relationship between molecular tumbling rate and T2 relaxation time

[aelster]

I think the answer to your question is pretty completely explained on the following Q&A on my site:

http://mriquestions.com/dipole-dipole-interactions.html

If you need more, click on the "Advanced Discussion" tab and you will be taken to a secret hidden page (!) that will fill in even more details.

By the way, the image you chose from the revise MRI site is incorrect. There should be a dip, not a bump in the T2 curve near the Larmor frequency. Use the correct graph from my site instead.