Conventional radiographs (X-rays) have long been the standard technique used to diagnose arthritis and track its progression.
Arthritis is a condition that causes pain, inflammation, swelling, stiffness, or tenderness in various joints in the body. Joints in the hands, elbows, feet, knees, hips, spine, and back are often affected. Arthritis can happen for many reasons such as older age, an overactive immune system, an injury, or repeated occupational stress on a joint.
When checking you for arthritis, the physician may order X-ray imaging.
How X-ray imaging detects arthritis
Based on a patient’s symptoms, specific areas of their body will be selected by the physician for X-ray imaging. During imaging, invisible electromagnetic energy beams (X-rays) will be passed through the selected body structure. You may be asked to position the area being imaged in a way that enables the physicians to have the best view of the affected region. Holding your position once imaging begins is important because any movement can cause blurry images.
The X-rays then pass through the body and are caught on plates that are similar to film on a camera. The X-rays that pass through blood and other soft tissues such as fat and muscle will encounter almost no resistance and most of them will land on the plate, making that area on the image appear dark. The X-rays that encounter hard structures such as bones will not all pass through, and that area on the plate will appear lighter.
Using the final image, a physician can determine whether the joint looks normal, or if it looks like it has arthritis. Your doctor will use these results to tailor your treatments. They may also prescribe routine X-rays to keep an eye on the progression of your arthritis.
Deficiencies in X-ray imaging
Conventional X-rays can be beneficial for detecting arthritis once the disease has progressed enough to have distinguishable bone abnormalities. X-rays are not suitable for early detection of some types of arthritis.
For example, for someone with osteoarthritis which is caused by the destruction of cartilage between the bones, the X-ray would show the bones closer together on the affected joints and further apart when there is cartilage covering the bone ends. As the disease progresses, the physician may notice the bones getting closer together. X-rays can also detect the formation of abnormal bone structures in the joint. But in the early stages of the disease when bone abnormalities are not significant, X-ray imaging can miss signs of the disease.
In people who have gout, urate crystals are found around the affected joints. These crystals cause inflammation in the joint which precedes any changes in the bone structure by 6-8 years.
However, despite their shortcomings in detecting early signs of arthritis, X-rays continue to be accessible and relatively inexpensive diagnostic tools for evaluating arthritis.
Early osteoarthritis can be viewed using MRI which can quite successfully visualize changes caused by the swelling of the bone marrow and inflammation of the tendons, tendon sheaths, and joint capsules.
When an MRI is not possible, for example, if the patient has a pacemaker or has claustrophobia, a CT scan may be prescribed. In patients with gout, urate crystals can be accurately visualized using dual-energy CT scan (DETC) and ultrasonography.
A full-body PET scan can visualize the body’s small and big joints at the same time, and detect the extent of the damage in the body overall. This can be especially useful in rheumatoid arthritis in which many joints in the body are affected at the same time.
Ultrasound can be useful to check the ligaments and tendons surrounding the joint.
The information provided in our blog posts is for informational purposes only and is not intended as a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this blog.