Acute elevations in systemic blood pressure can lead to a wide spectrum of central nervous system manifestations, including catastrophic scenarios like intracerebral hemorrhage. We hypothesized that brain swelling occurs in hypertensive crisis patients, assessed by structural MRI. We prospectively collected MRI data from a consecutive series of patients admitted to the emergency department with a diagnosis of hypertensive urgency but no neurologic symptoms. A second MRI was obtained at 3-months follow-up of blood pressure normalization. MRI analysis revealed reductions in cortical and sub-cortical gray matter after normalization of blood pressure.