In an embodiment, an intraluminal device is disclosed. One embodiment of the intraluminal device comprises a flexible elongate body comprising a distal portion configured to be positioned within a body lumen of a patient and a functional device disposed at the distal portion of the flexible elongate body, the functional device configured to obtain physiological data or perform a treatment within the body lumen. The intraluminal device further comprises a stiffening member moveably disposed within and along a longitudinal length of the flexible elongate body without extending beyond a distal end of the flexible elongate body, the stiffening member being moveable during an intraluminal procedure to selectively vary a stiffness of the intraluminal device.