Researchers Work to Boost MRI Sensitivity Dramatically

October 28, 2009 – 10:19 am

From left to right, Alex Pines, Xin Zhou and Dominic Graziani have created a new technique that boosts the signal strength of MRI and NMR spectroscopy up to 10,000 times. This enhanced sensitivity makes possible molecular imaging of clinical and environmental targets. Image courtesy of Roy Kaltschmidt, Berkeley Lab Public Affairs.

From left to right, Alex Pines, Xin Zhou and Dominic Graziani have created a new technique that boosts the signal strength of MRI and NMR spectroscopy up to 10,000 times. Image courtesy of Roy Kaltschmidt, Berkeley Lab Public Affairs.

A couple of days ago on medtechinsider, we covered research on ultrasound technology at the Lawrence Berkeley National Laboratory that potentially could lead to vastly improved resolution of ultrasound scanners. A different group of researchers at the Berkeley lab have announced similar efforts to improve the resolution of magnetic resonance imaging (MRI) systems. The scientists are exploring a new technique known as “Hyper-SAGE” that could detect ultralow concentrations of clincal targets such as lung cancer. Leading the efforts is MRI technology specialist Alexander Pines, a chemist who holds joint appointments with the Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California, Berkeley. The central concept behind the technique is the use of xenon gas that has been treated with laser light to “hyperpolarise” the atomic nuclei, aligning the spins of the majority of its atomic nuclei.

“By detecting the MRI signal of dissolved hyperpolarised xenon after the xenon has been extracted back into the gas phase, we can boost the signal’s strength up to 10,000 times,” Pines says. “It is absolutely amazing because we’re looking at pure gas and can reconstruct the whole image of our target. With this degree of sensitivity, Hyper-SAGE becomes a highly promising tool for in vivo diagnostics and molecular imaging.”

Though MRI is a popular image modality, its application to biomedical samples, for instance, has been limited by sensitivity issues. For the past three decades, Pines has led efforts to enhance the sensitivity of MRI and nuclear magnetic resonance (NMR) spectroscopy. Hyper-SAGE, the latest development, is a significant new advance for both technologies, says Xin Zhou, a member of Pines’ research group.

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This Hyper-SAGE image of xenon dissolved in water flowing through a phantom lung shows the intensity of the MRI signal 23 seconds into the process. The warm colors represent a stronger signal than the cool colors. Image courtesy of Xin Zhou.

A press release from the Berkeley Lab summarises the groups research:

Pines and his research group have developed numerous ways of increasing the sensitivity of MRI technology and expanding its applicability. Previous work showed that xenon, an inert gas whose nuclei naturally feature a tiny degree of spin polarization, can be hyperpolarized with laser light to produce a population of xenon atoms in which nearly five out of every 10 nuclei – instead of one out of every 100,000 – produce an MRI signal. Pines and his group also showed that xenon can be incorporated into a biosensor and linked to specific proteins or other biological molecules to produce spatial images of a chosen molecular or cellular target.

The new technique, Hyper-SAGE, for “hyperpolarized xenon signal amplification by gas extraction,” offers other major advantages over conventional MRI/NMR techniques in addition to a signal that is up to 10,000 times stronger than previous signals, according to Zhou.

“Xenon gas has an intrinsically long relaxation time, greater than 45 minutes, which means the signal lasts long enough for us to collect all the encoded information, which in turn can enable us to detect specific targets, such as cancer-related proteins, at micromolar or parts per million concentrations,” he says. “Also, Hyper-SAGE utilizes remote detection, meaning the signal encoding and detection processes are physically separated and carried out independently. This is a plus for imaging the lung, for example, where the signal of interest would occupy only a small portion of the traditional MRI signal receiver.”

In their PNAS paper, Zhou, Graziani and Pines describe the successful testing of the Hyper-SAGE technique on a pair of membranes that mimicked the function of the lungs. Hyper-polarized xenon was dissolved in solution in one membrane to mimic inhalation, and was then extracted as a gas for detection from the other membrane to represent exhalation.

Explains Zhou, “In a clinical setting, a patient would inhale the hyperpolarized xenon gas which would be dissolved in the blood and allowed to flow into the body and brain. The exhaled xenon gas would then be collected and its MRI signal would be detected. Used in combination with a target-specific xenon biomolecular sensor, we should be able to study the gas-exchange in the lung and detect cancerous cells at their earliest stage of development.”

More information on the research is available from the Berkeley Lab.

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  1. One Response to “Researchers Work to Boost MRI Sensitivity Dramatically”

  2. MRI has an intriguing quantum mechanical system of EM wave-magnetic processes which could have more to say. One relevant fact is the picoyoctoscale reality underlying NMR/MRI instrumentation performance, the quantized magnetic field-matrix precession of particles and their bonding sets. The modeling of waves and magnefield has progressed to definition of h-bar isotopes and a bevy of further innovations which should open new avanues of MRI technical advancements.
    Recent advancements in quantum science have produced the picoyoctometric, 3D, interactive video atomic model imaging function, in terms of chronons and spacons for exact, quantized, relativistic animation. This format returns clear numerical data for a full spectrum of variables. The atom’s RQT (relative quantum topological) data point imaging function is built by combination of the relativistic Einstein-Lorenz transform functions for time, mass, and energy with the workon quantized electromagnetic wave equations for frequency and wavelength.

    The atom labeled psi (Z) pulsates at the frequency {Nhu=e/h} by cycles of {e=m(c^2)} transformation of nuclear surface mass to forcons with joule values, followed by nuclear force absorption. This radiation process is limited only by spacetime boundaries of {Gravity-Time}, where gravity is the force binding space to psi, forming the GT integral atomic wavefunction. The expression is defined as the series expansion differential of nuclear output rates with quantum symmetry numbers assigned along the progression to give topology to the solutions.

    Next, the correlation function for the manifold of internal heat capacity energy particle 3D functions is extracted by rearranging the total internal momentum function to the photon gain rule and integrating it for GT limits. This produces a series of 26 topological waveparticle functions of the five classes; {+Positron, Workon, Thermon, -Electromagneton, Magnemedon}, each the 3D data image of a type of energy intermedon of the 5/2 kT J internal energy cloud, accounting for all of them.

    Those 26 energy data values intersect the sizes of the fundamental physical constants: h, h-bar, delta, nuclear magneton, beta magneton, k (series). They quantize atomic dynamics by acting as fulcrum particles. The result is the picoyoctometric, 3D, interactive video atomic model data point imaging function, responsive to keyboard input of virtual photon gain events by relativistic, quantized shifts of electron, force, and energy field states and positions.

    Images of the h-bar magnetic energy waveparticle of ~175 picoyoctometers are available online at http://www.symmecon.com with the complete RQT atomic modeling manual titled The Crystalon Door, copyright TXu1-266-788. TCD conforms to the unopposed motion of disclosure in U.S. District (NM) Court of 04/02/2001 titled The Solution to the Equation of Schrodinger.

    By Dale B. Ritter, B.A. on Oct 28, 2009

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