The present invention provides systems and methods for reducing noise in an imaging catheter system. In an embodiment, a catheter comprises an imaging transducer and a transmission line within the catheter to transmit signals to and from the transducer. To reduce noise caused by exposure of the transmission line to external interference, a choke balun is coupled to the transmission line. In another embodiment, the signal from a rotating imaging transducer of the catheter is coupled to a motor drive unit by a slip ring assembly. The transducer signal is passed through first and second transformers placed on opposite sides of the slip ring assembly to reduce noise from the slip ring assembly. In another embodiment, the catheter includes a position sensor to track the position of the catheter. The position sensor is coupled to a second choke balun to further reduce noise.
