The objective of this work was to evaluate the sonographic features of gouty arthritis and correlate findings
with disease duration. The study was conducted on 100 patients in ambulatory care aged $40 y. Inclusion
criteria included mono- or oligo-arthritis with effusion of the knee or the first metatarsophalangeal (MTP) joint
and no known history of gout. A complete medical history was obtained with emphasis on the known risk factors
or causes of gouty arthritis. A 12-MHz Medison linear probe was used for ultrasonography (US). Synovial fluid
analysis with polarizing light microscopy was performed on all patients. Ninety-eight knee joints and 33 first
MTP joints were examined. Gouty arthritis was found by US in four forms: (i) floating echogenic foci in effusion
fluid or Baker cysts, (ii) deposits on the cartilage surface (double contour sign), (iii) erosions and (iv) mature
tophus/tophi. These were found in 78.9%, 42.3%, 39.4% and 28.2% of patients, respectively. The overall sensitivity
and specificity of US in detecting gout (as defined by the clinical gold standard, i.e., detection of urate crystals by
polarizing light microscopy) were 85.9% and 86.7%, respectively. Detection of echogenic foci in effusion fluid was
associated with the shortest duration of symptoms (median duration 2 y) followed by double contour sign (3.5 y),
erosions (4 y) and tophus (12.5 y). Sonographic findings in gout can be assigned a temporal pattern, with echogenic
foci being associated with the shortest and full tophus formation with the longest disease duration