Abstract
This chapter discusses principles of nuclear magnetic resonance (NMR) and MRI followed by a survey on the major classes of MRI contrast agents (CA), their modes of action, and some of the most significative applications. The two more established classes of MRI-CA are represented by paramagnetic metal complexes (i.e., Gd(III) and Mn(II)) and iron oxide particles, acting on T1 and T2* of the water protons signals, respectively. Along the years many efforts have been devoted to endow these relaxation enhancement agents with improved sensitivity, targeting, and responsive properties that have markedly broadened the range of applications in respect to the clinically used systems. CEST agents represent innovative frequency-encoding probes that yield negative contrast in the MR images upon transfer of saturated magnetization from the agent to the “bulk” water signal. Interesting developments have been attained that markedly increase the number and typology of systems with CEST properties. Currently much attention is also devoted to hyperpolarized molecules that display a sensitivity enhancement sufficient for their direct exploitation for the formation of the MR image. A real breakthrough is provided by the use of molecules (such as pyruvate) that report about the cellular metabolism, thanks to the maintenance of the hyperpolarization in the derived species.
Original language | English |
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Title of host publication | Small Animal Imaging: Basics and Practical Guide |
Editors | Fabian Kiessling, Bernd J. Pichler, Peter Hauff |
Publisher | Springer |
Publication date | 2017 |
Pages | 227-324 |
Chapter | 13 |
ISBN (Print) | 978-3-319-42200-8 |
ISBN (Electronic) | 978-3-319-42202-2 |
DOIs | |
Publication status | Published - 2017 |
Keywords
- MRI
- Paramagnetic probes
- Molecular imaging
- Hyperpolarization
- CEST
- MRS
- MRSI
- Dissolution DNP
- Para-hydrogen
- Metabolism
- 13C