Introduction:Contrast-induced encephalopathy (CIE) is a rare complication associated with the use of contrast media. New contrast agents make contrast complications increasingly rare. The diagnosis of CIE is challenging, particularly in patients with acute ischemic stroke. Neuroimaging results for patients with CIE can also be highly variable.Patient concerns:A 63-year-old man with severe internal carotid artery stenosis who experienced several symptoms, including dizziness, nausea, vomiting, fever, and blurred vision after being administered the contrast agent iodixanol.Diagnoses:Multiple CT and MRI brain scans were performed. After excluding other differential diagnoses such as electrolytes imbalance, hypo/hyperglycemia and other neurological emergencies such as cerebral hemorrhage, cerebral infarction, the final diagnosis of CIE was made.Intervention:Treatment consisted of adequate hydration, intravenous dexamethasone, mannitol, and anticonvulsants.Outcome:The patient demonstrated progressive neurological improvement, and recovered from all symptoms on the fifth day. Follow-up at 3 months shows a good prognosis for patients.Conclusion:Patients with CIE may have a high signal on diffusion-weighted imaging and a low signal on apparent diffusion coefficient brain MRI. This is similar to the MRI findings in acute stroke. This needs to be distinguished from acute cerebral infarction and suggests that we should closely monitor patients’ neurological symptoms at the time of cerebral angiography and after the investigations.