Typical Imaging Findings in Posterior Reversible Encephalopathy Syndrome (PRES)

Posterior Reversible Encephalopathy Syndrome (PRES) has attracted increased interest in recent years. There are many publications on the topic, especially case reports and papers discussing radiological chances. Recently, a Chinese group published a retrospective series of 24 patients with PRES.1 Clinical studies with more than only a few cases are rare. Therefore, it is interesting to read a study focused on the clinical and neuroradiological features of PRES.1 It seems obvious; therefore, that PRES occurs not only just in the Western world, but worldwide. The authors found an atypical involvement of the frontal lobe in 54.2% and of the basal ganglia gray matter in 12.5%. Lesion of the parietal and occipital lobe occurred in 87.5% and 83.3%. The authors, consequently, have concluded that a large proportion of PRES-patients probably show atypical imaging abnormalities. These findings are comparable to other publications2 and to our own studies.3,4 We found an involvement of the basal ganglia, brainstem, or cerebellum in about one-third of cases studied. But, such an occurrence never appeared isolated (Fig 1). The main MRI lesions are located particularly in the parieto-occipital regions (90-95%).2,3 All our patients showed a bilateral affection, frequently asymmetrically. This suggests that PRES shows a typical MRI pattern on fluid-attenuated inversion recovery (FLAIR)-weighted imaging in PRES patients that makes the following diagnoses more likely: