Nobel Prize for MRI Discovery
Medical Editor: Barbara K. Hecht, Ph.D.
Oct 6, 2003 - Today two scientists who developed magnetic resonance imaging, better known as MRI, were awarded the 2003 Nobel Prize for Physiology or Medicine. The official announcement stated that: "The Nobel Assembly at Karolinska Institutet has today decided to award The Nobel Prize in Physiology or Medicine for 2003 jointly to Paul C Lauterbur and Peter Mansfield for their discoveries concerning "magnetic resonance imaging." Dr.Paul Lauterbur is American. Sir Peter Mansfield is British. The following summary and thumbnail sketches of the new Nobel laureates are based on information provided by the Nobel Assembly.
Atomic nuclei in a strong magnetic field rotate with a frequency that is dependent on the strength of the magnetic field. Their energy can be increased if they absorb radio waves with the same frequency (resonance). When the atomic nuclei return to their previous energy level, radio waves are emitted. These discoveries were awarded the Nobel Prize in Physics in 1952. During the following decades, magnetic resonance was used mainly for studies of the chemical structure of substances. In the beginning of the 1970s, this year's Nobel Laureates made pioneering contributions, which later led to the applications of magnetic resonance in medical imaging.
Paul C. Lauterbur
Lauterbur discovered that introduction of gradients in the magnetic field made it possible to create two-dimensional images of structures that could not be visualized by other techniques. In 1973, he described how addition of gradient magnets to the main magnet made it possible to visualize a cross section of tubes with ordinary water surrounded by heavy water. No other imaging method can differentiate between ordinary and heavy water.
Sir Peter Mansfield
Mansfield utilized gradients in the magnetic field in order to more precisely show differences in the resonance. He showed how the detected signals rapidly and effectively could be analyzed and transformed to an image. This was an essential step in order to obtain a practical method. Mansfield also showed how extremely rapid imaging could be achieved by very fast gradient variations (so called echo-planar scanning). This technique became useful in clinical practice a decade later.
The Resonance Phenomenon
Other fundamental discoveries concerning magnetic resonance have in recent years resulted in two Nobel Prizes in Chemistry. In 1991, Richard Ernst, Switzerland, was awarded for his contributions to the development of the methodology of high resolution nuclear magnetic resonance spectroscopy. In 2002, Kurt Wuthrich, also Switzerland, was awarded for his development of nuclear magnetic resonance spectroscopy for determination of the three-dimensional structure of biological macromolecules in solution.