Neuroimaging features of spontaneous intracranial hypotension.

We reviewed the cranial MRI and radionuclide cisternograms of four adults with postural headache indicating spontaneous intracranial hypotension (SIH). All four underwent clinical and radiological follow-up. MRI showed diffuse, thin meningeal enhancement; bilateral subdural fluid collections; and morphological abnormalities secondary to "sagging" of the brain. Radionuclide cisternography revealed direct or indirect signs of leakage of cerebrospinal fluid (CSF) along the spinal axis, and the symptoms resolved after the leak treated by epidural injection of blood at a level indicated by the cisternogram. The diffuse meningeal enhancement decreased but persisted on follow-up MRI, although the patients were asymptomatic. All morphologic abnormalities resolved during 3-5 months follow-up.