title: CO2 microbubble contrast enhancement in x-ray angiography.
abstract: OBJECTIVE
  To demonstrate that carbon dioxide (CO2) microbubble contrast enhancement depicts blood vessels when used for x-ray examinations.
  
  
  METHODS
  Microbubbles were generated by cavitation of physiological saline to which CO2 gas had been added using an ejector-type microbubble generator. The input pressure values for CO2 gas and physiological saline that produced a large quantity of CO2 microbubbles were obtained in a phantom. In an animal study, angiography was performed in three swine using three types of contrast: CO2 microbubbles, conventional CO2 gas, and iodinated contrast medium. For CO2 microbubble contrast enhancement, physiological saline, and CO2 gas were supplied at the input pressures calculated in the phantom experiment. Regions of interest were set in the abdominal aorta, external iliac arteries, and background. The difference in digital values between each artery and the background was calculated.
  
  
  RESULTS
  The input pressures obtained in the phantom experiment were 0.16 MPa for physiological saline and 0.5 MPa for CO2 gas, with physiological saline input volume being 8.1 ml/s. Three interventional radiologists all evaluated the depictions of all arteries as "present" in the CO2 microbubble contrast enhancement, conventional CO2 contrast enhancement, and iodinated contrast enhancement performed in three swine. Digital values for all vessels with microbubble CO2 contrast enhancement were higher than background values.
  
  
  CONCLUSIONS
  In x-ray angiography, blood vessels can be depicted by CO2 microbubble contrast enhancement, in which a large quantity of CO2 microbubbles is generated within blood vessels.
authors.affiliation: Department of Radiology, Kansai Medical University, Hirakata, Osaka, Japan. kariyas@hirakata.kmu.ac.jp
authors.forename: S
authors.initials: S
authors.lastname: Kariya
authors.forename: A
authors.initials: A
authors.lastname: Komemushi
authors.forename: M
authors.initials: M
authors.lastname: Nakatani
authors.forename: R
authors.initials: R
authors.lastname: Yoshida
authors.forename: S
authors.initials: S
authors.lastname: Sawada
authors.forename: N
authors.initials: N
authors.lastname: Tanigawa
mesh_terms: D015901:Angiography, Digital Subtraction / Q000379:methods*; D000818:Animals; D001012:Aorta, Abdominal / Q000000981:diagnostic imaging*; D002245:Carbon Dioxide; D003287:Contrast Media; D007083:Iliac Artery / Q000000981:diagnostic imaging*; D007479:Iopamidol / Q000008:administration & dosage; D045423:Microbubbles; D015588:Observer Variation; D019047:Phantoms, Imaging; D011856:Radiographic Image Enhancement / Q000379:methods*; D012965:Sodium Chloride; D013552:Swine
chemical_list: D003287:Contrast Media; D002245:Carbon Dioxide; D012965:Sodium Chloride; D007479:Iopamidol