61 years, Male, left optic atrophy and vision changes. Additional provided history includes Chiari I malformation without spina bifida or hydrocephalus. MRI BRAIN: No restricted diffusion to suggest acute ischemia. No intracranial hemorrhage. No intracranial mass or mass-effect. The ventricles are within normal limits in size and configuration. Minimal foci of T2/FLAIR hyperintensity are seen in the bilateral subcortical and periventricular white matter, which are nonspecific, but compatible with chronic small vessel ischemic changes. No other abnormal T2 signal is evident in the brain. There is been suboccipital craniectomy and resection of the posterior arch of C1 related to Chiari decompression surgery. The posterior fossa contents including the cerebellar tonsils are well decompressed. No abnormal parenchymal or meningeal enhancement. Major flow-voids are preserved.Sella and orbits are grossly within normal limits. Mild mucosal thickening is demonstrated in the frontal sinuses, posterior and anterior anterior ethmoid air cells, and bilateral maxillary sinuses. The mastoid cells are clear. Bone marrow signal and extracranial soft tissues are within normal limits. MRI ORBITS: No abnormal mass or abnormal enhancement is seen. The left optic nerve appears to be mildly asymmetrically diminutive compared to the right. There is no abnormal signal in the optic nerves. No retrobulbar mass, chiasmatic mass, or parasellar abnormality is seen. Extraocular muscles are unremarkable.
1. Postoperative changes related to prior posterior fossa decompression. Posterior fossa structures are well compressed. Remainder of the brain parenchyma is otherwise within normal limits for age.2. No abnormal signal within the optic nerves is definitively appreciated. The left optic nerve is mildly asymmetrically smaller than the right, which is of uncertain significance. Orbital MRI appear otherwise unremarkable.