What imaging study is typically used to evaluate PRES?

The imaging study that is typically used to evaluate Posterior Reversible Encephalopathy Syndrome (PRES) is MRI. This is because MRI is particularly adept at visualizing edema and changes in brain tissue that are characteristic of PRES. It can provide detailed images that reveal the specific areas of the brain affected, typically involving the posterior regions. This capability makes MRI the preferred imaging modality, as it is sensitive to the subtle changes in the white matter of the brain that may not be as clearly visible on other imaging methods.

In contrast, a CT scan can sometimes be used in acute settings but is generally less sensitive than MRI for detecting the changes associated with PRES. Ultrasound is not appropriate for evaluating this condition as it primarily assesses other structures, such as organs or blood flow, but does not provide adequate detail of brain pathology. X-rays do not provide useful imaging of the brain and would not be relevant in this context. Therefore, the use of MRI aligns with the need for a precise, detailed evaluation of brain changes in patients suspected of having PRES.