MRI Physics Chapter 3 Questions and
Answers 100% Pass
Why is a strong gradient field needed in MRI?
✔✔ To achieve precise spatial encoding of signals
What happens to image resolution when voxel size is reduced?
✔✔ Resolution improves, but SNR may decrease
How does increasing the bandwidth affect scan time?
✔✔ It reduces scan time but may increase noise
What is the purpose of fat suppression techniques in MRI?
✔✔ To eliminate fat signal and enhance tissue contrast
Why is steady-state free precession (SSFP) used in MRI?
✔✔ It provides high signal intensity with short scan times
1
,How does parallel imaging reduce scan time?
✔✔ It acquires fewer phase-encoding steps, speeding up image acquisition
What is the primary factor that determines tissue contrast in MRI?
✔✔ The relaxation properties of tissues
What is the function of gradient moment nulling?
✔✔ It reduces motion artifacts in MRI scans
How does motion affect MRI images?
✔✔ It causes blurring and ghosting artifacts
Why is MRI considered safer than CT for soft tissue imaging?
✔✔ It does not use ionizing radiation
What is the primary purpose of the main magnetic field in MRI?
✔✔ To align hydrogen protons in the body
2
, How does increasing the magnetic field strength affect signal-to-noise ratio (SNR)?
✔✔ It increases SNR, improving image quality
What happens to hydrogen protons when an RF pulse is applied?
✔✔ They absorb energy and move into a higher energy state
Why is relaxation time important in MRI?
✔✔ It determines how tissues appear on different sequences
What is the role of T1 relaxation in MRI?
✔✔ It measures the time it takes for protons to realign with the magnetic field
How does T2 relaxation differ from T1 relaxation?
✔✔ T2 measures the time it takes for protons to lose phase coherence
What factor primarily affects T1 relaxation time?
✔✔ The molecular structure of the tissue
3
Answers 100% Pass
Why is a strong gradient field needed in MRI?
✔✔ To achieve precise spatial encoding of signals
What happens to image resolution when voxel size is reduced?
✔✔ Resolution improves, but SNR may decrease
How does increasing the bandwidth affect scan time?
✔✔ It reduces scan time but may increase noise
What is the purpose of fat suppression techniques in MRI?
✔✔ To eliminate fat signal and enhance tissue contrast
Why is steady-state free precession (SSFP) used in MRI?
✔✔ It provides high signal intensity with short scan times
1
,How does parallel imaging reduce scan time?
✔✔ It acquires fewer phase-encoding steps, speeding up image acquisition
What is the primary factor that determines tissue contrast in MRI?
✔✔ The relaxation properties of tissues
What is the function of gradient moment nulling?
✔✔ It reduces motion artifacts in MRI scans
How does motion affect MRI images?
✔✔ It causes blurring and ghosting artifacts
Why is MRI considered safer than CT for soft tissue imaging?
✔✔ It does not use ionizing radiation
What is the primary purpose of the main magnetic field in MRI?
✔✔ To align hydrogen protons in the body
2
, How does increasing the magnetic field strength affect signal-to-noise ratio (SNR)?
✔✔ It increases SNR, improving image quality
What happens to hydrogen protons when an RF pulse is applied?
✔✔ They absorb energy and move into a higher energy state
Why is relaxation time important in MRI?
✔✔ It determines how tissues appear on different sequences
What is the role of T1 relaxation in MRI?
✔✔ It measures the time it takes for protons to realign with the magnetic field
How does T2 relaxation differ from T1 relaxation?
✔✔ T2 measures the time it takes for protons to lose phase coherence
What factor primarily affects T1 relaxation time?
✔✔ The molecular structure of the tissue
3
