I recently had an MRI done on my neck. Although I understand the report, there is one part of the scans I would like to understand better. On the axial view (T2) there are two main blood vessels slightly behind the spine. There is one on each side and the space between the two is a little greater than the width of the spine. Sorry I do not have medical terms, I hope this makes sense to you. Anyhow, my question is, what makes these blood vessels white and what makes them black on an MRI? One of mine is white and the other is black. Every “normal MRI” picture I have seen has the both of them as the same color.
These vessels are the vertebral arteries. They ascend from the upper chest and enter the skull at the base of the brain- the foramen magnum. These two vessels form the “Circle of Willis” and bring blood supply to the base of the brain and the cerebellum.
The reason these arteries can have different appearances is the movement of the blood while the scan is being taken. MRI scans are like old time pictures in the wild west. If you have ever seen these pictures, some individuals look like ghosts as their appearance is smudged if they move while the picture is being taken.
The same thing happens with movement while the scan is taken. You can’t ask blood to stand still and this motion will “color” the blood depending upon the phase of the scan taken.