Rotational shape-memory actuators and associated devices, systems, and methods

An intravascular imaging device, comprising:

• a flexible elongate member;
• a first anchor fixedly secured to the flexible elongate member;
• a second anchor;
• an imaging element coupled to the second anchor;
• at least two shape memory elements extending between the first and second anchors, a proximal portion of each of the at least two shape memory elements secured to the first anchor and a distal portion of each of the at least two shape memory elements secured to the second anchor;
• wherein the at least two shape memory elements are configured to transition between a first state and a second state such that when the at least two shape memory elements are in the first state the at least two shape memory elements are in a first configuration in which the at least two shape memory elements are twisted together and when the at least two shape memory elements are in the second state the at least two shape memory elements are in a second configuration in which the at least two shape memory elements are less twisted together than in the first configuration;
• and
• wherein the transitions of the at least two shape memory elements between the first and second states cause the second anchor to rotate about a longitudinal axis of the flexible elongate member with respect to the first anchor.