title: Ultrasound in the diagnosis of calcium pyrophosphate dihydrate deposition disease. A systematic literature review and a meta-analysis.
abstract: Ultrasonography (US) demonstrated to be a promising tool for the diagnosis of calcium pyrophosphate dihydrate deposition disease (CPPD). The aim of this systematic literature review (SLR) was to collect the definitions for the US elementary lesions and to summarize the available data about US diagnostic accuracy in CPPD.
  
  
  
  We systematically reviewed all the studies that considered US as the index test for CPPD diagnosis without restrictions about the reference test or that provided definitions about US identification of CPPD. Sensitivity and specificity were calculated for each study and definitions were extrapolated. Subgroup analyses were planned by anatomical site included in the index text and different reference standards.
  
  
  
  Thirty-seven studies were included in this review. All the studies were eligible for the collection of US findings and all definitions were summarized. US description of elementary lesions appeared heterogeneous among the studies. Regarding US accuracy, 13 articles entered in the meta-analysis. Considering each joint structure, the sensitivity ranged between 0.77 (0.63-0.87) and 0.34 (0.16-0.58) while the specificity varies between 1.00 (0.89-1.00) and 0.92 (0.16-1.00). Considering the reference standards used, the sensibility ranged between 0.34 (0.02-0.65) and 0.87 (0.76-0.99) while specificity ranged between 0.84 (0.52-1.00) and 1.00 (0.99-1.00).
  
  
  
  US is potentially a useful tool for the diagnosis of CPPD but universally accepted definitions and further testing are necessary in order to assess the role of the technique in the diagnostic process.
authors.affiliation: Department of Medicine, Surgery and Neurosciences, Rheumatology Section, University of Siena, Siena, Italy. Electronic address: gf.filippou@gmail.com.
authors.forename: G
authors.initials: G
authors.lastname: Filippou
authors.affiliation: Department of Medicine, Surgery and Neurosciences, Rheumatology Section, University of Siena, Siena, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Adinolfi
authors.affiliation: Rheumatology Unit, Sapienza Università di Roma, Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Iagnocco
authors.affiliation: Rheumatology Department, Università Politecnica delle Marche, Jesi, Ancona, Italy.
authors.forename: E
authors.initials: E
authors.lastname: Filippucci
authors.affiliation: Research Laboratory and Academic Division of Clinical Rheumatology, Dipartimento di Medicina Interna, University of Genoa, Genova, Italy.
authors.forename: M A
authors.initials: MA
authors.lastname: Cimmino
authors.affiliation: Department of Medicine, Surgery and Neurosciences, Rheumatology Section, University of Siena, Siena, Italy.
authors.forename: I
authors.initials: I
authors.lastname: Bertoldi
authors.affiliation: Department of Medicine, Surgery and Neurosciences, Rheumatology Section, University of Siena, Siena, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Di Sabatino
authors.affiliation: Department of Medicine, Surgery and Neurosciences, Rheumatology Section, University of Siena, Siena, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Picerno
authors.affiliation: Rheumatology Unit, University of Pisa, Pisa, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Delle Sedie
authors.affiliation: Unit of Radiology, San Donato Hospital, San Donato Milanese, Milan, Italy.
authors.forename: L M
authors.initials: LM
authors.lastname: Sconfienza
authors.affiliation: Department of Medicine, Surgery and Neurosciences, Rheumatology Section, University of Siena, Siena, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Frediani
authors.affiliation: Epidemiology Unit, Italian Society for Rheumatology, Milan, Italy.
authors.forename: C A
authors.initials: CA
authors.lastname: Scirè
mesh_terms: D002131:Calcium Pyrophosphate; D002805:Chondrocalcinosis; D006801:Humans; D014463:Ultrasonography
chemical_list: D002131:Calcium Pyrophosphate
keywords: Chondrocalcinosis; Crystal arthropathies; Radiology; Synovial fluid analysis; Systematic review; Ultrasonography