Combination of Gas and Increasing Density in the Dural Venous Sinus After Blunt Head Trauma Contributes to Early Diagnosis of Dural Venous Sinus Thrombosis

Abstract

Dural venous sinus thrombosis (DVST) after blunt head trauma is not rare; however, its clinical manifestations are vague, which impedes early diagnosis that is vital for its management. Prior studies have demonstrated that the presence of gas in the dural venous sinus (DVS) after blunt head trauma increases the likelihood of DVST. On nonenhanced computed tomography (CT), hyperdensity in the DVS is considered a direct sign of thrombosis, which can enable early diagnosis of traumatic DVST with high specificity but low sensitivity. We describe a case of traumatic DVST, which was diagnosed early based on the findings of gas and increasing density in the DVS on regular nonenhanced CT. A 41-year-old man was admitted to our hospital after he landed on his head in a car accident. The initial CT (each slice 5.0 mm thick), taken 40 minutes after the injury, indicated right occipital skull fracture and gas in the right sigmoid sinus. Next, 16 hours after the injury, the patient underwent another head CT (each slice 1.25 mm thick). The image showed increasing density (>65 Hounsfield units) in the right sigmoid sinus and the area of intrasinus gas, which is an indication of traumatic DVST, and the bone window revealed right occipital skull fracture that extended to the right sigmoid sinus. Anticoagulant therapy was immediately started after subsequent computed tomographic venography confirmed nonocclusive venous thrombi in the right transverse sinus, the right sigmoid sinus, and the right internal jugular vein on the level of the second cervical vertebra. Three weeks after the injury, computed tomographic venography re-examination showed that the thrombi had resolved dramatically. Traumatic DVST was diagnosed early through findings of gas and increasing density in DVS on different nonenhanced CTs. Finding this combination is a practical, sensitive method for early diagnosis of traumatic DVST, especially in patients with hidden skull fractures involving DVS and patients with hypocythemia.