title: Correlation between pixel values in a cone-beam computed tomographic scanner and the computed tomographic values in a multidetector row computed tomographic scanner.
abstract: OBJECTIVE
  The study's objectives were to investigate the correlation between pixel values obtained from a cone-beam computed tomographic (CBCT) scanner and the computed tomographic (CT) values from a multidetector row CT scanner and to determine whether they have a linear relationship at various tube voltages and tube currents.
  
  
  METHODS
  A phantom with different concentrations of contrast medium at the center of a multidetector row CT and a CBCT scanner was scanned at various imaging parameters. Computed tomographic values and pixel values were measured using ImageJ. Regression analysis was performed, as well as correlation tests with a Pearson correlation coefficient.
  
  
  RESULTS
  A significant correlation between pixel values and the CT values of the same specimen was observed (P < 0.0001), and a linear relationship was found between the values from the 2 scanners at each parameter.
  
  
  CONCLUSIONS
  A high correlation and linear relationship between the CT values and pixel values were found at each parameter. Therefore, linear functions can be used to convert a pixel value from the CBCT machine used in this study to the CT values.
authors.affiliation: Department of Oral and Maxillofacial Radiology, Osaka University Graduate School of Dentistry, Osaka, Japan.
authors.forename: Jira
authors.initials: J
authors.lastname: Chindasombatjaroen
authors.forename: Naoya
authors.initials: N
authors.lastname: Kakimoto
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Shimamoto
authors.forename: Shumei
authors.initials: S
authors.lastname: Murakami
authors.forename: Souhei
authors.initials: S
authors.lastname: Furukawa
mesh_terms: D054893:Cone-Beam Computed Tomography; D003287:Contrast Media / Q000008:administration & dosage; D007479:Iopamidol / Q000008:administration & dosage; D019047:Phantoms, Imaging; D011856:Radiographic Image Enhancement / Q000379:methods*; D012044:Regression Analysis; D015898:Tomography Scanners, X-Ray Computed; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007479:Iopamidol