Interactions of paramagnetic contrast agents and the spin echo pulse sequence

Peter L. Davis, Dennis L. Parker, James A. Nelson, Joseph S. Gillen, Val M. Runge

Research output: Contribution to journalArticlepeer-review


The theoretical equations for paramagnetic contrast agent effects and the spin echo pulse sequence are combined to graph magnetic resonance (MR) intensity as a function of paramagnetic contrast agent concentration for various tissues. Analysis of the graphs and equations demonstrate several technical and clinical implications. These include: (1) positive enhancement is most likely to occur with short TEs and TRs; (2) changes in machine parameters TE and TR will change the concentration of agent at which the peak enhancing MR intensity will occur; (3) there is an absolute max-ium MR intensity that can be reached with contrast enhancement; (4) the maximum MR intensity reached with enhancement is dependent on the tissues’ T2 and, to a lesser degree, T1 relaxation times; (5) certain TE and TR combinations will cause no enhancement; (6) if positive enhancement does occur, it will usually occur only over a limited range of agent concentration; and (7) the tissues’ T1 relaxation time but not its T2 time determines whether positive enhancement will occur and the relative amount of enhancement.

Original languageEnglish (US)
Pages (from-to)381-388
Number of pages8
JournalInvestigative radiology
Issue number5
StatePublished - May 1988
Externally publishedYes


  • Contrast enhancement
  • Contrast media
  • Magnetic resonance imaging
  • Nuclear magnetic resonance
  • Paramagnetic agents
  • Spin echo

ASJC Scopus subject areas

  • Radiology Nuclear Medicine and imaging


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