title: Vessel imaging by interferometric phase-contrast X-ray technique.
abstract: BACKGROUND
  Phase-contrast x-ray imaging using an x-ray interferometer has great potential to reveal the structures inside soft tissues, because the sensitivity of this method to hydrogen, carbon, nitrogen, and oxygen is approximately 1000 times higher than that of the absorption-contrast x-ray method. Imaging of vessels is very important to understand the vascular distribution of organs and tumors, so the possibility of selective angiography based on phase contrast is examined with a physiological material composed of low-atomic-number elements.
  
  
  RESULTS
  Phase-contrast x-ray imaging was performed with a synchrotron x-ray source. Differences in refractive index, ddelta, of physiological saline, lactated Ringer's solution, 5% glucose, artificial blood such as pyridoxylated hemoglobin-polyoxyethylene conjugate, and perfluorotributylamine were measured. Because the ddelta of physiological saline has highest contrast, it was used for the phase-contrast x-ray imaging of vessel, and this was compared with absorption-contrast x-ray images. Vessels >0.03 mm in diameter of excised liver from rats and a rabbit were revealed clearly in phase-contrast x-ray imaging, whereas the vessel could not be revealed at all by the absorption-contrast x-ray image. Absorption-contrast x-ray images with iodine microspheres depicted only portal veins >0.1 mm in diameter with nearly the same x-ray dose as the present phase-contrast x-ray imaging.
  
  
  CONCLUSIONS
  Phase-contrast x-ray imaging explored clear depiction of the vessels using physiological saline with small doses of x-rays.
authors.affiliation: Institute of Clinical Medicine, University of Tsukuba, Tsukuba-shi, Ibaraki, Japan. ttakeda@md.tsukuba.ac.jp
authors.forename: Tohoru
authors.initials: T
authors.lastname: Takeda
authors.forename: Atsushi
authors.initials: A
authors.lastname: Momose
authors.forename: Jin
authors.initials: J
authors.lastname: Wu
authors.forename: Quanwen
authors.initials: Q
authors.lastname: Yu
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Zeniya
authors.lastname: Thet-Thet-Lwin
authors.forename: Akio
authors.initials: A
authors.lastname: Yoneyama
authors.forename: Yuji
authors.initials: Y
authors.lastname: Itai
mesh_terms: D000792:Angiography / Q000295:instrumentation / Q000379:methods*; D000818:Animals; D003287:Contrast Media; D004307:Dose-Response Relationship, Radiation; D007368:Interferometry / Q000295:instrumentation / Q000379:methods*; D008099:Liver / Q000098:blood supply / Q000000981:diagnostic imaging; D008863:Microspheres; D019047:Phantoms, Imaging; D011169:Portal Vein / Q000000981:diagnostic imaging; D011817:Rabbits; D011856:Radiographic Image Enhancement / Q000295:instrumentation / Q000379:methods; D051381:Rats; D017208:Rats, Wistar; D012031:Refractometry; D012680:Sensitivity and Specificity; D017356:Synchrotrons; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*
chemical_list: D003287:Contrast Media