###Human: Is it fine to not visualize right internal jugular vein in MRV? ###Assistant: Hi. The internal jugular vein carries blood from the brain and neck area to the heart. There are many reasons for the non-visualization of the internal jugular vein on MRV and the causes can be technical due to slow flow of blood or can be due to a mild compression of the vein due to a secondary cause. Rarely it can be from a thrombus in the lumen of the vein. If the MRV of the brain and rest of the internal jugular vein is normal, then the non-visualization is likely due to technical reasons and is artefactual. If you are having headaches, then it is better to talk to your doctors and get a neck venous Doppler done to rule out any external compression of the vein or any luminal thrombosis of chronic nature.