An ultrasound catheter has an elongate flexible catheter body having a lumen extending longitudinally therethrough, and an ultrasound transmission member extending longitudinally through the lumen of the catheter body. The ultrasound transmission member has a proximal end that is coupled to a separate ultrasound generating device, and a distal tip that is attached to the distal end of the ultrasound transmission member and which is located at the distal end of the catheter body. The distal tip has at least one dimensional step. The ultrasound transmission member is directly attached to the catheter body and/or to a guidewire tube, either directly or via an attachment device. The catheter has an additional radiopaque marker positioned on the distal end the catheter.
