Twisted‐pair RF coil suitable for locating the track of a catheter

An RF coil, made by twisting a conventional wire loop, was tuned to form an extended sensor to provide an effective method of showing the track of a catheter. A twisted‐pair coil can be made small enough in diameter to pass through needles in common clinical use. The coil has a very small field of view and in transmit/receive operation has minimal effect on the magnetization of the surrounding tissue. Magn Reson Med 41:636–638, 1999.  © 1999 Wiley‐Liss, Inc.