Posterior reversible encephalopathy syndrome: do predisposing risk factors make a difference in MRI appearance?

Posterior reversible encephalopathy syndrome (PRES) is a clinico-neuroradiological entity, characterized by typical neurological deficits, distinctive magnetic resonance imaging (MRI) features, and a usually benign clinical course. Although frequently seen in association with hypertensive conditions, many other predisposing factors, notably cytotoxic and immunosuppressant drugs have been associated with PRES. The aim of this study was to determine differences in the MR appearance of PRES according to various risk factors. Thirty consecutive patients with clinical and MRI findings consistent with PRES were included. We identified 24 patients with hypertension-related conditions, including 14 patients with preeclampsia-eclampsia, and six patients without hypertension, in whom PRES was associated with exposition to neurotoxic substances. Lesion distribution, extent of disease, and number of affected brain regions were compared between patients with PRES with and without hypertension, and patients with PRES with and without preeclampsia-eclampsia, respectively. No statistically significant differences in distribution of lesions and extent of disease were observed between patients with PRES with or without hypertension, and patients with or without preeclampsia-eclampsia, respectively. The number of affected brain regions was significantly higher in patients with preeclampsia-eclampsia (p = 0.046), and the basal ganglia region was more frequently involved in these patients (p = 0.066). Apart from a significant higher number of involved brain regions and a tendency for basal ganglia involvement in patients with PRES associated with preeclampsia-eclampsia, the MRI appearance of patients with PRES does not seem to be influenced by predisposing risk factors.