What feature allows the operator to scroll back through several seconds worth of captured frames once the image has been frozen?

The correct answer is cine-loop. This feature enables the operator to review a series of previously acquired frames in succession, allowing them to scroll back through several seconds of captured data even after the image has been frozen. Cine-loop is particularly useful in ultrasound imaging, as it helps the operator assess dynamic movements, such as blood flow or fetal activity, by providing a playback option that showcases the frames leading up to the frozen image. This capability enhances diagnostic evaluation by allowing the sonographer to observe and analyze sequential changes in an area of interest that might not be evident in a single still image.

The other options do not offer the same functionality. Still image capture refers to saving a single frame of the ultrasound, which does not allow for subsequent review of earlier frames. Frame review typically involves looking at individual images without the ability to scroll through a sequence interactively. Image archive is related to storing images for future access but does not facilitate the dynamic review of captured frames.