Objective:To define clinical associations and radiologic findings of posterior reversible encephalopathy syndrome（PRES）

and to further identify relationship between clinical conditions and specific imaging findings and its pathophysiological mechanism.Methods:PRES patients admitted to the First Affiliated Hospital of Chongqing Medical University from May 1

2007 to December 1

2016 were retrospectively identified. A detailed review of clinical information and radiological findings was performed. Results:Twenty-three PRES patients（mean age of 33.0 years）were identified. Etiologies of PRES mainly included hypertension

preeclampsia or eclampsia and cytotoxic medications. Autoimmune disease and kidney dysfunction were also presented in some patients. Clinical presentations included seizures（n=16

69.6%）

encephalopathy

headache（n=18

78.2%）

and visual disturbances

which were all resolved in a week. In 21 patients who received magnetic resonance imaging

the parieto-occipital regions were the most commonly involved

followed by the frontal lobe

basal ganglia

temporal lobe

brain stem and cerebellum. And 1/3 patients had asymmetry lesions.Patients with seizures had strong associations with temporal involvement. Cerebellar involvement was significantly more frequent in patients with a history of autoimmunity. Conclusion:So far

no conclusive evidence supports a clear relationship between clinical conditions and specific imaging findings. But atypical PRES is more common than normally considered.Clinical physicians should have a full picture of the clinical and radiological spectrum of this entity to make correct diagnosis.