Picker International, Inc.

Kenneth S Foster

David A Lampman

Terrence J Provost

Terrence J Brovost

A magnetic resonance imaging sequence (FIG. 2 ) is applied with a phase encode gradient (60) between an RF excitation pulse (50) and a refocusing pulse (54) such that out-of-slice artifacts are collapsed into a single line or column (64) in a resultant image display (38). A digital radio frequency transmitter (20) adds an adjustable RF phase component (70) to the excitation pulse and digital radio frequency receiver (26) adds the inverse or negative of the phase component (72) to a received magnetic resonance echo (56). The RF phase increment is adjusted such that the artifact line is displayed at the edge or other selected portion of the resultant image away from a region (74) of primary interest. An operator control (80) enables the field of view to be shifted in the phase encode direction to view different portions of the patient along the phase encode axis. As the field of view is translated, the RF phase increment is adjusted correspondingly and the reconstructed image representation is rebinned (82) such that the artifact line remains at the edge of the image display.

Technique for shifting out-of-slice artifacts to the edge of the field

In-slice magnetic resonance is excited with a 90.degree. RF pulse (50, 50'). A 180.degree. RF pulse (56, 56') is applied to cause a magnetic resonance spin echo (58, 58'). However, the 180.degree. pulse also induces resonance in material outside the selected slice. The out-of-slice data is superimposed on the magnetic resonance spin echoes. Two views of magnetic resonance data are collected with the same phase encode gradient and stored temporarily in first and second memories (72, 74). The views are combined (76) such that the out-of-slice data sums and the in-slice data cancels. The magnitude of the out-of-slice data is magnitude adjusted (78) to create an out-of-slice magnetization view which is stored in an out-of-slice magnetization memory (80). A plurality of views with different phase encode gradients are subsequently collected during a magnetic resonant imaging sequence. Each view is subtracted from (90) the out-of-slice data view and transformed (92) into an image representation.

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Eastlake, OH, United States of America

Kenneth S Foster