Ultrasonic diagnostic apparatus and method for propagation speed analysis of shear wave and elastic modulus measurement of a tissue

Patent metadata

Field	Value
Publication number	US-11540809-B2
Application number	US-202016896816-A
Country	US
Kind code	B2
Filing date	Jun 9, 2020
Priority date	Jul 12, 2019
Publication date	Jan 3, 2023
Grant date	Jan 3, 2023

Abstract

An ultrasonic diagnostic apparatus includes: a hardware processor that determines a focal position of a push wave, and positions of observation points in a region of interest indicating an analysis target range within the subject, causes the ultrasonic probe to perform transmission of a push wave focusing on the focal position, and subsequent to the transmission, causes the ultrasonic probe to transmit a detection wave passing through the region of interest within the subject, and calculates amounts of displacement of tissue of the subject at the observation points on the basis of a reflected wave obtained by the ultrasonic probe in response to the transmission of the detection wave, calculates propagation speeds of the shear wave in the tissue of the subject with respect to the observation points on the basis of the amounts of displacement, and evaluates values of the propagation speeds calculated to create an evaluation result.

First claim

What is claimed is:

1. An ultrasonic diagnostic apparatus that calculates a propagation speed of a shear wave by exciting the shear wave within a subject by using an ultrasonic probe, the ultrasonic diagnostic apparatus comprising a hardware processor configured to:
determine a focal position of a push wave for generating a displacement within the subject, and positions of a plurality of observation points in a region of interest indicating an analysis target range within the subject,
cause the ultrasonic probe to perform transmission of a push wave focusing on the focal position, and subsequent to the transmission, cause the ultrasonic probe to transmit a detection wave passing through the region of interest within the subject, and calculate amounts of displacement of tissue of the subject at the plurality of observation points on the basis of a reflected wave obtained by the ultrasonic probe in response to the transmission of the detection wave,
calculate propagation speeds of the shear wave in the tissue of the subject with respect to the plurality of observation points on the basis of the amounts of displacement, and
evaluate values of the propagation speeds calculated to create an evaluation result,
wherein the hardware processor is further configured to,
when the evaluation result does not satisfy a predetermined requirement, determine a new focal position and positions of a new plurality of observation points in which at least one of the focal position or the positions of the plurality of observation points is changed on the basis of the evaluation result, and for the new focal position and the positions of the new plurality of observation points determined, calculate the amounts of displacement, calculate the propagation speeds, and evaluate values of the propagation speeds newly calculated to create an evaluation result, and
when the evaluation result satisfies the requirement, calculate a propagation speed value in the region of interest on the basis of the propagation speeds with respect to the plurality of observation points,
wherein the hardware processor includes an evaluation target division selector configured to select a first division and a final division to be evaluated among divisions between adjacent observation points of the plurality of observation points, the first division being closest to the focal point of the push wave and the final division being farthest from the focal point of the push wave, wherein at least one observation point of the plurality of observation points is separate from and disposed between the first division and the final division;
an evaluation target speed obtainer configured to obtain a propagation speed corresponding to the first division and a propagation speed corresponding to the final division; and
a target speed evaluator configured to determine whether the evaluation result of the propagation speed corresponding to the first division and of the propagation speed corresponding to the final division satisfy the predetermined requirement.

2. The ultrasonic diagnostic apparatus according to claim 1 , wherein
the target speed evaluator is configured to output an evaluation result as being appropriate when the propagation speed corresponding to the first division is less than a first threshold, and output an evaluation result as being inappropriate when the propagation speed corresponding to the first division is greater than or equal to the first threshold, and
wherein the hardware processor is further configured to, when the evaluation result is output as being inappropriate, determine a new focal position and positions of a new plurality of observation points that are obtained by increasing distances between the focal position and the positions of the plurality of observation points.

3. The ultrasonic diagnostic apparatus according to claim 1 , wherein
the evaluation target division selector is configured to select a second division adjacent to the first division,
the evaluation target speed obtainer is configured to obtain a propagation speed corresponding to the second division,
the target speed evaluator is configured to output an evaluation result as being appropriate when the propagation speed corresponding to the second division is greater than or equal to the propagation speed corresponding to the first division, and output an evaluation result as being inappropriate when the propagation speed corresponding to the second division is less than the propagation speed corresponding to the first division, and
wherein the hardware processor is further configured to, when the evaluation result is output as being inappropriate, determine a new focal position and positions of a new plurality of observation points that are obtained by increasing distances between the focal position and the positions of the plurality of observation points.

4. The ultrasonic diagnostic apparatus according to claim 1 , wherein
the evaluation target speed obtainer is configured to obtain a measurement quality value of time-series data of the amount of displacement at an observation point corresponding to the final division,
the target speed evaluator is configured to output an evaluation result as being appropriate when the measurement quality value is greater than or equal to a second threshold, and output an evaluation result as being inappropriate when the measurement quality value is less than the second threshold, and
wherein the hardware processor is further configured to, when the evaluation result is output as being inappropriate, determine a new focal position and positions of a new plurality of observation points that are obtained by decreasing distances between the focal position and the positions of the plurality of observation points.

5. The ultrasonic diagnostic apparatus according to claim 4 , wherein
the measurement quality value is a parameter based on one or more elements selected from a variance, a signal level, and a noise level of the amounts of displacement or acoustic ray signals on which the amounts of displacement depend.

6. The ultrasonic diagnostic apparatus according to claim 1 , wherein
in a case where the target speed evaluator outputs an evaluation result as being inappropriate, and
in a case where the plurality of observation points on which the evaluation target division depends is obtained by determination of the new focal position and the positions of the new plurality of observation points by the hardware processor having already performed a first change for distances between the focal position and the positions of the plurality of observation points, and
in a case where, on the basis of the evaluation result as being inappropriate, the hardware processor is configured to determine a further new focal position and positions of a further new plurality of observation points by performing a second change opposite to the first change for the distances between focal position and the positions of the plurality of observation points,
the target speed evaluator is configured to output an evaluation result as being appropriate regarding the evaluation target division, and
the hardware processor is further configured to calculate a propagation speed value of the region of interest by multiplying the propagation speeds with respect to the plurality of observation points by a weight sequence in which a weight of a central part of the region of interest along a propagation direction is increased.

7. A method for controlling an ultrasonic diagnostic apparatus that calculates a propagation speed of a shear wave by exciting the shear wave within a subject by using an ultrasonic probe,
the ultrasonic diagnostic apparatus including a hardware processor performing the method comprising:
determining a focal p

Assignees

• Konica Minolta Inc

Inventors

• Fuse Masaru

Classifications

• A61B8/485 Primary

  involving measuring strain or elastic properties · CPC title

• A61B8/461

  Displaying means of special interest · CPC title

• G01S15/8915

  using a transducer array · CPC title

• A61B8/469

  for selection of a region of interest · CPC title

• A61B8/5223

  for extracting a diagnostic or physiological parameter from medical diagnostic data (for algorithms to analyse biomedical images G06T7/0012) · CPC title