Interactions of paramagnetic contrast agents and the spin echo pulse sequence

Invest Radiol. 1988 May;23(5):381-8. doi: 10.1097/00004424-198805000-00010.

Abstract

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 maximum 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.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Contrast Media*
  • Gadolinium DTPA
  • Humans
  • Magnetic Resonance Imaging*
  • Organometallic Compounds
  • Pentetic Acid

Substances

  • Contrast Media
  • Organometallic Compounds
  • Pentetic Acid
  • Gadolinium DTPA