Acoustic border detection using power modulation

• US 6,997,875 B2
• Filed: 04/08/2002
• Issued: 02/14/2006
• Est. Priority Date: 02/11/2000
• Status: Expired due to Term

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Brock-Fisher, George A, Prater, David M
• Primary Examiner(s): Jaworski, Francis J.
• Application Number:
  US10/117,809
• Publication Number:
  US 20020111553A1
• Time in Patent Office: 1,408 Days
• Field of Search: 600/437, 600440-441, 600/443, 600/447, 600454-456, 600/458, 128/916
• US Class Current: 600/443
• CPC Class Codes: A61B 8/0858 involving measuring tissue layers, e.g. skin, interfaces
• CPC Class Codes: A61B 8/481 involving the use of contrast agent, e.g. microbubbles introduced into the bloodstream analysis of echo signal exploiting properties of a contrast enhancer in devices for short-range imaging with acoustic waves G01S7/52039

Abstract

The method of the invention controls an ultrasound system to identify a boundary between a tissue region and a blood-filled region that lies within an ROI. The method initially administers a contrast agent to the region of interest and then transmits first and second ultrasound beams at a different power levels into the ROI. Signal returns from the first and second beams are processed to derive first and second digital values, respectively. It has been determined that, under certain circumstances, a phase change of echo returns occurs at the boundary between tissue and blood-containing contrast agent. Detection of the phase change enables precise identification of the boundary, based upon the time segment in which the phase change is detected. Accordingly, time segment values of the first and second stored digital values are then phase-compared to enable determination of a boundary location between the tissue region and the blood-filled region by detection of the phase change.

Claims

1. An ultrasound method for determining boundaries of a fluid-filled cavity, comprising the steps of:

introducing a contrast agent into a fluid-filled cavity within a body; and

imaging the fluid-filled cavity and surrounding tissue such that an image is created where the contrast agent in the fluid-filled cavity is represented in brighter intensities than is said surrounding tissue;

applying a threshold value to pixel data values comprising regions of the image;

classifying brighter areas of the image as representing the fluid-filled cavity and darker areas of the image as representing surrounding tissue, wherein the classifying includes detecting pixels comprising the fluid/tissue cavity boundary utilizing phase comparison means.

2. The method as recited in claim 1, comprising the further step of:

determining a boundary between said fluid-filled cavity and said surrounding tissue by detecting a region where brighter areas of the fluid-filled cavity adjoin darker areas of said surrounding tissue.

3. The method as recited in claim 2, comprising the further step of:

performing real time calculations employing said determined boundary.

4. A memory media including instructions for controlling an ultrasound system to determine boundaries of a fluid-filled cavity into which a contrast agent has been introduced, comprising

a) means for controlling said ultrasound system to image the fluid-filled cavity and surrounding tissue such that an image is created where the contrast agent in the fluid-filled cavity is represented in brighter intensities than is said surrounding tissue;

b) means for controlling said ultrasound system to apply a threshold value to pixel data values comprising regions of the image; and

c) means for controlling said ultrasound system to classify brighter areas of the image as representing the fluid-filled cavity and darker areas of the image as representing surrounding tissue, wherein pixels comprising a fluid-tissue boundary are identified utilizing phase comparator means.

5. The memory media as recited in claim 4, further comprising:

d) means for controlling said ultrasound system to determine a boundary between said fluid-filled cavity and said surrounding tissue by detecting of a region where brighter areas of the fluid-filled cavity adjoin darker areas of said surrounding tissue.

6. The memory media as recited in claim 5, further comprising:

d) means for controlling said ultrasound system to perform real time calculations employing said determined boundary.