Parameters 1 Flashcards
Increasing TR will:
a) Increase SNR and scan time
b) Decrease SNR and scan time
c) Improve spatial resolution
d) Decrease SAR
a) Increase SNR and scan time
A shorter TR leads to:
a) Increased SNR
b) Decreased scan time
c) Increased SAR
d) Both b & c
d) Both b & c
Longer TR allows more signal recovery (higher SNR) but takes more time
Tissues are more exposed to the RF pulses at a time
Which parameter is directly affected by TR?
a) T2 weighting
b) T1 weighting
c) Spatial resolution
d) Chemical shift
b) T1 weighting
A long TR is required for:
a) T1-weighted imaging
b) PD-weighted imaging
c) Susceptibility-weighted imaging
d) STIR
b) PD-weighted imaging
Long TR removes T1 contrast, short TE removes T2 contrast → PD contrast remains
Decreasing TR will:
a) Decrease SNR
b) Increase scan time
c) Reduce SAR
d) Increase motion artifacts
a) Decrease SNR
Increasing TE will:
a) Increase T1 contrast
b) Increase T2 contrast
c) Decrease scan time
d) Increase SNR
b) Increase T2 contrast
A long TE is best suited for:
a) T1-weighted imaging
b) PD-weighted imaging
c) T2-weighted imaging
d) Gradient echo sequences
c) T2-weighted imaging
Reducing TE will:
a) Improve T2 weighting
b) Reduce scan time
c) Increase spatial resolution
d) Increase SNR
d) Increase SNR
TE primarily affects:
a) Image resolution
b) Contrast weighting
c) SNR and spatial resolution equally
d) SAR
b) Contrast weighting
TE controls T2 contrast—long TE enhances T2 effects, short TE minimizes them
A very short TE is typically used in:
a) T2-weighted images
b) Gradient echo sequences
c) DWI scans
d) Inversion recovery sequences
b) Gradient echo sequences
Gradient echoes don’t refocus T2* decay, so short TE helps keep signal strong
Increasing FOV will:
a) Improve spatial resolution
b) Increase SNR
c) Reduce chemical shift artifacts
d) Both b & c
d) Both b & c
Bigger FOV = bigger pixels (less detail) but more signal per pixel (better SNR)
Decreasing FOV results in:
a) Lower SNR
b) Higher spatial resolution
c) Increased scan time
d) Both a & b
d) Both a & b
A small FOV is used when:
a) High SNR is needed
b) High spatial resolution is required
c) Motion artifacts are a concern
d) Fat suppression is required
b) High spatial resolution is required
What is a common disadvantage of increasing FOV?
a) Increased truncation artifacts
b) Lower spatial resolution
c) Increased motion artifacts
d) Increased SAR
b) Lower spatial resolution
A large FOV will result in:
a) Improved spatial resolution
b) Increased partial volume effects
c) Higher chemical shift artifacts
d) Higher SAR
b) Increased partial volume effects
Increasing NSA/NEX:
a) Reduces motion artifacts
b) Increases scan time
c) Improves SNR
d) All of the above
d) All of the above
What happens when NSA is reduced?
a) Scan time increases
b) Motion artifacts increase
c) SNR decreases
d) Both b & c
d) Both b & c
More averages reduce noise and help smooth out motion-related distortions
The primary reason to increase NSA is:
a) To increase spatial resolution
b) To reduce motion artifacts
c) To decrease scan time
d) To increase contrast
b) To reduce motion artifacts
A high NSA is beneficial when:
a) Imaging pediatric patients
b) Performing fast scans
c) Reducing motion artifacts
d) Increasing spatial resolution
c) Reducing motion artifacts
Averaging multiple signals cancels out motion errors
If you need to reduce scan time but maintain image quality, what is the best adjustment to NSA?
a) Decrease NSA
b) Increase NSA
c) Keep NSA constant
d) Increase FOV instead
a) Decrease NSA
Increasing ETL will:
a) Decrease scan time
b) Increase SAR
c) Reduce SNR
d) All of the above
d) All of the above
A longer ETL is beneficial for:
a) Reducing motion artifacts
b) Increasing scan time
c) Improving spatial resolution
d) Decreasing SAR
a) Reducing motion artifacts
Shorter scan time = less chance for movement
What happens to blurring when ETL is increased?
a) It increases
b) It decreases
c) It stays the same
d) It is eliminated
a) It increases
Reducing ETL leads to:
a) Shorter scan times
b) Improved spatial resolution
c) Higher SNR
d) Both b & c
d) Both b & c
Later echoes have weaker signals, causing blur and reducing SNR
What is a potential disadvantage of increasing ETL?
a) Higher SNR
b) More truncation artifacts
c) Increased blurring
d) Decreased SAR
c) Increased blurring
Signal loss in later echoes leads to image blur
Increasing rBW will:
a) Reduce chemical shift artifacts
b) Increase SNR
c) Increase scan time
d) Decrease SAR
a) Reduce chemical shift artifacts
A low rBW results in:
a) Higher SNR
b) More chemical shift artifacts
c) Longer scan times
d) Both a & b
d) Both a & b
Wider rBW reduces frequency-related distortions
What is the main reason to increase rBW?
a) Improve SNR
b) Reduce SAR
c) Reduce metal artifacts
d) Improve spatial resolution
c) Reduce metal artifacts
A wide rBW is beneficial when imaging:
a) Fat-suppressed sequences
b) Metal implants
c) Pediatric patients
d) High-field MRI
b) Metal implants
Higher rBW reduces metal distortion
Narrowing the rBW results in:
a) Lower SNR
b) Increased chemical shift
c) Shorter scan times
d) Reduced SAR
b) Increased chemical shift
Increasing the flip angle will:
a) Increase SNR
b) Increase SAR
c) Decrease scan time
d) Both a & b
d) Both a & b
A small flip angle is used in:
a) T1-weighted imaging
b) Gradient echo sequences
c) Spin echo sequences
d) DWI
b) Gradient echo sequences
SAR increases when:
a) Flip angle is decreased
b) Flip angle is increased
c) TR is shortened
d) Both b & c
d) Both b & c
Flip angle depends on TR and the tissue’s T1 properties
What happens when flip angle is too high?
a) SAR increases
b) SNR decreases
c) Scan time decreases
d) Image contrast improves
a) SAR increases
What happens to T1 contrast when the flip angle increases?
a) It increases
b) It decreases
c) It stays the same
d) It depends on TR
a) It increases
Which combination of TR and TE produces T2-weighted images?
a) Short TR, short TE
b) Long TR, short TE
c) Short TR, long TE
d) Long TR, long TE
Long TR, long TE
Long TR removes T1 contrast, long TE enhances T2 contrast
How does increasing the field of view (FOV) affect image quality?
a) Increases spatial resolution and decreases SNR
b) Increases SNR and decreases spatial resolution
c) Increases both SNR and spatial resolution
d) Decreases both SNR and spatial resolution
b) Increases SNR and decreases spatial resolution
Larger pixels collect more signal (better SNR) but reduce detail (lower resolution)
What is the primary benefit of increasing NSA/NEX?
a) Reducing scan time
b) Reducing motion artifacts
c) Increasing spatial resolution
d) Reducing SAR exposure
b) Reducing motion artifacts
More averages smooth out motion-related distortions
What is a drawback of using a longer Echo Train Length (ETL)?
a) Increased spatial resolution
b) Increased blurring
c) Increased SNR
d) Reduced scan time
b) Increased blurring
Later echoes lose signal, causing blurring
Why is a higher receive bandwidth (rBW) useful in MRI?
a) Reduces chemical shift and metal artifacts
b) Increases spatial resolution
c) Increases SNR
d) Increases T1 contrast
a) Reduces chemical shift and metal artifacts
A wider rBW reduces frequency-related distortions
