Osmotic demyelination can also occur in the setting of hyperglycemia, hypoglycemia, normonatremia, and hypernatremia. Without the pertinent clinical history, however, the differential considerations for the imaging findings may include microangiopathy (Fig. 36.2), infarct (Fig. 36.2), neoplasms, such as glioma (Fig. 36.3), and viral encephalitis (Fig. 36.4). Microangiopathy is a chronic process that can produce streaky FLAIR hyperintensity in the central pons and supratentorial white matter without associated restricted diffusion. Unlike central pontine myelinolysis, pontine infarcts can involve the corticospinal tracts and are often unilateral, with a sharp margin along the midline. Furthermore, concomitant involvement of the brainstem and bilateral basal ganglia with stroke is distinctly uncommon. Pontine gliomas tend to present with a mass-like appearance and may or may not demonstrate enhancement. In certain cases, viral encephalitis can affect the brainstem and basal ganglia in a bilateral symmetric manner similar to osmotic demyelination, although involvement of the external capsules is relatively uncommon.