45 years, Female, Reason: Visual hallucination and loss of consciousness. Recurrent syncope with history of penetrating cerebellar injury. Brain MRI: Again seen are postsurgical changes of Chiari 1 decompression with suboccipital craniectomy and resection of posterior arch of C1. There is improved CSF space at the neo foramen magnum. Brain parenchyma appears otherwise within normal limits. No restricted diffusion to suggest acute ischemia. No intracranial hemorrhage. No intracranial mass or mass-effect. The ventricles are within normal limits with cavum septum pellucidum incidentally noted. No abnormal parenchymal or meningeal enhancement. Major flow-voids are preserved.Sella and orbits are grossly within normal limits. Trace mucosal thickening involving the paranasal sinuses. Bone marrow signal is within normal limits.Brain MRA: The intracranial internal carotid arteries demonstrate no significant stenosis. The middle and anterior cerebral arteries are also patent. The vertebral arteries, basilar artery, and posterior cerebral arteries also are patent with no significant stenosis. No evidence of aneurysms or vascular malformations. Left posterior cerebral arteries is predominantly fetal in origin with small left P1 segment incidentally noted.
1. Postsurgical changes related to Chiari I decompression. Examination is otherwise within normal limits with no intracranial mass or mass effect. No evidence of infarct or hemorrhage. No abnormal enhancement.2. MRA of the head is within normal limits.