Apparently, oxygenated hemoglobin and blood plasma are diamagnetic, while deoxygenated hemoglobin is paramagnetic. Meaning, magnetic properties are determined by the molecules, not its elements. I assume that whatever attraction or repulsion caused by even the MRI magnets are weak compared to the forces involved in Brownian motion. So don't expect anything substantial.
This reminds me of something I've always thought that Toph – spoiler about Avatar: The Last Airbender – should also be able to blood bend since she created metal bending and the blood is full of iron.
There is a scene in one of the X-men movies where Magneto escapes a completely non-metallic prison by extracting iron from a guard's body. I initially thought that Raven had injected him the previous day with something to increase his iron content. But realized later that she had injected metallic iron as a suspension.
That aside, you don't need ferromagnetic substances for it be manipulated by magnetic fields. Anything conducting can be moved around by fluctuating magnetic fields. Even non-conducting paramagnetic or diamagnetic substance will eventually respond to very high strength magnetic fields - just not at the 'feeble' strengths of an MRI machine's superconducting magnets. Here is something I collected previously on the same fun topic: https://phanpy.social/#/fosstodon.org/s/111504060685437481?v...
Why were you downvoted? I was going to read more on it later. So far, I know that Iron III oxide is magnetic. I don't know anything about the other oxides, ions in other oxidation states or iron in other compounds. I wish the people explained the reason why they downvoted.
