18 years, Female, apneic while sleeping. Evaluate for abnormality of the upper cervical spine and lower brainstem. History of Chiari type I malformation status post decompression surgery with C1 laminectomy and dural graft. Previously identified restricted diffusion within the right greater than left cerebellum is decreased in T2 hyperintensity compared to prior, with unchanged extent, compatible with subacute posterior inferior cerebral artery infarction.There is no new restricted diffusion. There is no susceptibility artifact to suggest hemorrhage. There is no extra-axial collection. No intracranial mass or mass-effect is identified. The ventricles are within normal limits in size and configuration. Major flow-voids are preserved. Sella and orbits are grossly within normal limits. There are persistent retained secretions within the bilateral mastoid air cells. There is a left maxillary sinus mucous retention cysts, unchanged. Patient is status post Chiari decompression with suboccipital craniectomy and resection of the posterior arch of C1. There is redistribution of fluid within the posterior occiput soft tissues, though unchanged in size.CERVICAL SPINE: There is residual mild T2 hyperintensity within the upper cervical cord, though evaluation is limited on this study. The cervical spine alignment is within normal limits, with preserved cervical lordosis. The vertebral body and disc space heights are preserved. The vertebral bone marrow signal is unremarkable. There is no significant spinal canal stenosis.
1. Evolving subacute infarction within the right greater than left cerebellum, in a PICA distribution.2. Stable postsurgical changes status post Chiari decompression.3. Residual mild T2 hyperintensity within the upper cervical cord, though evaluation is limited.