MRI MRI Image Quality and Optimization

Question 1

Which parameter, when increased, will most directly improve the signal-to-noise ratio (SNR) in an MRI image?

Accepted Answer

Increasing the number of excitations (NEX/NSA)

Answer

Increasing the echo train length (ETL)

Answer

Decreasing the field of view (FOV)

Answer

Increasing the bandwidth

Question 2

What is the relationship between voxel size and SNR in MRI?

Accepted Answer

Larger voxels produce higher SNR

Answer

Smaller voxels produce higher SNR

Answer

Voxel size has no effect on SNR

Answer

SNR decreases as voxel volume doubles

Question 3

Which of the following changes will increase spatial resolution without changing the FOV?

Accepted Answer

Increasing the matrix size

Answer

Decreasing the matrix size

Answer

Increasing slice thickness

Answer

Increasing NEX

Question 4

A technologist wants to reduce scan time while maintaining similar SNR. Which strategy is most effective?

Accepted Answer

Use parallel imaging (SENSE/GRAPPA)

Answer

Increase slice thickness

Answer

Decrease the matrix size

Answer

Increase the repetition time (TR)

Question 5

What happens to image contrast when the echo time (TE) is increased in a T2-weighted sequence?

Accepted Answer

T2 contrast increases as tissues with short T2 decay faster

Answer

T1 contrast increases

Answer

SNR improves due to longer signal collection

Answer

Tissues appear uniformly bright

Question 6

Which of the following parameters most directly controls T1 contrast in a spin echo sequence?

Accepted Answer

Repetition time (TR)

Answer

Echo time (TE)

Answer

Flip angle in gradient echo

Answer

Bandwidth

Question 7

What is the primary trade-off when reducing the field of view (FOV) in MRI?

Accepted Answer

Improved spatial resolution but increased risk of aliasing artifacts

Answer

Decreased scan time and improved SNR

Answer

Improved SNR with no change in resolution

Answer

Increased slice coverage with same resolution