Cross-sectional imaging is the next step to fully document the abnormality although the diagnosis can be made with confidence on a good quality ultrasound.
The majority of the skull is filled with fluid. Cerebral tissue is seen centrally (~thalami) and posteriorly (occipital lobes and cerebellum). No frontal or parietal lobes are identifiable. Falx is noted in the midline, and it appears normal.