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IBM Science

IBM Creates MRI With 100M Times the Resolution 161

Posted by kdawson
from the little-tiny-hairs dept.
An anonymous reader writes "IBM Research scientists, in collaboration with the Center for Probing the Nanoscale at Stanford University, have demonstrated magnetic resonance imaging with volume resolution 100 million times finer than conventional MRI. This result, published today in the Proceedings of the National Academy of Sciences, signals a significant step forward in tools for molecular biology and nanotechnology by offering the ability to study complex 3D structures at the nanoscale."
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IBM Creates MRI With 100M Times the Resolution

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  • by im_thatoneguy (819432) on Tuesday January 13, 2009 @06:17PM (#26440299)

    My understanding of this specific MRI technology is that its applications are similar to that of an electron microscope.

    Unless you plan on crawling into a pitri dish your precious little thoughts should be safe. You don't even need tinfoil!

  • by kebes (861706) on Tuesday January 13, 2009 @06:33PM (#26440509) Journal
    The actual scientific paper is:
    C. L. Degen, M. Poggio, H. J. Mamin, C. T. Rettner, D. Rugar Nanoscale magnetic resonance imaging [pnas.org] PNAS 2009, doi: 10.1073/pnas.0812068106 [doi.org].

    The abstract:

    We have combined ultrasensitive magnetic resonance force microscopy (MRFM) with 3D image reconstruction to achieve magnetic resonance imaging (MRI) with resolution <10 nm. The image reconstruction converts measured magnetic force data into a 3D map of nuclear spin density, taking advantage of the unique characteristics of the 'resonant slice' that is projected outward from a nanoscale magnetic tip. The basic principles are demonstrated by imaging the 1H spin density within individual tobacco mosaic virus particles sitting on a nanometer-thick layer of adsorbed hydrocarbons. This result, which represents a 100 million-fold improvement in volume resolution over conventional MRI, demonstrates the potential of MRFM as a tool for 3D, elementally selective imaging on the nanometer scale.

    I think it's important to emphasize that this is a nanoscale magnetic imaging technique. The summary implies that they created a conventional MRI that has nanoscale resolution, as if they can now image a person's brain and pick out individual cells and molecules. That is not the case! And that is likely to never be possible (given the frequencies of radiation that MRI uses and the diffraction limit [wikipedia.org] that applies to far-field imaging.

    That having been said, this is still a very cool and noteworthy piece of science. Scientists use a variety of nanoscale imaging tools (atomic force microscopes [wikipedia.org], electron microscopes [wikipedia.org], etc.), but having the ability to do nanoscale magnetic imaging is amazing. In the article they do a 3D reconstruction of a tobacco mosaic virus. One of the great things about MRI is that is has some amount of chemical selectivity: there are different magnetic imaging modes that can differentiate based on makeup. This nanoscale analog can use similar tricks: instead of just getting images of surface topography or electron density, it could actually determine the chemical makeup within nanostructures. I expect this will become a very powerful technique for nano-imaging over the next decade.

  • Re:Interesting! (Score:4, Informative)

    by Anonymous Coward on Tuesday January 13, 2009 @06:38PM (#26440563)

    This device won't work on large samples (think brain) because the detection mechanism is a microcantilever. It will work for small particles, since the resonant frequency of the cantilever can remain high with only a small mass on the end. Large objects will simply make the detector extremely slow and insensitive. While a whole brain won't work, I'd expect a few cells or small tissue sample might be possible to image, giving impressive detail on the chemical pathways in the cell and between cells.

  • by reverseengineer (580922) on Tuesday January 13, 2009 @06:58PM (#26440793)
    What it amounts to is an atomic force microscope [wikipedia.org] combined with a magnetic needle that allows it to perform proton NMR. An AFM is a pretty general and adaptable technique- the key element is the cantilever system that allows you to detect a tiny amount of force exerted on atoms in a sample; how you supply that force, via magnetic resonance, van der Waals forces, the Casimir effect, etc., makes it versatile. The significant drawback of this instrument is that it is a supermicroscope, not a macroscale scanner like a medical MRI machine. Samples are usually limited to a surface area of a few hundred square microns. The resolution achieved here is impressive, but is best understood as an advancement in microscopy. Just as with a light microscope or an electron microscope, this is a technique for scanning cells, not bodies.
  • Re:Interesting! (Score:5, Informative)

    by ViennaSt (1138481) on Tuesday January 13, 2009 @07:22PM (#26441097)
    Unfortunately, this 3D MRI can not be applied to imaging the human brain yet.

    One problem is that though this machine has great spatial resolution (precision in space)....it may not have great temporal resolution (precision in time).

    In regards to your curiosity about imaging dendritic connections: It may image where/how the connections are made, which is a great leap for Neuroanatomists. But it cannot measure or record the hundreds of thousands of mechanisms and live actions that the dendrites/axons/cell bodies and their connections make during every one action potential that takes place...Even if this machine could measure outside the nanoscale.

    Here's why: Neurons may fire a number of action potentials in millisecond time and increase/decrease in volume as the influx of sodium brings in water into the cell causing it to expand. As enough sodium (positively charged particals) are in the cell causing a depolarization, the voltage-gated ion channels shut off and K+ outflux/Na+ influx ceases. The cell hyperpolarizes, shrinks in volume and it's morphology is changed drastically once again. To capture all this change with such fine resolution is a feat, that sadly, cannot be accoplished by this 3D Machine--since everything it measures must be fixed and perfectly still. What neuroscientist use now for "partial real time brain imaging" is a function MRI or fMRI which measure changes in metabolism (glucose metabolism to be exact) but compromises the great spatial resolution this 3D machine has for the temporal resolution.

  • by GeckoAddict (1154537) on Tuesday January 13, 2009 @07:27PM (#26441165)
    With a user ID of 1444615 and that being the only post... I seriously doubt they're joking, which is a sad fact in itself.
  • Re:Similar to MEG? (Score:5, Informative)

    by reverseengineer (580922) on Tuesday January 13, 2009 @07:52PM (#26441455)
    No, this technique isn't anything like magnetoencephalography. The only way it could scan your brain is if you allowed them to cut out a cell at a time. Medical scale MRI works by aligning the spins of certain nuclei (usually hydrogen atoms, which are mostly bound in water molecules in your body) using a powerful magnetic field, then using a radiofrequency field to flip those spins, and then measuring the magnetic fields produced by the nuclei as they relax to their equilibrium state. Functional MRI, or fMRI, the type often used in brain activity monitoring, measures the differing magnetic properties of hemoglobin has when oxygen is bound versus free. Therefore, the technique monitors areas of increased oxygen usage by regions of the brain, which generally correlate to increase activity.

    The technique the article discusses, however, is not to measure the magnetic properties of a bunch of atoms, but to make a picture of a sample by scanning atom by atom. A very precisely constructed magnetic needle scans over a surface, in this case, the surface of a virus. Whenever the needle hovers over a hydrogen nucleus, the nucleus flips, generating a tiny force that pushes down on the stage the virus is mounted on. By recording each of these events, a map is generated of all of the hydrogen nuclei the needle passed over. It's a great way to look at protein structure, but an awfully slow way to look at a brain.
  • Re:Interesting! (Score:1, Informative)

    by Anonymous Coward on Tuesday January 13, 2009 @11:59PM (#26443779)

    Your post is wrong at so many levels. First of all, this MRI machine is meant to be operated at small scale situations (that means: not scanning an entire brain). Second of all, the workings of the brain are not purely defined by the synaptic interconnections, but also the individual chemistry of each neuron and its surroundings (and that's only the beginning for newbies). Third of all, it is unlikely we can currently create a synthetic one, even though we would have all the current information, since our computers are still not fast enough. Fourth of all, we do have interfaces for communicating with a human brain, although they are usually not providing the detail our own organs can give us.

    So, having debunked almost everything you said, you leave me with: "we can model the human brain". Yes, given we have the right data, we could theoretically model it. But it would be a pretty worthless model if we cannot get it operational, wouldn't it?

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