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Hyperdensity Factors

  • S. Wende
  • B. Ludwig
  • R. S. Simon
  • K. Kretzschmar
Conference paper

Abstract

The tissue density in CT depends on several factors of which the first is the atomic number. Iodine contrast agents have such high atomic numbers that they appear white on pictures even at the highest window settings. Secondly, tissue density depends on the compactness or electron density. Thus, if the fluid element of blood is removed it appears more dense. Conversely, the presence of edema lowers the tissue density. We also know that tumors of a higher cell count may exhibit a higher density in the plain scan. Thirdly, it is known that tissue density is also energy-dependent. The importance of recording the kV used for a particular examination is therefore obvious. For the visibility of a dense structure in a CT-image the following facts are also relevant: the amount of the tissue of interest in the z-direction of the slice; the attenuation difference between this tissue and the adjacent tissue, the amount of noise in the reconstruced image.

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References

  1. 1.
    Gado, M.H., Phelps, M.E., Coleman, R.E.: An extravascular component of contrast enhancement in cranial computed tomography. Part I: The tissue-blood ratio of contrast enhancement. Radiology 117, 589–593 (1975)PubMedGoogle Scholar
  2. 2.
    Gado, M.H., Eichling, J., Currie, M.: Quantitative aspects of CT images. In: Computed Tomography 1977, Ed.: D. Norman, M. Korobkin, Th.H. Newton, The C.V. Mosby Comp. St. Louis, 1977Google Scholar
  3. 3.
    Hiibener, K.-H., Schmitt, W.G.H.: Computertomographische Densitometrie des menschlichen Blutes. Einfluß auf das Absorptionsverhalten von parenchymatösen Organen und Ergußbildungen. Fortschr.Rontgenstr. 130:2, 185–188 (1979)Google Scholar
  4. 4.
    Marshall, W.H., Easter, W., Zatz, L.M.: Analysis of the dense lesion at computed tomography with Dual kVp Scans. Radiology 124, 87–89 (1977)PubMedGoogle Scholar
  5. 5.
    McDavid, W.D., Waggener, R.G., Sank, V.J., Dennis, M.J., Payne, W.H.: Correlating computed tomographic numbers with physical properties and operating kilovoltage. Radiology 123, 761–762 (1977)PubMedGoogle Scholar
  6. 6.
    Messina, A.V., Chernik, N.L.: Computed tomography: The “resolving” intracerebral hemorrhage. Radiology 118, 609–613 (1975)Google Scholar
  7. 7.
    New, P.F.J., Aronow, S.: Attenuation measurements of whole blood and blood fractions in computed tomography. Radiology 121, 635–640 (1976)PubMedGoogle Scholar
  8. 8.
    Norman, D.: Computed tomography in intracranial hemorrhage. In: Computed Tomography 1977, Ed.: D. Norman, M. Korobkin, Th.H. Newton, The C.V. Mosby Comp. St. Louis, 1977Google Scholar
  9. 9.
    Norman, D., Price, D., Boyd, D., Fishman, R., Newton, Th.H.: Quantitative aspects of computed tomography of the blood and cerebrospinal fluid. Radiology 123, 335–338 (1977)PubMedGoogle Scholar
  10. 10.
    Phelps, M.E., Kuhl, D.E.: Pitfalls in the measurements of cerebral blood volume with computed tomography. Radiology 121, 375–377 (1976)PubMedGoogle Scholar
  11. 11.
    Som, P.M., Patel, S., Nakagawa, H., Anderson, P.J.: The iron rim sign. J. Comp. Ass. Tomography 3: 1, 109–112 (1979)CrossRefGoogle Scholar
  12. 12.
    Zatz, L.M.: The effect of the kVp level on EMI values. Radiology 119, 683–688 (1976)PubMedGoogle Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 1980

Authors and Affiliations

  • S. Wende
  • B. Ludwig
  • R. S. Simon
  • K. Kretzschmar

There are no affiliations available

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