 MRI BRAINThere is mild ectopia of the left cerebellar tonsil which is somewhat pointed inferiorly and extends to about 2 mm below the foramen magnum. CINE phase contrast CSF flow imaging shows no significant flow through the posterior foramen magnum or around the cerebellar tonsils. Elsewhere, normal biphasic flow is seen.The ventricles, sulci and cisterns are symmetric and unremarkable. The gray-white matter differentiation is normal. There is no mass, mass effect, edema, midline shift, intra- or extra-axial fluid collection, hemorrhage, or restricted diffusion/acute ischemia. Normal flow voids are identified in the major intracranial vessels. The paranasal sinuses and mastoid air cells are clear.
1. No acute intracranial abnormality.2. Cerebellar tonsillar ectopia with no evidence of CSF flow through the posterior foramen magnum.