## Abstract Computer simulations of water transverse relaxation induced by superparamagnetic particles are shown to disagree with the available theories, covering the slow diffusion domain. Understanding these new simulations, not in the slow diffusion domain, thus requires a new theoretical approa
T2-shortening by strongly magnetized spheres: A chemical exchange model
โ Scribed by Rodney A. Brooks
- Publisher
- John Wiley and Sons
- Year
- 2002
- Tongue
- English
- Weight
- 87 KB
- Volume
- 47
- Category
- Article
- ISSN
- 0740-3194
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โฆ Synopsis
Abstract
It is shown that a chemical exchange model can reproduce nuclear magnetic relaxation caused by diffusion of water molecules near strongly magnetized particles. The agreement is based on the similarity (but not equivalence) of the respective โvisitโlimitingโ mechanisms in the echoโlimited regime. The model leads to a single equation that predicts relaxation behavior in both the motionalโaveraging and visitโlimited regimes. When combined with the staticโdephasing regime equation, the result is a simple theory (for spheres) that covers the entire range of diffusion times. Magn Reson Med 47:388โ391, 2002. Published 2002 WileyโLiss, Inc.
๐ SIMILAR VOLUMES
Chemical exchange (CE) theory is compared with two theories of T2-shortening caused by microscopic magnetic centers: inner- and outer-sphere relaxation theory (long-echo limit) and mean gradient diffusion theory (short-echo limit). The CE equation is shown to be identical to these theories in the re