A dynamic ultrasound image catheter includes a catheter body with an acoustic window on the distal end, an ultrasound phased array transducer assembly configured to rotate within the acoustic window through an angle of rotation, an acoustic coupling fluid filling a gap between the transducer array and the acoustic window, and a drive motor at the proximal end of the catheter body that is configured to rotate the transducer array. The drive motor may transmit a rotational force to the ultrasound phased array transducer by a drive wire or by tension wires coupled to drive spools. A system processor coupled to the drive motor controls rotation of the transducer array and estimates the angular orientation of the transducer array. By taking ultrasound images at increments through the angle of rotation, the dynamic ultrasound image catheter can obtain images spanning a volume which can be processed to generate three-dimensional composite images.
