MRI 0 Flashcards
What are the spin number, gyromagnetic ratio, and natural abundance of hydrogen?
1/2, 42.575 MHz/T, 99.985%
How many energy levels has a proton? What is its energy?
2, gammahbarB0/2
What is the larmor frequency?
w0 = gamma* B0
What is a dipolar magnetic momentum?
Protons behave as small magnets with two poles creating a magnetic field
what are the relaxations mechanisms?
Longitudinal relaxation: consist of the decaying off the Mz component to M0, caused by the protons losing energy by dipolar interactions with other nuclei. It is characterized by the T1 constant, and by the equaition M0 - exp(-t/T1). It is also known as spin-lattice relaxation.
Transversal: consists of the decaying of the transverse magnetization to zero. It happens because of the interaction between the spins, causing dephasing and loss of coherence.