A method and an apparatus for determining a three-dimensional directedness-determined motion are provided, including a forward-backward directedness, characterizing the motion of a movable ultrasound probe (10) during acquisition of an ultrasound image of a volume portion (2) by the ultrasound probe. The method comprises determining, by a machine-learning module (50), a motion indicator (60) indicating a three-dimensional motion between the ultrasound image frames (22)； and determining, by a directedness-determining system (56), a directedness indicator (66) of the three-dimensional motion between the ultrasound image frames (22). The method further comprises determining a directedness-determined motion indicator (96) indicating the three-dimensional directedness-determined motion, including a determined the forward-backward directedness of the motion, between the ultrasound image frames (22) from the motion indicator (60) and the directedness indicator (66).
