Methods and apparatus for detecting partial volume image artifacts

• US 5,812,628 A
• Filed: 12/12/1996
• Issued: 09/22/1998
• Est. Priority Date: 12/12/1996
• Status: Expired due to Fees

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Hsieh, Jiang
• Primary Examiner(s): Porta, David P.
• Assistant Examiner(s): Bruce, David Vernon
• Application Number:
  US08/763,928
• Time in Patent Office: 649 Days
• Field of Search: 378/4, 378/8, 378/901
• US Class Current: 378/8
• CPC Class Codes: A61B 6/027 characterised by the use of a particular data acquisition trajectory, e.g. helical or spiral
• CPC Class Codes: G01N 2223/419 computed tomograph
• CPC Class Codes: G01N 23/04 and forming images of the material
• CPC Class Codes: G01N 23/046 using tomography, e.g. computed tomography [CT]
• CPC Class Codes: Y10S 378/901 Computer tomography program or processor

Abstract

The present invention, in one form, is a method for detecting a partial volume artifact in scan data acquired during a tomographic scan. In accordance with one embodiment of the algorithm, an object of interest is scanned to generate scan data. Sampling pairs of the scan data are identified and used to generate an inconsistency map. The inconsistency map is weighted and filtered to generate a partial volume signature which identifies partial volume artifacts.

Claims

1. A method for detecting partial volume artifacts in scan data of an object, the scan data collected in a tomographic scan, said method comprising the steps of:

identifying at least one sampling pair of the scan data; and

generating an inconsistency map using the identified sampling pair.

2. A method in accordance with claim 1 further comprising the step of weighting the generated inconsistency map.

3. A method in accordance with claim 2 further comprising the step of filtering the weighted inconsistency map to generate an initial partial volume signature.

4. A method in accordance with claim 3 wherein filtering the weighted inconsistency map comprises the step of low pass filtering the weighted inconsistency map along a channel direction.

5. A method in accordance with claim 3 further comprising the step of filtering the initial partial volume signature to generate a final partial volume signature.

6. A method in accordance with claim 5 wherein filtering the initial partial volume signature comprises the step of low pass filtering the initial partial volume signature along a view direction.

7. A method in accordance with claim 1 wherein the sampling pair is identified in accordance with:

space="preserve" listing-type="equation">β

.sub.2 =β

.sub.1 +π

+2γ

.sub.1 ; and

space="preserve" listing-type="equation">γ

.sub.2 =γ

.sub.1 ;

where;

β

₁ is a view angle at a first x-ray source location;

γ

₁ is a detector angle at the first x-ray source location;

β

₂ is a view angle at a second x-ray source location; and

γ

₂ is a detector angle at the second x-ray source location.

8. A method in accordance with claim 1 wherein generating the inconsistency map comprises the step of identifying differences between scan data of each sampling pair.

9. A method in accordance with claim 1 further comprising the step of generating a signal representative of potential partial volume artifacts utilizing the inconsistency map.

10. A method in accordance with claim 9 further comprising transmitting the signal to a control device for varying slice thickness.

11. A system for detecting partial volume artifacts in scan data of an object collected in a tomographic scan, said system configured to:

identify a sampling pair of the scan data; and

generate an inconsistency map using the identified sampling pair.

12. A system in accordance with claim 11 further configured to weight the generated inconsistency map.

13. A system in accordance with claim 12 further configured to filter the weighted inconsistency map to generate an initial partial volume signature.

14. A system in accordance with claim 13 wherein to filter the weighted inconsistency map, said system is configured to low pass filter the weighted inconsistency map along a channel direction.

15. A system in accordance with claim 12 further configured to filter the initial partial volume signature to generate a final partial volume signature.

16. A system in accordance with claim 15 wherein to filter the initial partial volume signature, said system is configured to low pass filter the initial partial volume signature.

17. A system in accordance with claim 11 configured to identify the sampling pair in accordance with:

space="preserve" listing-type="equation">β

.sub.2 =β

.sub.1 +π

+2γ

.sub.1 ; and

space="preserve" listing-type="equation">β

.sub.2 =-γ

.sub.1 ;

where;

β

₁ is a view angle at a first x-ray source location;

γ

₁ is a detector angle at the first x-ray source location;

β

₂ is a view angle at a second x-ray source location; and

γ

₂ is a detector angle at the second x-ray source location.

18. A system in accordance with claim 11 wherein generate the inconsistency map, said system is further configured to identify differences in the scan data of each sampling pair.

19. A system in accordance with claim 11 further configured to generate a signal representative of potential partial volume artifacts utilizing the inconsistency map.

20. A system in accordance with claim 19 further configured to transmit the signal to a control device for varying slice thickness.