‘Dense Inverted Triangle Sign' in Cerebral Venous Thrombosis

The early diagnosis of cerebral venous thrombosis in the emergency department is challenging. A 70-year-old man presented to the emergency department after falling with new-onset convulsions. Brain unenhanced computed tomography (CT) revealed right frontal hemorrhage indicative of traumatic subarachnoid hemorrhage (SAH). Brain unenhanced CT on day 2 revealed increased density in the anterior superior sagittal sinus (SSS), namely ‘dense inverted triangle sign.' Brain magnetic resonance venography showed a filling defect in the anterior SSS. When interpreting unenhanced brain CT findings in the setting of acute convulsions or cortical stroke, including SAH, cerebral sinus abnormalities near stroke foci should be evaluated carefully.