CN-122004920-A - Sound velocity imaging method based on concave ultrasonic transducer and related device

CN122004920ACN 122004920 ACN122004920 ACN 122004920ACN-122004920-A

Abstract

The application provides a sound velocity imaging method and a related device based on a concave ultrasonic transducer, the method comprises the steps of obtaining full matrix ultrasonic radio frequency data of a tested tissue through a semi-ring array ultrasonic transducer in a synthetic aperture acquisition mode, reconstructing complex radio frequency images of the full matrix data, carrying out mask and Gaussian weighted synthesis based on semi-ring array sound field distribution characteristics to obtain focused complex radio frequency images with higher signal to noise ratio and richer angle information, obtaining stable and accurate cross-event propagation time delay difference through cross-event phase difference extraction and two-stage Gaussian weighted filtering processing according to the focused images, and reconstructing a high-resolution sound velocity distribution map of the tested tissue by taking the time delay difference as an observation vector and combining a ray tracing inversion model and regularization solution which are suitable for the semi-ring array geometry, so that tiny time difference in the observation data can be decoded into a high-quality spatial sound velocity distribution map, and high-accuracy and high-robustness quantitative sound velocity imaging can be realized under the scene constraint of the semi-ring array geometry characteristic.

Inventors

Bi Zelin
ZHAO YUAN
SHAN TIANQI

Assignees

重庆医科大学

Dates

Publication Date: 20260512
Application Date: 20260130

Claims (10)

1. A method of acoustic velocity imaging based on a concave ultrasound transducer, comprising: Acquiring full matrix ultrasonic radio frequency data of the tested tissue in a synthetic aperture acquisition mode through a semi-loop ultrasonic transducer; performing complex radio frequency image reconstruction on the full matrix ultrasonic radio frequency data, and performing mask and Gaussian weighted synthesis based on the semi-circular array sound field distribution characteristics to obtain a focused complex radio frequency image; According to the focused complex radio frequency image, acquiring a cross-event propagation time delay difference through cross-event phase difference extraction and spatial filtering processing; And taking the propagation time delay difference as an observation vector, combining a sound velocity inversion model which is suitable for the semi-circular array geometry, and reconstructing a high-resolution sound velocity distribution map of the tested tissue.
2. The acoustic velocity imaging method based on a concave ultrasonic transducer according to claim 1, wherein the acquiring, by the semi-loop ultrasonic transducer, full matrix ultrasonic radio frequency data of the tissue under test in a synthetic aperture acquisition mode comprises: the semi-annular array ultrasonic transducer is controlled, and single array elements are sequentially excited to emit ultrasonic pulses according to a preset sequence; In each transmitting event, all array elements of the semi-annular array are controlled to synchronously receive scattered echo signals from the tested tissue; And combining radio frequency signals acquired by all receiving channels in each transmitting event to form full matrix radio frequency data containing all transmitting-receiving channel pair information.
3. The acoustic velocity imaging method based on a concave ultrasonic transducer according to claim 1, wherein the reconstructing the complex radio frequency image of the full matrix ultrasonic radio frequency data and performing mask and gaussian weighted synthesis based on the semi-circular array acoustic field distribution characteristics to obtain a focused complex radio frequency image comprises: reconstructing a corresponding complex domain radio frequency image by a delay-superposition beam forming algorithm for each transmitting event in the full matrix radio frequency data; defining and applying a circular mask based on the effective coverage area of the sound field of the semi-circular array so as to exclude pixel signals of the area which is not effectively irradiated by sound waves; And performing Gaussian weighted coherent synthesis on the complex radio frequency images subjected to the mask processing to generate a group of complex radio frequency images focused on the appointed synthetic aperture angle.
4. The acoustic velocity imaging method based on a concave ultrasonic transducer according to claim 1, wherein, in obtaining a cross-event propagation time delay difference by cross-event phase difference extraction and spatial filtering processing according to the focused complex radio frequency image, a calculation formula of the cross-event phase difference at a target pixel point (x, z) is as follows for an mth and an nth emission event: , In the formula, To phase difference between corresponding complex radio frequency images at the pixel points (x, z) at the mth and nth emission events, And Representing complex values at pixel points (x, z) of complex radio frequency images reconstructed from echo data of the mth and nth transmit events.
5. The method of claim 1, wherein the obtaining a cross-event propagation time delay difference from the focused complex radio frequency image by cross-event phase difference extraction and spatial filtering processing, further comprises: Gaussian weighting processing is carried out on the calculated cross-event phase difference distribution, and weighted cross-event phase difference distribution is obtained; The weighted cross-event phase difference distribution is converted into a cross-event propagation time delay difference according to the center frequency of the ultrasonic pulse.
6. The acoustic velocity imaging method based on a concave ultrasonic transducer according to claim 1, wherein the reconstructing a high-resolution acoustic velocity distribution map of the tissue under test by using the propagation time delay difference as an observation vector and combining an acoustic velocity inversion model suitable for a semi-circular array geometry comprises: interpolating the focused complex radio frequency image to a preset tomographic grid; Simulating ultrasonic wave propagation paths through a ray tracing method based on array element geometric positions of the semi-ring array and the fault scanning grid, calculating the passing length of each path in a grid unit, and constructing a system matrix; Constructing a linear inversion equation taking acoustic slowness as an unknown number by taking the propagation time delay difference as an observation vector and combining the system matrix; Solving the linear inversion equation by adopting a Tikhonov regularization method to obtain the acoustic slowness distribution of an imaging region; and taking the reciprocal of the acoustic slowness distribution to obtain the high-resolution sound velocity distribution diagram.
7. The concave ultrasound transducer-based acoustic velocity imaging method of claim 6, wherein solving the linear inversion equation using a Tikhonov regularization method comprises: constructing a regularization term containing zero-order, first-order or second-order smoothness constraint; and adding the regularization term into an objective function of an inversion equation, and obtaining a stable acoustic slowness distribution solution by solving the regularized equation.
8. A concave ultrasound transducer-based acoustic velocity imaging system, comprising: the acquisition unit is used for acquiring full-matrix ultrasonic radio frequency data of the tested tissue in a synthetic aperture acquisition mode through the semi-ring array ultrasonic transducer; The first processing unit is used for reconstructing a complex radio frequency image of the full-matrix ultrasonic radio frequency data, and performing mask and Gaussian weighted synthesis based on the distribution characteristics of the semi-loop array sound field to obtain a focused complex radio frequency image; The second processing unit is used for obtaining a cross-event propagation time delay difference through cross-event phase difference extraction and spatial filtering processing according to the focused complex radio frequency image; And the third processing unit is used for reconstructing a high-resolution sound velocity distribution diagram of the tested tissue by taking the propagation time delay difference as an observation vector and combining a sound velocity inversion model which is suitable for the semi-loop array geometry.
9. A terminal comprising a processor, an input device, an output device, and a memory, the processor, the input device, the output device, and the memory being interconnected, wherein the memory is configured to store a computer program comprising program instructions, the processor being configured to invoke the program instructions to perform the concave ultrasound transducer-based acoustic velocity imaging method of any of claims 1-7.
10. A computer readable storage medium, characterized in that the computer readable storage medium stores a computer program comprising program instructions which, when executed by a processor, cause the processor to perform the concave ultrasound transducer-based sound velocity imaging method according to any one of claims 1-7.

Description

Sound velocity imaging method based on concave ultrasonic transducer and related device Technical Field The application relates to the technical field of data processing, in particular to a sound velocity imaging method based on a concave ultrasonic transducer and a related device; Background In the field of medical ultrasound imaging, the distribution of sound velocity (SpeedofSound, soS) within tissue is a critical physical parameter that directly reflects the biological properties and pathological state of the tissue. Different tissue types, such as fat, muscle, bone and various tumors, have characteristic sonic velocity values due to their composition and structural differences. Therefore, the acquisition of the high-resolution sound velocity distribution diagram has important significance, namely firstly, the sound velocity diagram can be used as a brand-new imaging contrast, the acoustic attribute difference of tissues is directly and quantitatively revealed, key information is provided for differential diagnosis of diseases, and secondly, the accurate sound velocity distribution is the basis for improving the quality of modal images such as traditional B-mode ultrasound and photoacoustic imaging. In the image reconstruction algorithm, an accurate sound velocity value is used for calculating ultrasonic propagation delay, and geometric distortion, edge blurring and position offset caused by the assumption of uniform sound velocity are corrected, so that geometric fidelity and spatial resolution of an image are remarkably improved. In addition, the sound velocity is internally related to the elastic modulus of the tissue, and the sound velocity graph can be used as a powerful complement of elastography, so that mechanical information of another dimension is provided for quantifying the hardness of the tissue, evaluating fibrosis and the like. At present, sound velocity imaging research and commercialization methods based on reflection ultrasound mainly spread around arrays and convex arrays. These techniques typically rely on plane waves or specific wave front emission patterns, and the algorithmic model of these techniques is also optimized for the regular geometry and sound field characteristics of such arrays. However, the semi-circular array has defects when being used for reflective acoustic velocity imaging due to the unique arc-shaped structure, firstly, the semi-circular array has the advantages that the array elements are distributed in an arc shape, the acoustic wave radiation directions of all the array elements are different, the method of generating ideal plane waves through simple channel delay control in the linear array cannot be used, the multi-angle wavefront data for inversion is poor in quality and limited in visual angle coverage is caused, secondly, the arc-shaped structure is easy to introduce complex multipath reflection interference, and if a curved wave emission and processing scheme designed for the convex array is directly applied, the reconstruction model is seriously mismatched, obvious artifacts are generated, and the spatial resolution is reduced. Disclosure of Invention The embodiment of the application provides a sound velocity imaging method based on a concave ultrasonic transducer and a related device, which can decode tiny time difference in observed data into a high-quality spatial sound velocity distribution diagram, and ensure that high-precision and high-robustness quantitative sound velocity imaging can be realized under the scene constraint of the geometric characteristics of a semi-loop array. A first aspect of an embodiment of the present application provides a sound velocity imaging method based on a concave ultrasonic transducer, the method including: Acquiring full matrix ultrasonic radio frequency data of the tested tissue in a synthetic aperture acquisition mode through a semi-loop ultrasonic transducer; performing complex radio frequency image reconstruction on the full matrix ultrasonic radio frequency data, and performing mask and Gaussian weighted synthesis based on the semi-circular array sound field distribution characteristics to obtain a focused complex radio frequency image; According to the focused complex radio frequency image, acquiring a cross-event propagation time delay difference through cross-event phase difference extraction and spatial filtering processing; And taking the propagation time delay difference as an observation vector, combining a sound velocity inversion model which is suitable for the semi-circular array geometry, and reconstructing a high-resolution sound velocity distribution map of the tested tissue. In one possible implementation manner, the acquiring, by the semi-array ultrasonic transducer, the full matrix ultrasonic radio frequency data of the tested tissue in the synthetic aperture acquisition mode includes: the semi-annular array ultrasonic transducer is controlled, and single array elements are sequentially exci