Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New MRI signaling method could picture disease metabolism in action

30.03.2009
Duke University chemists are using modified magnetic resonance imaging to see molecular changes inside people's bodies that could signal health problems such as cancer.

Their new method, reported in the March 27 issue of the research journal Science, makes more of the body's chemistry visible by MRI, said Warren Warren, James B. Duke Professor of chemistry at Duke.

Standard MRI and the functional MRI used for brain imaging enlist the hydrogen atoms in water to create a graphic display in response to magnetic pulses and radio waves. But a huge array of water molecules are needed to pull that off.

"Only one out of every 100,000 water molecules in the body will actually contribute any useful signal to build that image," Warren said. "The water signal is not much different between tumors and normal tissue, but the other internal chemistry is different. So detecting other molecules, and how they change, would aid diagnosis."

The Duke team has been able to see these other molecules with MRI by "hyperpolarizing" some atoms in a sample, adjusting the spins of their nuclei to drastically increase their signal. This creates large imbalances among the populations of those spin states, making the molecules into more powerful magnets.

Unlike normal MRI, hyperpolarization and a technique called "dynamic nuclear polarization" (DNP) which was used for this research, can produce strong MRI signals from a variety of other kinds of atoms besides water. Without hyperpolarization, detecting signals from atoms besides water is exceedingly difficult because the signal size is so small. But "these signals are strong enough to see, even though the molecules are much more complex than water," Warren said.

Warren's group uses what he calls the "first DNP hyperpolarizer in the South," which is installed in his laboratory. It also uses Duke's Small Molecule Synthesis Facility to create custom molecular architectures.

"You thus have a signal that, at least transiently, can be thousands or ten thousands times stronger than regular hydrogen in an MRI," Warren said. "It lets you turn molecules you are interested in into MRI lightbulbs."

Duke's hyperpolarizer includes a superconducting magnet, a cryogenic cooling system that initially plunges temperatures to a scant 1.4 Kelvin degrees while microwave radiation transfers spin polarization from electrons to nuclei, and a heating system to rapidly warm the molecules back up.

Hyperpolarized spin states don't last for long inside the body, but ways have been found to lengthen them. Several years ago, another group discovered a method to make DNP work at room temperature in some biological molecules by substituting carbon-13 atoms for some of those molecules' normal carbon-12s. Unlike carbon-12, carbon-13 emits an NMR signal like hydrogen atoms do.

Using this room-temperature DNP, the biological molecule pyruvate can retain its MRI signal for as long as 40 seconds -- long enough to observe it undergoing rapid chemical change. "So you can watch pyruvate metabolize to produce lactate, acetic acid and bicarbonate -- all breakdown products that might correlate with cancer," Warren said. But most biological processes are much slower, and thus can't be seen with this method.

In its Science report, the Duke team describes a new method that can further extend the signals of molecules carrying swapped carbon-13s. It works by temporarily bottling-up the hyperpolarization in the longest-lived spin states -- called "singlet eigenstates" -- within specially designed molecular architectures. "You can actually use their own chemistries to get the molecules in and out of those protected states," Warren said.

For example, hyperpolarized populations locked within a specially prepared form of diacetyl -- a bacterially-made chemical that imparts buttery flavoring to foods -- can be stored using this method, according to the report. Once triggered, the MRI signal can be extended over many minutes before the spin states decay.

Thus bottled-up, the signals could be kept in temporary isolation. By dehydrating and shielding them from water within microscopic capsules, for example, these "signaling" molecules could be transported through the bloodstream to a potential disease site, Warren said.

Once at that site, a focused burst of ultrasound or heat could restore the molecules' missing water. That would cause a telltale signal to be released just as a rapidly progressing metabolic event was unfolding.

The Duke group is evaluating the potentials for a number of other possible signaling molecules, such as those involved in Parkinson's disease, osteoporosis and bladder control, said Warren, who has filed for a provisional patent.

The research was funded by the National Institutes of Health and the North Carolina Biotechnology Center.

Other authors of the Science report were graduate student Elizabeth Jenista, and Duke assistant research professors Rosa Tamara Branca and Xin Chen.

Monte Basgall | EurekAlert!
Further information:
http://www.duke.edu

More articles from Medical Engineering:

nachricht UTSA study describes new minimally invasive device to treat cancer and other illnesses
02.12.2016 | University of Texas at San Antonio

nachricht Earlier Alzheimer's diagnosis may be possible with new imaging compound
02.11.2016 | Washington University School of Medicine

All articles from Medical Engineering >>>

The most recent press releases about innovation >>>

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

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

Im Focus: Molecules change shape when wet

Broadband rotational spectroscopy unravels structural reshaping of isolated molecules in the gas phase to accommodate water

In two recent publications in the Journal of Chemical Physics and in the Journal of Physical Chemistry Letters, researchers around Melanie Schnell from the Max...

Im Focus: Fraunhofer ISE Develops Highly Compact, High Frequency DC/DC Converter for Aviation

The efficiency of power electronic systems is not solely dependent on electrical efficiency but also on weight, for example, in mobile systems. When the weight of relevant components and devices in airplanes, for instance, is reduced, fuel savings can be achieved and correspondingly greenhouse gas emissions decreased. New materials and components based on gallium nitride (GaN) can help to reduce weight and increase the efficiency. With these new materials, power electronic switches can be operated at higher switching frequency, resulting in higher power density and lower material costs.

Researchers at the Fraunhofer Institute for Solar Energy Systems ISE together with partners have investigated how these materials can be used to make power...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

UTSA study describes new minimally invasive device to treat cancer and other illnesses

02.12.2016 | Medical Engineering

Plasma-zapping process could yield trans fat-free soybean oil product

02.12.2016 | Agricultural and Forestry Science

What do Netflix, Google and planetary systems have in common?

02.12.2016 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>