System and method for automatic determination of a region of interest within an image

• US 7,090,640 B2
• Filed: 11/12/2003
• Issued: 08/15/2006
• Est. Priority Date: 11/12/2003
• Status: Expired due to Fees

• Current Assignee: Q-Vision
• Original Assignee: Q-Vision
• Inventors: Zonjee, Maud Maria, King, John David Heaton, Barth, Jacques Dov
• Primary Examiner(s): Jaworski, Francis J.
• Application Number:
  US10/712,834
• Publication Number:
  US 20060056672A1
• Time in Patent Office: 1,007 Days
• Field of Search: 600437- 8, 600443- 7, 600463- 7, 128/916, 382/128, 382/130, 382/173, 382/256, 382/266, 382/273
• US Class Current: 600/443
• CPC Class Codes: A61B 8/0858 involving measuring tissue layers, e.g. skin, interfaces
• CPC Class Codes: A61B 8/0891 for diagnosis of blood vessels
• CPC Class Codes: A61B 8/469 for selection of a region of interest
• CPC Class Codes: G06T 2207/30101 Blood vessel; Artery; Vein; Vascular
• CPC Class Codes: G06T 7/0012 Biomedical image inspection
• CPC Class Codes: G06T 7/62 of area, perimeter, diameter or volume

Abstract

A system and method for automated image analysis selects a Region Of Interest (ROI) within a frame, suitable for subsequent Quantitative Intima Media Thickness (QIMT) analysis. Presently, a time consuming manual analysis by a highly trained technician is required to select the ROI within the frame for subsequent automated analysis. The automated image analysis provides an immediate and accurate identification of the ROI within the selected frame. In one embodiment, the automated image quality analysis may be directed to an ultrasound image of the carotid artery.

Claims

1. A method for defining a Region Of Interest (ROI) of a carotid artery for measuring the arterial wall thickness in a patient, comprising:

providing at least one image including a portion of the carotid artery;

slicing the image into vertical slices;

selecting a stripe which corresponds to the Common Carotid Artery (CCA), within each of the slices;

computing a size of each selected stripe;

comparing the sizes of the selected stripes;

identifying a base of a bulb of the carotid artery as corresponding to the stripe having at least a minimum increase in size compared to stripes in lower slices;

positioning the ROI below the base of the bulb, and measuring the arterial wall thickness of the patient in the ROI.

2. The method of claim 1 wherein selecting a stripe which corresponds to the CCA, within each of the slices, comprises selecting a stripe which corresponds to the CCA based on the order of the stripe within the slice.

3. The method of claim 1, wherein selecting the stripe which corresponds to the CCA, within each of the slices, comprises:

comparing the number of stripes within each of the slices to determine which slices have a valid number of stripes; and

selecting the stripe which corresponds to the CCA, within each of the slices having a valid number of stripes.

4. The method of claim 1 wherein positioning an ROI with respect to the base of the bulb comprises positioning the ROI horizontally centered approximately 1.25 centimeters below the base of the bulb.

5. The method of claim 4, further including vertically centering the ROI approximately 0.05 centimeters above the highest point of a far wall of the carotid artery within a horizontal extent of the ROI.

6. The method of claim 5, wherein positioning an ROI comprises positioning an ROI having an approximately 0.5 inch height and an approximately 0.5 inch width.

7. The method of claim 1 wherein computing a size of each selected stripe comprises computing a diameter of each selected stripe.

8. The method of claim 1 wherein comparing the sizes of the selected stripes comprises comparing averages of the sizes of the selected stripes of consecutive slices to averages of the sizes of the selected stripes of lower consecutive slices.

9. The method of claim 8 wherein selecting the slice including the stripe corresponding to at least a minimum increase in size compared to lower slices comprises selecting the slice including the stripe corresponding to at least an approximately ten percent increase in average size compared to lower slices.

10. The method of claim 1 further including, if the base of the bulb is not identified, providing a technician-generated ROI.

11. A method for determining a Region Of Interest (ROI) for subsequent Intima Media Thickness (IMT) analysis in a patient, the method comprising:

providing at least one digital frame of a portion of a carotid artery, wherein the frame includes at least one of a set consisting of a bulb of the carotid artery and a bifurcation of the carotid artery;

automatically processing the frame to identify the ROI in the frame, the automatically processing comprising at least one of the set consisting of;

determining the ROI by detecting a bifurcation of the carotid artery, the determining comprising;

slicing the frame into vertical slices;

automatically comparing at least one of the vertical slices to at least one other of the vertical slices to find the bifurcation of the carotid artery;

determining the ROI horizontal extent to range from approximately 1.75 cm below the bifurcation to approximately 2.25 cm below the bifurcation;

identifying the highest point of a far wall segment of the carotid artery within the ROI horizontal extent; and

determining the ROI vertical extent to range from approximately 0.3 cm above the highest point to approximately 0.2 cm below the highest point; and

determining the ROI by detecting a bulb of the carotid artery, the determining comprising;

slicing the frame into vertical slices;

automatically comparing at least one of the vertical slices to at least one other of the vertical slices to find the bulb of the carotid artery;

determining the ROI horizontal extent to range from approximately 1.0 cm below the bulb to approximately 1.5 cm below the bulb;

identifying the highest point of a far wall segment of the carotid artery within the ROI horizontal extent; and

determining the ROI vertical extent to range from approximately 0.3 cm above the highest point to approximately 0.2 cm below the highest point; and

determining the ROI by pattern-matching a portion of the frame to a previous ROI having a previous horizontal extent and a previous vertical extent;

the determining comprising;

determining an expanded ROI horizontal extent to be the previous horizontal extent expanded horizontally by a factor of approximately 1.2;

determining an expanded ROI vertical extent to be the previous vertical extent expanded vertically by a factor of approximately 1.2;

performing an automatic pattern match comparing the previous ROI to the region defined by the expanded ROI horizontal extent and the expanded ROI vertical extent; and

determining the ROI based on the highest correlation of the automatic pattern match, and thereafter analyzing the Intima Media Thickness(IMT) in said ROI in said patient.

12. A system for processing ultrasound images of the carotid artery, comprising:

an ultrasound sensor;

an ultrasound apparatus adapted to generate frames;

a sensor cable connecting the ultrasound sensor to the ultrasound apparatus,

wherein the ultrasound apparatus is adapted to receive measurements from the ultrasound sensor, and wherein

the ultrasound apparatus is further adapted to process the measurements to generate ultrasound data;

a computer; and

a path adapted to carry the ultrasound data from the ultrasound apparatus to the computer, wherein the path is selected from a group consisting of dedicated cables, phone lines, a Local Area Network (LAN), the Internet, and a wireless path,

wherein the computer is adapted to pre-process the ultrasound data to generate Regions Of Interest (ROIs) within the data for subsequent processing, wherein the ROIs are subsets of the ultrasound data.

13. A method for defining a Region Of Interest (ROI) of the carotid artery for measuring the arterial wall thickness in a patient, comprising:

providing at least one image of a portion of the carotid artery;

slicing the image into vertical slices;

identifying stripes within each slice, which stripes correspond to vessels; and

identifying a bifurcation of the carotid artery when two stripes in a higher first slice correspond to one stripe in a lower second slice,

positioning the ROI below the bifurcation, and

measuring the arterial wall thickness of the patient within the ROI.

14. The method of claim 13, wherein identifying a bifurcation of the carotid artery when two stripes in the first slice correspond to one stripe in the second slice comprises identifying a bifurcation of the carotid artery when two stripes in the first slice correspond to one stripe in the second slice, wherein each of the two stripes in the first slice a least partly overlap the one stripe in the second slice.

15. The method of claim 13, wherein identifying stripes within each slice comprises identifying three bands comprising:

a dark band corresponding to a vessel lumen; and

light bands above and below the dark band, wherein the light bands correspond to vessel walls.

16. The method of claim 13, wherein identifying a bifurcation of the carotid artery when two stripes in the first slice correspond to one stripe in the second slice comprises identifying a bifurcation of the carotid artery when two stripes in the first slice correspond to one stripe in a substantially adjacent second slice.

17. The method of claim 13 wherein identifying a bifurcation of the carotid artery when two stripes in the first slice correspond to one stripe in the second slice includes:

identifying if the first slice includes more stripes than the second slice, which first slice is above of the second slice;

identifying if a first top edge of a higher stripe in the first slice corresponds to a second top edge of a single stripe in the second slice; and

identifying if a first bottom edge of a lower stripe in the first slice corresponds to a second bottom edge of the single stripe in the second slice.

18. The method of claim 13 wherein positioning the ROI with respect to the bifurcation comprises positioning the ROI horizontally centered approximately two centimeters below the bifurcation.

19. The method of claim 18 wherein positioning the ROI with respect to the bifurcation comprises positioning the ROI to range horizontally between approximately 1.75 cm below the bifurcation and approximately 2.25 cm below the bifurcation.

20. The method of claim 19 wherein positioning the ROI with respect to the bifurcation further comprises:

identifying a highest point of a far wall segment of the carotid artery within the ROI horizontal range; and

positioning the ROI vertically centered approximately 0.05 cm above the highest point.

21. The method of claim 20 wherein positioning the ROI with respect to the bifurcation further comprises positioning the ROI to range vertically from approximately 0.3 cm above the highest point to approximately 0.2 cm below the highest point.