If hyponatremia is rapidly corrected, there is rapid accumulation of fluid in the brain, particularly in white matter, and white matter tracts are tightly packed in the pons. The resulting osmotic damage can lead to central pontine myelinolysis. Note the area of decreased signal intensity in the pons, as shown here in this midline sagittal MR image. With Luxol Fast Blue myelin stain, note the loss of white matter tracts in the microscopic image below.