1. Case 4.
Case 4. A, Sagittal TSE T2 image demonstrates enlarged third ventricle, extensive flow void phenomenon in the cerebral aqueduct, the fourth ventricle, and prepontine/interpeduncular cisterns compatible with communicating hydrocephalus. B, Sagittal 3D-CISS image shows Liliequist membrane just below the downward bulging floor of the third ventricle. In addition to this, there is a thin membrane extending from the clivus to the basilar artery, dividing the prepontine cistern into upper and lower parts. The signal intensity difference between 2 parts with a sharp, linear zone of transition was seen. C, Coronal oblique reformatted image of 3D-CISS through the cisterns demonstrates lateral extension of the prepontine membrane, trapping CSF between the Liliequist membrane and the prepontine membrane. D, During ETV, after the floor of the third ventricle through the Liliequist membrane is opened, a complete membrane without any aperture is seen. E, The same view after the membrane is opened and removed, the cisternal part of the left abducens nerve is seen partly. F, On the follow-up sagittal 3D-CISS image, there is free communication between the third ventricle and the prepontine cistern through the interpeduncular cistern. G, Follow-up coronal oblique reformatted image of 3D-CISS after ETV through the cisterns (same view as in C) reveals nearly complete removal of the prepontine membrane. The difference in signal intensity between the 2 parts of the cisterns has almost completely disappeared.
A. Dinçer et al. AJNR Am J Neuroradiol 2009;30:
©2009 by American Society of Neuroradiology