Bilateral Paramedian Thalamic Lesions Following Cerebral Angiography: A Case Suggestive of Contrast-Induced Neurotoxicity

Digital subtraction angiography (DSA) is essential for the diagnosis and management of intracranial aneurysms but may rarely cause central nervous system complications. We report a 50-year-old man who developed acute neurological deficits immediately after follow-up DSA with iodixanol, 10 months after successful embolization of a left middle cerebral artery aneurysm. He presented with drowsiness, language impairment, memory disturbance, and vertical gaze palsy without motor or sensory deficits. Magnetic resonance imaging demonstrated bilateral paramedian thalamic lesions with diffusion restriction in the territory of the artery of Percheron (AOP), mimicking acute ischemic infarction. Considering the temporal relationship and subsequent radiologic regression, contrast-induced neurotoxicity (CIN) was suspected. The patient received antiplatelet therapy, corticosteroids, vasodilators, and supportive treatment, leading to marked clinical and radiologic improvement. At 3-month follow-up, he was functionally independent with only mild residual memory impairment. This case highlights that CIN may present as a reversible bilateral thalamic injury resembling ischemic stroke, emphasizing the importance of early recognition and careful differential diagnosis.