Ultrasound-detected musculoskeletal urate crystal deposition: which joints and what findings should be assessed for diagnosing gout?

Abstract

Our results suggest that US bilateral assessment of one joint, three articular cartilages and two tendons may be valid for diagnosing gout with acceptable sensitivity and specificity.

Is the Double Contour Sign Specific for Gout? Or Only for Crystal Arthritis?

“…It is currently unclear whether a diagnostic approach that involves scanning only a single affected joint provides sufficient accuracy for gout diagnosis. Recent work by Naredo and colleagues 5 indicates that systematic bilateral scanning for hyperechoic aggregates at the radiocarpal joint, patellar tendon and triceps tendon, and DC sign in 3 articular cartilages (i.e., first metatarsal, talar, and second metacarpal/femoral) is required for adequate diagnostic accuracy; this approach had a sensitivity of 85% and specificity of 83%. In contrast, the sensitivity and specificity for DC sign at the femoral condyle was 42% and 100%, respectively, and at the first metatarsal dorsal cartilage was 62% and 98%, respectively 5 .…”

“…Recent work by Naredo and colleagues 5 indicates that systematic bilateral scanning for hyperechoic aggregates at the radiocarpal joint, patellar tendon and triceps tendon, and DC sign in 3 articular cartilages (i.e., first metatarsal, talar, and second metacarpal/femoral) is required for adequate diagnostic accuracy; this approach had a sensitivity of 85% and specificity of 83%. In contrast, the sensitivity and specificity for DC sign at the femoral condyle was 42% and 100%, respectively, and at the first metatarsal dorsal cartilage was 62% and 98%, respectively 5 . Thus, the variation in diagnostic accuracy between different studies may reflect not just expertise in musculoskeletal US, but also the characteristics of the control population, and the sites and number of joints scanned.…”

“…To avoid artifact, some US experts have recommended that the DC sign should be defined as a "hyperechoic irregular enhancement of the chondrosynovial margin of the cartilage that is independent See Differentiating gouty arthritis from CPPD and other arthritides, of the insonation angle of the US beam" 5 . A false-negative DC sign may be due to poorly visualized joints with thin cartilage (tarsal joints) or damaged cartilage, as in osteoarthritis (OA).…”

Ultrasound as an Outcome Measure in Gout. A Validation Process by the OMERACT Ultrasound Working Group

“…The first steps in evaluating the reliability of the definitions show moderate-to-perfect reliability in static images and somewhat lower results in patients, indicating that a standardized scanning technique and a core set of joints are needed. Existing studies indicate that such a core set of joints may include 1st MTP joints and knees, although ankles and some tendons also appear to be frequently involved 19,20 . The next step is to validate the definitions following all steps covered by the OMERACT filter.…”

The Relationship Between Clinical Symptoms and Ultrasonographic Signs in Gout

“…Clinical signs, such as the number of gout attacks per year, the total number of gout attacks per life, and clinically detectable tophi are considered as markers of dise-ase severity, according to which the decision for hypouricemic treatment for many years has been made [3,4]. The use of non-invasive radiologic diagnostic techniques, such as high-resolution ultrasound or dual-energy CT (DECT) for gout diagnosis, incorporated into the recent 2015 ACR/ EULAR gout classification criteria [5] let us visualise the MSU crystal deposits, as well as measure the total body urate burden in the joints and periarticular structures [6,7]. High-resolution ultrasound (US) was shown to be more sensitive than conventional radiography in revealing joint damage -joint erosions -in gout [8].…”