System and method for ultrasound imaging of tissue through bone

Inventors

Sehnert, William J. • Ignjatovic, Zeljko • Mitrovic, Jovan

Assignees

University of Rochester • Carestream Health Inc

Abstract

A transducer transmits into the bone a first plurality of excitation pulses at a plurality of frequencies and measures a plurality of echoes corresponding to the plurality of excitation pulses. An ultrasound machine calculates a plurality of energies each corresponding to a respective one of the plurality of echoes and identifies a lowest echo corresponding to a lowest of the plurality of energies. The ultrasound machine matches the lowest echo to a corresponding one of the first plurality of excitation pulses, the corresponding one of the first plurality of excitation pulses having a chosen frequency. The ultrasound machine generates an acoustic impulse response by deconvolving the corresponding one of the first plurality of excitation pulses with the lowest echo, and generates an updated sensing matrix by convolving the initial sensing matrix with the acoustic impulse response. Subsequent ultrasounds use the updated sensing matrix.

Core Innovation

The invention relates to ultrasound imaging of tissue through bone using a transducer and an ultrasound machine with an initial sensing matrix. The method transmits into the bone a first plurality of excitation pulses at a plurality of frequencies and measures a first plurality of echoes corresponding to the first plurality of excitation pulses reflected from the bone. It calculates a plurality of energies each corresponding to a respective one of the first plurality of echoes and identifies a lowest echo corresponding to a lowest of the plurality of energies.

After the lowest echo is identified, the invention matches the lowest echo to a corresponding one of the first plurality of excitation pulses, where the corresponding excitation pulse has a chosen frequency. The invention generates an acoustic impulse response by deconvolving the corresponding excitation pulse with the lowest echo. Using this acoustic impulse response, it generates an updated sensing matrix by convolving the initial sensing matrix with the acoustic impulse response.

With the updated sensing matrix, the invention transmits a second plurality of excitation pulses into the tissue and generates an image of the tissue based on a second plurality of echoes corresponding to the second plurality of excitation pulses and the updated sensing matrix. The imaging pipeline includes estimating reflectance coefficients, converting the coefficients into a pixel grid/matrix, and generating the image, including using neural networks in some implementations. The disclosed rationale includes bone impedance mismatch and selecting frequencies based on bone thickness using a wavelength relationship.

Claims Coverage

The provided independent claims cover two aspects: a method and a system. Both independent claims share three main inventive elements: selecting a chosen frequency based on a lowest-energy echo, generating an acoustic impulse response via deconvolution, and updating an initial sensing matrix to generate a tissue image from tissue echoes.

Across both independent claims, the key coverage is the end-to-end flow from multi-frequency excitation into bone, selecting a chosen excitation pulse via a lowest echo, deconvolving to obtain an acoustic impulse response, convolving to update the sensing matrix, and then using tissue echoes with the updated sensing matrix to generate an ultrasound image of tissue through bone.

Stated Advantages

Documented Applications