System and method for highly attenuating material artifact reduction in x-ray computed tomography
First Claim
1. A method for producing, with an x-ray computed tomography (“
- CT”
) system, an image of a subject in which artifacts associated with a highly attenuating material are substantially suppressed, the steps of the method comprising;
a) acquiring, with the CT system and using a helical-scan with a selected pitch factor, projection data that includes a plurality of projection views of a subject at a plurality of view angles over a selected longitudinal scan range;
b) producing, from the acquired projection data, a projection plane data set by combining a plurality of projection views from the projection data that were acquired at the same view angle;
c) producing a reformatted projection by mapping attenuation information in the projection plane data set to an image matrix;
d) correcting the reformatted projection for errors resulting from the selected pitch factor;
e) segmenting a region of the corrected reformatted projection that corresponds to an object composed of a highly attenuating material;
f) removing attenuation information in the segmented region from the corrected reformatted projection;
g) interpolating attenuation information from portions of the corrected reformatted projection into the segmented region to produce an interpolated reformatted projection; and
h) producing an image of the subject, in which artifacts caused by highly attenuating materials are substantially suppressed, by mapping the interpolated reformatted projection to a corrected projection plane data set and performing image reconstruction on the projection plane data set.
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Abstract
The present invention is a method for reducing artifacts caused by highly attenuating materials in x-ray computed tomography (“CT”) images. The method includes combining projection views acquired at equivalent view angles to generate a projection plane data set, from which a reformatted projection is produced. The reformatted projection is then processed to detect and segment regions corresponding to objects composed of metals, metal alloys, or other highly attenuating materials. These segmented regions are then removed from the reformatted projection and the removed portions replaced by attenuation information interpolated from portions of the reformatted projection adjacent the removed portions. The interpolated reformatted projection is then mapped back to a projection plane data set, and an image of the subject is reconstructed from the projection views contained in that data set. The reconstructed image, therefore, is one in which artifacts caused by highly attenuating materials are substantially suppressed.
28 Citations
20 Claims
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1. A method for producing, with an x-ray computed tomography (“
- CT”
) system, an image of a subject in which artifacts associated with a highly attenuating material are substantially suppressed, the steps of the method comprising;a) acquiring, with the CT system and using a helical-scan with a selected pitch factor, projection data that includes a plurality of projection views of a subject at a plurality of view angles over a selected longitudinal scan range; b) producing, from the acquired projection data, a projection plane data set by combining a plurality of projection views from the projection data that were acquired at the same view angle; c) producing a reformatted projection by mapping attenuation information in the projection plane data set to an image matrix; d) correcting the reformatted projection for errors resulting from the selected pitch factor; e) segmenting a region of the corrected reformatted projection that corresponds to an object composed of a highly attenuating material; f) removing attenuation information in the segmented region from the corrected reformatted projection; g) interpolating attenuation information from portions of the corrected reformatted projection into the segmented region to produce an interpolated reformatted projection; and h) producing an image of the subject, in which artifacts caused by highly attenuating materials are substantially suppressed, by mapping the interpolated reformatted projection to a corrected projection plane data set and performing image reconstruction on the projection plane data set. - View Dependent Claims (2, 3, 4)
- CT”
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5. A method for producing, with an x-ray computed tomography (“
- CT”
) system, an image of a subject in which artifacts associated with a highly attenuating material are substantially suppressed, the steps of the method comprising;a) acquiring, with the CT system, projection data that includes a plurality of projection views of a subject at a plurality of view angles over a selected longitudinal scan range; b) producing, from the acquired projection data, a reformatted projection by combining a plurality of projection views from the projection data that were acquired at a common view angle; c) detecting a region in the produced reformatted projection that corresponds to an object composed of a highly attenuating material; d) producing a corrected reformatted projection from the produced reformatted projection using the detected region; and e) reconstructing, from the corrected reformatted projection, an image of the subject in which artifacts caused by highly attenuating materials are substantially suppressed. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
- CT”
Specification