Arthritis is the inflammation of the joints. There are several types of arthritis. Some of the most common types are:

  • Osteoarthritis: It is the most common type of arthritis. It occurs due to the breakdown of cartilage that cushions the joints. It eventually leads to the rubbing of bones against each other, causing pain, stiffness, and limited mobility.
  • Rheumatoid arthritis: It is an autoimmune disorder that causes chronic inflammation of the joints. It can affect any joint in the body and can lead to severe deformities in the affected joints.
  • Psoriatic arthritis: It is a type of arthritis that affects people with psoriasis, an autoimmune skin disorder. It causes joint pain, stiffness, and swelling.
  • Gout: It is a type of arthritis that occurs due to the buildup of uric acid crystals in the joints. It causes sudden and severe pain, swelling, and redness in the affected joint.
  • Ankylosing spondylitis: It is a type of arthritis that affects the spine and can cause severe back pain and stiffness. It can also affect other joints in the body.
  • Juvenile idiopathic arthritis: It is a type of arthritis that affects children below the age of 16. It causes joint pain, stiffness, and swelling.
  • Reactive arthritis: It is a type of arthritis that occurs due to an infection in the body. It causes joint pain, eye inflammation, and urinary tract infection.
  • Infectious arthritis: It is a type of arthritis that occurs due to a bacterial, viral, or fungal infection. It causes joint pain, stiffness, and swelling.

Radiographic features of arthritis
All types of Arthritis have few common radiographic features that include:
Joint space narrowing: Arthritis causes the loss of cartilage in the joint space, resulting in decreased joint space on radiographs.
Osteophyte formation: Osteophytes, also known as bone spurs, develop at the edges of bones in the joint as a result of the body trying to repair the damage caused by arthritis.
Subchondral sclerosis: The subchondral bone immediately below the cartilage can become sclerotic or hardened as a result of the inflammation associated with arthritis.
Subchondral cyst formation: Areas of focal bone destruction can lead to the formation of subchondral cysts or subchondral bone marrow edema.
Erosions: Erosive arthritis can cause destruction of the bone, often seen as sharply defined areas of bone loss on radiographs.
Soft tissue swelling: Arthritis can cause soft tissue swelling around the joint, seen as increased soft tissue density on radiographs.
Deformity: Chronic arthritis can lead to joint deformities, which are often seen on radiographs as malalignment of bones, flattening of joint surfaces, and joint space narrowing.
Changes in bone density: Arthritis can cause abnormal changes in bone density, often seen as areas of increased or decreased bone density on radiographs.

Imaging Techniques Used in Arthritis
There are numerous imaging techniques used in the diagnosis and management of arthritis. Some of these techniques are:
X-rays: X-rays are commonly used to diagnose arthritis as they help in visualizing the bones and cartilage of the joint. X-rays can also detect any bone spurs or deformities in the joint.
Magnetic Resonance Imaging (MRI): MRI is a non-invasive imaging technique that uses powerful magnets and radio waves to create detailed images of the joint structures. It is particularly useful in detecting early signs of arthritis and providing information about joint erosion, inflammation, and synovitis.
Computed Tomography (CT) Scan: It is an advanced imaging technique that provides a detailed view of the joints in three dimensions. It is particularly useful in detecting bone damage, bone spurs, and fractures.
Ultrasound: Ultrasound is a non-invasive imaging technique that uses sound waves to create images of the joint structures. It is particularly useful in detecting inflammation, synovitis, and joint effusion.
Dual-energy X-ray Absorptiometry (DEXA) Scan: It is a specialized X-ray that measures bone density and is used to diagnose osteoporosis, a common complication of arthritis.
Fluoroscopy: It is a real-time X-ray technique used to visualize joint movement and guide procedures such as joint injections and arthroscopy.
Positron Emission Tomography (PET) Scan: PET scan is a specialized imaging technique that uses radioactive tracers to visualize metabolic activity in the joint. It is particularly useful in detecting early signs of rheumatoid arthritis and monitoring disease activity.
Overall, these imaging techniques help in the early diagnosis, accurate staging, and effective treatment of arthritis, improving the quality of life of patients with arthritis.