiple frequency encoding gradients with alternating polarities.

The polarities of phase encoding gradients are alternating every TR in case of multi-shot EPI.

Single-shot EPI can acquire a whole image with only one RF excitation.

The echoes filling the K-space center region determine the contrast of both gradient echo-EPI and spin echo-EPI.

Question 14

Choose the correct expectations when the number of segments in echo planar imaging increases.

The number of lines per segment increases

The number of RF excitations increases

The scan time decreases

The number of phase encoding lines increases

Question 15

Which statement is not correct regarding non-Cartesian imaging?

In radial K-space imaging, single or multiple trajectory acquisition is possible.

Noncartesian imaging is robust to object movement.

K-space central portion is oversampled.

2D Fast Fourier Transform cannot be directly used on acquired noncartesian K-space.

Question 16

What is the wrong decision to the situation described?

A fast spin echo sequence showed image blurring. Increasing the echo train length can resolve the problem.

For better temporal resolution, the number of trajectories in spiral imaging should be decreased.

To have very short TE, an echo-planar imaging sequence is replaced with a spiral imaging sequence because the k-space is sampled from the center right after the slice selection in spiral imaging.

Significant artifacts are observed in single-shot echo planar imaging (EPI). Multi-shot EPI can resolve the problem.

In accordance with the Coursera Honor Code, I (Anonymous Student) certify that the answers here are my own work.

You cannot submit your work until you agree to the Honor Code. Thanks!

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