1. A medical imaging system comprising: an elongated tubular member having distal and proximal ends, configured to be inserted into a vessel of a patient; an ultrasound imaging device coupled to the distal end of the elongated tubular member and configured to emit one or more energy pulses and receive one or more echo signals; and a console electrically coupled to the imaging device, wherein the console comprises a computer-usable medium having a sequence of instructions which, when executed by a processor, causes the processor to execute a process comprising generating a composite longitudinal ultrasound image of the vessel by stacking cross-sectional frames generated as the imaging device is being pulled back within the vessel, and generating a user interface with controls that allow a user to playback the longitudinal image frame-by-frame, wherein the user interface comprises a graphical palette, the graphical palette comprising graphical representations of a stent generated in at least two different sizes, each graphical representation having predefined dimensions, wherein the user interface is configured and arranged to allow the user to select and drag at least one of the graphical representations to a selected location on the image.