A system and a method for disrupting an occlusion within a blood vessel is provided The system includes an elongated catheter body having a proximal portion, a distal portion, and a first lumen. The system further includes an ultrasound transmitter extending longitudinally through the first lumen of the catheter body and having a proximal end and a distal end. The system further includes a positioning mechanism located at a distal end of the catheter body. The positioning mechanism has a first retracted position and a second deployed position, and the positioning mechanism is radially expandable from the first retracted position to the second deployed position to position the catheter in the blood vessel.