Pachymeningeal enhancement-a comprehensive review of literature.

Pachymeningeal enhancement, synonymous with dural enhancement, is a radiological feature best appreciated on a contrast-enhanced magnetic resonance imaging (MRI). The vasculature of the dura mater is permeable, facilitating avid uptake of contrast agent and subsequent enhancement. Thin, discontinuous enhancement can be normal, seen in half the normal population. In patients complaining of postural headaches worse on sitting, gadolinium-enhanced MRI findings of diffuse pachymeningeal enhancement is highly suggestive of benign intracranial hypotension. In these cases, the process of pachymeningeal enhancement is explained by the Monro-Kellie doctrine as compensatory volume changes by vasocongestion and interstitial oedema of the dura mater due to decreased cerebrospinal fluid (CSF) pressure. Focal and diffuse pachymeningeal enhancement can also be attributed to infectious or inflammatory, neoplastic and iatrogenic aetiologies. Correction of the underlying pathology often results in spontaneous resolution of the pachymeningeal enhancement. There have also been reports of pachymeningeal enhancement associated with cerebral venous sinus thrombosis, temporal arteritis, baroreceptor reflex failure syndrome and arteriovenous fistulae.