FIG 4. Postinterventional CT scans of the head with Ethibloc filling of the vertebrobasilar system (A), causing cerebellar and brain stem infarction. Signal intensity changes in the brain stem and the cerebellum, cerebellar swelling with brain stem compression, and up- and downward herniation are shown on axial FLAIR, sagittal T1-weighted, and coronal T2-weighted MR images (B).