Patient with rheumatoid arthritis. a Shoulder, posterior scan. Expansion of posterior capsular recess with inhomogeneous hypoechoic synovial proliferation (*).b,c Images taken before (b),and after (c),injection of contrast agent (Ce-US).These scans show a significant hyperemia of synovial proliferation.The hyperechoic appearance is due to the contrasting microbub-bles. G = posterior margin of humeral glenoid process; H = posterior aspect of humeral head
Bursae are anatomical entities located near joints (non-communicating bursae) or in direct communication with the joint cavity (communicating bursae). The main function of non-communicating bursae, located at the insertional areas of the anchor tendons of several joints, is to reduce the friction between tendon and bone. Communicating bursae, on the other hand, when an abundant intra-articu-lar fluid collection occurs, function by reducing the joint cavity pressure, by expanding and being filled with the fluid coming from the cavity.
Bursitis represents the most common bursal pathology and US is the first choice diagnostic technique.
Non-communicating bursitis a. Acute traumatic bursitis: affecting several synovial bursae, the bursal expansion follows direct impact or chronic frictional microtrauma. The most commonly involved bursae are the sub-
acromial-deltoid bursa, the pre-patellar and deep infra-patellar bursa, the retro-calcaneal and superficialis bursa of the Achilles tendon and the trochanteric bursa. In acute forms, an increase in anechoic fluid within the bursa is observed (a comparison with the controlateral limb may be useful), while the synovial wall keeps its original thickness (Fig. 4.17 a, b). In chronic forms, the fluid often appears hypoe-choic and contains hyperechoic spots consistent with microcalcification, and the bursal walls are thickened  (Fig. 4.18 a,b). b. Hemorrhagic bursitis: usually following a violent sporting trauma on artificial surfaces and mainly affect the hands and knees. The hem-orrhagic effusion may organize and form adhesions or calcifications. Clots and fibrin, appearing as irregular hyperechoic masses, are easily distinguished from synovial hypertrophy because of their mobility and the absence of vascular signal on power or color Doppler analysis.
Was this article helpful?