title: Digitized cerebral synchrotron radiation angiography: quantitative evaluation of the canine circle of Willis and its large and small branches.
abstract: OBJECTIVE
  Conventional X-ray angiography lacks the sensitivity and spatial resolution needed to detect small amounts of iodinated contrast material and to quantitate diameters of the small vessels in the brain. The purpose of this study was to ascertain whether digitized synchrotron radiation microangiography, with the use of a high-definition TV camera system, can accurately show small cerebral vessels.
  
  
  METHODS
  Six anesthetized dogs were exposed to monochromatic synchrotron radiation with an energy level of 33.3 keV optimized for iodine detection while iodinated contrast material was injected into the brachiocephalic and vertebral arteries. The images were detected with a high-definition TV camera system with a spatial resolution of 30 microm. In all, 26 cerebral angiograms of the circle of Willis with its branches were obtained, and the images were digitized at a workstation.
  
  
  RESULTS
  The small branches of the circle of Willis were clearly visible on all images. Vasodilatation of the circle of Willis and its large and small branches induced by CO2 inhalation was quantitatively confirmed on the images: for example, the diameter of one small branch was increased from 0.24 +/- 0.04 mm to 0.38 +/- 0.12 mm. Temporal subtraction improved the image quality.
  
  
  CONCLUSIONS
  The synchrotron radiation angiographic system is useful for visualizing large and small vessels deep in the brain as well as for quantitating their diameters.
authors.affiliation: Department of Physiology, Tokai University School of Medicine, Isehara, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Tanaka
authors.forename: A
authors.initials: A
authors.lastname: Tanaka
authors.forename: T
authors.initials: T
authors.lastname: Sekka
authors.forename: Y
authors.initials: Y
authors.lastname: Shinozaki
authors.forename: K
authors.initials: K
authors.lastname: Hyodo
authors.forename: K
authors.initials: K
authors.lastname: Umetani
authors.forename: H
authors.initials: H
authors.lastname: Mori
mesh_terms: D015901:Angiography, Digital Subtraction / Q000379:methods; D000818:Animals; D002533:Cerebral Angiography; D002941:Circle of Willis / Q000000981:diagnostic imaging*; D003287:Contrast Media; D004285:Dogs; D007091:Image Processing, Computer-Assisted; D008852:Microradiography; D017356:Synchrotrons
chemical_list: D003287:Contrast Media