@lisa2022 I do know that imaging can be done in different positions that can demonstrate movement or instability of the spine, and then on the computer on the MRI or X-ray image, they can measure if there is movement by clicking the cursor and get a precise measurement on how much movement. They also measure stenosis this way to show narrowing as compared to what normal measurements are. I think the motion X-rays are used for things like a swallowing study that depends on needing to see the moving image of a barium drink as it is swallowed. They will ask for the imaging they need, and don't want to add unnecessary tests and costs. Does that help clarify?