Objective: Prior studies have shown that skull fractures overlying the dural venous sinuses predispose the patient to an increased risk of dural venous sinus thrombosis (DVST). However, extrinsic compression may also cause sinus compromise and simulate thrombosis. This study set out to evaluate the prevalence and discernibility of DVST versus direct sinus compression in the setting of an overlying skull fracture.
Materials and methods: All initial head MDCT venography examinations performed at a level 1 trauma center over an 8-year period were reviewed (n = 347 patients). The examinations that showed an acute fracture overlying a dural sinus were included for review (n = 107 patients). Three neuroradiologists classified the MDCT venography findings as category 0 (normal), 1 (solely sinus compression), 2 (solely intraluminal thrombus), 3 (mixed sinus compression and DVST), or 4 (indeterminate). Clinical outcomes were assessed at 30-45 days after hospital discharge.
Results: The percentage of patients in each category was as follows: category 0 (31-33% patients), 1 (38-46%), 2 (5-9%), 3 (8-11%), and 4 (8-13%). Categories 2-4 were more likely in the transverse sinus-sigmoid sinus complex (22-30%) and multiple dural sinuses (47-53%) than in the superior sagittal sinus (SSS) (5%). Interobserver reliability was strong (κ = 0.627-0.772; p < 0.0001). Sinus category was associated with fracture site (p = 0.014) but not with clinical outcome (p = 0.236).
Conclusion: Sinus compromise is common in patients with overlying skull fractures. Sinus compression can be distinguished from DVST on MDCT venography and is likely more prevalent than previously estimated. The fracture site may in part determine the pattern of compromise because fractures involving the transverse sinus-sigmoid sinus complex or multiple dural sinuses seem more likely to be affected by thrombosis than fractures involving the SSS.
Keywords: CT venography; dural venous sinus thrombosis; skull fracture.