Atypical postoperative radiographical findings in a patient with moyamoya disease: A case report.

Moyamoya disease is a chronic cerebrovascular disease characterized by spontaneous and progressive stenosis or occlusion of the internal carotid artery and its branches. Revascularization procedures have been shown to improve cerebral hemodynamics and decrease the risk of strokes, but several postoperative complications are known to occur.A 14-year-old girl with moyamoya disease with a history of left-sided revascularization surgery underwent right-sided revascularization. On postoperative day 4, she experienced a transient neurological event (left hemiparesis). Magnetic resonance imaging revealed large cortical and subcortical hyperintense lesions in the middle cerebral artery territory on diffusion-weighted imaging and apparent diffusion coefficient imaging. Subsequently, the radiographic findings improved within several days with resolution of the symptoms. This case is a reminder that hemodynamic complications can develop subacutely in patients who have undergone successful revascularization for moyamoya disease. The radiological features and mechanisms of this rare condition associated with revascularization surgery for moyamoya disease are discussed.