A method for using an endoluminal device to modify an intravascular lesion includes providing an ultrasound-producing mechanism that converts an electric current into vibrational energy at an ultrasonic frequency； providing a sheath including a sheath lumen, wherein the sheath is configured to retract from a first, fully extended position of the sheath and extend from a second, fully retracted position of the sheath； providing a core wire disposed within the sheath lumen of the sheath, the core wire being coupled to the ultrasound-producing mechanism via a sonic connector, the core wire being excited by the vibrational energy at the ultrasonic frequency when the ultrasound-producing mechanism is activated； and retracting the sheath relative to the core wire to expose a working length of a distal portion of the core wire for ultrasound-based modification of one or more intravascular lesions.
