Ultrasound catheter devices and methods provide enhanced disruption of blood vessel obstructions. Ultrasound catheter devices generally include an elongate flexible catheter body with one or more lumens, an ultrasound transmission member extending longitudinally through the catheter body lumen and a distal head coupled with the transmission member and positioned adjacent the distal end of the catheter body for disrupting occlusions. Improved features of ultrasound catheters include catheter bodies and ultrasound transmission members with increasing distal flexibility, guidewire tubes allowing contact between a guidewire and an ultrasound transmission member, distal heads with improved guidewire lumens, and torquable proximal housings for enhancing disruption of blood vessel occlusions.