Hallmarks of Posterior Reversible Encephalopathy Syndrome

The classic imaging hallmark of Posterior Reversible Encephalopathy Syndrome (PRES) is bilateral, predominantly subcortical T2/FLAIR hyperintensity.

This abnormal signal typically demonstrates increased signal on Apparent Diffusion Coefficient (ADC) maps, confirming it represents reversible vasogenic edema rather than cytotoxic ischemic infarction.

The clinical constellation of headaches, seizures, altered mental status, and blindness should immediately trigger a search for this condition.

Importantly, despite the name PRES, these lesions are not always strictly posterior in location, nor are they inevitably reversible.