title: Diagnosis of calcium pyrophosphate dihydrate crystal deposition disease: ultrasonographic criteria proposed.
abstract: OBJECTIVE
  To investigate by high frequency ultrasonography the appearance of calcium pyrophosphate dihydrate (CPPD) calcifications, in the most commonly affected sites in CPPD disease, and the relationship between ultrasonographic CPPD deposits and the presence of CPPD crystals in synovial fluid.
  
  
  METHODS
  Three ultrasonographic patterns of CPPD calcification were identified and 11 patients enrolled. A control group comprised 13 patients with no evidence of CPPD deposits. Synovial fluid was aspirated from all patients and controls and examined for identification of crystals. All patients underwent a standard radiography examination at the same sites investigated by ultrasound.
  
  
  RESULTS
  In all patients with ultrasonographically defined CPPD deposits, CPPD crystals were found in the synovial fluid. In two cases, standard radiographic examination did not show evidence of the calcific deposits that were identified by ultrasonography. CPPD crystals were not found in the synovial fluid of controls. In four control group patients, ultrasonography identified calcifications defined as deposits of another nature.
  
  
  CONCLUSIONS
  The ultrasonographic pattern used in this study for the diagnosis of CPPD disease demonstrated a very high correlation with the presence of CPPD crystals in synovial fluid. Ultrasonography demonstrated a sensitivity and specificity at least equal to that of radiography in identifying CPPD crystal calcifications.
authors.affiliation: Department of Clinical Medicine and Immunological Sciences, Section of Rheumatology, University of Siena, 53100 Siena, Italy.
authors.forename: B
authors.initials: B
authors.lastname: Frediani
authors.forename: G
authors.initials: G
authors.lastname: Filippou
authors.forename: P
authors.initials: P
authors.lastname: Falsetti
authors.forename: S
authors.initials: S
authors.lastname: Lorenzini
authors.forename: F
authors.initials: F
authors.lastname: Baldi
authors.forename: C
authors.initials: C
authors.lastname: Acciai
authors.forename: C
authors.initials: C
authors.lastname: Siagkri
authors.forename: D
authors.initials: D
authors.lastname: Marotto
authors.forename: M
authors.initials: M
authors.lastname: Galeazzi
authors.forename: R
authors.initials: R
authors.lastname: Marcolongo
mesh_terms: D000368:Aged; D002131:Calcium Pyrophosphate / Q000032:analysis; D002358:Cartilage, Articular / Q000000981:diagnostic imaging; D002805:Chondrocalcinosis / Q000000981:diagnostic imaging* / Q000473:pathology; D003460:Crystallization; D005260:Female; D006801:Humans; D007719:Knee Joint / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012680:Sensitivity and Specificity; D013582:Synovial Fluid / Q000737:chemistry; D014463:Ultrasonography; D014955:Wrist Joint / Q000000981:diagnostic imaging
chemical_list: D002131:Calcium Pyrophosphate