Dual-Energy Computed Tomography (DECT) for Diagnosing Contrast-Induced Encephalopathy (CIE) Mimicking Intracranial Hemorrhage (ICH): A Rare Case

Contrast-induced encephalopathy (CIE) is a rare complication after percutaneous coronary intervention (PCI) that mimics intracranial hemorrhage (ICH). Its computed tomography (CT) findings (cortical contrast enhancement, sulci effacement) overlap with cerebrovascular conditions (e.g., cerebral infarction, subarachnoid hemorrhage). Dual-energy CT (DECT) differentiates blood/calcification from iodinated contrast medium (CM) extravasation via material decomposition, contributing to the accurate diagnosis of CIE. We report a CIE case highlighting DECT's value. A 74-year-old woman underwent PCI. 50 min post-PCI, she had moderate headache (Numeric Rating Scale 4), dizziness, non-projectile vomiting (no seizures); vital signs were stable, no focal deficits, mannitol ineffective. Non-contrast CT demonstrated a left parietal 75 Hounsfield unit (HU) high-attenuation lesion, indistinguishable from acute intracerebral hemorrhage. Conventional non-contrast CT revealed a high-attenuation lesion (75 HU) in the left parietal lobe-indistinguishable from ICH. DECT clarified the diagnosis: virtual non-contrast maps showed CM extravasation, iodine concentration maps confirmed focal CM accumulation, and effective atomic number maps improved lesion visualization. The patient's headache resolved within 5 h; follow-up non-contrast CT at 24 h showed complete disappearance of the lesion. She resumed clopidogrel, discharged day 3 without sequelae. This case underscores DECT's role in distinguishing CIE (transient CM, normal neuro exam) from ICH (persistent hemorrhage), guiding safe post-PCI antiplatelet therapy.