Provided herein is a catheter assembly including, in some embodiments, a core wire configured for linear actuation and a damping mechanism around the core wire. The core wire includes a proximal end with a sonic connector configured to couple to an ultrasound-producing mechanism. The core wire includes a distal end configured to modify intravascular lesions with vibrational energy from the ultrasound-producing mechanism. The damping mechanism includes a gasket system and a retainer to retain the gasket system in a damping-mechanism bore of the catheter assembly. The damping mechanism is around a proximal-end portion of the core wire, where the damping system can provide a compressive force sufficient to dampen transverse wave-producing vibrational energy in the proximal-end portion of the core wire without restricting the linear actuation of the core wire through the damping mechanism including extension and retraction of the core wire through the damping mechanism.
