Normal variations in MR venography that may cause pitfalls in the diagnosis of cerebral venous sinus thrombosis

Magnetic resonance venography (MRV) is a widely used non-invasive imaging technique to diagnose cerebral dural venous sinus thrombosis (CVST) and intracranial venous abnormalities. Non-visualization of a dural venous sinus is diagnostic of CVST on MRV. However, there are numerous common variances and technical aberrations on MRV that mimic filling defects and might be confused with CVST, making diagnosis difficult. These include aberrant veins and missing, hypoplastic or asymmetric venous sinuses. In addition, reconstruction artifacts might take the form of flow gaps with various lengths. The purpose of this study is to examine the occurrences, geographic distribution, and imaging properties of these variations and artifacts on MRV. After obtaining clearance from the Institution’s Ethics Committee, magnetic resonance imaging (MRI) brain of 60 patients were taken for the study. MRI was performed using 1.5 Tesla Intera PHILIPS. A cross-sectional study was conducted to study the normal anatomy of the intracranial venous system and its normal variations. This study showed that hypoplasia of the left transverse sinus was found to be more predominant (60%) among other sinuses of the brain followed by right transverse sinuses (31%); the left sigmoid sinus was hypoplastic in 35%, the right sigmoid sinus hypoplastic in 18% and superior sagittal sinuses in 5%. It is essential to know the anatomical variations of the dural venous system for the discrimination between pathological processes such as thrombosis and physiologic conditions. Furthermore, the association of these variations with each other must be kept in mind for explanation of the presence of multiple variations in the same individuals.