MRI - Central pontine myelinolysis: This 40-year-old man had a past medical history significant for alcoholism. He initially presented with seizures and hyponatremia (Na+ = 112 meq/L). He developed a spastic quadriparesis after a rapid correction of the serum sodium concentration. This T2-weighted axial MR image shows an area of high signal within the central pons without corresponding mass effect.