Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Noninvasive and accurate

20.09.2010
A new method that allows absolute temperature mapping with a previously unmatched accuracy shows promise for biomedical applications

Researchers in Germany and the US have developed a new approach to magnetic resonance imaging (MRI) thermometry using encaged hyperpolarized xenon as a temperature sensor. The method allows absolute temperature mapping with an unprecedented accuracy of 0.1˚C at low and ultralow sensor concentrations.

The new technique, which has the potential to become a helpful tool in clinical diagnostics and therapy monitoring, is presented online in ChemPhysChem. According to Franz Schilling, now a researcher at the Technical University of Munich and lead author of the paper, the method benefits from all the advantages of MRI including its non-invasiveness and the ability to image in any scan orientation with good spatial and temporal resolution.

Many magnetic resonance parameters are inherently temperature-sensitive; for example, proton resonance frequency (PRF), diffusion coefficient or transverse and longitudinal relaxation times. The accuracy of many conventional thermometry methods such as PRF is however limited and although such techniques provide useful relative temperature results, MRI thermometry based on encapsulated hyperpolarized xenon appears to be a more promising technology for in vivo applications because it can be used to map absolute temperatures.

Hydrogen is the most frequently imaged nucleus in MRI, but any nucleus with a net nuclear spin can potentially be imaged, including xenon (129Xe). Such gaseous isotopes must be hyperpolarized before use as their net magnetization is too low to yield a good signal under normal conditions. Schilling and co-workers have introduced xenon sensors as a temperature contrast agent for MRI thermometry to gain both high accuracy and sensitivity. They have achieved this by hyperpolarization through spin exchange optical pumping, which increases the equilibrium net spin polarization by three to four orders of magnitude.

The new technique is based on the temperature-dependent chemical shift of hyperpolarized xenon in a cryptophane-A cage. This shift is linear with a slope of 0.29 ppm per °C, which is almost 30 times higher than that of the proton resonance frequency that is currently used for MRI thermometry. According to Schilling, this new direct mapping concept allows absolute temperature mapping with a previously unmatched accuracy of 0.1˚C at a sensor concentration of 150 µM. But the researchers have also demonstrated an indirect temperature detection technique, via chemical exchange saturation transfer of hyperpolarized xenon (Hyper-CEST, introduced previously by co-author Leif Schröder who currently works at the Leibniz Institute for Molecular Pharmacology in Berlin), which makes temperature mapping with nanomolar agent concentrations as low as 10 nM possible. “This absolute temperature imaging concept offers high temperature accuracy at ultralow agent concentrations”, Schilling says. The new sensors consist of three major components: a cryptophane-A cage for hosting the xenon atom, a linker, and a peptide for sufficient water solubility.

Author: Franz Schilling, Alexander Pines, Lawrence Berkeley National Laboratory, Berkeley (USA), http://www.lbl.gov/

Title: MRI Thermometry Based on Encapsulated Hyperpolarized Xenon

ChemPhysChem 2010, 11, No. 16, Permalink to the article: http://dx.doi.org/10.1002/cphc.201000507

Franz Schilling | Wiley-VCH
Further information:
http://www.lbl.gov/
http://www.wiley-vch.de

Further reports about: MRI Noninvasive magnetic resonance temperature map

More articles from Life Sciences:

nachricht Not of Divided Mind
19.01.2017 | Hertie-Institut für klinische Hirnforschung (HIH)

nachricht CRISPR meets single-cell sequencing in new screening method
19.01.2017 | CeMM Forschungszentrum für Molekulare Medizin der Österreichischen Akademie der Wissenschaften

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Traffic jam in empty space

New success for Konstanz physicists in studying the quantum vacuum

An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Sustainable Water use in Agriculture in Eastern Europe and Central Asia

19.01.2017 | Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

 
Latest News

New Study Will Help Find the Best Locations for Thermal Power Stations in Iceland

19.01.2017 | Earth Sciences

Not of Divided Mind

19.01.2017 | Life Sciences

Molecule flash mob

19.01.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>