COMBINING X-RAY WITH INTRAVASCULARLY ACQUIRED DATA

A system for estimating a position in an x-ray projection image that corresponds to a projected probe position of an intravascular probe at a time of intravascular ultrasound (IVUS) imaging. A marker detector identifies in the x-ray projection image a plurality of projected positions of markers that are located at predetermined distances along an acquisition trajectory of the intravascular probe. The projected positions are interpolated to obtain the projected probe position on the trajectory. The projected probe position corresponds to a location of the intravascular probe at a time of the IVUS imaging and is based on a distance along the acquisition trajectory between the intravascular probe at the time of the IVUS imaging and at least one of the markers.