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Cross-encoded magnetic resonance imaging in inhomogeneous fields
Raphael Paquin1, Philippe Pelupessy, Geoffrey Bodenhausen
1Département de Chimie, associé au CNRS, Ecole Normale Supérieure, 24 rue Lhomond, 75231 Paris Cedex 05, France. raphael.paquin@ens.fr
Journal of Magnetic Resonance (San Diego, Calif. : 1997)
|October 3, 2009
Summary
Magnetic resonance imaging (MRI) can now produce clear images despite magnetic field distortions using a novel cross-encoded method. This technique employs adiabatic pulses and simultaneous gradients to correct unknown field variations, enabling undistorted imaging.
Area of Science:
- Medical Imaging
- Physics
Background:
- Magnetic resonance imaging (MRI) is sensitive to magnetic field inhomogeneities.
- Severe field distortions can degrade image quality and limit applications.
Purpose of the Study:
- To develop a method for obtaining undistorted MRI images in the presence of unknown, severe magnetic field inhomogeneities.
- To demonstrate the effectiveness of a new 'cross-encoded' technique.
Main Methods:
- The study introduces a 'cross-encoded' method utilizing adiabatic frequency-modulated pulses.
- Two orthogonal gradients are applied simultaneously during both encoding and decoding phases.
- This approach is designed to function even when the magnetic field profile is unknown.
Main Results:
- The cross-encoded method successfully cancels the effects of severe magnetic field inhomogeneities.
- Undistorted two- and three-dimensional MRI images were obtained.
- The technique is effective even when the water resonance breadth exceeds several kHz.
Conclusions:
- The novel cross-encoded method enables robust MRI in highly inhomogeneous magnetic fields.
- This technique overcomes limitations posed by unknown field distortions, improving image quality and diagnostic potential.
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