MRI Physics Chapter 2 Questions and
Answers Latest Version Already Passed
What is the primary component of the human body that interacts with an MRI scanner?
✔✔ Hydrogen atoms
Why do hydrogen nuclei align with the external magnetic field in MRI?
✔✔ Because they have a magnetic moment due to their single proton
What happens when an RF pulse is applied at the Larmor frequency?
✔✔ Protons absorb energy and move to a higher energy state
What determines the precessional frequency of hydrogen nuclei?
✔✔ The strength of the external magnetic field
Why is the net magnetization vector important in MRI?
✔✔ It represents the overall magnetic alignment of protons in the body
1
,What happens to protons when the RF pulse is turned off?
✔✔ They relax back to their original alignment with the magnetic field
Why does T1 relaxation occur?
✔✔ Energy is transferred from protons to the surrounding lattice
What is another term for T2 relaxation?
✔✔ Transverse relaxation
Why does T2 relaxation lead to signal loss?
✔✔ Protons lose phase coherence and dephase over time
How does the external magnetic field affect proton behavior?
✔✔ It causes them to align and precess at a specific frequency
What is the unit of measurement for the magnetic field strength in MRI?
✔✔ Tesla (T)
2
, Why is the Larmor equation important in MRI?
✔✔ It defines the precessional frequency of hydrogen nuclei
How does an increase in magnetic field strength affect the Larmor frequency?
✔✔ It increases the precessional frequency
What is the role of the RF coil in MRI?
✔✔ It transmits and receives radiofrequency signals
Why do different tissues have different relaxation times?
✔✔ Due to variations in molecular composition and interaction with water
What is the relationship between T1 and TR in MRI imaging?
✔✔ TR must be long enough to allow sufficient T1 recovery
Why does T2 decay occur more rapidly than T1 recovery?
✔✔ T2 relaxation involves loss of phase coherence, which happens faster than energy transfer
3
Answers Latest Version Already Passed
What is the primary component of the human body that interacts with an MRI scanner?
✔✔ Hydrogen atoms
Why do hydrogen nuclei align with the external magnetic field in MRI?
✔✔ Because they have a magnetic moment due to their single proton
What happens when an RF pulse is applied at the Larmor frequency?
✔✔ Protons absorb energy and move to a higher energy state
What determines the precessional frequency of hydrogen nuclei?
✔✔ The strength of the external magnetic field
Why is the net magnetization vector important in MRI?
✔✔ It represents the overall magnetic alignment of protons in the body
1
,What happens to protons when the RF pulse is turned off?
✔✔ They relax back to their original alignment with the magnetic field
Why does T1 relaxation occur?
✔✔ Energy is transferred from protons to the surrounding lattice
What is another term for T2 relaxation?
✔✔ Transverse relaxation
Why does T2 relaxation lead to signal loss?
✔✔ Protons lose phase coherence and dephase over time
How does the external magnetic field affect proton behavior?
✔✔ It causes them to align and precess at a specific frequency
What is the unit of measurement for the magnetic field strength in MRI?
✔✔ Tesla (T)
2
, Why is the Larmor equation important in MRI?
✔✔ It defines the precessional frequency of hydrogen nuclei
How does an increase in magnetic field strength affect the Larmor frequency?
✔✔ It increases the precessional frequency
What is the role of the RF coil in MRI?
✔✔ It transmits and receives radiofrequency signals
Why do different tissues have different relaxation times?
✔✔ Due to variations in molecular composition and interaction with water
What is the relationship between T1 and TR in MRI imaging?
✔✔ TR must be long enough to allow sufficient T1 recovery
Why does T2 decay occur more rapidly than T1 recovery?
✔✔ T2 relaxation involves loss of phase coherence, which happens faster than energy transfer
3
