Contrast‐Induced Encephalopathy Following Elective Endovascular Aneurysm Treatment: The Role of Dual‐Energy CT and Correlation With Delphi Diagnostic Criteria

INTRODUCTION: Contrast-induced encephalopathy (CIE) is an increasingly recognised neurological complication of iodinated contrast administration during neurointerventional procedures. Recently published 2025 Delphi-based diagnostic criteria and management algorithms aim to standardise clinical practice; however, optimal neuroimaging strategies remain undefined. We evaluated the role of dual-energy computed tomography (DECT) as first-line neuroimaging and correlated institutional cases with proposed diagnostic and management frameworks. METHODS: A retrospective review was performed of all patients diagnosed with CIE following elective endovascular intracranial aneurysm treatment at a tertiary neurovascular centre between 2023 and 2025. Inclusion criteria included neurologically asymptomatic patients at presentation who underwent DECT during admission. Cases were assessed against the Delphi diagnostic criteria in consensus with two neurointerventionalists. RESULTS: Six patients met inclusion criteria. Five underwent DECT as first-line neuroimaging. Of these, four (80%) demonstrated parenchymal contrast staining confirmed on iodine overlay imaging, and one was completely normal despite clinical features consistent with CIE. All patients underwent brain MRI during admission. Of these, all patients (100%) demonstrated punctate, non-contributory diffusion changes while two developed confluent diffusion restriction consistent with cerebral ischaemia. Four patients (66.6%) were diagnostically concordant with the Delphi diagnostic criteria. Supportive treatment for suspected CIE did not adversely affect outcomes in patients with concurrent ischaemia. CONCLUSION: DECT appears to be a useful first-line neuroimaging modality for evaluating suspected CIE in patients undergoing elective endovascular aneurysm treatment. MRI remains essential to perform after DECT to assess for concurrent or occult cerebral ischaemia. New diagnostic and management algorithms are useful tools; however, further refinements are recommended.