FIG 4.

A, T2-weighted axial image (section thickness = 3 mm) shows a prominent CSF flow void around the basilar artery confined to the prepontine cistern. The lateral margins of the flow void (arrows) are likely due to the anterior pontine membranes. B, T2-weighted midline sagittal image (section thickness = 3 mm) demonstrates a CSF flow void tracking along the prepontine and interpeduncular cisterns, with an abrupt change in signal superiorly at the expected location of the diencephalic leaf of the LM (arrow).