An ultrasonic imaging catheter and guidewire system for acoustic imaging and electromagnetic positioning, with low noise, is described. An ultrasonic imaging guidewire uses two opposed imaging transducers laterally disposed near the distal end of an interventional guidewire. The tortuous position of the guidewire in the vasculature is monitored by a proximally positioned perpendicular position and orientation coil. Accurate vascular imaging is afforded by the use of opposed transducers operating alternately, thereby providing an accurate total distance measurement on each side of the guidewire regardless of the position of the guidewire in the lumen.
