A transmission cable for use in an elongate medical device (420) such as a catheter, guide wire, etc., wherein the transmission cable is capable of being switched to an MR-safe mode only when necessary, while retaining its optimal electrical transmission properties otherwise, is disclosed herein. The transmission cable comprises a transmission line including at least two electrically conductive line segments (104a, 104b) separated by a non-conductive gap (106a), a bridging unit comprising at least one electrically conductive bridge segment (108a) capable of bridging the non-conductive gap, and a switching unit (112) arranged to move the bridging unit and/or the transmission line to electrically connect the two line segments by closing the non-conductive gap using the bridge segment or to electrically disconnect the two line segments by opening the non-conductive gap.