Delayed CSF enhancement in posterior reversible encephalopathy syndrome.

We present a case of increased fluid-attenuated inversion recovery signal intensity in the subarachnoid spaces on 6-hour delayed enhanced MR imaging in a patient with posterior reversible encephalopathy syndrome (PRES) in the setting of acute hypertensive encephalopathy. This hyperintensity was believed due to CSF gadolinium enhancement, a finding that would be anticipated in light of the suspected pathogenesis of increased microvascular permeability in PRES.