An ultrasound catheter (10) comprising: an elongate flexible catheter body (12) having a proximal end (14), a distal end (16), and a main lumen (40) extending longitudinally therethrough, a distal head (44) having a bore with a proximal section and a distal section that has an inner diameter that is smaller than the inner diameter of the proximal section of the bore an ultrasound transmission member (42) extending longitudinally through the main lumen of the catheter body, the ultrasound transmission member having a proximal end and a distal end positioned at the distal head and a guidewire lumen (60) extending longitudinally through a portion of the main lumen, and into the proximal section of the bore of the distal head, the guidewire lumen terminating before the distal section of the bore of the distal head.
