Contrast-induced encephalopathy following endovascular treatment of intracranial aneurysms

Contrast-induced encephalopathy (CIE) is a rare but potentially serious complication that can occur after endovascular procedures involving iodinated contrast media. This report describes two cases of CIE following elective treatment of intracranial aneurysms. The first case involved patients in their 70s patient with multiple comorbidities who developed neurological symptoms, including right gaze preference, left hemibody incoordination, and diffuse right cerebral hemispheric edema, after receiving a flow-diverting stent. The second case was a patient in their late 70s with a history of subarachnoid hemorrhage who experienced progressive encephalopathy after coil embolization, despite initially normal imaging findings. Both patients were managed with supportive care, including anticonvulsants and aggressive fluid management, and both showed significant neurological improvement within days. These cases highlight the diagnostic challenges of CIE, as imaging findings may vary, and underscore the need for clinicians to maintain a high index of suspicion, particularly in patients with risk factors such as advanced age, hypertension, and prior cerebrovascular events. Early recognition, prompt supportive management, and close monitoring are essential. Importantly, CIE can occur even with the use of modern, low-osmolar contrast agents like Isovue-300, emphasizing the need for continued vigilance and further research into prevention and risk factor identification.