title: The significance of sinonasal radiodensities: ossification, calcification, or residual bone?
abstract: OBJECTIVE
  To determine whether very radiodense material within a sinonasal soft-tissue mass on CT can be differentiated as calcification, ossification, or residual bone.
  
  
  METHODS
  We retrospectively described the radiodensities within 235 sinonasal soft-tissue masses as discrete, solitary or multiple, or as a diffuse process with either a well-defined or poorly defined margin. They were also classified as calcification, ossification, or residual bone. Findings were correlated with pathologic specimens.
  
  
  RESULTS
  Residual bone was underdiagnosed; calcification was overdiagnosed. A solitary discrete density was most likely to be calcification within an inflammatory mass. However, multiple discrete densities were as likely to be in a tumor as in an inflammatory lesion. If the process was diffuse with a well-defined margin, it was most likely to be a benign fibroosseous lesion. If the process was diffuse with a poorly defined margin, it was most likely to be a high-grade sarcoma. Densities within inverted papillomas were shown to be residual bone, not calcifications; densities within esthesioneuroblastomas were calcifications.
  
  
  CONCLUSIONS
  Radiodensities may help in refining a CT diagnosis, but one may not know based on CT whether the density is a calcification, ossification, or residual bone.
authors.affiliation: Department of Radiology, Mount Sinai School of Medicine, City University of New York, NY 10029.
authors.forename: P M
authors.initials: PM
authors.lastname: Som
authors.forename: M
authors.initials: M
authors.lastname: Lidov
mesh_terms: D002114:Calcinosis / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D006801:Humans; D009668:Nose Diseases / Q000000981:diagnostic imaging*; D009669:Nose Neoplasms / Q000000981:diagnostic imaging*; D009999:Ossification, Heterotopic / Q000000981:diagnostic imaging*; D010254:Paranasal Sinus Diseases / Q000000981:diagnostic imaging*; D010255:Paranasal Sinus Neoplasms / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed