A method for real-time displaying of cross-sectional images during an intravascular ultrasound (IVUS) imaging procedure includes, during an intravascular ultrasound imaging procedure, receiving electrical signals from at least one transducer in a catheter as the at least one transducer rotates and moves longitudinally along a lumen of a patient blood vessel； during the intravascular ultrasound imaging procedure, processing the received electrical signals to form a series of cross-sectional images that are longitudinally-offset from one another along a length of the lumen； during the intravascular ultrasound imaging procedure, concurrently displaying i) a most recent image and ii) a previous image that is either a) selected by the operator or b) automatically selected as having a maximum or minimum of a selected image characteristic； and, during the intravascular ultrasound imaging procedure, updating the display of the most recent image as a new image from the series of cross-sectional images is processed.
