Signal Detection

Yu‐Chung Norman Cheng1, E. Mark Haacke1

1 The MRI Institute for Biomedical Research, St. Louis, Missouri
Publication Name:  Current Protocols in Magnetic Resonance Imaging
Unit Number:  Unit B2.1
DOI:  10.1002/0471142719.mib0201s13
Online Posting Date:  May, 2005
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Abstract

The bulk magnetization represents the equilibrium value of the magnetization when all spins have aligned themselves parallel to the main field. When this magnetization is tipped into the transverse plane, it precesses about the main field. This precession generates a changing flux through the face of an appropriately placed coil inducing an electromotive force (emf) in the coil. The measured signal is proportional to the induced emf. This unit discusses the basic physics behind detecting MR signal. The process of calculating induced emf based on Faradays law of induction is explained.

     
 
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Table of Contents

  • Overview
  • Technical Discussion
  • Figures
  • Tables
     
 
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Materials

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Figures

Videos

Literature Cited

Literature Cited
   Haacke, E.M., Brown, R.W., Thompson, M.R., and Venkatesan, R. 1999. Magnetic Resonance Imaging: Physical Principles and Sequence Design. John Wiley & Sons, New York.
Key References
   Beall, P.T., Amtey, S.R., and Kasturi, S.R. 1984. NMR Data Handbook for Biomedical Applications. Pergamon Press, New York.
  This text has a more comprehensive list of active NMR elements (i.e., those with nonzero spin).
   Haacke et al., 1999. See above.
  This text covers the technical aspects presented here, but in more detail, and also discusses more advanced materials.
   Hinshaw, W.S. and Lent, A.H. 1983. An introduction to NMR imaging: From the Bloch equation to the imaging equation. Proc. IEEE 71:338.
  This article has a good introduction to basic NMR signal detection.
   Hoult, D.I. and Richards, R.E. 1976. The signal‐to‐noise ratio of the nuclear magnetic resonance experiment. J. Magn. Reson. 24:71.
  The basic interaction between the nuclear magnetic moment and the rf coil as well as the reciprocity concept are introduced in this widely quoted paper.
   Jackson, J.D. 1975. Classical Electrodynamics. John Wiley & Sons, New York.
  This is an advanced textbook of classical electromagnetism.
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