Method and apparatus to minimize phase misregistration artifacts in gated CT images
First Claim
1. A method to be used with a CT imaging system for minimizing phase misregistration among the two dimensional CT images that make up a working image set corresponding to a region of interest (ROI), the method comprising the steps of:
- identifying separate sequential acquisition phases during an acquisition period;
obtaining helical data corresponding to the separate acquisition phase;
for each acquisition phase;
(i) identifying at least two different phase ranges; and
(ii) generating and storing images as phase image sets corresponding to the different phase ranges;
comparing the phase image sets corresponding to sequential ranges to identify substantially aligned phase image sets; and
selecting the substantially aligned phase image sets as the working image set for the ROI.
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Abstract
A method and apparatus for generating an optimally registered working set of two-dimensional CT images in a gated CT system, the method including, where an acquisition period is divided into sequential acquisition phases, obtaining CT image data for separate phase ranges during each acquisition phase, generating phase image sets including 2D images for each phase range and selecting one phase range image set corresponding to each acquisition phase to generate a working image set where the selected phase range image sets are optimally aligned.
68 Citations
21 Claims
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1. A method to be used with a CT imaging system for minimizing phase misregistration among the two dimensional CT images that make up a working image set corresponding to a region of interest (ROI), the method comprising the steps of:
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identifying separate sequential acquisition phases during an acquisition period;
obtaining helical data corresponding to the separate acquisition phase;
for each acquisition phase;
(i) identifying at least two different phase ranges; and
(ii) generating and storing images as phase image sets corresponding to the different phase ranges;
comparing the phase image sets corresponding to sequential ranges to identify substantially aligned phase image sets; and
selecting the substantially aligned phase image sets as the working image set for the ROI. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
(a) identifying working set image sets corresponding to sequential acquisition phases that have the greatest degree of misalignment as first and second image sets;
(b) identifying a non-working set image set corresponding to the same acquisition phase as the second image set as a substitute image set;
(c) substituting the substitute image set for the second image set; and
(d) repeating steps (a) through (c) until a substantially aligned working image set results.
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10. The method of claim 9 wherein the step of identifying a non-working set image set includes the step of identifying a non-working set image set corresponding to the same acquisition phase as the second image set that is most aligned with the first image set as the substitute image set.
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11. The method of claim 1 wherein the phase ranges overlap.
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12. The method of claim 1 wherein the phase ranges are consecutive.
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13. The method of claim 1 wherein the step of identifying at least two phase ranges includes the step of identifying more than two phase ranges for each acquisition phase.
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14. The apparatus of claim 1 wherein the program causes the processor to perform the step of obtaining by acquiring a full set of helical data while monitoring the cycle of a cyclical anatomical function and storing the helical data as a function of the cyclical anatomical data, the program causes the processor to perform the step of identifying acquisition phases by, after the helical data is stored, identifying a separate phase of the anatomical function cycle and wherein the the step of obtaining further includes retrieving the helical data corresponding to the separate acquisition phase.
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15. An apparatus to be used with a CT imaging system for minimizing phase misregistration among the two dimensional CT images that make up a working image set corresponding to a region of interest (ROI), the apparatus comprising:
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a processor running a pulse sequencing program to perform the steps of;
identifying separate sequential acquisition phases during an acquisition period;
obtaining helical data corresponding to the separate acquisition phase;
for each acquisition phase;
(i) identifying at least two different phase ranges; and
(ii) generating and storing images as phase image sets corresponding to the different phase ranges;
comparing the phase image sets corresponding to sequential ranges to identify substantially aligned phase image sets; and
selecting the substantially aligned phase image sets as the working image set for the ROI. - View Dependent Claims (16, 17, 18, 19, 20, 21)
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Specification