You're making me feel lucky about what was otherwise a very unpleasant experience!
A chemist gave a great talk about this at a big MRI conference (ISMRM) in Paris 10ish years ago. His explanation was that gad behaves a lot like iron does in the body. It deposits where iron does and like iron it lacks a metabolic route for removal (though menstruating females lose iron).
He stated that deposition was entirely predictable. However the harm caused is still debated.
The article here says ‘ Dr Wagner theorized that nanoparticle formation could trigger a disproportionate immune response, with affected cells sending distress signals that intensify the body’s reaction.’
Emphasis on ‘theorised’.
Deposition is discussed in the below link, and the comparison with iron is briefly mentioned.
So this reveals to me two issues
1. In general side effects of the contrast agent are not communicated properly. If I knew, I might have asked - hey can you do the analysis without the agent?
2. There’s no recommendation to avoid vitamin C prior and right after the MRI, heightening the risk.
Pretty much just diluting it out of your system.