Chapter 3 Study Questions

What is the difference between “magnetic moment” and “angular momentum”? How do physicists describe nuclei that possess both?
What is precession? What kind of objects precess and why?
What is net magnetization?
What is the difference between longitudinal magnetization and transverse magnetization?
What happens during excitation?
What is the gyromagnetic ratio? Why is it important for MRI?
What are the parallel and antiparallel states of a nucleus? How does a nucleus change from one state to the other?
What is the Larmor frequency? How does it relate to the gyromagnetic ratio? How does it relate to magnetic resonance?
How does the net magnetization of a spin system (e.g., a set of atomic nuclei in a voxel) change over time when exposed to a strong magnetic field?
How is an excitation pulse calibrated to have maximum effect upon a spin system?
Why does the net magnetization need to be tipped from the longitudinal plane to the transverse plane?
What is off-resonance excitation, why does it occur, and what are its consequences?
How do we measure MR signal?
What is T1 relaxation? Does it relate primarily to longitudinal or transverse magnetization? Is it best thought of as recovery or decay?
What is T2 relaxation? Does it relate primarily to longitudinal or transverse magnetization? Is it best thought of as recovery or decay?
What is T2* relaxation? Does it relate primarily to longitudinal or transverse magnetization? Is it best thought of as recovery or decay?
Why is T2* relaxation important for fMRI?
What is the Bloch equation, and why is it important?