Magnetic resonance imaging in early detection of rheumatoid arthritis.

Magnetic resonance imaging (MRI) is the modality of choice in early diagnosis and management of rheumatoid arthritis (RA). The pathologic processes in RA involve synovitis, joint effusion, proliferation of fibrovascular connective tissue, and the formation of pannus. Other imaging techniques available for imaging of RA include ultrasound, scintigraphy, computed tomography, and plain radiography (PR). MRI provides high sensitivity in detecting inflammatory changes in the joints. Several studies report high intra- and interobserver reliability and low variation for MRI. MRI allows detection and, in some cases, quantification of synovial changes. Dynamic MRI is a new technique that utilizes rate of synovial enhancement in evaluation of inflammatory changes. MRI allows visualization of erosions in three orthogonal planes. MRI has been shown in many studies to have much greater sensitivity than PR in detecting erosions. Use of a contrast agent further increases the sensitivity in detecting erosions and differentiates and outlines synovial proliferation from fluid collection. Other manifestations of RA such as intraosseous cysts, tenosynovitis, bone marrow edema, and carpal tunnel syndrome can also be visualized on magnetic resonance images. Advances in MRI include contrast-enhancement, dynamic, and quantitative techniques. MRI assists in the early detection of RA, which allows earlier initiation of treatment with disease-modifying therapies.