Abstract 367: Contrast‐Induced Encephalopathy After Stent‐Assisted Coil Embolization: A Rare Complication Case Report

Introduction Contrast‐induced encephalopathy is a rare but potentially serious neurological complication that occurs following the administration of iodinated contrast agents during endovascular procedures. CIE is characterized by acute neurological deficits such as confusion, focal deficits, and seizures, which develop within hours after the procedure. The underlying pathophysiology is not fully understood, but it is believed that disruption of the blood‐brain barrier and direct endothelial toxicity from the contrast agent may contribute to its development. This condition is important to recognize early, as timely intervention with supportive therapy can lead to a favorable outcome. Materials and Methods We report the case of a 74‐year‐old male with multiple comorbidities, including colon cancer and non‐small cell lung cancer with metastasis, who was incidentally found to have an anterior communicating artery aneurysm during routine cancer work‐up. The patient underwent a stent‐assisted coil embolization procedure to treat a large unruptured aneurysm. During the procedure, a total of 300 mL of iodixanol, an iso‐osmolar contrast agent, was administered. The procedure was completed without any immediate complications. However, approximately four hours post‐procedure, the patient developed acute confusion and left‐sided hemiparesis, which prompted further investigation. Results Upon admission to the neurointensive care unit, brain imaging was performed. A non‐contrast brain CT revealed gyriform hyperdensity and sulcal effacement in the right hemisphere, but no hemorrhage was noted. Diffusion‐weighted MRI was performed to rule out ischemic injury, which showed no evidence of infarction. These imaging findings suggested a diagnosis of CIE rather than a stroke or hemorrhage. The patient was immediately started on supportive therapy, which included mannitol for brain edema, dexamethasone for anti‐inflammatory treatment, anticonvulsants for seizure prophylaxis, and aggressive hydration. Over the next three days, the patient's neurological symptoms improved significantly, and he regained full functional recovery without any sequelae. Conclusion CIE is an uncommon but important differential diagnosis in patients who experience acute neurological deterioration following endovascular procedures, particularly when large volumes of iodinated contrast agents are used. Although most patients recover fully with supportive care, severe cases can lead to permanent neurological deficits or even death. Early recognition and management, including aggressive hydration, osmotic therapy, anti‐inflammatory drugs, and seizure prophylaxis, are essential for favorable outcomes. Clinicians should remain vigilant in identifying CIE, especially in high‐risk patients, to ensure timely intervention and prevent long‐term complications.