# US 2017/0281129 A1 · Coherence-based Beamforming for Improved Microbubble Detection in Contrast Enhanced Ultrasound

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- Number: US 2017/0281129 A1
- Document ID: US20170281129A1
- Status: Published application
- Kind: A1
- Application number: 15/474,994
- Filed: 2017-03-30
- Published: 2017-10-05
- Earliest claimed: 2016-04-01
- Assignees: The Board of Trustees of the Leland Stanford Junior University
- Applicants: The Board of Trustees of the Leland Stanford Junior University
- Inventors: Jeremy Joseph Dahl; Dongwoon Hyun; Juergen K. Willmann
- Web page: https://patentgrep.com/patent/US20170281129A1

## CPC

- A61B 8/481: {involving the use of contrast agents, e.g. microbubbles introduced into the bloodstream}
- A61B 8/0825: {for diagnosis of the breast, e.g. mammography}
- A61B 8/085: {for locating body or organic structures, e.g. tumours, calculi, blood vessels, nodules}
- A61B 8/5207: {involving processing of raw data to produce diagnostic data, e.g. for generating an image}
- A61B 8/5223: {for extracting a diagnostic or physiological parameter from medical diagnostic data (for algorithms to analyse biomedical images G06T7/0012)}
- G16H 50/30: for calculating health indices; for individual health risk assessment
- A61B 8/4494: {characterised by the arrangement of the transducer elements}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA

## Abstract

Ultrasonic imaging is performed by constructing spatial coherence images of a target having microbubbles in it. The basis for this approach is the observation that the spatial coherence of microbubbles differs from the spatial coherence of tissue and the spatial coherence of image noise. Therefore, imaging based on spatial coherence provides a way to suppress noise signals and tissue signals relative to the microbubble signals.

## Claims

### Claim 1

A method for ultrasound medical imaging, the method comprising:
providing a contrast agent to a target being imaged, wherein the contrast agent includes microbubbles;
providing incident acoustic radiation to the target with an ultrasound transducer array, wherein the target provides an acoustic signal responsive to the incident acoustic radiation;
receiving the acoustic signal with the ultrasound transducer array;
providing an ultrasound image of the target by applying a beamforming method to the acoustic signal;
wherein the beamforming method includes:
i) estimating a spatial coherence function of the target;
ii) integrating the spatial coherence function over a predetermined integration window.

### Claim 2 (depends on 1)

The method of claim 1, wherein the microbubbles are configured to have a spatial coherence distinct from a spatial coherence of tissue in the target and distinct from a spatial coherence of measurement noise.

### Claim 3 (depends on 1)

The method of claim 1, wherein the ultrasound transducer array has N elements and wherein the predetermined integration window is a lag range from 1 to N/2.

### Claim 4 (depends on 1)

The method of claim 1, wherein the ultrasound transducer array has Nx×Ny elements and wherein the predetermined integration window is a lag range from 1 to Nx/2 and from 1 to Ny/2.

### Claim 5 (depends on 1)

The method of claim 1, wherein an intensity of the incident acoustic radiation is sufficiently low that the microbubbles do not burst during imaging.

### Claim 6 (depends on 1)

The method of claim 1,
wherein a first part of an imaging sequence has an intensity of the incident acoustic radiation that is sufficiently low that the microbubbles do not burst during the first part, and
wherein a second part of the imaging sequence has an intensity of the incident acoustic radiation that is sufficient to burst the microbubbles.

### Claim 7 (depends on 1)

The method of claim 1, wherein the incident acoustic radiation is configured as pulse sequences having linear echoes that substantially cancel in the acoustic signal.

### Claim 8 (depends on 1)

The method of claim 1, wherein the microbubbles are configured to provide a nonlinear acoustic signal at one or more frequencies distinct from frequencies in the incident acoustic radiation.

### Claim 9 (depends on 1)

The method of claim 1, further comprising specifically binding the microbubbles to features within the target.

### Claim 10 (depends on 1)

The method of claim 1, wherein the target is selected from the group consisting of: heart, liver, kidney, pancreas, and breast.

### Claim 11 (depends on 1)

The method of claim 1, wherein the microbubbles are configured to deliver a therapeutic agent when burst by the incident acoustic radiation.

### Claim 12 (depends on 1)

The method of claim 1, wherein the beamforming method includes providing time delays for focusing prior to the estimating a spatial coherence function of the target.

### Claim 13 (depends on 1)

The method of claim 1, wherein two or more beams of the incident acoustic radiation are provided to the target, each of the two or more beams having its corresponding acoustic signal, wherein the acoustic signals are combined retrospectively to form a synthetic transmit aperture.