Nickel-associated delayed multiple white matter lesions after stent-assisted coil embolization of intracranial unruptured aneurysm

Metal-induced encephalopathy after stent-assisted coil embolization is extremely rare. The present report describes two patients who presented with symptomatic intracranial parenchymal edematous lesions after stent-assisted coil embolization. A 64-year-old woman underwent stent-assisted coil embolization for a left internal carotid artery aneurysm; 21days after the procedure she presented with right hand weakness and MRI revealed multifocal white matter lesions. Another woman aged 52years underwent stent-assisted coil embolization for right vertebral artery aneurysm; 18days after the procedure she presented with left-sided sensory disturbance and MRI demonstrated multiple white matter lesions. Treatment in both cases resulted in improvement of these lesions after steroid pulse therapy, and the patients had no associated morbidity 4months after the procedures. Clinicians should monitor for neurologic symptoms and postoperative delayed radiologic parenchymal edematous changes associated with the metal allergic reaction after nitinol stent-assisted coil embolization.