Evaluation of Dural Venous Sinus Variations through Three-dimensional Phase-Contrast Magnetic Resonance Venography

Objective: The aim of this study was to evaluate the anatomy of dural venous sinus variations through three-dimensional phase-contrast (3D-PC) magnetic resonance venography (MRV). Awareness of the normal anatomical variations of venous sinuses and apparent MRV flow gaps prevent misdiagnosis of dural venous sinus diseases. Materials and Methods: The dural venous sinuses were assessed using nonenhanced 3D PC-MRV. Of these 968 patients, 154 were excluded due to venous thrombosis and mass invasion. A total of 814 patients (186 male and 628 female) were included in the study. Results: The most common variation of superior sagittal sinus (SSS) was atresia of anterior one-third SSS 19 (2.3%). Other variations were hypoplasia of the anterior half of SSS 2 (0.2%), atresia of posterior one-third of SSS (7, 0.9%), and combined variation of SSS (13, 1.6%). The left transverse sinus was hypoplastic in 224 (27.5%) and aplastic/atretic in 259 (31.8%) cases. The right transverse sinus was hypoplastic in 76 (9.3%) and aplastic/atretic in 57 (7.0%) patients. The combined variation of bilateral transverse sinuses had 42 (5.2%) cases. The left sigmoid sinus was hypoplastic in 22.2% (181) of cases. The right sigmoid sinus was hypoplastic in 60 (7.4%). Two patients had hypoplastic bilateral sigmoid sinuses (0.2%). The right occipital sinus was identified in 20 (2.5%) patients. Left occipital sinus was noted in 2 (0.2%) patients. Duplication or triplication of the occipital sinus is noted in 5 (0.6%) study populations. Straight sinus continued in 13 (1.6%) cases with the right transverse sinus and in 29 (3.6%) patients with left transverse sinus. Conclusion: These anatomical variants can be a potential pitfall in the MRV diagnosis of dural sinus variations, especially when there are no supportive imaging features such as brain infarcts or appropriate clinical background. 3D PC-MRV is a great option for patients with gadolinium allergy/renal insufficiency/pregnant patients. We hope this article can add information and assist in preoperative venous analysis for neurosurgeons and neuroradiologists.