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You are here: Home › Applications Overview › IC-ICP/MS Analysis: Gadolinium-based MRI Contrast Agents

IC-ICP/MS Analysis: Gadolinium-based MRI Contrast Agents

Jan. 11, 2012
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The use of contrast agents in non-invasive diagnostics provides a specific and high-detailed picture of organs and makes it possible to differentiate between healthy and diseased tissue. Whilst radiocontrast agents (RCA) change the X-ray absorption of the radiographed organ relative to its surrounding tissue, contrast agents for magnetic resonance imaging (MRI) are based on the use of magnetic fields caused by charged elementary particles such as protons and electrons. Compared to traditional X-ray imaging, MRI uses no ionizing radiation. MRI is based on the same principles as NMR spectroscopy and thus takes advantage of the absorption and emission of energy in the radiofrequency range.

Magnetic Resonance Imaging (MRI)
The nucleus of the hydrogen atom, the proton, is of particular importance in MRI because of the magnetic momentum caused by its intrinsic angular momentum (spin) and the frequency with which it occurs in water, fat, or protein molecules in the organism. A short, high-frequency radio pulse changes the spin orientation of the protons before the spin releases the previously absorbed energy again, after the signal is switched off, and returns to the initial state. This phenomenon is termed relaxation. The signals emitted are recorded by highly-sensitive detector coils and are shown in high-contrast cross sections.

Paramagnetic contrast agents, which have unpaired electrons in the outer electron shell and thus also a magnetic momentum, are used to improve imaging. Electrons affect the protons since they have a 657-times stronger magnetic momentum than protons. As a result, both the proton density in the tissue is changed directly and the local magnetic field is changed indirectly by the interaction between the electron spin of the contrast agent and the surrounding hydrogen nuclei.

Read more within the pdf.

 

 

Authors:
Alfred Steinbach, Metrohm International Headquarters

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Keywords : Gadolinum IC-ICP/MS Analysis imaging Magnetic Resonance Imaging Magnevist Metrohm MRI Spectroscopy X-Ray Imaging

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