MRI compatible localization and/or guidance systems for facilitating placement of an interventional therapy and/or device in vivo include: (a) a mount adapted for fixation to a patient； (b) a targeting cannula with a lumen configured to attach to the mount so as to be able to controllably translate in at least three dimensions； and (c) an elongate probe configured to snugly slidably advance and retract in the targeting cannula lumen, the elongate probe comprising at least one of a stimulation or recording electrode. In operation, the targeting cannula can be aligned with a first trajectory and positionally adjusted to provide a desired internal access path to a target location with a corresponding trajectory for the elongate probe. Automated systems for determining an MR scan plane associated with a trajectory and for determining mount adjustments are also described.
