Posterior reversible encephalopathy syndrome (PRES): features on CT and MR imaging.

Posterior reversible encephalopathy syndrome (PRES) is a rare but severe condition of the central nervous system. It develops in a variety of clinical settings and it has diverse patterns of expression, which can sometimes make diagnosis difficult. Characteristic features are often demonstrated on computed tomography imaging and/or magnetic resonance imaging, meaning that when there is a suspicious clinical picture, this diagnosis should suggest itself. However, clinicians should be aware of some of the less typical features in order to more fully understand this condition, in which early treatment is key to good clinical progress.