What types of Shielding and Filtering would allow devices to be used in a MRI environment?
The biggest field from an MRI system is DC and therefore not a problem as long as you pay attention to ferromagnetic materials as the previous responder said. The RF field is the one that may annoy electronics connected to the patient. As a first principle, ALWAYS use balanced transmission plus an overall shield -- i.e. 2-core shielded cable for a 2-pin sensor -- and a differential amp as the receiver; NEVER use single-ended (earth referenced) transmission. This will immediately give you big attenuation of the RFI, which of course will be common-mode on the two cores. Given that, a fairly simple RC filter on each core at the point of entry into your equipment is probably all you'll need, unless you're working with microvolt signals! (Anyone for an intra-MRI EEG, perhaps? ). Any small-signal circuitry should also be in a screening can to keep the RF field out, unless the outer casing is very, very well EMC'ed.