Ankylosing spondylitis (AS) is an inflammatory disease of the spine that can cause fusion of the vertebrae over time. It typically affects the sacroiliac joints in the lower back and can cause pain, stiffness, and limited mobility.
When it comes to diagnosing ankylosing spondylitis, CT and MRI scans are the two primary imaging modalities used. CT scans are used to detect structural changes that might be associated with ankylosing spondylitis, such as bone erosion, fusion of the vertebrae, and narrowing of the spinal canal. MRI scans are used to detect inflammation of the sacroiliac joints, ligaments, and tendons.
In general, CT scans are more useful for detecting structural changes associated with ankylosing spondylitis, while MRI scans are more useful for detecting inflammation. In some cases, CT and MRI scans may be used together to get a better picture of the condition. Additionally, both scans may be used to rule out other causes of back pain that could be mistaken for ankylosing spondylitis.
Ultimately, CT and MRI scans are the two primary imaging modalities used to diagnose ankylosing spondylitis. Each scan has its own advantages and disadvantages, but when used together they can provide a comprehensive picture of the condition and help to diagnose and treat it more effectively.