Ultrasound waveform tomography with wave-energy-based preconditioning
View Patent ↗Synthetic-aperture ultrasound tomography systems and methods using scanning arrays and algorithms configured to simultaneously acquire ultrasound transmission and reflection data, and process the data using ultrasound waveform tomography with a wave-energy-based preconditioning method for improved ultrasound tomography imaging.
1. An ultrasound tomography Imaging system for imaging a tissue medium, the system comprising:
one or more ultrasound transducer arrays;
said one or more ultrasound transducer arrays comprising a plurality of ultrasound transducers;
said plurality of transducers comprising transmitting source transducers for transmitting an ultrasound wavefield within the tissue medium and receiving transducers for receiving an ultrasound wavefield from the tissue medium;
a processor; and
programming executable on said processor and configured for:
calculating back propagated synthetic wavefields from one or more of the receiving transducers;
calculating forward propagated wavefields from one or more of the transmitting source transducers;
computing a precondition gradient as a function of a product of the forward propagated wavefields and back propagated synthetic wavefields; and
generating an ultrasound waveform tomographic image as a function of the precondition gradient,
wherein the precondition gradient is a function of a square root of the product of the forward propagated wavefields and the back propagated synthetic wavefields.
2. A system as recited in claim 1 , wherein the precondition gradient is not an approximation of diagonal terms of an approximate Hessian associated with the wavefields.
3. A system as recited in claim 1 , wherein said programming is further configured for calculating a conjugate gradient from said wavefields.
4. A system as recited in claim 1 , wherein said programming is further configured for:
exciting a first transducer of the plurality of transducers to generate the ultrasound wavefield within the tissue medium; and
receiving a transmission signal and a reflection signal from a second transducer within the one or more ultrasound transducer arrays,
wherein the generating the ultrasound waveform tomography Image comprises using both the acquired reflection and transmission signals, and
wherein the back propagated synthetic wavefields are calculated using the acquired reflection signals and the forward propagated wavefields are calculated using the transmission signals.
5. A system as recited in claim 4 , wherein said programming is further configured for simultaneously receiving the reflection and transmission signals from the second transducer.
6. A synthetic aperture ultrasound tomography imaging method for imaging a tissue medium with one or more ultrasound transducer arrays comprising a plurality of receiving transducers and source transducers, the method comprising:
exciting a first transducer of the plurality of source transducers to generate an ultrasound field within the tissue medium;
receiving a transmission signal and a reflection signal from a second transducer of the plurality of receiving transducers
calculating back propagated synthetic wavefields from one or more of the receiving transducers;
calculating forward propagated wavefields from one or more of the source transducers;
computing a precondition gradient as a function of a product of the forward propagated wavefields and back propagated synthetic wavefields; and
generating an ultrasound waveform tomography image reconstruction using both the acquired reflection and transmission signals and the precondition gradient,
wherein the precondition gradient is a function of a square root of the product of the forward propagated wavefields and the back propagated synthetic wavefields.
7. A method as recited in claim 6 , wherein the generating an ultrasound waveform tomography image reconstruction is a function of:
E
(
m
)
=
min
m
{
d
-
f
(
m
)
2
2
}
,
where ∥d−f(m)∥ 2 2 comprises a misfit function, and d comprises data relating to the acquired reflection signal and transmission signal.
8. A method as recited in claim 6 :
wherein the plurality of transducers are configured such that the source transducers are positioned at an opposing spaced-apart orientation from the receiving transducers such that the source transducers face the receiving transducers; and
wherein the source and receiving transducers are positioned at spaced-apart locations so as to allow for the tissue medium to be positioned in between the source and receiving transducers.
9. A method as recited in claim 8 , further comprising:
receiving the reflection signal from all transducers in the one or more arrays.
10. A method as recited in claim 9 , further comprising simultaneously receiving the reflection and transmission signals from the receiving transducers.
11. A synthetic aperture ultrasound tomography imaging system for imaging a tissue medium with one or more ultrasound transducer arrays comprising a plurality of receiving transducers and source transducers, the system comprising:
a processor; and
programming executable on said processor and configured for:
exciting a first transducer of the plurality of source transducers to generate an ultrasound field within the tissue medium;
receiving a transmission signal and a reflection signal from a second transducer of the plurality of receiving transducers;
calculating back propagated synthetic wavefields from one or more of the receiving transducers;
calculating forward propagated wavefields from one or more of the source transducers;
computing a precondition gradient as a function of a product of the forward propagated wavefields and back propagated synthetic wavefields; and
generating an ultrasound waveform tomography image reconstruction using both the acquired reflection and transmission signals and the precondition gradient,
wherein the precondition gradient is a function of a square root of the product of the forward propagated wavefields and the back propagated synthetic wavefields.
12. A system as recited in claim 11 , wherein the generating an ultrasound waveform tomography image reconstruction is a function of:
E
(
m
)
=
min
m
{
d
-
f
(
m
)
2
2
}
,
where ∥d−f(m)∥ 2 2 comprises a misfit function, and d comprises data relating to the acquired reflection signal and transmission signal.
13. A system as recited in claim 11 :
wherein the plurality of transducers are configured such that the source transducers are positioned at an opposing spaced-apart orientation from the receiving transducers such that the source transducers face the receiving transducers; and
wherein the source and receiving transducers are positioned at spaced-apart locations so as to allow for the tissue medium to be positioned in between the source and receiving transducers.
14. A system as recited in claim 13 , wherein said programming is further configured for receiving the reflection signal from all transducers in the one or more arrays.
15. A system as recited in claim 14 , wherein said programming is further configured for simultaneously receiving the reflection and transmission signals from the receiving transducers.
16. A system as recited in claim 11 , wherein the precondition gradient is not an approximation of diagonal terms of an approximate Hessian associated with the wavefields.
17. A system as recited in claim 11 , wherein said programming is further configured for calculating a conjugate gradient from said wavefields.