How do docs tell the difference between regular degenerative changes in facet joints and ankylosing spondylitis or autoimmune on imagine(mri, xrays etc?

See below: Each have distinct finding by x-rays. A MRI is even better. With contrast on a mri, you can detect whether ankylosing spondylitis is active or not and it can detect early changes unlike a x-ray which may not have changes early on x-ray. A MRI with contrast can also distinguish whether or not anylosing spondylitis is present in the setting of osteoarthritis of the spine.