Background: Computed tomography is performed in suspicious cases of cerebral venous thrombosis. Although an empty delta sign is not uncommonly reported, a cord sign is rarely reported. But this is, if present, pathognomonic, especially in the case of cortical vein thrombosis.
Case description: A young man with antithrombin III deficiency sought emergency treatment for headache and seizure. Noncontrast computed tomography showed a typical cord sign in multiple sections. It seemed to be independent from the adjacent pathologic findings in most sections. Brain magnetic resonance imaging verified it as a thrombosed vein in conjunction with acute venous infarction.
Conclusion: The cord sign should be considered for early and accurate diagnosis of cortical vein thrombosis.