Hewlett-packard Company

Hewlett-packard Corporation

U.S. Phillips Corporation

Steven A Scampini

Bernard Joseph Savord

Lennart Hofland

In a magnetic resonance method for imaging of a moving part of a body (106) temporary magnetic gradient fields (230) are applied and a echo signal (641, 642) is obtained after an excitation pulse (201). An image of the moving part is reconstructed from the received echo signals (240). The moving part introduces artefacts in the reconstructed image. These artefacts could be reduced when the instantaneous position of the moving part is known and the region of the moving part to be excited is adjusted according to this instantaneous position. This instantaneous position is derived from navigator signals (640). These navigator signals (640) could be generated independently from the other echo signals (641, 642) in the moving part of the body. A further reduction of artefacts in the image could be obtained by deriving a phase correction and a frequency correction from the navigator signals (640) and to apply the derived corrections to the received echo signals (641, 642). Also this method could be combined with ECG-triggering and respiratory gating.

Method of and device for magnetic resonance imaging

A protective circuit controls electronic equipment in the presence of a high level electro-magnetic field. The protective circuit includes a field sensor arrangement which provides output signals that are indicative of magnetic field strength components that are aligned along desired spatial axes. A vector converter circuit is connected to the field sensors and provides an output having a magnitude that is indicative of the vector sum of the electro-magnetic field strength components. A first indicator is responsive to an output from the vector converter reaching a first threshold to manifest a caution signal that the magnetic field strength has reached a cautionary level. A second indicator is responsive to an output from the vector converter reaching a second threshold that is higher than the first threshold, to disable the electronic equipment. Further circuitry is provided to re-enable the electronic equipment if it is moved outside of the area where the magnetic field exceeds the first threshold.

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Bedford, MA, United States of America

Steven A Scampini