Rheumatoid arthritis | Spondyloarthritis | Crystal arthropathies | Polymyalgia rheumatica | Septic arthritis |
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• Joint effusion, synovial proliferation, synovial pannus, and hyperemia in typical RA distribution • Tenosynovial effusions, synovial hypertrophy, and hyperemia • Cortical bone erosions and cartilage lesions • Multijoint assessments confirming typical distribution of involvement | • Enthesitis characterized by tendon/ligament hypoechogenicity and thickening, calcification, bone erosions, intralesional focal calcification or fibrous tissue, and abnormal vascularization at enthesis insertion on power Doppler ultrasound • Cortical bone erosions and enthesophytes (heterogeneous to RA) • Synovitis and tenosynovitis • Confounding factors: age, BMI | • Tophaceous deposits: • Cartilage: double contour sign (gout) • Periarticular: heterogeneous collection in soft tissue, “snowstorm” appearance sometimes with anechoic rim • Tendons and ligaments: intratendinous tophi and ovoid-shaped microdeposits with hyperechoic densities • Cortical bone erosions • CPPD deposits: • Hyaline cartilage: hyperechoic, within the layer of cartilage • Fibrocartilage: hyperechoic, rounded or amorphous deposits • Basic calcium phosphate: • Hyperechoic foci with variable acoustic shadowing • Hyperemia on Doppler | • Bilateral subacromial/subdeltoid bursitis • Biceps long-head tenosynovitis • Trochanteric bursitis • Synovitis • Hip effusion • Less common findings include enthesitis, glenohumeral effusions, flexor tenosynovitis, and peripheral synovitis • Should not have hand- or wrist-joint synovitis | • Joint effusion, sometimes with hyperechogenicity and heterogeneity • Increased peri-synovial vascularity with color Doppler • Ultrasound can guide joint aspiration • Clinical suspicion has the highest priority |