Imaging evaluation is one of important diagnostic tools for rheumatic disease. X ray remains primary modality for imaging diagnosis of arthritis. Rheumatoid arthritis (RA) mainly demonstrates bone erosion, joint space narrowing, osteoporosis, and joint deformity or subluxation in plain X ray. RA tends to be symmetric and proximal distribution in hand and wrists. Seronegative spondyloarthropathy is related with HLA- B27. Ankylosing spondylitis is characterized by sacroiliitis, spondylitis, osteitis, and syndesmophyte. Psoriatic arthritis may share similar imaging findings with RA: such as bone erosion, joint space narrowing, and joint deformity. Psoriatic arthritis and Reiter’s disease reveals enthesis, bone proliferation, sacroiliitis, and paraspinal ossification.

　　Magnetic resonance imaging (MRI) is thought currently to play an important role in evaluation of rheumatic disease. MRI has the advantage of good soft tissue and bone marrow contrast, high spatial resolution, multi-plantar sections, and non irradiation. It has been reported MRI is accurate in evaluation of bone erosion and marrow edema, synovitis, tenosynovitis, and tendinitis. MRI is also sensitive in assessment of cartilage loss, bone proliferation, enthesopathy in rheumatic arthritis. Conventional plain radiography frequently reveals late manifestation of arthritis, whereas MRI is especially valuable in detection of early arthritis, monitoring therapeutic effect, and predicting the outcome of arthritis.