Time reversal and phase coherent music techniques for super-resolution ultrasound imaging

Patent metadata

Field	Value
Publication number	US-9955944-B2
Application number	US-201414339791-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. A modified TR-MUSIC imaging algorithm is used to account for ultrasound scattering from both density and compressibility contrasts. The phase response of ultrasound transducer elements is accounted for in a PC-MUSIC system.

First claim

What is claimed is:

1. A method of performing ultrasound imaging of a medium, the method comprising:
exciting a first transducer element in an array of transducer elements to direct an ultrasound signal into a target region of the medium;
receiving a backscatter signal from the target region within the medium from the array of transducer elements;
generating an inter-element transfer matrix of the received backscatter signal;
said inter-element transfer matrix comprising density contrast data relating to one or more scatterers within said medium;
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,
said pseudo-spectrum comprising density contrast data relating to one or more scatterers within said medium,
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 said inter-element transfer matrix further comprises compressibility contrast data; and
wherein said pseudo-spectrum comprises density contrast data and compressibility contrast data relating to one or more scatterers within said medium.

3. A method as recited in claim 2 , further comprising obtaining said density contrast data and compressibility contrast data from least squares estimation of a pseudo-spectrum generated from TR-MUSIC imaging.

4. A method as recited in claim 2 , wherein said inter-element transfer matrix K is calculated according to the function:

K
=

F
⁡

(
ω
)

⁢

∑

m
=
1

M

⁢

γ
κ

⁡

(

r
m

)

⁢

A
⁡

(

r
m

)

⁢

A
T

⁡

(

r
m

)

+

γ
ρ

⁡

(

r
m

)

⁡

[

B
1

⁡

(

r
m

)

B
2

⁡

(

r
m

)

…

B
N

⁡

(

r
m

)

]

where F(ω) is a electromechanical transfer function, M is the number of the scatterers within said medium, r m is a location of an m th point scatter, γ ρ is the density contrast, γ κ , is the compressibility contrast, and superscript T denotes the transpose of the vector, A(r m ) is a vector given by:
A T ( r m )=[ a 1 ( r m ) a 2 ( r m ) . . . a N ( r m )], B n ( r m )

is a vector given by:
B n T ( r m )=[cos(θ m 1,n ) a 1 ( r m ) a n ( r m )cos(θ m 2,n ) a 2 ( r m ) a n ( r m ) . . . cos(θ m N,n ) a N ( r m ) a n ( r m )],

a i is the integral of Green's function over the surface element i, i is 1 to N, and θ m i ,n is the angle between a vector from the center of the transmitting element to a point where an inhomogeneity is located.

5. A method as recited in claim 4 , wherein the pseudo-spectrum φ(r) is calculated according to the equation:

Φ
⁡

(
r
)

=

1

∑

σ
p

=
0

⁢



u
p
†

Assignees

• Los Alamos Nat Security Llc

Inventors

• Huang Lianjie
• Labyed Yassin

Classifications

• A61B8/5207

  involving processing of raw data to produce diagnostic data, e.g. for generating an image · CPC title

• G01S15/8977 Primary

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

• G01S15/8997

  using synthetic aperture techniques · CPC title

• G01S7/52095

  using multiline receive beamforming · CPC title

• A61B8/13

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