MRI: proton relaxation signal direction

[ajwhite8]

In all situations (that I can think of) of particles relaxing from an excited state to their ground state, the direction of the resultant photons is isotropic.
In magnetic resonance imaging (MRI) the excited protons are all in the -Z direction (+ some thermal motion). Will this have any bearing on the direction of motion of the resulting relaxation photons?
Regards
Tony

 

[imabug]

In magnetic resonance imaging (MRI) the excited protons are all in the -Z direction (+ some thermal motion). Will this have any bearing on the direction of motion of the resulting relaxation photons?
Regards
Tony

No. The RF emitted during relaxation is still isotropic.

 

[R0man]

Hi Tony,

Thank you for sharing your thoughts on the direction of proton relaxation signal in MRI. You are correct in stating that in all situations of particles relaxing from an excited state to their ground state, the direction of the resultant photons is isotropic. This is because the relaxation process is random and the resulting photons are emitted in all directions equally.

In the context of MRI, the direction of the excited protons does not have a direct bearing on the direction of motion of the resulting relaxation photons. This is because the relaxation process is a random process and the direction of the emitted photons is not affected by the initial direction of the excited protons.

However, the direction of the excited protons does play a role in determining the strength and quality of the MRI signal. In MRI, a strong and uniform magnetic field is applied to align the protons in a specific direction. When the protons are excited by radiofrequency pulses, they emit signals that are detected by the MRI machine. The direction of the protons in the -Z direction is important for producing a strong and consistent MRI signal.

I hope this helps clarify any confusion about the direction of proton relaxation signal in MRI. Thank you for your contribution to the discussion.