1) illustrates the variable presentations of PRES, including cases with atypical imaging findings. We illustrate cases of PRES with varying distributions of vasogenicoedema as well as cases with atypical imaging findings, such as variations of haemorrhage and restricted diffusion. 2) review the best imaging approach in such cases.

Posterior reversible encephalopathy syndrome (PRES) a neuro- radiological syndromecharacterized by seizures, altered level of consciousness and visual disturbance.regardless of the underlying cause, the main abnormality is cerebral vasogenicedema, the pathogenesis of which is still under debate [1, 2]. PRES is typicallyreversible once the cause is removed. However, patients with severe manifestationsof PRES, such as coma and/or status epilepticus, may require admission tothe intensive care unit (ICU) [9, 10]. Moreover, permanent neurological impairmentor death occurs in a minority of patients [5, 7, 8]. PRES is well...

Posterior reversible encephalopathy syndrome (PRES) [1, 2] is a clinicoradiologicalentity that was well described by Hinchey et al. This condition has been designated by a variety of names (reversible posterior leukoencephalopathy syndrome, reversible posterior cerebral edema syndrome, and reversible occipital syndrome, reversible posterior cerebral edema syndrome, and reversible occipitalparietal encephalopathy). PRES is now the accepted term [1, 2, 3] but has been challenged recently based on the risk of neurological impairment and up to 15 %mortality rate [7, 8]. Diagnosis PRES is a clinicoradiological entity....

Neuroradiologists should be aware that atypical imaging manifestations of PRES are more common than commonly perceived. Recognition of atypical variants of PRES can be helpful to manage these patients and avoid complications in a timely manner.

1. Bartynski WS (2008) Posterior reversible encephalopathy syndrome, part 1: fundamentalimaging and clinical features. AJNR Am J Neuroradiol 29: 1036–1042 2. Bartynski WS (2008) Posterior reversible encephalopathy syndrome, part 2: controversiessurrounding pathophysiology of vasogenic edema. AJNR Am J Neuroradiol 29: 1043–1049 3. Hinchey J, Chaves C, Appignani B, et al (1996) A reversible posterior leukoencephalopathysyndrome. N Engl J Med 334: 494–500 4. Schwartz RB, Jones KM, Kalina P, et al (1992) Hypertensive encephalopathy: findings onCT, MR imaging, and SPECT imaging in 14 cases. AJR Am...