Fig 1.

Sagittal single-shot fast spin-echo sequence of a 32-week fetus demonstrating normal midline anatomy. Note the fully formed corpus callosum (white arrows), normal tectum (black arrow), a patent cerebral aqueduct with normal intraluminal proportions (white arrowhead), and a normal fourth ventricle (asterisk). Note also the normal expected midline morphology of the third ventricle (light gray shaded area) with normal supraoptic and infundibular third ventricular recesses (black arrowheads).