Abstract: A system and method are provided for simplifying off-line quantification of ultrasound images by displaying a graphical user interface showing a real-time ultrasound image for enabling a user to freeze the real-time ultrasound image to display an image sequence capable of being modified and played back by the user. Upon freezing the real-time image, the graphical user interface displays a tagging system having a corresponding identification tag for each ultrasound image of the image sequence. Each tag of the tagging system records the exact point in a physiologic periodic waveform represented by the image identified by the tag using a timing reference. In order for a user to generate a modified image sequence having only ultrasound image frames representing a particular point over a plurality of physiologic periodic waveforms, the user indicates which point of the physiologic periodic waveform is desired.