The characteristic findings in a brain MRI, present in approximately 70% of patients, are subdural fluid collections, enhancement of the pachymeninges
, engorgement of venous structures, pituitary hyperaemia and sagging of the brain (11).
The five characteristic imaging features of SIH visible on MRI are: (1) Subdural fluid collection and presence of extrathecal CSF (2) Enhancement of the pachymeninges
(3) Engorgement of venous structures (4) Pituitary hyperaemia and (5) Sagging of brain or downward displacement of brain.
13) There is enhancement of the pachymeninges
because they have no blood-brain barrier, contrary to the leptomeninges, which have an intact blood-brain barrier and no enhancement.