Given the initial segmentation of nucleus, the annotation protocol which was used to crop early gestational sac in ultrasound images (Zhang et al., 2012) is utilized since such a protocol ensures involving the entire nucleus area and a sufficiently large cytoplasm/background region around the nucleus. Briefly, a nucleus sub-image is defined based on the coarse boundary of the nucleus,using which we can compute the length L of the major axis and the center x0 of the smallest upright bounding rectangle. Then a rectangle with sides of Len = L + L centered at x0 is cropped and determined to be the sub-image for graph-search based segmentation.