Musculoskeletal ImagingTenosynovitis
inflammation of a
tendon sheath. Various types of microorganisms (gonococcal, meningococcal, mycobacterial, streptococcal) may cause septic tenosynovitis in various rheumatological conditions. In addition, stenosing (or constrictive) tenosynovitis may develop if adhesions form between the
tendon sheath and the
tendon; granulomatous tenosynovitis may occur in
sarcoidosis, after exposure to beryllium or after puncture wounds; and
nodular tenosynovitis may occur in persons with
giant cell tumour of a
tendon sheath or
pigmented villonodular synovitis.
CT scanning and MR imaging are the two techniques employed most commonly for evaluation of the tenosynovitis. With CT, ultrasonography and MR imaging, the major finding in tenosynovitis is abnormal accumulation of fluid within the tendon sheath. This fluid is of low signal intensity on T1-weighted spin-echo MR images and of high signal intensity on T2-weighted spin-echo images. Pannus and scar formation about a tendon are characterized by intermediate signal intensity on T1-weighted spin-echo MR images and intermediate to high signal intensity on T2-weighted spin-echo MR images. Tendinitis is accompanied by focal areas of high signal intensity within the substance of the tendon on proton density and T2-weighted spin-echo MR images. With chronic tendinitis, the tendon is enlarged and of low signal intensity in both T1-weighted and T2-weighted spin-echo MR images.
In rheumatoid arthritis tenosynovitis is prominent on the dorsum of the hand, the fingers and the foot. In association with tenosynovitis, the tendon itself may become affected, leading to a variety of complications, including weakening, subluxation, entrapment and rupture. The most common radiographic finding associated with tenosynovitis is soft tissue swelling. Erosion of subjacent bone can be observed, particularly in the posterosuperior aspect of the calcaneus (in relation to retrocalcaneal bursitis), the olecranon process (in relation to olecranon bursitis), the inferior surface of the acromion and distal end of the clavicle (in relation to subacromial bursitis) and the outer aspect of the distal portion of the ulna (reflecting extensor carpi ulnaris tenosynovitis). Arthrography, bursography, tenography and MR imaging can be used to delineate the nature of the soft tissue swelling.
DR