title: Ultrasound-detected musculoskeletal urate crystal deposition: which joints and what findings should be assessed for diagnosing gout?
abstract: OBJECTIVE
  The primary objective of this prospective case-control study was to assess the diagnostic value of several intra-articular and periarticular ultrasound (US)-detected abnormalities in the upper and lower limbs in gout. The secondary objective was to test the concurrent validity of US abnormalities using as gold standard the microscopic demonstration of monosodium urate (MSU) crystals.
  
  
  METHODS
  Ninety-one men with gout and 42 age-matched controls were prospectively recruited. All patients with gout and controls underwent US assessment of several US abnormalities in 26 joints, six bursae, eight tendons, 20 tendon compartments, four ligaments, and 18 articular cartilages by experts in US blinded to the patients' group. Patients with gout and controls with US abnormalities were asked to undergo US-guided aspiration for microscopic identification of MSU crystals. Interobserver and intraobserver reliability of the US assessment was evaluated in a web-based exercise.
  
  
  RESULTS
  The assessment of one joint (ie, radiocarpal joint) for hyperechoic aggregates (HAGs), two tendons (ie, patellar tendon and triceps tendon) for HAGs and three articular cartilages (ie, first metatarsal, talar and second metacarpal/femoral) for double contour sign showed the best balance between sensitivity and specificity (84.6% and 83.3%, respectively). Intraobserver reliability was good (mean κ 0.75) and interobserver reliability was moderate (κ 0.52). The aspirated material from HAGs was positive for MSU crystals in 77.6% of patients with gout and negative in all controls.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Rheumatology, Hospital General Universitario Gregorio Marañón, Complutense University, Madrid, Spain Department of Rheumatology, Hospìtal Universitario Severo Ochoa, Madrid, Spain.
authors.forename: Esperanza
authors.initials: E
authors.lastname: Naredo
authors.affiliation: Department of Rheumatology, Hospital Universitario de Móstoles, Madrid, Spain.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Uson
authors.affiliation: Department of Rheumatology, Hospital Puerta de Hierro, Madrid, Spain.
authors.forename: Mercedes
authors.initials: M
authors.lastname: Jiménez-Palop
authors.affiliation: Department of Rheumatology, Hospital Universitario de Alicante, Alicante, Spain.
authors.forename: Agustín
authors.initials: A
authors.lastname: Martínez
authors.affiliation: Department of Rheumatology, Hospital de la Princesa, IIS-Princesa, Madrid, Spain.
authors.forename: Esther
authors.initials: E
authors.lastname: Vicente
authors.affiliation: Department of Rheumatology, Hospital Ramón y Cajal, Madrid, Spain.
authors.forename: Elia
authors.initials: E
authors.lastname: Brito
authors.affiliation: Department of Rheumatology, Hospital Ramón y Cajal, Madrid, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Rodríguez
authors.affiliation: C.S. Mendiguchia Carriche, Leganés, Madrid.
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Cornejo
authors.affiliation: Department of Rheumatology, Hospital de la Princesa, IIS-Princesa, Madrid, Spain.
authors.forename: Santos
authors.initials: S
authors.lastname: Castañeda
authors.affiliation: Department of Rheumatology, Hospital Universitario de Móstoles, Madrid, Spain.
authors.forename: María Jesús
authors.initials: MJ
authors.lastname: Martínez
authors.affiliation: Department of Rheumatology, Hospital Puerta de Hierro, Madrid, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Sanz
authors.affiliation: Department of Rheumatology, Instituto Poal, Barcelona, Spain.
authors.forename: Ingrid
authors.initials: I
authors.lastname: Möller
authors.affiliation: Department of Rheumatology, Hospital Clínico de San Juan, Alicante, Spain.
authors.forename: Enrique
authors.initials: E
authors.lastname: Batlle-Gualda
authors.affiliation: Department of Social Psychology and Methodology, Faculty of Psychology, Autonoma University, Madrid, Spain.
authors.forename: Jesús
authors.initials: J
authors.lastname: Garrido
authors.affiliation: Department of Rheumatology, Hospital Universitario de Alicante, Alicante, Spain.
authors.forename: Eliseo
authors.initials: E
authors.lastname: Pascual
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002358:Cartilage, Articular / Q000000981:diagnostic imaging / Q000378:metabolism; D016022:Case-Control Studies; D003460:Crystallization; D005260:Female; D006073:Gout / Q000150:complications / Q000000981:diagnostic imaging* / Q000378:metabolism; D006801:Humans; D007596:Joints / Q000000981:diagnostic imaging / Q000378:metabolism; D008297:Male; D050279:Metacarpal Bones / Q000000981:diagnostic imaging / Q000378:metabolism; D008682:Metatarsal Bones / Q000000981:diagnostic imaging / Q000378:metabolism; D008875:Middle Aged; D009140:Musculoskeletal Diseases / Q000000981:diagnostic imaging* / Q000209:etiology / Q000378:metabolism; D015588:Observer Variation; D011446:Prospective Studies; D012015:Reference Standards; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013710:Tendons / Q000000981:diagnostic imaging / Q000378:metabolism; D014463:Ultrasonography / Q000379:methods / Q000592:standards* / Q000706:statistics & numerical data; D014527:Uric Acid / Q000737:chemistry / Q000378:metabolism*
chemical_list: D014527:Uric Acid
keywords: Arthritis; Gout; Ultrasonography