Visualization of Penetrating Transmural Arteries In Situ by Monochromatic Synchrotron Radiation

BackgroundPenetrating transmural arteries with a diameter of <500 μm are considered to be a critical vascular component that causes a transmural variation of myocardial blood flow under various pathophysiological conditions. However, the conventional coronary angiographic system is not oriented to the visualization of such small arteries as these. Methods and ResultsWe magnified and monochromatized the inherently narrow beam (3 mm along the vertical direction) of synchrotron radiation by using an asymmetrically cut silicon crystal with 311 reflecting planes to obtain a monochromatic x-ray with relatively large beam size (60×25 mm) and with an energy of just above (+130 eV) the K-absorption edge of the contrast materials (33.17 and 37.41 keV for iodine and barium, respectively). We irradiated dogs or excised hearts with the monochromatic x-ray and obtained coronary angiograms using an image intensifier and video system with a spatial resolution of 170 μm. In the anesthetized dog experiments, we visualized the transmural penetrating arteries (5 to 15 μm in length) arising every 4 to 7 mm from the epicardial branch. Visualization of these arteries filled with heavy element- loaded microspheres (15 gm in diameter) in the excised- heart experiments, in which the monochromatic x-ray was irradiated to the hearts through a 10- to 20-cm acrylic plate, indicated that this system could be used for human patients, in whom body absorption of x-ray is substantial. ConclusionsCoronary angiogram by means of monochromatic x-ray is useful for a precise evaluation of coronary circulation, both in clinical settings and in physiological animal experiments.

[1]  H. Zeman,et al.  Synchrotron radiation coronary angiography with a dual-beam, dual-detector imaging system , 1990 .

[2]  K. Yanagida,et al.  Construction of compact electron storage ring JSR , 1989 .

[3]  Kazuyuki Hyodo,et al.  An attempt at coronary angiography with a large size monochromatic SR beam , 1986 .

[4]  Keiji Umetani,et al.  Two-dimensional real-time imaging system for subtraction angiography using an iodine filter , 1992 .

[5]  T. Tomimasu Industrial Applications of Synchrotron Radiation J, Matsui, Chairman Review of Japanese compact electron storage rings and their applications (invited) , 1989 .

[7]  J I Hoffman,et al.  Pressure-flow relations in coronary circulation. , 1990, Physiological reviews.

[8]  T. Tomimasu An Electron Undulating Ring Dedicated to VLSI Lithography , 1987 .

[9]  W. Chilian,et al.  Microvascular pressures and resistances in the left ventricular subepicardium and subendocardium. , 1991, Circulation research.

[10]  Y. Shinozaki,et al.  New nonradioactive microspheres and more sensitive X-ray fluorescence to measure regional blood flow. , 1992, The American journal of physiology.

[11]  Kazuyuki Hyodo,et al.  High‐speed image‐acquisition system for energy subtraction angiography , 1989 .

[12]  K. Höhne,et al.  NIKOS — A system for non-invasive examination of coronary arteries by means of digital subtraction angiography with synchrotron radiation , 1986 .

[13]  M. Ando,et al.  Real time K‐edge subtraction x‐ray imaging , 1989 .

[14]  Ping-chin Cheng,et al.  X-Ray Microscopy: Instrumentation and Biological Applications , 1987 .

[15]  D C Harrison,et al.  Transvenous coronary angiography in humans using synchrotron radiation. , 1986, Proceedings of the National Academy of Sciences of the United States of America.

[16]  F. S. Goulding,et al.  TRACE ELEMENT ANALYSIS BY X-RAY FLUORESCENCE , 1971 .

[17]  H. Wiedemann Pulsed X-Ray Source for Non-Invasive Digital Subtraction Angiography , 1985, IEEE Transactions on Nuclear Science.

[18]  P. Cheng,et al.  X-ray Microscopy , 1987, Springer Berlin Heidelberg.

[19]  E. N. Dementyev,et al.  First results of experiments with a medical one-coordinate X-ray detector on synchrotron radiation of VEPP-4 , 1986 .