Disproportionately enlarged subarachnoid space hydrocephalus (DESH)

Disproportionately enlarged subarachnoid space hydrocephalus (DESH) is a pattern of communicating hydrocephalus characterized by crowding of the sulci superiorly near the vertex accompanied by enlargement of CSF spaces more inferiorly, particularly in the Sylvian fissures . It is a prominent feature of idiopathic normal pressure hydrocephalus (iNPH) and is a central component of the Japanese iNPH diagnostic guidelines .

Multiple, but not all, studies have found that the presence of DESH is predictive of shunt-response in patients with iNPH .

The finding of DESH without neurologic symptoms has been termed asymptomatic ventriculomegaly with features of idiopathic normal pressure hydrocephalus on MRI (AVIM) . It is felt by some authors that AVIM is actually a pre-clinical form of iNPH .