Out of control atoms provide sharper MRI images

Scientists here and in France have made a new theoretical advance in atomic behavior that could lead to sharper magnetic resonance imaging (MRI) pictures.

The discovery could one day help enable the development of portable MRI machines.

In the November 25 online issue of the Journal of Chemical Physics, they explain why scientists couldn't completely control the behavior of atomic nuclei during some nuclear magnetic resonance (NMR) experiments.

Some loss of control isn't such a bad thing, explained Philip Grandinetti, professor of chemistry at Ohio State University. Now that he and his colleagues have derived a mathematical explanation of the strange atomic behavior, scientists can use it to make MRI images sharper.

The advance may one day help scientists to look inside people and objects without having to put them inside giant magnets -- an advance which could lead to portable MRIs.

NMR and its medical counterpart, MRI, reveal the inside of objects by detecting atoms that behave like tiny magnets. Inside the machine's strong magnetic field, atoms align according to north and south magnetic poles, spinning and precessing like tiny tops. Each type of atom broadcasts its identity by emitting a unique radio frequency, depending on its environment.

NMR can reveal the structure of individual molecules. But pictures of complex objects -- such as the human brain -- often lack detail, because whenever atoms happen to broadcast in opposite directions, they cancel each other out of the final image.

In a quest to boost NMR resolution, scientists routinely perform a certain type of experiment that keeps the spins of atoms under very strict control. They refer to such experiments as adiabatic.

The Ohio State scientist and his collaborators found that atoms in adiabatic experiments don't always behave as scientists intend them to.