Medical diagnostic ultrasound imaging system and method for displaying a portion of an ultrasound image

Some medical diagnostic ultrasound imaging systems allow a user to capture images for later playback and review. In particular, some ultrasound systems allow the user to capture a full-size, multi-frame ultrasound image (or "clip") for later playback and review. Some ultrasound systems allow a user to capture a quarter-size clip instead of the entire full-size clip. The user can play back the captured quarter-size clip in a quad-screen format to compare the captured quarter-size clip with other quarter-size clips. To capture a quarter-size clip, a user moves a quarter-size region of interest ("ROI") indicator (e.g., a highlighted box edge) over a displayed full-size image during image acquisition. Only the portion of the image bounded by the ROI indicator is captured, and only the captured portion of the full-size image can be played back during image review. If the user wishes to view a different portion of the image, the user must acquire another ultrasound image of the patient and repeat the above steps with the ROI indicator in the desired position. In one embodiment, a region of interest indictor is positioned over a first portion of an ultrasound image, and the first portion and at least some other portion of the ultrasound image are saved in a post-scan-converted format. The stored ultrasound image is played, and a region of interest indicator is positioned over a second portion of the played ultrasound image. In another embodiment, an ultrasound image is stored in a post-scan-converted format. The ultrasound image is played, and a region of interest indicator is positioned over a portion of the ultrasound image. In yet another embodiment, a user requests storage of a multi-frame ultrasound image for a first length of time. The ultrasound system instead stores the multi-frame ultrasound image for a second length of time, which is longer than the first length of time.