Table 6

Neuroimaging patterns in Wernicke's and posterior reversible encephalopathy

Wernicke's encephalopathy
 CTHypodense paraventricular thalamic regions with or without contrast enhancement and, less frequent, hypodense periaqueductal regions, tectum of the midbrain and tegmentum of the pons
  • ▸ T2 and FLAIR hyperintense periaqueductal and medial thalamic regions. Less frequent hyperintense mammillary bodies, periaqueductal regions, hypothalamus, tectum and cerebellum

  • ▸ Minimised mammillary bodies

  • ▸ Contrast-enhanced mammillary bodies is related to alcohol abuse

  • ▸ Atrophic mammillary bodies and cerebellar vermis (chronic phase)

  • ▸ Thalamic lactate increase and low N-acetyl-aspartate/creatine on MRS

 SPECTHypoperfusion frontoparietal and in the right basal ganglia
Posterior reversible encephalopathy
 CTHypodensities in the parieto-occipital subcortical white matter and cerebellum with increased cerebral blood volume, blood flow, and reduced time to peak mainly in the posterior vascular distribution
  • ▸ T2, FLAIR, and DWI hyperintensities in the posterior circulation areas and, less frequent, in the anterior circulation structures. ADC values in areas of abnormal T2 signal are high

  • ▸ Contrast enhancement, restrictions on DWI and ADC

  • ▸ Decrease in N-acetyl-aspartate in patients with normal MRI or reversible MRI changes and only minimal elevation of choline on MRS

  • ADC, apparent diffusion coefficient; DWI, diffusion-weighted imaging; FLAIR, fluid-attenuated inversion recovery; MRS, MR spectroscopy; SPECT, single-photon emission CT.