A system and device for cryoablation of tissue that is suitable for use within an MRI environment. The device may include an elongate body, a treatment element at the distal portion of the elongate body, and one or more pull fibers. The pull fibers may be composed of a non-ferromagnetic material, such as a polymer. Likewise, none of the other device components may be composed of a ferromagnetic material. The device may also include at least one fiber optic sensor. The elongate body distal portion may include a distal tip to which the pull fibers are directly coupled. Additionally or alternatively, the elongate body may include one or more pull fiber lumens configured to allow the pull fibers to deflect the distal portion when a pull force is exerted on the pull fibers.