Systems and methods for filtering images

• US 20050135554A1
• Filed: 12/18/2003
• Published: 06/23/2005
• Est. Priority Date: 12/18/2003
• Status: Active Grant

• Current Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Original Assignee: GE Medical Systems Global Technology Company LLC (GE Healthcare Technologies, Inc.)
• Inventors: Thomson, Helen Jane, Launay, Laurent, Mohr, Kelly Ann, Okerlund, Darin R.
• Granted Patent: US 6,968,032 B2
• Time in Patent Office: Days
• US Class Current: 378/19
• CPC Class Codes: A61B 6/032 Transmission computed tomography [CT]
• CPC Class Codes: A61B 6/4085 Cone-beams
• CPC Class Codes: Y10S 378/901 Computer tomography program or processor

Abstract

A method for filtering images is provided. The method includes obtaining at least one set of image data of a subject using an imaging system, removing at least one slice of image data from the at least one set to form a filtered set, and reconstructing images from the filtered set.

Claims

1. A method for filtering images, the method comprising:

obtaining at least one set of image data of a subject using an imaging system;

removing at least one slice of image data from the at least one set to form a filtered set; and

reconstructing images from the filtered set.

2. A method in accordance with claim 1 wherein removing at least one slice of image data from the at least one set comprises using a filter to remove the at least one slice of image data from the at least one set.

3. A method in accordance with claim 1 wherein removing at least one slice of image data from the at least one set comprises using a comb filter to remove the at least one slice of image data from the at least one set.

4. A method in accordance with claim 1 wherein removing at least one slice of image data from the at least one set comprises removing a slice of image data located at one of a lowest z-location and a highest z-location of all z-locations in the at least one set.

5. A method in accordance with claim 1 wherein removing at least one slice of image data from the at least one set comprises removing a slice of image data located at a lowest z-location of all z-locations in the at least one set and removing a slice of image data at a highest z-location of all z-locations in the at least one set.

6. A method in accordance with claim 1 wherein obtaining at least one set of image data of a subject comprises obtaining at least one set of image data of a subject, wherein each slice of image data in the at least one set is obtained at a different z-location than z-locations of any other slices of image data in the at least one set.

7. A method in accordance with claim 1 further comprising:

determining at least one point that lies on a z-axis along which the subject lies and at which there is a change in a midscan time, the change in the midscan time occurring between two consecutive sets of the at least one set, the two consecutive sets including a first set and a second set; and

determining to remove at least one of a slice of image data having a highest z-location among all z-locations in the first set and a slice of image data having a lowest z-location among all z-locations in the second set.

8. A method in accordance with claim 1 further comprising:

determining at least one point that lies on a z-axis along which the subject lies and at which there is a change in a midscan time, the change in the midscan time occurring between a set of image data of the at least one set and a slice of ungated image data; and

determining to remove the slice of ungated image data.

9. A method for filtering images comprising:

obtaining at least one set of image data over a range of z-locations after scanning a subject, wherein each set is acquired at the same time in a physiological cycle of motion of an object within the subject; and

removing at least one slice of image data from the at least one set.

10. A computer-readable medium encoded with a program configured to:

obtain at least one set of image data of a subject using an imaging system;

remove at least one slice of image data from the at least one set to form a filtered set; and

reconstruct images from the filtered set.

11. A computer-readable medium in accordance with claim 10 wherein the program is configured to use a filter to remove the at least one slice of image data from the at least one set.

12. A computer-readable medium in accordance with claim 11 wherein the program is configured to use a comb filter to remove the at least one slice of image data from the at least one set.

13. A computer-readable medium in accordance with claim 10 wherein to remove at least one slice of image data from the at least one set the program is configured to remove a slice of image data located at one of a lowest z-location and a highest z-location of all z-locations in the at least one set.

14. A computer-readable medium in accordance with claim 10 wherein to remove at least one slice of image data from the at least one set the program is configured to remove a slice of image data located at a lowest z-location of all z-locations in the at least one set and to remove a slice of image data at a highest z-location of all z-locations in the at least one set.

15. A computer-readable medium in accordance with claim 10 wherein to obtain at least one set of image data of a subject the program is configured to obtain at least one set of image data of a subject, wherein each slice of image data in the at least one set is obtained at a different z-location than z-locations of any other slices of image data in the at least one set.

16. A computer-readable medium in accordance with claim 10 wherein the program is configured to:

determine at least one point that lies on a z-axis along which the subject lies and at which there is a change in a midscan time, the change in the midscan time occurring between two consecutive sets of the at least one set, the two consecutive sets including a first set and a second set; and

determine to remove at least one of a slice of image data having a highest z-location among all z-locations in the first set and a slice of image data having a lowest z-location among all z-locations in the second set.

17. A computer-readable medium in accordance with claim 10 wherein the program is configured to:

determine at least one point that lies on a z-axis along which the subject lies and at which there is a change in a midscan time, the change in the midscan time occurring between a set of image data of the at least one set and a slice of ungated image data; and

determine to remove the slice of ungated image data.

18. A computed tomography (CT) system comprising:

an X-ray source configured to generate X-rays;

a detector configured to detect the X-rays to generate electrical signals;

a data acquisition system (DAS) for sampling the electrical signals to create projection data that is converted into at least one set of image data;

a controller configured to;

obtain the at least one set of image data of a subject using the CT system;

remove at least one slice of image data from the at least one set to form a filtered set; and

reconstruct images from the filtered set.

19. A CT system in accordance with claim 18 wherein the controller is configured to use a filter to remove the at least one slice of image data from the at least one set.

20. A CT system in accordance with claim 19 wherein the filter is a comb filter.

21. A CT system in accordance with claim 18 wherein to remove at least one slice of image data from the at least one set the controller is configured to remove a slice of image data located at a lowest z-location of all z-locations in the at least one set.

22. A CT system in accordance with claim 18 wherein to remove at least one slice of image data from the at least one set the controller is configured to remove a slice of image data located at a lowest z-location of all z-locations in the at least one set and to remove a slice of image data at a highest z-location of all z-locations in the at least one set.

23. A CT system in accordance with claim 18 wherein to obtain at least one set of image data of a subject the controller is configured to obtain at least one set of image data of a subject, wherein each slice of image data in the at least one set is obtained at a different z-location than z-locations of any other slices of image data in the at least one set.

24. A CT system in accordance with claim 18 wherein the controller is configured to:

determine at least one point that lies on a z-axis along which the subject lies and at which there is a change in a midscan time, the change in the midscan time occurring between two consecutive sets of the at least one set, the two consecutive sets including a first set and a second set; and

determine to remove at least one of a slice of image data having a highest z-location among all z-locations in the first set and a slice of image data having a lowest z-location among all z-locations in the second set.

25. A computer configured to:

obtain at least one set of image data of a subject using an imaging system;

remove at least one slice of image data from the at least one set to form a filtered set; and

reconstruct images from the filtered set.