MRI Protocol Optimization Exam
Practice Questions and Correct Answers
(Verified Answers) Plus Rationales 2027
Q&A | Instant Download Pdf
1. Which parameter primarily controls the amount of longitudinal
magnetization recovered between successive RF excitations?
A. Echo time (TE)
B. Flip angle
C. Repetition time (TR)
D. Echo train length
Correct answer: C
TR is the time between successive RF excitations of the same slice or volume.
Increasing TR generally allows more longitudinal magnetization to recover and
reduces T1 weighting, while shortening TR increases T1 weighting.
2. What is the primary effect of increasing TE in a conventional spin-echo
sequence?
A. Increased T2 weighting
B. Increased T1 weighting
C. Reduced proton density
D. Reduced susceptibility sensitivity
Correct answer: A
TE determines how long transverse magnetization evolves before the signal is
measured. A longer TE allows more T2 decay to occur, increasing T2 weighting.
,3. A technologist wants to increase T1 weighting in a conventional spin-echo
sequence. Which parameter combination is most appropriate?
A. Long TR and long TE
B. Long TR and short TE
C. Short TR and long TE
D. Short TR and short TE
Correct answer: D
Short TR emphasizes differences in longitudinal recovery, producing stronger T1
weighting. A short TE minimizes T2 decay so that T2 effects do not dominate the
image contrast.
4. What is the primary consequence of increasing the flip angle in a spoiled
gradient-echo sequence, assuming other parameters remain unchanged?
A. Elimination of T1 weighting
B. Greater T1 weighting
C. Elimination of T2* effects
D. Automatic reduction of SAR
Correct answer: B
Increasing the flip angle can increase T1 weighting in spoiled gradient-echo
imaging because the amount of longitudinal magnetization remaining after each
excitation becomes more dependent on T1 recovery.
5. Which change generally increases T2* weighting in a gradient-echo
acquisition?
A. Shortening TE
B. Increasing TR only
C. Lengthening TE
D. Increasing receiver bandwidth only
Correct answer: C
,Gradient-echo sequences do not use a 180-degree refocusing pulse to eliminate
static field variations. A longer TE allows more T2 decay and susceptibility-related
signal loss to develop.*
6. What is the main purpose of selecting an appropriate receiver bandwidth
during protocol optimization?
A. To determine the patient's position
B. To control only T1 contrast
C. To eliminate all motion artifacts
D. To balance chemical-shift effects, SNR, and geometric distortion
Correct answer: D
Receiver bandwidth influences several image characteristics. Increasing
bandwidth can reduce chemical-shift displacement and susceptibility-related
geometric distortion but generally decreases SNR. Therefore, bandwidth selection
is an optimization trade-off.
7. Which modification most directly improves in-plane spatial resolution?
A. Increasing the acquisition matrix while maintaining the same FOV
B. Increasing slice thickness
C. Increasing voxel volume
D. Decreasing the acquisition matrix
Correct answer: A
Increasing the matrix while keeping FOV constant produces smaller in-plane
pixels, improving spatial resolution. This may also reduce SNR and increase scan
time depending on the specific acquisition.
8. A protocol uses a 240-mm FOV and a 256 × 256 acquisition matrix. What is
the approximate in-plane pixel dimension?
, A. 1.5 mm
B. 0.94 mm
C. 2.4 mm
D. 0.24 mm
Correct answer: B
Pixel dimension is approximately FOV divided by matrix size. Therefore, 240 mm ÷
256 ≈ 0.94 mm.
9. Which adjustment generally increases SNR most directly?
A. Decreasing voxel volume
B. Increasing receiver bandwidth
C. Increasing voxel volume
D. Increasing parallel-imaging acceleration
Correct answer: C
Larger voxels contain more signal-producing spins, generally increasing SNR. The
trade-off is reduced spatial resolution and potentially greater partial-volume
averaging.
10. What is the primary effect of decreasing slice thickness while keeping other
parameters unchanged?
A. Increased voxel volume
B. Increased SNR
C. Reduced spatial resolution
D. Improved through-plane spatial resolution
Correct answer: D
Thinner slices reduce voxel dimension in the slice-select direction, improving
through-plane spatial resolution. However, the smaller voxel volume usually
reduces SNR.
Practice Questions and Correct Answers
(Verified Answers) Plus Rationales 2027
Q&A | Instant Download Pdf
1. Which parameter primarily controls the amount of longitudinal
magnetization recovered between successive RF excitations?
A. Echo time (TE)
B. Flip angle
C. Repetition time (TR)
D. Echo train length
Correct answer: C
TR is the time between successive RF excitations of the same slice or volume.
Increasing TR generally allows more longitudinal magnetization to recover and
reduces T1 weighting, while shortening TR increases T1 weighting.
2. What is the primary effect of increasing TE in a conventional spin-echo
sequence?
A. Increased T2 weighting
B. Increased T1 weighting
C. Reduced proton density
D. Reduced susceptibility sensitivity
Correct answer: A
TE determines how long transverse magnetization evolves before the signal is
measured. A longer TE allows more T2 decay to occur, increasing T2 weighting.
,3. A technologist wants to increase T1 weighting in a conventional spin-echo
sequence. Which parameter combination is most appropriate?
A. Long TR and long TE
B. Long TR and short TE
C. Short TR and long TE
D. Short TR and short TE
Correct answer: D
Short TR emphasizes differences in longitudinal recovery, producing stronger T1
weighting. A short TE minimizes T2 decay so that T2 effects do not dominate the
image contrast.
4. What is the primary consequence of increasing the flip angle in a spoiled
gradient-echo sequence, assuming other parameters remain unchanged?
A. Elimination of T1 weighting
B. Greater T1 weighting
C. Elimination of T2* effects
D. Automatic reduction of SAR
Correct answer: B
Increasing the flip angle can increase T1 weighting in spoiled gradient-echo
imaging because the amount of longitudinal magnetization remaining after each
excitation becomes more dependent on T1 recovery.
5. Which change generally increases T2* weighting in a gradient-echo
acquisition?
A. Shortening TE
B. Increasing TR only
C. Lengthening TE
D. Increasing receiver bandwidth only
Correct answer: C
,Gradient-echo sequences do not use a 180-degree refocusing pulse to eliminate
static field variations. A longer TE allows more T2 decay and susceptibility-related
signal loss to develop.*
6. What is the main purpose of selecting an appropriate receiver bandwidth
during protocol optimization?
A. To determine the patient's position
B. To control only T1 contrast
C. To eliminate all motion artifacts
D. To balance chemical-shift effects, SNR, and geometric distortion
Correct answer: D
Receiver bandwidth influences several image characteristics. Increasing
bandwidth can reduce chemical-shift displacement and susceptibility-related
geometric distortion but generally decreases SNR. Therefore, bandwidth selection
is an optimization trade-off.
7. Which modification most directly improves in-plane spatial resolution?
A. Increasing the acquisition matrix while maintaining the same FOV
B. Increasing slice thickness
C. Increasing voxel volume
D. Decreasing the acquisition matrix
Correct answer: A
Increasing the matrix while keeping FOV constant produces smaller in-plane
pixels, improving spatial resolution. This may also reduce SNR and increase scan
time depending on the specific acquisition.
8. A protocol uses a 240-mm FOV and a 256 × 256 acquisition matrix. What is
the approximate in-plane pixel dimension?
, A. 1.5 mm
B. 0.94 mm
C. 2.4 mm
D. 0.24 mm
Correct answer: B
Pixel dimension is approximately FOV divided by matrix size. Therefore, 240 mm ÷
256 ≈ 0.94 mm.
9. Which adjustment generally increases SNR most directly?
A. Decreasing voxel volume
B. Increasing receiver bandwidth
C. Increasing voxel volume
D. Increasing parallel-imaging acceleration
Correct answer: C
Larger voxels contain more signal-producing spins, generally increasing SNR. The
trade-off is reduced spatial resolution and potentially greater partial-volume
averaging.
10. What is the primary effect of decreasing slice thickness while keeping other
parameters unchanged?
A. Increased voxel volume
B. Increased SNR
C. Reduced spatial resolution
D. Improved through-plane spatial resolution
Correct answer: D
Thinner slices reduce voxel dimension in the slice-select direction, improving
through-plane spatial resolution. However, the smaller voxel volume usually
reduces SNR.
