Windowed time-reversal music technique for super-resolution ultrasound imaging

Patent metadata

Field	Value
Publication number	US-9955943-B2
Application number	US-201414339780-A
Country	US
Kind code	B2
Filing date	Jul 24, 2014
Priority date	Feb 3, 2012
Publication date	May 1, 2018
Grant date	May 1, 2018

Abstract

Systems and methods for super-resolution ultrasound imaging using a windowed and generalized TR-MUSIC algorithm that divides the imaging region into overlapping sub-regions and applies the TR-MUSIC algorithm to the windowed backscattered ultrasound signals corresponding to each sub-region. The algorithm is also structured to account for the ultrasound attenuation in the medium and the finite-size effects of ultrasound transducer elements.

First claim

What is claimed is:

1. A method of performing ultrasound imaging of a medium, comprising:
exciting a first transducer element in an array of transducer elements to direct an ultrasound signal into a target region within the medium;
receiving a backscatter signal from the target region within the medium with the array of transducer elements;
generating an inter-element transfer matrix of the received backscatter signal;
generating a generalized time-reversal (TR) matrix from the inter-element transfer matrix; and
generating a pseudo-spectrum for generalized TR-Music imaging of the target region,
wherein generating the inter-element transfer matrix comprises calculating the inter-element transfer matrix as a function of an electro-mechanical response of each transducer element in the array, a diffraction response of each transducer element in the array, and attenuation in the target region.

2. A method as recited in claim 1 , wherein the diffraction response of each transducer element is a function of finite size effects of the array of transducer elements.

3. A method as recited in claim 2 ,
wherein the inter-element transfer matrix is calculated as according to a function a i (r 0 ,ω) over a surface of a transducer element i,
wherein:

a
i

⁡

(

r
0

,
ω

)

=

∫
∫

S
i

⁢

g
0

⁡

(

r
❘

r
0

)

⁢
d
⁢

⁢
s

,

and
wherein ω is an angular frequency, ds is a delimiter of integration, g 0 (ω,r|r 0 ) is the free-space Green's function, a i (r 0 ,ω) is the integral of the Green's function over the surface of element i, and r corresponds to a location of a wavefield resulting from a point source at a location r 0 .

4. A method as recited in claim 1 ,
wherein the inter-element transfer matrix K is calculated according to the function:

K
=

2
⁢

⁢
i
⁢

⁢

k
_

4

ω
⁢

⁢

κ
0

⁢

F
⁡

(
ω
)

⁢

∫

∫
∫

V
0

⁢

γ
κ

⁡

(

r
0

)

⁢

A

r
0

⁢

A

r
0

T

⁢
d
⁢

⁢

v
0

;

and
wherein i is an imaginary unit, k is a complex wave number, ω is an angular frequency, κ 0 is an average compressibility of the medium, F(ω) is an electromechanical transfer function, V 0 is a scattering volume, γ κ is a fluctuation equation, r 0 is a location, dv 0 is a delimiter of integration, and the superscript T in A r a T denotes that A r 0 T is the transpose of A r 0 which is an N-dimensional column vector given by:
[ a 1 ( r 0 ,ω) a 2 ( r 0 ,ω) . . . a N ( r 0 ,ω)].

5. A method as recited in claim 1 ,
wherein the generalized time-reversal matrix is calculated according to:

T
=

-
4

⁢

⁢

k
_

8

(

ω
⁢

⁢

κ
0

)

2

⁢



F
⁡

Assignees

• Los Alamos Nat Security Llc

Inventors

• Huang Lianjie
• Labyed Yassin

Classifications

• A61B8/5253

  combining overlapping images, e.g. spatial compounding · CPC title

• G01S15/8915

  using a transducer array · CPC title

• G01S15/8997

  using synthetic aperture techniques · CPC title

• G01S15/8977 Primary

  using special techniques for image reconstruction, e.g. FFT, geometrical transformations, spatial deconvolution, time deconvolution · CPC title

• A61B8/13

  Tomography (A61B8/10, A61B8/12 take precedence) · CPC title