The role of magnetic resonance imaging in assessing venous vascular abnormalities in the head and neck: a demonstration of cerebrospinal venous insufficiency in a subset of multiple sclerosis patients

The study of chronic cerebrospinal venous insufficiency (CCSVI) and its impact on the development and progression of multiple sclerosis (MS) remains controversial. Although the initial thrust in evaluating CCSVI was with ultrasound, other modalities including magnetic resonance imaging (MRI) have been used to study venous vascular abnormalities. This review focuses on the findings of a number of past MRI studies including a look at a combined study of four previous works with a cohort of 559 MS patients regarding structure and function of the extra-cranial vasculature. Strengths and limitations of each paper are discussed which give insight into conflicting reports of venous abnormalities in MS patients and healthy controls. Guidelines for data acquisition and analysis for future studies related to extra-cranial structure and flow, both arterial and venous, are discussed. This includes the grading of stenosis of the internal jugular veins (IJVs) as well as normalized flows through major veins of the neck. The lack of agreement between most studies is likely due to inconsistent data acquisition and incomplete data analysis. Our own work over four independent sites shows good agreement, indicating that there is a high incidence of stenosis and structural venous abnormalities in the MS population and that this change results in reduced outflow of the IJVs and increased collateralization of venous return to the heart compared to healthy controls.