|Axial T2 weighted and FLAIR images of brain: Bilateral optic nerves are tortuous with distension of perioptic subarachnoid space and posterior flattening of sclera. Empty sella is also noted.|
Friday, 15 June 2012
BENIGN INTRACRANIAL HYPERTENSION
· Also known as Pseudotumor Cerebri and Idiopathic Intracranial Hypertension(IIH).
· A syndrome characterized by increased CSF pressure and papilledema in patients without focal neurologic findings, except for occasional CN VI palsy.
· Direct transmission of the elevated CSF pressure results in distension of the perioptic subarachnoid space and ballooning of the optic papilla, causing it to protrude physically into the posterior aspect of the globe.
· The long-standing effect of pulsatile CSF under high pressure also leads to downward herniation of an arachnocele through a defect in the diaphragma sella causing empty sella.
· The use of high-resolution, thin-slice MR imaging improves the visualization of the optic nerves and pituitary gland.
· MR imaging of the optic nerves and pituitary gland may provide important clues for the diagnosis of IIH, with a return to normal appearance after normalization of CSF pressure.
Reference: MR Imaging of Idiopathic Intracranial Hypertension, AJNR 2001 22: 196-199