OBJECTIVE. Posterior reversible encephalopathy syndrome (PRES) is classically
characterized as symmetric parietooccipital edema but may occur in other distributions with
varying imaging appearances. This study determines the incidence of atypical and typical
regions of involvement and unusual imaging manifestations. MATERIALS AND METHODS.
Seventy-six patients were eventually included as having confirmed PRES from 111 initially
suspected cases, per imaging and clinical follow-up. Two neuroradiologists retrospectively …

Posterior reversible encephalopathy syndrome (PRES) is characterized by headache,
altered mental status, visual disturbances, and seizures. Radiological features typically
include edema of the posterior cerebral regions, especially of the parietooccipital lobes.
Atypical imaging features, such as involvement of anterior cerebral regions, deep white
matter, and the brain stem are also frequently seen. Vasoconstriction is common in vascular
imaging. Different conditions have been associated with PRES, but toxemia of pregnancy …