Medical diagnostic system includes a user interface having a user screen that is configured to display a medical image to an operator of the diagnostic system. The user interface is configured to show first and second markers on the medical image. The first and second markers represent endpoints of a distance to be measured. The user interface is configured to receive user inputs to move the first marker or the second marker in the ROI. The diagnostic system also includes a controller that is configured to designate a localized section of the medical image that includes the corresponding location of the first marker and display a zoom frame of the localized section over the medical image. The user interface is configured to receive user inputs to move the first marker within the zoom frame to a new location in the ROI within the zoom frame.
