An ultrasound image processing apparatus (16) is disclosed comprising a processor arrangement (46, 50) adapted to receive a temporal sequence (15) of ultrasound images (150) of at least a chest region (151) of a fetal entity (62) from an ultrasound probe (14), said chest region including the fetal heart (171), said temporal sequence capturing at least part of a cardiac cycle of the fetal heart； identify the chest region of the fetal entity in one or more of the ultrasound images of said temporal sequence； identify a portion of the spine in the identified chest region； calculate an orientation axis (160) of the fetal chest from the identified chest region and the identified spine portion； identify the septum of the fetal heart as a linear structure which is temporally more stable than its surrounding structures in said temporal sequence of ultrasound images and which defines a region of convergence of the movements of the fetal heart during said cardiac cycle； calculate an orientation axis (170) of the fetal heart from the identified septum； and calculate an angle (0) between the orientation axis of the fetal chest and the orientation axis of the fetal heart. Also disclosed are an ultrasound imaging system comprising such an ultrasound image processing apparatus, a computer-implemented method of visualizing an orientation of the heart of a fetal entity within said entity and a computer program product for implementing such a method.
