Doing an MRI without contrast is probably benign (and typical of what you would do for sports injuries), but gadolinium contrast is likely to be reevaluated in the near future, as it is a toxic heavy metal that is not fully removed from the body, even in its chelated form [0]. If you ever had a brain MRI with contrast, you would know it's a lot worse than a typical hangover, which is usually not a great sign for health impact.

[0] https://www.fda.gov/drugs/fda-drug-safety-podcasts/fda-drug-...