MRI of brain sagging with low CSF pressure headache

Brain MRI of a patient with low CSF pressure headache (spontaneous intracranial hypotension). Noncontrast T1-weighted sagittal images were obtained before (A) and after (B) treatment. There is crowding and pointing of the cerebellar tonsils at the foramen magnum mimicking a Chiari 1 malformation on the first study (arrow, image A). In addition, there is sagging of the brain resulting in inferior displacement of the floor of the third ventricle (arrowhead, image A) as well as loss of CSF space in the suprasellar cistern. These findings have resolved on MRI six months later after treatment (B), which included draining of associated subdural collections.