 The right cerebellar tonsil lies 5 mm below the level of the foramen magnum and demonstrates a primarily rounded morphology. The left cerebellar tonsil is normal in position and morphology. These findings are more suggestive of right cerebellar tonsillar ectopia. Biphasic CSF flow is noted posteriorly around the cerebellar tonsils. There is mild retroflexion of the odontoid tip.Brain MRI:The ventricles and sulci are normal in size. There are no masses, mass effect or midline shift. The pituitary gland is normal in size. There is no evidence for intracranial hemorrhage or acute cerebral, brainstem or cerebellar infarction. No diffusion-weighted abnormalities are identified. There are no extraaxial fluid collections or subdural hematomas. Flow voids are present within the major vessels indicating patency. The paranasal sinuses and mastoid air cells are clear. There is no abnormal enhancement within the brain. Cervical spine MRI:There is slight reversal of upper cervical curvature centered at C5/6. There are no fractures or subluxations. The marrow signal is benign. The cervical and upper thoracic cord are normal in signal. The cervicomedullary junction is normal. The cerebellar tonsils are in normal position. The visualized paraspinal contents are unremarkable. Incidental note is made of subcentimeter T2 hyperintense foci within the thyroid lobes (left more than right).C2/3: UnremarkableC3/4: UnremarkableC4/5: UnremarkableC5/6: Mild disc bulge and right uncinate hypertrophy without stenosis.C6/7: Minimal disc bulge without stenosis.C7/T1: Unremarkable
1.The right cerebellar tonsil lies 5 mm below the level of the foramen magnum and demonstrates a primarily rounded morphology. The left cerebellar tonsil is normal in position and morphology. These findings are more suggestive of right cerebellar tonsillar ectopia.2.Minimal to mild degenerative changes at C5/6 and C6/7 without associated stenosis.3.Incidental note is made of subcentimeter T2 hyperintense foci within the thyroid lobes (left more than right). These are nonspecific in appearance, and most likely represent thyroid nodules. These could be further characterized with ultrasound.