title: Calibration with currently available low-radiopacity catheters for scaling in digital quantitative coronary angiography.
abstract: OBJECTIVE
  In quantitative coronary angiography, the absolute diameters of coronary artery lumina are obtained by using a catheter as a scaling device.
  
  
  METHODS
  We examined the effect of x-ray opacity on the accuracy of calibration methods that use such catheters by varying the concentration of contrast medium in the catheters in phantom experiments with a digital cine imaging system.
  
  
  RESULTS
  With contrast-filled, currently available catheters, the average increase in the measured calibration factor from the gold standard (as determined by using a measuring scale) was 1.0% and 0.4% in the 13-cm and 17-cm image-intensifier modes, respectively, compared with -9.9% and -12.4% for catheters without contrast medium. The corresponding figures for catheters of the previous generation that lacked contrast medium were 1.0% and 0.4%, respectively. The image contrast of previous-generation catheters filled with saline was closer to that of current-generation catheters filled with contrast medium than that of current-generation catheters filled with saline.
  
  
  CONCLUSIONS
  When used for quantitative coronary angiography by digital angiography, currently available low-radiopacity catheters give more accurate data when filled with contrast medium.
authors.affiliation: Department of Cardiology, Mazda Hospital, 2-15 Aosaki-minami, Fuchu-cho, Hiroshima 735-8585, Japan. tadehara@hospital.mazda.co.jp
authors.forename: F
authors.initials: F
authors.lastname: Tadehara
authors.forename: M
authors.initials: M
authors.lastname: Imazu
authors.forename: S
authors.initials: S
authors.lastname: Kono
authors.forename: K
authors.initials: K
authors.lastname: Sano
mesh_terms: D002138:Calibration; D002404:Catheterization / Q000295:instrumentation*; D003287:Contrast Media; D017023:Coronary Angiography / Q000295:instrumentation* / Q000379:methods; D007091:Image Processing, Computer-Assisted / Q000295:instrumentation*; D019047:Phantoms, Imaging
chemical_list: D003287:Contrast Media