MRI Features of Posterior Reversible Encephalopathy Syndrome

Abstract

PRES is a clinico-radiological syndrome entity which represents a constellation of neurological symptoms with a radiological evidence of vasogenic edema which is predominant posteriorly. Though many atypical PRES features were identified in the last years, many of the old concepts like posterior dominance, bilaterality and the dominant white matter affection are essentially still accepted for the majority of the cases. The syndrome tends to present in four different radiological patterns, namely: the Holo-hemispheric Watershed pattern, the Dominant Pareito-Occipital pattern, the Superior Frontal Sulcus pattern, and the Partial or Asymmetric pattern. These patterns may in fact reflect the different underlying mechanisms and etiologies by which PRES is mediated. The radiological severity assessment of the syndrome classifies PRES patients into 3 categories: mild, moderate, and severe type. The assessment which can be easily done might become a good prognostic tool in the future. Further studies are recommended to decide whether the tool do truly have a role in anticipating the occurrence of complications or not.