Magnetic resonance imaging in spontaneous intracranial hypotension

Abstract

The authors aimed to evaluate the magnetic resonance (MR) imaging features characterizing spontaneous intracranial hypotension (SIH) in comparison with radionucleotide cisternography (RNC) findings in this condition. Five patients with postural headache and idiopathic low cerebrospinal fluid (CSF) pressure presented to our institution from October 2000 to July 2002. RNC demonstrated early filling of the bladder in five cases, and CSF leak was detected on the left side of the cervicothoracic junction in four cases. In two cases, intracranial MR imaging failed to demonstrate typical diffuse pachymeningeal enhancement; however, spinal MR imaging showed intense epidural or meningeal enhancement in those cases. Post-contrast spinal MR imaging was performed in four patients, revealing intense epidural or meningeal enhancement, mainly at the ventral cervical level and dorsal thoracic level of the spine. Among the four patients with obvious CSF leaks detected on the RNC, three patients demonstrated slight dilatation of the perineural root sleeve, without epidural fluid collection or spinal hygroma. In SIH, spinal MR imaging was very helpful in establishing the diagnosis when intracranial MR imaging failed to demonstrate typical findings. However, identification of the level of a CSF leak using MRI alone remains difficult, since the variety of imaging results is considerable and typical findings do not necessarily appear.