28-year-old female with transient alteration of mental status. There is new hyperintense T2/FLAIR signal in bilateral posterior occipital lobe white matter. There is also very mild new increased T2/FLAIR signal within the subcortical white matter of bilateral, left greater than right, posterior frontal and parietal lobes. Increased T2/FLAIR signal is present in the right temporal lobe cortex posteriorly and inferiorly adjacent to the temporal horn of the right lateral ventricle, and may be involving the hippocampus.The ventricles and sulci are normal in size. The cerebellar tonsils are in normal position. There are no masses, mass effect or midline shift. The pituitary gland is normal in size. There is no evidence for intracranial hemorrhage. No diffusion-weighted abnormalities are identified. There are no extraaxial fluid collections or subdural hematomas. Flow voids are present within the major vessels indicating patency. The paranasal sinuses and mastoid air cells are clear.
1. Interval development of areas of increased T2/FLAIR signal predominantly within the bilateral posterior occipital lobe white matter, corresponding to regions of hypoattenuation on previous CT. Additional frontal and parietal lobe abnormalities as well, with findings compatible with posterior reversible encephalopathy syndrome (PRES).2. No evidence of acute infarct, intracranial hemorrhage, mass effect or midline shift.